identity: "disconnect app" — revoke_app(Subject, Client) (+4 tests)

identity_tokens:revoke_app(Subject, Client) revokes every grant a subject
holds for one client at once (audited one revoke per grant), exposed at the
facade as identity:revoke_app. The action counterpart to the grants view —
completing the account-security view+action pairs (sessions/logout_all,
grants/revoke_app, history). Other subjects' same-client grants are
untouched. account 11/11, 233/233.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/acl/api.sx

@@ -0,0 +1,45 @@
+;; lib/acl/api.sx — public ACL surface over an implicit current db.
+;;
+;; Callers load a fact set once, then issue decisions without threading the db
+;; through every call. The current db is module state; (acl/load! facts) rebuilds
+;; it. This is the boundary the rest of rose-ash imports.
+
+(define acl-current-db nil)
+
+;; Replace the current fact base. Rebuilds the Datalog db under the active
+;; ruleset (see lib/acl/engine.sx).
+(define
+  acl/load!
+  (fn
+    (facts)
+    (do (set! acl-current-db (acl-build-db facts)) acl-current-db)))
+
+;; Ensure a db exists, building an empty one on first use.
+(define
+  acl-ensure-db!
+  (fn
+    ()
+    (do
+      (when
+        (= acl-current-db nil)
+        (set! acl-current-db (acl-build-db (list))))
+      acl-current-db)))
+
+;; Public decision against the current db (pure, no logging).
+(define
+  acl/permit?
+  (fn (subj act res) (acl-permit? (acl-ensure-db!) subj act res)))
+
+;; Decision-with-proof against the current db. See lib/acl/explain.sx.
+(define
+  acl/explain
+  (fn (subj act res) (acl-explain (acl-ensure-db!) subj act res)))
+
+;; Audited decision: logs the outcome to the append-only audit log and returns
+;; the boolean. See lib/acl/audit.sx.
+(define
+  acl/audit
+  (fn (subj act res) (acl-audit-decide! (acl-ensure-db!) subj act res)))
+
+;; Recent audited decisions (chronological).
+(define acl/audit-tail (fn (n) (acl-audit-tail n)))

lib/acl/audit.sx

@@ -0,0 +1,110 @@
+;; lib/acl/audit.sx — append-only decision log.
+;;
+;; Every decision routed through acl-audit-decide! is appended to an in-memory
+;; log with a monotonic sequence number (no wall-clock — deterministic and
+;; testable; a host can stamp time at the serializer boundary). The log is
+;; append-only: there is no mutate or delete, only append, tail, clear,
+;; snapshot/restore, and serialize-for-disk.
+
+(define acl-audit-log (list))
+(define acl-audit-seq 0)
+
+;; Copy a list into a fresh, append!-able list. `map`/`rest`-derived lists are
+;; NOT extensible by append! in this runtime (it silently no-ops), so the live
+;; log must always be a list built with `list` + `append!`.
+(define
+  acl-audit-copy
+  (fn
+    (xs)
+    (let
+      ((fresh (list)))
+      (do (for-each (fn (e) (append! fresh e)) xs) fresh))))
+
+(define
+  acl-audit-clear!
+  (fn
+    ()
+    (do (set! acl-audit-log (list)) (set! acl-audit-seq 0) nil)))
+
+;; Append a decision record. Returns the record.
+(define
+  acl-audit-record!
+  (fn
+    (subj act res allowed?)
+    (let
+      ((entry {:allowed? allowed? :act act :subj subj :res res :seq acl-audit-seq}))
+      (do
+        (set! acl-audit-seq (+ acl-audit-seq 1))
+        (append! acl-audit-log entry)
+        entry))))
+
+;; Decide against db, log the outcome, and return the boolean. This is the
+;; audited path; acl-permit? remains the pure, side-effect-free decision.
+(define
+  acl-audit-decide!
+  (fn
+    (db subj act res)
+    (let
+      ((allowed? (acl-permit? db subj act res)))
+      (do (acl-audit-record! subj act res allowed?) allowed?))))
+
+(define acl-audit-count (fn () (len acl-audit-log)))
+
+;; Most recent n entries (in chronological order). n >= log size returns all.
+(define
+  acl-audit-tail
+  (fn
+    (n)
+    (let
+      ((total (len acl-audit-log)))
+      (if
+        (<= total n)
+        acl-audit-log
+        (acl-audit-drop acl-audit-log (- total n))))))
+
+(define
+  acl-audit-drop
+  (fn
+    (xs k)
+    (if (<= k 0) xs (acl-audit-drop (rest xs) (- k 1)))))
+
+;; Structured snapshot for save/restore — a {:seq :entries} value carrying a
+;; copy of the log (so later appends don't mutate a held snapshot).
+(define acl-audit-snapshot (fn () {:seq acl-audit-seq :entries (acl-audit-copy acl-audit-log)}))
+
+;; Replace the live log from a snapshot. Restores both entries and the seq
+;; counter so subsequent records continue numbering correctly. The log is
+;; rebuilt as a fresh append!-able list (see acl-audit-copy).
+(define
+  acl-audit-restore!
+  (fn
+    (snap)
+    (do
+      (set! acl-audit-log (acl-audit-copy (get snap :entries)))
+      (set! acl-audit-seq (get snap :seq))
+      nil)))
+
+;; Serialize the whole log to a disk-ready string: one record per line,
+;; "seq\tsubj\tact\tres\tallowed?". A host writes this; structured reload is via
+;; snapshot/restore.
+(define
+  acl-audit-serialize
+  (fn
+    ()
+    (reduce
+      (fn
+        (acc e)
+        (str
+          acc
+          (get e :seq)
+          "\t"
+          (get e :subj)
+          "\t"
+          (get e :act)
+          "\t"
+          (get e :res)
+          "\t"
+          (get e :allowed?)
+          "\n"))
+      ""
+      acl-audit-log)))

lib/acl/conformance.conf

@@ -0,0 +1,32 @@
+# ACL conformance config — sourced by lib/guest/conformance.sh.
+
+LANG_NAME=acl
+MODE=dict
+
+PRELOADS=(
+  lib/datalog/tokenizer.sx
+  lib/datalog/parser.sx
+  lib/datalog/unify.sx
+  lib/datalog/db.sx
+  lib/datalog/builtins.sx
+  lib/datalog/aggregates.sx
+  lib/datalog/strata.sx
+  lib/datalog/eval.sx
+  lib/datalog/api.sx
+  lib/datalog/magic.sx
+  lib/acl/schema.sx
+  lib/acl/facts.sx
+  lib/acl/engine.sx
+  lib/acl/explain.sx
+  lib/acl/audit.sx
+  lib/acl/federation.sx
+  lib/acl/api.sx
+)
+
+SUITES=(
+  "direct:lib/acl/tests/direct.sx:(acl-direct-tests-run!)"
+  "inherit:lib/acl/tests/inherit.sx:(acl-inherit-tests-run!)"
+  "explain:lib/acl/tests/explain.sx:(acl-explain-tests-run!)"
+  "fed:lib/acl/tests/fed.sx:(acl-fed-tests-run!)"
+  "harden:lib/acl/tests/harden.sx:(acl-harden-tests-run!)"
+)

lib/acl/conformance.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+# Thin wrapper — see lib/guest/conformance.sh and lib/acl/conformance.conf.
+exec bash "$(dirname "$0")/../guest/conformance.sh" "$(dirname "$0")/conformance.conf" "$@"

lib/acl/engine.sx

@@ -0,0 +1,72 @@
+;; lib/acl/engine.sx — ACL ruleset + decision reducer over lib/datalog/.
+;;
+;; The engine is a thin layer: it owns the permit ruleset (SX data rules) and
+;; reduces a (subject, action, resource) decision to a Datalog query against a
+;; db built from EDB facts. The rule engine itself is Datalog's.
+;;
+;; Policy — inheritance + federation with deny-overrides:
+;;
+;;   eff_grant(S,A,R) :- grant(S,A,R).                         ; direct
+;;   eff_grant(S,A,R) :- member_of(S,G), eff_grant(G,A,R).     ; group/role chain
+;;   eff_grant(S,A,R) :- child_of(R,P), eff_grant(S,A,P).      ; resource tree
+;;   eff_grant(S,A,R) :- member_of(S,Role), role_grant(Role,A,R). ; role expansion
+;;   eff_grant(S,A,R) :- delegate(Peer,S,A,R),                 ; federated grant
+;;                       trust(Peer,L), level_covers(L,A).
+;;
+;;   eff_deny(S,A,R)  :- deny(S,A,R).                          ; direct
+;;   eff_deny(S,A,R)  :- member_of(S,G), eff_deny(G,A,R).      ; group chain
+;;   eff_deny(S,A,R)  :- child_of(R,P), eff_deny(S,A,P).       ; resource tree
+;;
+;;   permit(S,A,R)    :- eff_grant(S,A,R), not eff_deny(S,A,R).
+;;
+;; DENY-OVERRIDES: an effective deny anywhere in the inheritance closure of
+;; (S,A,R) defeats any effective grant — including federated grants. Deny
+;; inherits through the *same* group and resource chains as grant, so a
+;; group-level or ancestor-resource deny is authoritative for members/
+;; descendants. This is the principled, fail-safe reading of "deny wins".
+;;
+;; FEDERATION — non-transitive trust: a peer's `delegate` fact only grants if a
+;; *local* `trust(Peer, L)` exists AND that level `level_covers` the action.
+;; Trust is re-checked on every query (it is a body literal), never baked in at
+;; fact-ingestion time, so revoking trust or narrowing a level takes effect
+;; immediately on the next decision.
+;;
+;; Termination & stratification:
+;;   - eff_grant/eff_deny recurse only over member_of and child_of, which are
+;;     EDB relations with no function symbols, so the closure is finite (cyclic
+;;     membership/containment just reaches a fixpoint, never loops). The
+;;     federation rule is non-recursive.
+;;   - permit negates eff_deny; neither eff_grant nor eff_deny depends on
+;;     permit, so the program is stratifiable (permit sits in a higher stratum).
+
+(define
+  acl-rules
+  (quote
+    ((eff_grant S A R <- (grant S A R))
+      (eff_grant S A R <- (member_of S G) (eff_grant G A R))
+      (eff_grant S A R <- (child_of R P) (eff_grant S A P))
+      (eff_grant S A R <- (member_of S Role) (role_grant Role A R))
+      (eff_grant
+        S
+        A
+        R
+        <-
+        (delegate Peer S A R)
+        (trust Peer L)
+        (level_covers L A))
+      (eff_deny S A R <- (deny S A R))
+      (eff_deny S A R <- (member_of S G) (eff_deny G A R))
+      (eff_deny S A R <- (child_of R P) (eff_deny S A P))
+      (permit S A R <- (eff_grant S A R) {:neg (eff_deny S A R)}))))
+
+;; Build a Datalog db from a list of EDB facts under the ACL ruleset.
+(define acl-build-db (fn (facts) (dl-program-data facts acl-rules)))
+
+;; Core decision: does the db permit subject S to perform action A on
+;; resource R? Reduces to a ground Datalog query on the derived `permit`
+;; relation — non-empty result means permitted.
+(define
+  acl-permit?
+  (fn
+    (db subj act res)
+    (> (len (dl-query db (list (quote permit) subj act res))) 0)))

lib/acl/explain.sx

@@ -0,0 +1,125 @@
+;; lib/acl/explain.sx — proof-tree reconstruction over the saturated db.
+;;
+;; lib/datalog/ records derived facts but not their provenance, so the proof is
+;; reconstructed here by goal-directed search over the *saturated* db: for a
+;; ground goal we find the first ACL rule (in rule order) whose body holds, take
+;; the first solution binding its remaining variables, and recurse on each body
+;; literal. Negated literals are recorded as verified `:neg-ok` leaves.
+;;
+;; CANONICAL DERIVATION: the Datalog derivation graph is a DAG (a fact may hold
+;; many ways). We pick ONE canonical proof — first matching rule, first solution
+;; — matching the rule order in lib/acl/engine.sx (direct/EDB rules first). A
+;; depth cap guards against pathological cyclic data producing unbounded search.
+;;
+;; A proof node is one of:
+;;   {:fact <lit> :via "edb"}                       — base EDB fact
+;;   {:fact <lit> :rule <head> :body (<node|negleaf> ...)}  — derived
+;;   {:neg-ok <lit>}                                — negation verified to fail
+;;   {:fact <lit> :truncated true}                  — depth cap hit
+
+(define acl-proof-max-depth 64)
+
+;; Substitute a body literal, descending into {:neg ...} dicts (dl-apply-subst
+;; does not recurse into dicts, which would leak the neg's free vars).
+(define
+  acl-subst-lit
+  (fn
+    (lit s)
+    (if
+      (and (dict? lit) (has-key? lit :neg))
+      {:neg (dl-apply-subst (get lit :neg) s)}
+      (dl-apply-subst lit s))))
+
+(define
+  acl-lit-edb?
+  (fn
+    (lit)
+    (and
+      (list? lit)
+      (> (len lit) 0)
+      (symbol? (first lit))
+      (has-key? acl-edb-arity (symbol->string (first lit))))))
+
+(define
+  acl-subst-zip!
+  (fn
+    (d ks vs)
+    (when
+      (> (len ks) 0)
+      (do
+        (dict-set! d (symbol->string (first ks)) (first vs))
+        (acl-subst-zip! d (rest ks) (rest vs))))))
+
+;; Bind a rule head's variables to a ground goal's arguments (positional).
+(define
+  acl-bind-head
+  (fn
+    (head goal)
+    (let
+      ((d {}))
+      (do (acl-subst-zip! d (rest head) (rest goal)) d))))
+
+(define
+  acl-subst-union
+  (fn
+    (a b)
+    (let
+      ((d {}))
+      (do
+        (for-each (fn (k) (dict-set! d k (get a k))) (keys a))
+        (for-each (fn (k) (dict-set! d k (get b k))) (keys b))
+        d))))
+
+(define acl-prove (fn (db goal) (acl-prove-d db goal 0)))
+
+(define
+  acl-prove-d
+  (fn
+    (db goal depth)
+    (cond
+      ((> depth acl-proof-max-depth) {:truncated true :fact goal})
+      ((acl-lit-edb? goal)
+        (if (> (len (dl-query db goal)) 0) {:via "edb" :fact goal} nil))
+      (else (acl-prove-rules db goal acl-rules depth)))))
+
+(define
+  acl-prove-rules
+  (fn
+    (db goal rules depth)
+    (if
+      (= (len rules) 0)
+      nil
+      (let
+        ((p (dl-rule-from-list (first rules))))
+        (if
+          (= (first (get p :head)) (first goal))
+          (let
+            ((hs (acl-bind-head (get p :head) goal)))
+            (let
+              ((qbody (map (fn (l) (acl-subst-lit l hs)) (get p :body))))
+              (let
+                ((sols (dl-query db qbody)))
+                (if
+                  (> (len sols) 0)
+                  (acl-prove-build db goal p hs (first sols) depth)
+                  (acl-prove-rules db goal (rest rules) depth)))))
+          (acl-prove-rules db goal (rest rules) depth))))))
+
+(define
+  acl-prove-build
+  (fn
+    (db goal p hs sol depth)
+    (let ((full (acl-subst-union hs sol))) {:body (map (fn (l) (let ((g (acl-subst-lit l full))) (if (and (dict? g) (has-key? g :neg)) {:neg-ok (get g :neg)} (acl-prove-d db g (+ depth 1))))) (get p :body)) :rule (get p :head) :fact goal})))
+
+;; Public decision-with-proof. Returns:
+;;   {:allowed? <bool> :proof <node|nil> :reason <eff_deny proof|nil>}
+;; When permitted, :proof is the permit derivation. When denied, :proof is nil
+;; and :reason carries the blocking eff_deny proof if one exists (an explicit or
+;; inherited deny), else nil (simply no grant).
+(define
+  acl-explain
+  (fn
+    (db subj act res)
+    (let
+      ((proof (acl-prove db (list (quote permit) subj act res))))
+      (if (= proof nil) {:allowed? false :proof nil :reason (acl-prove db (list (quote eff_deny) subj act res))} {:allowed? true :proof proof :reason nil}))))

lib/acl/facts.sx

@@ -0,0 +1,47 @@
+;; lib/acl/facts.sx — EDB fact constructors.
+;;
+;; Each constructor returns a Datalog fact tuple (a list whose head is the
+;; predicate symbol). These are the only shapes lib/acl/engine.sx feeds to
+;; lib/datalog/.
+;;   Phase 1: actor/resource/grant/deny.
+;;   Phase 2: member_of (subject -> group/role), child_of (resource -> parent),
+;;            role_grant (role -> action,resource capability).
+;;   Phase 4: peer/trust/delegate/level_covers (federation).
+
+(define acl-actor (fn (id kind) (list (quote actor) id kind)))
+
+(define acl-resource-fact (fn (id kind) (list (quote resource) id kind)))
+
+(define acl-grant (fn (subj act res) (list (quote grant) subj act res)))
+
+(define acl-deny (fn (subj act res) (list (quote deny) subj act res)))
+
+;; subject S is a member of group/role G (one hop; transitivity is derived).
+(define acl-member-of (fn (subj grp) (list (quote member_of) subj grp)))
+
+;; resource R is a child of parent P (one hop; transitivity is derived).
+(define acl-child-of (fn (res parent) (list (quote child_of) res parent)))
+
+;; role confers capability (act on res) to every member of the role.
+(define
+  acl-role-grant
+  (fn (role act res) (list (quote role_grant) role act res)))
+
+;; --- federation ---
+
+;; a known peer instance at addr, of some kind (e.g. peer).
+(define acl-peer (fn (addr kind) (list (quote peer) addr kind)))
+
+;; local trust in a peer at a named level. Gates delegated grants at query time.
+(define acl-trust (fn (peer level) (list (quote trust) peer level)))
+
+;; a peer asserts that subject S may A on R. Only takes effect if local trust in
+;; that peer covers action A (see level_covers).
+(define
+  acl-delegate
+  (fn (peer subj act res) (list (quote delegate) peer subj act res)))
+
+;; local policy: trust `level` authorises delegated grants for action `act`.
+(define
+  acl-level-covers
+  (fn (level act) (list (quote level_covers) level act)))

lib/acl/federation.sx

@@ -0,0 +1,61 @@
+;; lib/acl/federation.sx — cross-instance ACL facts + revocation.
+;;
+;; fed-sx replicates ACL facts between instances; this module models the local
+;; side. A peer's authority arrives as `delegate(Peer, S, A, R)` facts, which
+;; only take effect when a local `trust(Peer, L)` and `level_covers(L, A)`
+;; authorise them (enforced by the engine rule, re-checked every query). The
+;; actual network transport is fed-sx's job and is mocked in tests as a dict.
+;;
+;; Trust is NOT transitive: trusting peer α does not extend to peers α trusts.
+;; Only delegate facts that α itself asserts, and that local trust covers, flow.
+
+;; Mock fed-sx pull: `transport` is a dict mapping a peer address (its string
+;; name) to the list of delegate facts that peer asserts. Returns the facts for
+;; `addr`, or an empty list if the peer is unknown / unreachable.
+(define
+  acl-fed-fetch
+  (fn
+    (transport addr)
+    (let
+      ((k (if (symbol? addr) (symbol->string addr) addr)))
+      (if (has-key? transport k) (get transport k) (list)))))
+
+;; Gather delegate facts from every peer in `addrs` via the transport.
+(define
+  acl-fed-collect
+  (fn
+    (transport addrs)
+    (let
+      ((acc (list)))
+      (do
+        (for-each
+          (fn
+            (addr)
+            (for-each
+              (fn (f) (append! acc f))
+              (acl-fed-fetch transport addr)))
+          addrs)
+        acc))))
+
+;; Build a db from local facts plus delegate facts pulled from `peers`. Local
+;; facts must include the `trust`/`level_covers` policy; replicated delegate
+;; facts are gated against it by the engine rule at query time.
+(define
+  acl-fed-build-db
+  (fn
+    (local-facts transport peers)
+    (let
+      ((all (list)))
+      (do
+        (for-each (fn (f) (append! all f)) local-facts)
+        (for-each
+          (fn (f) (append! all f))
+          (acl-fed-collect transport peers))
+        (acl-build-db all)))))
+
+;; Propagated revocation: retract a replicated fact (e.g. a peer's delegate, or
+;; local trust) from a live db. The next decision re-saturates and reflects it.
+(define acl-revoke! (fn (db fact) (do (dl-retract! db fact) db)))
+
+;; Propagated assertion: ingest a newly replicated fact into a live db.
+(define acl-fed-assert! (fn (db fact) (do (dl-assert! db fact) db)))

lib/acl/schema.sx

@@ -0,0 +1,71 @@
+;; lib/acl/schema.sx — ACL sorts and EDB predicate vocabulary.
+;;
+;; Datalog is untyped; this module is the schema-as-data layer. It declares
+;; the subject/resource/action sorts and the arity of every EDB predicate the
+;; ACL engine recognises, plus light validators. Facts that pass these checks
+;; are well-formed inputs to lib/acl/engine.sx.
+
+(define acl-subject-kinds (quote (user group role service)))
+(define acl-resource-kinds (quote (page post thread peer)))
+
+;; Actions are open-ended (a grant may name any action symbol), but these are
+;; the platform's well-known verbs.
+(define acl-actions (quote (read edit comment moderate federate)))
+
+;; EDB predicate name -> arity.
+;;   Phase 1: actor/resource/grant/deny.
+;;   Phase 2: member_of (subject->group/role), child_of (resource->parent),
+;;            role_grant (role->action,resource).
+;;   Phase 4: peer (addr->kind), trust (peer->level),
+;;            delegate (peer->subj,action,resource), level_covers (level->action).
+(define acl-edb-arity {:role_grant 3 :child_of 2 :trust 2 :peer 2 :actor 2 :level_covers 2 :delegate 4 :member_of 2 :deny 3 :grant 3 :resource 2})
+
+(define
+  acl-member?
+  (fn
+    (x xs)
+    (cond
+      ((= (len xs) 0) false)
+      ((= (first xs) x) true)
+      (else (acl-member? x (rest xs))))))
+
+(define acl-subject-kind? (fn (k) (acl-member? k acl-subject-kinds)))
+
+(define acl-resource-kind? (fn (k) (acl-member? k acl-resource-kinds)))
+
+(define acl-known-action? (fn (a) (acl-member? a acl-actions)))
+
+;; A fact is a list whose head is a predicate symbol. Valid when the predicate
+;; is known and the argument count matches the declared arity.
+(define
+  acl-fact-valid?
+  (fn
+    (f)
+    (and
+      (list? f)
+      (> (len f) 0)
+      (symbol? (first f))
+      (let
+        ((pred (symbol->string (first f))))
+        (and
+          (has-key? acl-edb-arity pred)
+          (= (- (len f) 1) (get acl-edb-arity pred)))))))
+
+;; Return the sublist of facts that fail acl-fact-valid?. Empty list means the
+;; whole set is well-formed. acl-build-db stays lenient (Datalog accepts any
+;; tuple, and custom action symbols are allowed); callers opt in to checking.
+(define
+  acl-validate-facts
+  (fn
+    (facts)
+    (let
+      ((bad (list)))
+      (do
+        (for-each
+          (fn (f) (when (not (acl-fact-valid? f)) (append! bad f)))
+          facts)
+        bad))))
+
+(define
+  acl-facts-valid?
+  (fn (facts) (= (len (acl-validate-facts facts)) 0)))

lib/acl/scoreboard.json

@@ -0,0 +1,14 @@
+{
+  "lang": "acl",
+  "total_passed": 145,
+  "total_failed": 0,
+  "total": 145,
+  "suites": [
+    {"name":"direct","passed":24,"failed":0,"total":24},
+    {"name":"inherit","passed":30,"failed":0,"total":30},
+    {"name":"explain","passed":35,"failed":0,"total":35},
+    {"name":"fed","passed":31,"failed":0,"total":31},
+    {"name":"harden","passed":25,"failed":0,"total":25}
+  ],
+  "generated": "2026-06-06T22:43:27+00:00"
+}

lib/acl/scoreboard.md

@@ -0,0 +1,11 @@
+# acl scoreboard
+
+**145 / 145 passing** (0 failure(s)).
+
+| Suite | Passed | Total | Status |
+|-------|--------|-------|--------|
+| direct | 24 | 24 | ok |
+| inherit | 30 | 30 | ok |
+| explain | 35 | 35 | ok |
+| fed | 31 | 31 | ok |
+| harden | 25 | 25 | ok |

lib/acl/tests/direct.sx

@@ -0,0 +1,170 @@
+;; lib/acl/tests/direct.sx — Phase 1: direct grants + deny-overrides.
+
+(define acl-dt-pass 0)
+(define acl-dt-fail 0)
+(define acl-dt-failures (list))
+
+(define
+  acl-dt-check!
+  (fn
+    (name got expected)
+    (if
+      (= got expected)
+      (set! acl-dt-pass (+ acl-dt-pass 1))
+      (do
+        (set! acl-dt-fail (+ acl-dt-fail 1))
+        (append!
+          acl-dt-failures
+          (str name "\n    expected: " expected "\n    got:      " got))))))
+
+;; A small fixture used by most cases: alice can read page1, is denied edit on
+;; page1, and a service may federate peer1.
+(define
+  acl-dt-fixture
+  (fn
+    ()
+    (acl-build-db
+      (list
+        (acl-actor (quote alice) (quote user))
+        (acl-actor (quote svc1) (quote service))
+        (acl-resource-fact (quote page1) (quote page))
+        (acl-resource-fact (quote peer1) (quote peer))
+        (acl-grant (quote alice) (quote read) (quote page1))
+        (acl-grant (quote alice) (quote edit) (quote page1))
+        (acl-deny (quote alice) (quote edit) (quote page1))
+        (acl-grant (quote svc1) (quote federate) (quote peer1))))))
+
+(define
+  acl-dt-run-all!
+  (fn
+    ()
+    (let
+      ((db (acl-dt-fixture)))
+      (do
+        (acl-dt-check!
+          "direct grant permits"
+          (acl-permit? db (quote alice) (quote read) (quote page1))
+          true)
+        (acl-dt-check!
+          "service grant permits federate"
+          (acl-permit? db (quote svc1) (quote federate) (quote peer1))
+          true)
+        (acl-dt-check!
+          "missing action denied"
+          (acl-permit? db (quote alice) (quote comment) (quote page1))
+          false)
+        (acl-dt-check!
+          "missing resource denied"
+          (acl-permit? db (quote alice) (quote read) (quote page2))
+          false)
+        (acl-dt-check!
+          "missing subject denied"
+          (acl-permit? db (quote bob) (quote read) (quote page1))
+          false)
+        (acl-dt-check!
+          "wrong subject for service grant denied"
+          (acl-permit? db (quote alice) (quote federate) (quote peer1))
+          false)
+        (acl-dt-check!
+          "grant plus deny -> deny wins"
+          (acl-permit? db (quote alice) (quote edit) (quote page1))
+          false)
+        (acl-dt-check!
+          "deny alone still denies"
+          (acl-permit?
+            (acl-build-db
+              (list (acl-deny (quote alice) (quote read) (quote page1))))
+            (quote alice)
+            (quote read)
+            (quote page1))
+          false)
+        (acl-dt-check!
+          "deny on edit does not block read"
+          (acl-permit? db (quote alice) (quote read) (quote page1))
+          true)
+        (acl-dt-check!
+          "empty db denies"
+          (acl-permit?
+            (acl-build-db (list))
+            (quote alice)
+            (quote read)
+            (quote page1))
+          false)
+        (let
+          ((db2 (acl-build-db (list (acl-grant (quote a) (quote read) (quote r)) (acl-grant (quote b) (quote read) (quote r)) (acl-deny (quote b) (quote read) (quote r))))))
+          (do
+            (acl-dt-check!
+              "subject a allowed"
+              (acl-permit? db2 (quote a) (quote read) (quote r))
+              true)
+            (acl-dt-check!
+              "subject b denied by override"
+              (acl-permit? db2 (quote b) (quote read) (quote r))
+              false)))
+        (let
+          ((db3 (acl-build-db (list (acl-actor (quote editors) (quote role)) (acl-grant (quote editors) (quote edit) (quote post1))))))
+          (acl-dt-check!
+            "role subject direct grant"
+            (acl-permit? db3 (quote editors) (quote edit) (quote post1))
+            true))
+        (do
+          (acl/load!
+            (list
+              (acl-grant (quote carol) (quote moderate) (quote thread1))))
+          (acl-dt-check!
+            "api permit via current db"
+            (acl/permit? (quote carol) (quote moderate) (quote thread1))
+            true)
+          (acl-dt-check!
+            "api deny via current db"
+            (acl/permit? (quote carol) (quote read) (quote thread1))
+            false))
+        (do
+          (acl/load! (list))
+          (acl-dt-check!
+            "api reload clears prior grants"
+            (acl/permit? (quote carol) (quote moderate) (quote thread1))
+            false))
+        (acl-dt-check!
+          "schema grant arity valid"
+          (acl-fact-valid? (acl-grant (quote x) (quote read) (quote y)))
+          true)
+        (acl-dt-check!
+          "schema bad arity invalid"
+          (acl-fact-valid? (list (quote grant) (quote x)))
+          false)
+        (acl-dt-check!
+          "schema unknown predicate invalid"
+          (acl-fact-valid? (list (quote frobnicate) (quote x)))
+          false)
+        (acl-dt-check!
+          "schema subject kind known"
+          (acl-subject-kind? (quote service))
+          true)
+        (acl-dt-check!
+          "schema resource kind unknown"
+          (acl-resource-kind? (quote galaxy))
+          false)
+        (acl-dt-check!
+          "schema known action"
+          (acl-known-action? (quote moderate))
+          true)
+        (acl-dt-check!
+          "grant constructor shape"
+          (acl-grant (quote u) (quote read) (quote p))
+          (list (quote grant) (quote u) (quote read) (quote p)))
+        (acl-dt-check!
+          "actor constructor shape"
+          (acl-actor (quote u) (quote user))
+          (list (quote actor) (quote u) (quote user)))))))
+
+(define
+  acl-direct-tests-run!
+  (fn
+    ()
+    (do
+      (set! acl-dt-pass 0)
+      (set! acl-dt-fail 0)
+      (set! acl-dt-failures (list))
+      (acl-dt-run-all!)
+      {:failures acl-dt-failures :total (+ acl-dt-pass acl-dt-fail) :passed acl-dt-pass :failed acl-dt-fail})))

lib/acl/tests/explain.sx

@@ -0,0 +1,316 @@
+;; lib/acl/tests/explain.sx — Phase 3: proof correctness + audit completeness.
+
+(define acl-et-pass 0)
+(define acl-et-fail 0)
+(define acl-et-failures (list))
+
+;; Name-based deep equality. The host `=` compares symbols by interned
+;; identity, which is unstable across substitution/saturation; comparing by
+;; name (as the datalog suite does) makes structural assertions deterministic.
+(define
+  acl-et-eq?
+  (fn
+    (a b)
+    (cond
+      ((and (list? a) (list? b))
+        (and (= (len a) (len b)) (acl-et-eq-l? a b 0)))
+      ((and (dict? a) (dict? b))
+        (let
+          ((ka (keys a)) (kb (keys b)))
+          (and (= (len ka) (len kb)) (acl-et-eq-d? a b ka 0))))
+      ((and (symbol? a) (symbol? b))
+        (= (symbol->string a) (symbol->string b)))
+      (else (= a b)))))
+
+(define
+  acl-et-eq-l?
+  (fn
+    (a b i)
+    (cond
+      ((>= i (len a)) true)
+      ((not (acl-et-eq? (nth a i) (nth b i))) false)
+      (else (acl-et-eq-l? a b (+ i 1))))))
+
+(define
+  acl-et-eq-d?
+  (fn
+    (a b ka i)
+    (cond
+      ((>= i (len ka)) true)
+      ((let ((k (nth ka i))) (not (acl-et-eq? (get a k) (get b k))))
+        false)
+      (else (acl-et-eq-d? a b ka (+ i 1))))))
+
+(define
+  acl-et-check!
+  (fn
+    (name got expected)
+    (if
+      (acl-et-eq? got expected)
+      (set! acl-et-pass (+ acl-et-pass 1))
+      (do
+        (set! acl-et-fail (+ acl-et-fail 1))
+        (append!
+          acl-et-failures
+          (str name "\n    expected: " expected "\n    got:      " got))))))
+
+;; --- proof-tree walkers ---
+
+;; True if EDB fact `target` appears as a base leaf anywhere in the proof.
+(define
+  acl-et-has-leaf?
+  (fn
+    (node target)
+    (cond
+      ((= node nil) false)
+      ((and (dict? node) (has-key? node :via))
+        (acl-et-eq? (get node :fact) target))
+      ((and (dict? node) (has-key? node :body))
+        (acl-et-any-leaf? (get node :body) target))
+      (else false))))
+
+(define
+  acl-et-any-leaf?
+  (fn
+    (nodes target)
+    (cond
+      ((= (len nodes) 0) false)
+      ((acl-et-has-leaf? (first nodes) target) true)
+      (else (acl-et-any-leaf? (rest nodes) target)))))
+
+;; True if the proof records a verified negation (deny did not fire).
+(define
+  acl-et-has-negok?
+  (fn
+    (node)
+    (cond
+      ((= node nil) false)
+      ((and (dict? node) (has-key? node :neg-ok)) true)
+      ((and (dict? node) (has-key? node :body))
+        (acl-et-any-negok? (get node :body)))
+      (else false))))
+
+(define
+  acl-et-any-negok?
+  (fn
+    (nodes)
+    (cond
+      ((= (len nodes) 0) false)
+      ((acl-et-has-negok? (first nodes)) true)
+      (else (acl-et-any-negok? (rest nodes))))))
+
+(define
+  acl-et-run-all!
+  (fn
+    ()
+    (do
+      (let
+        ((db (acl-build-db (list (acl-grant (quote u) (quote read) (quote p))))))
+        (let
+          ((e (acl-explain db (quote u) (quote read) (quote p))))
+          (do
+            (acl-et-check! "direct: allowed?" (get e :allowed?) true)
+            (acl-et-check!
+              "direct: proof root fact"
+              (get (get e :proof) :fact)
+              (list (quote permit) (quote u) (quote read) (quote p)))
+            (acl-et-check!
+              "direct: grant leaf present"
+              (acl-et-has-leaf?
+                (get e :proof)
+                (list (quote grant) (quote u) (quote read) (quote p)))
+              true)
+            (acl-et-check!
+              "direct: negation verified"
+              (acl-et-has-negok? (get e :proof))
+              true)
+            (acl-et-check!
+              "direct: reason nil when allowed"
+              (get e :reason)
+              nil))))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote alice) (quote team)) (acl-member-of (quote team) (quote org)) (acl-grant (quote org) (quote read) (quote doc))))))
+        (let
+          ((e (acl-explain db (quote alice) (quote read) (quote doc))))
+          (do
+            (acl-et-check! "group: allowed?" (get e :allowed?) true)
+            (acl-et-check!
+              "group: member_of alice leaf"
+              (acl-et-has-leaf?
+                (get e :proof)
+                (list (quote member_of) (quote alice) (quote team)))
+              true)
+            (acl-et-check!
+              "group: member_of team leaf"
+              (acl-et-has-leaf?
+                (get e :proof)
+                (list (quote member_of) (quote team) (quote org)))
+              true)
+            (acl-et-check!
+              "group: grant org leaf at base"
+              (acl-et-has-leaf?
+                (get e :proof)
+                (list (quote grant) (quote org) (quote read) (quote doc)))
+              true))))
+      (let
+        ((db (acl-build-db (list (acl-child-of (quote sec) (quote book)) (acl-grant (quote u) (quote read) (quote book))))))
+        (let
+          ((e (acl-explain db (quote u) (quote read) (quote sec))))
+          (do
+            (acl-et-check! "resource: allowed?" (get e :allowed?) true)
+            (acl-et-check!
+              "resource: child_of leaf"
+              (acl-et-has-leaf?
+                (get e :proof)
+                (list (quote child_of) (quote sec) (quote book)))
+              true)
+            (acl-et-check!
+              "resource: grant on parent leaf"
+              (acl-et-has-leaf?
+                (get e :proof)
+                (list (quote grant) (quote u) (quote read) (quote book)))
+              true))))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote bob) (quote editor)) (acl-role-grant (quote editor) (quote edit) (quote page1))))))
+        (let
+          ((e (acl-explain db (quote bob) (quote edit) (quote page1))))
+          (do
+            (acl-et-check! "role: allowed?" (get e :allowed?) true)
+            (acl-et-check!
+              "role: member_of leaf"
+              (acl-et-has-leaf?
+                (get e :proof)
+                (list (quote member_of) (quote bob) (quote editor)))
+              true)
+            (acl-et-check!
+              "role: role_grant leaf"
+              (acl-et-has-leaf?
+                (get e :proof)
+                (list
+                  (quote role_grant)
+                  (quote editor)
+                  (quote edit)
+                  (quote page1)))
+              true))))
+      (let
+        ((db (acl-build-db (list (acl-grant (quote u) (quote edit) (quote p)) (acl-deny (quote u) (quote edit) (quote p))))))
+        (let
+          ((e (acl-explain db (quote u) (quote edit) (quote p))))
+          (do
+            (acl-et-check! "deny: not allowed" (get e :allowed?) false)
+            (acl-et-check! "deny: no proof" (get e :proof) nil)
+            (acl-et-check!
+              "deny: reason root is eff_deny"
+              (get (get e :reason) :fact)
+              (list (quote eff_deny) (quote u) (quote edit) (quote p)))
+            (acl-et-check!
+              "deny: reason has deny leaf"
+              (acl-et-has-leaf?
+                (get e :reason)
+                (list (quote deny) (quote u) (quote edit) (quote p)))
+              true))))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote alice) (quote team)) (acl-grant (quote alice) (quote read) (quote doc)) (acl-deny (quote team) (quote read) (quote doc))))))
+        (let
+          ((e (acl-explain db (quote alice) (quote read) (quote doc))))
+          (do
+            (acl-et-check!
+              "inherited deny: not allowed"
+              (get e :allowed?)
+              false)
+            (acl-et-check!
+              "inherited deny: reason has member_of leaf"
+              (acl-et-has-leaf?
+                (get e :reason)
+                (list (quote member_of) (quote alice) (quote team)))
+              true)
+            (acl-et-check!
+              "inherited deny: reason has group deny leaf"
+              (acl-et-has-leaf?
+                (get e :reason)
+                (list (quote deny) (quote team) (quote read) (quote doc)))
+              true))))
+      (let
+        ((db (acl-build-db (list))))
+        (let
+          ((e (acl-explain db (quote u) (quote read) (quote p))))
+          (do
+            (acl-et-check! "no grant: not allowed" (get e :allowed?) false)
+            (acl-et-check! "no grant: proof nil" (get e :proof) nil)
+            (acl-et-check! "no grant: reason nil" (get e :reason) nil))))
+      (let
+        ((db (acl-build-db (list (acl-grant (quote u) (quote read) (quote p)) (acl-deny (quote u) (quote edit) (quote p))))))
+        (do
+          (acl-audit-clear!)
+          (acl-et-check! "audit: starts empty" (acl-audit-count) 0)
+          (acl-et-check!
+            "audit decide allowed returns true"
+            (acl-audit-decide! db (quote u) (quote read) (quote p))
+            true)
+          (acl-et-check!
+            "audit decide denied returns false"
+            (acl-audit-decide! db (quote u) (quote edit) (quote p))
+            false)
+          (acl-audit-decide! db (quote u) (quote comment) (quote p))
+          (acl-et-check!
+            "audit: count after three decisions"
+            (acl-audit-count)
+            3)
+          (acl-et-check!
+            "audit: tail size respects n"
+            (len (acl-audit-tail 2))
+            2)
+          (acl-et-check!
+            "audit: tail returns most recent"
+            (get (first (acl-audit-tail 1)) :act)
+            (quote comment))
+          (acl-et-check!
+            "audit: first record seq is 0"
+            (get (first (acl-audit-tail 3)) :seq)
+            0)
+          (acl-et-check!
+            "audit: allowed flag recorded"
+            (get (first (acl-audit-tail 3)) :allowed?)
+            true)
+          (acl-et-check!
+            "audit: serialize line count"
+            (len (acl-et-lines (acl-audit-serialize)))
+            3)
+          (acl-audit-clear!)
+          (acl-et-check!
+            "audit: clear resets count"
+            (acl-audit-count)
+            0))))))
+
+;; count newline-terminated lines in a serialized log
+(define acl-et-lines (fn (s) (acl-et-count-nl s 0 0)))
+(define
+  acl-et-count-nl
+  (fn
+    (s i n)
+    (if
+      (>= i (len s))
+      (if (= n 0) (list) (acl-et-rangelist n))
+      (acl-et-count-nl
+        s
+        (+ i 1)
+        (if (= (slice s i (+ i 1)) "\n") (+ n 1) n)))))
+(define
+  acl-et-rangelist
+  (fn
+    (n)
+    (if
+      (<= n 0)
+      (list)
+      (cons n (acl-et-rangelist (- n 1))))))
+
+(define
+  acl-explain-tests-run!
+  (fn
+    ()
+    (do
+      (set! acl-et-pass 0)
+      (set! acl-et-fail 0)
+      (set! acl-et-failures (list))
+      (acl-et-run-all!)
+      {:failures acl-et-failures :total (+ acl-et-pass acl-et-fail) :passed acl-et-pass :failed acl-et-fail})))

lib/acl/tests/fed.sx

@@ -0,0 +1,273 @@
+;; lib/acl/tests/fed.sx — Phase 4: federation (peer trust, delegation,
+;; cross-instance chains, revocation). fed-sx transport is mocked as a dict.
+
+(define acl-ft-pass 0)
+(define acl-ft-fail 0)
+(define acl-ft-failures (list))
+
+;; Name-based deep equality (host `=` compares symbols by unstable interned
+;; identity; see lib/acl/tests/explain.sx).
+(define
+  acl-ft-eq?
+  (fn
+    (a b)
+    (cond
+      ((and (list? a) (list? b))
+        (and (= (len a) (len b)) (acl-ft-eq-l? a b 0)))
+      ((and (symbol? a) (symbol? b))
+        (= (symbol->string a) (symbol->string b)))
+      (else (= a b)))))
+(define
+  acl-ft-eq-l?
+  (fn
+    (a b i)
+    (cond
+      ((>= i (len a)) true)
+      ((not (acl-ft-eq? (nth a i) (nth b i))) false)
+      (else (acl-ft-eq-l? a b (+ i 1))))))
+
+(define
+  acl-ft-check!
+  (fn
+    (name got expected)
+    (if
+      (acl-ft-eq? got expected)
+      (set! acl-ft-pass (+ acl-ft-pass 1))
+      (do
+        (set! acl-ft-fail (+ acl-ft-fail 1))
+        (append!
+          acl-ft-failures
+          (str name "\n    expected: " expected "\n    got:      " got))))))
+
+;; proof leaf walker (federated proofs reconstruct through the engine rule).
+(define
+  acl-ft-has-leaf?
+  (fn
+    (node target)
+    (cond
+      ((= node nil) false)
+      ((and (dict? node) (has-key? node :via))
+        (acl-ft-eq? (get node :fact) target))
+      ((and (dict? node) (has-key? node :body))
+        (acl-ft-any-leaf? (get node :body) target))
+      (else false))))
+(define
+  acl-ft-any-leaf?
+  (fn
+    (nodes target)
+    (cond
+      ((= (len nodes) 0) false)
+      ((acl-ft-has-leaf? (first nodes) target) true)
+      (else (acl-ft-any-leaf? (rest nodes) target)))))
+
+(define acl-ft-p? (fn (db s a r) (acl-permit? db s a r)))
+
+;; A standard federation fixture: local trusts peer alpha at "readonly", which
+;; covers read+comment. alpha delegates several capabilities to alice.
+(define
+  acl-ft-fixture
+  (fn
+    ()
+    (acl-build-db
+      (list
+        (acl-trust (quote alpha) (quote readonly))
+        (acl-level-covers (quote readonly) (quote read))
+        (acl-level-covers (quote readonly) (quote comment))
+        (acl-delegate (quote alpha) (quote alice) (quote read) (quote doc))
+        (acl-delegate (quote alpha) (quote alice) (quote edit) (quote doc))))))
+
+(define
+  acl-ft-run-all!
+  (fn
+    ()
+    (do
+      (let
+        ((db (acl-ft-fixture)))
+        (do
+          (acl-ft-check!
+            "trusted delegate, level covers action -> permit"
+            (acl-ft-p? db (quote alice) (quote read) (quote doc))
+            true)
+          (acl-ft-check!
+            "trusted delegate, level does NOT cover action -> deny"
+            (acl-ft-p? db (quote alice) (quote edit) (quote doc))
+            false)
+          (acl-ft-check!
+            "delegated but action class uncovered (comment has no delegate)"
+            (acl-ft-p? db (quote alice) (quote comment) (quote doc))
+            false)))
+      (let
+        ((db (acl-build-db (list (acl-level-covers (quote readonly) (quote read)) (acl-delegate (quote beta) (quote bob) (quote read) (quote doc))))))
+        (acl-ft-check!
+          "untrusted peer delegate -> deny"
+          (acl-ft-p? db (quote bob) (quote read) (quote doc))
+          false))
+      (let
+        ((db (acl-build-db (list (acl-trust (quote alpha) (quote readonly)) (acl-delegate (quote alpha) (quote alice) (quote read) (quote doc))))))
+        (acl-ft-check!
+          "trust but no level_covers -> deny"
+          (acl-ft-p? db (quote alice) (quote read) (quote doc))
+          false))
+      (let
+        ((db (acl-build-db (list (acl-trust (quote alpha) (quote full)) (acl-level-covers (quote full) (quote read)) (acl-delegate (quote alpha) (quote alice) (quote read) (quote doc)) (acl-delegate (quote beta) (quote bob) (quote read) (quote doc))))))
+        (do
+          (acl-ft-check!
+            "trust is per-peer: alpha's delegate applies"
+            (acl-ft-p? db (quote alice) (quote read) (quote doc))
+            true)
+          (acl-ft-check!
+            "trust not transitive: beta's delegate does not apply"
+            (acl-ft-p? db (quote bob) (quote read) (quote doc))
+            false)))
+      (let
+        ((db (acl-build-db (list (acl-trust (quote alpha) (quote full)) (acl-level-covers (quote full) (quote read)) (acl-delegate (quote alpha) (quote alice) (quote read) (quote doc)) (acl-deny (quote alice) (quote read) (quote doc))))))
+        (acl-ft-check!
+          "local deny overrides federated grant"
+          (acl-ft-p? db (quote alice) (quote read) (quote doc))
+          false))
+      (let
+        ((db (acl-build-db (list (acl-trust (quote alpha) (quote full)) (acl-level-covers (quote full) (quote read)) (acl-member-of (quote alice) (quote team)) (acl-delegate (quote alpha) (quote team) (quote read) (quote doc))))))
+        (acl-ft-check!
+          "federated grant to group reaches member"
+          (acl-ft-p? db (quote alice) (quote read) (quote doc))
+          true))
+      (let
+        ((db (acl-build-db (list (acl-trust (quote alpha) (quote full)) (acl-level-covers (quote full) (quote read)) (acl-child-of (quote sec) (quote book)) (acl-delegate (quote alpha) (quote u) (quote read) (quote book))))))
+        (acl-ft-check!
+          "federated grant on parent resource reaches child"
+          (acl-ft-p? db (quote u) (quote read) (quote sec))
+          true))
+      (let
+        ((transport {:gamma (list (acl-delegate (quote gamma) (quote carol) (quote read) (quote post))) :alpha (list (acl-delegate (quote alpha) (quote alice) (quote read) (quote doc)))}))
+        (do
+          (acl-ft-check!
+            "fetch known peer returns its delegates"
+            (len (acl-fed-fetch transport (quote alpha)))
+            1)
+          (acl-ft-check!
+            "fetch unknown peer returns empty"
+            (len (acl-fed-fetch transport (quote delta)))
+            0)
+          (acl-ft-check!
+            "collect across peers"
+            (len
+              (acl-fed-collect transport (list (quote alpha) (quote gamma))))
+            2)
+          (let
+            ((db (acl-fed-build-db (list (acl-trust (quote alpha) (quote readonly)) (acl-trust (quote gamma) (quote readonly)) (acl-level-covers (quote readonly) (quote read))) transport (list (quote alpha) (quote gamma)))))
+            (do
+              (acl-ft-check!
+                "fed-build-db: alpha delegate permits"
+                (acl-ft-p? db (quote alice) (quote read) (quote doc))
+                true)
+              (acl-ft-check!
+                "fed-build-db: gamma delegate permits"
+                (acl-ft-p? db (quote carol) (quote read) (quote post))
+                true)
+              (acl-ft-check!
+                "fed-build-db: untrusted action still denied"
+                (acl-ft-p? db (quote alice) (quote edit) (quote doc))
+                false)))))
+      (let
+        ((db (acl-build-db (list (acl-trust (quote alpha) (quote full)) (acl-level-covers (quote full) (quote read)) (acl-delegate (quote alpha) (quote alice) (quote read) (quote doc))))))
+        (do
+          (acl-ft-check!
+            "before revoke: permitted"
+            (acl-ft-p? db (quote alice) (quote read) (quote doc))
+            true)
+          (acl-revoke!
+            db
+            (acl-delegate
+              (quote alpha)
+              (quote alice)
+              (quote read)
+              (quote doc)))
+          (acl-ft-check!
+            "after delegate revoked: denied"
+            (acl-ft-p? db (quote alice) (quote read) (quote doc))
+            false)))
+      (let
+        ((db (acl-build-db (list (acl-trust (quote alpha) (quote full)) (acl-level-covers (quote full) (quote read)) (acl-delegate (quote alpha) (quote alice) (quote read) (quote doc))))))
+        (do
+          (acl-ft-check!
+            "before trust revoke: permitted"
+            (acl-ft-p? db (quote alice) (quote read) (quote doc))
+            true)
+          (acl-revoke! db (acl-trust (quote alpha) (quote full)))
+          (acl-ft-check!
+            "after trust revoked: denied"
+            (acl-ft-p? db (quote alice) (quote read) (quote doc))
+            false)))
+      (let
+        ((db (acl-build-db (list (acl-level-covers (quote full) (quote read)) (acl-delegate (quote alpha) (quote alice) (quote read) (quote doc))))))
+        (do
+          (acl-ft-check!
+            "delegate without trust: denied"
+            (acl-ft-p? db (quote alice) (quote read) (quote doc))
+            false)
+          (acl-fed-assert! db (acl-trust (quote alpha) (quote full)))
+          (acl-ft-check!
+            "trust ingested then re-checked: permitted"
+            (acl-ft-p? db (quote alice) (quote read) (quote doc))
+            true)))
+      (let
+        ((db (acl-ft-fixture)))
+        (let
+          ((e (acl-explain db (quote alice) (quote read) (quote doc))))
+          (do
+            (acl-ft-check! "federated proof allowed?" (get e :allowed?) true)
+            (acl-ft-check!
+              "federated proof has delegate leaf"
+              (acl-ft-has-leaf?
+                (get e :proof)
+                (list
+                  (quote delegate)
+                  (quote alpha)
+                  (quote alice)
+                  (quote read)
+                  (quote doc)))
+              true)
+            (acl-ft-check!
+              "federated proof has trust leaf"
+              (acl-ft-has-leaf?
+                (get e :proof)
+                (list (quote trust) (quote alpha) (quote readonly)))
+              true)
+            (acl-ft-check!
+              "federated proof has level_covers leaf"
+              (acl-ft-has-leaf?
+                (get e :proof)
+                (list (quote level_covers) (quote readonly) (quote read)))
+              true))))
+      (acl-ft-check!
+        "schema delegate arity valid"
+        (acl-fact-valid?
+          (acl-delegate (quote p) (quote s) (quote a) (quote r)))
+        true)
+      (acl-ft-check!
+        "schema trust arity valid"
+        (acl-fact-valid? (acl-trust (quote p) (quote l)))
+        true)
+      (acl-ft-check!
+        "schema peer arity valid"
+        (acl-fact-valid? (acl-peer (quote p) (quote peer)))
+        true)
+      (acl-ft-check!
+        "schema level_covers arity valid"
+        (acl-fact-valid? (acl-level-covers (quote l) (quote read)))
+        true)
+      (acl-ft-check!
+        "schema delegate bad arity invalid"
+        (acl-fact-valid? (list (quote delegate) (quote p) (quote s)))
+        false))))
+
+(define
+  acl-fed-tests-run!
+  (fn
+    ()
+    (do
+      (set! acl-ft-pass 0)
+      (set! acl-ft-fail 0)
+      (set! acl-ft-failures (list))
+      (acl-ft-run-all!)
+      {:failures acl-ft-failures :total (+ acl-ft-pass acl-ft-fail) :passed acl-ft-pass :failed acl-ft-fail})))

lib/acl/tests/harden.sx

@@ -0,0 +1,228 @@
+;; lib/acl/tests/harden.sx — adversarial / cross-phase hardening.
+;;
+;; Diamond hierarchies, conflict resolution where deny must win through every
+;; path, chain inheritance, cycle termination, multi-peer delegation, fact
+;; validation, and audit save/restore.
+;;
+;; PROVER-FREE BY DESIGN: this suite calls only acl-permit? (which runs in
+;; compiled Datalog, safe at any depth) plus pure data ops — never acl-explain /
+;; acl-prove-d. The SX-side proof reconstructor recurses, and once the kernel
+;; JIT-compiles it (after the explain/fed suites warm the process) it loops on
+;; chains deeper than ~3 (substrate JIT bug — see plan Blockers). Proof
+;; reconstruction is covered by tests/explain.sx (and federated proofs by
+;; tests/fed.sx), both of which stay under the warm-process depth threshold.
+
+(define acl-hd-pass 0)
+(define acl-hd-fail 0)
+(define acl-hd-failures (list))
+
+(define
+  acl-hd-check!
+  (fn
+    (name got expected)
+    (if
+      (= got expected)
+      (set! acl-hd-pass (+ acl-hd-pass 1))
+      (do
+        (set! acl-hd-fail (+ acl-hd-fail 1))
+        (append!
+          acl-hd-failures
+          (str name "\n    expected: " expected "\n    got:      " got))))))
+
+(define acl-hd-p? (fn (db s a r) (acl-permit? db s a r)))
+
+(define
+  acl-hd-run-all!
+  (fn
+    ()
+    (do
+      (let
+        ((grant-deny (acl-build-db (list (acl-child-of (quote r) (quote p1)) (acl-child-of (quote r) (quote p2)) (acl-grant (quote u) (quote read) (quote p1)) (acl-deny (quote u) (quote read) (quote p2)))))
+          (both-grant
+            (acl-build-db
+              (list
+                (acl-child-of (quote r) (quote p1))
+                (acl-child-of (quote r) (quote p2))
+                (acl-grant (quote u) (quote read) (quote p1))
+                (acl-grant (quote u) (quote read) (quote p2))))))
+        (do
+          (acl-hd-check!
+            "diamond resource: grant+deny parents -> deny wins"
+            (acl-hd-p? grant-deny (quote u) (quote read) (quote r))
+            false)
+          (acl-hd-check!
+            "diamond resource: both grant -> permit"
+            (acl-hd-p? both-grant (quote u) (quote read) (quote r))
+            true)
+          (acl-hd-check!
+            "diamond resource: deny does not leak to other parent"
+            (acl-hd-p? grant-deny (quote u) (quote read) (quote p1))
+            true)))
+      (let
+        ((grant-deny (acl-build-db (list (acl-member-of (quote alice) (quote g1)) (acl-member-of (quote alice) (quote g2)) (acl-grant (quote g1) (quote read) (quote doc)) (acl-deny (quote g2) (quote read) (quote doc)))))
+          (both-grant
+            (acl-build-db
+              (list
+                (acl-member-of (quote alice) (quote g1))
+                (acl-member-of (quote alice) (quote g2))
+                (acl-grant (quote g1) (quote read) (quote doc))
+                (acl-grant (quote g2) (quote read) (quote doc))))))
+        (do
+          (acl-hd-check!
+            "diamond group: grant+deny groups -> deny wins"
+            (acl-hd-p? grant-deny (quote alice) (quote read) (quote doc))
+            false)
+          (acl-hd-check!
+            "diamond group: both grant -> permit"
+            (acl-hd-p? both-grant (quote alice) (quote read) (quote doc))
+            true)))
+      (let
+        ((chain (acl-build-db (list (acl-member-of (quote a0) (quote a1)) (acl-member-of (quote a1) (quote a2)) (acl-member-of (quote a2) (quote a3)) (acl-member-of (quote a3) (quote a4)) (acl-grant (quote a4) (quote read) (quote res)))))
+          (chain-deny
+            (acl-build-db
+              (list
+                (acl-member-of (quote a0) (quote a1))
+                (acl-member-of (quote a1) (quote a2))
+                (acl-member-of (quote a2) (quote a3))
+                (acl-member-of (quote a3) (quote a4))
+                (acl-grant (quote a4) (quote read) (quote res))
+                (acl-deny (quote a0) (quote read) (quote res))))))
+        (do
+          (acl-hd-check!
+            "chain: top-group grant reaches leaf member"
+            (acl-hd-p? chain (quote a0) (quote read) (quote res))
+            true)
+          (acl-hd-check!
+            "chain: intermediate also covered"
+            (acl-hd-p? chain (quote a2) (quote read) (quote res))
+            true)
+          (acl-hd-check!
+            "chain: leaf-member deny overrides top grant"
+            (acl-hd-p? chain-deny (quote a0) (quote read) (quote res))
+            false)
+          (acl-hd-check!
+            "chain: deny on leaf does not block sibling level"
+            (acl-hd-p? chain-deny (quote a1) (quote read) (quote res))
+            true)))
+      (let
+        ((self-member (acl-build-db (list (acl-member-of (quote a) (quote a)) (acl-grant (quote a) (quote read) (quote r)))))
+          (self-child
+            (acl-build-db
+              (list
+                (acl-child-of (quote r) (quote r))
+                (acl-grant (quote u) (quote read) (quote r)))))
+          (two-cycle
+            (acl-build-db
+              (list
+                (acl-member-of (quote x) (quote y))
+                (acl-member-of (quote y) (quote x))
+                (acl-grant (quote y) (quote read) (quote r))))))
+        (do
+          (acl-hd-check!
+            "self-membership cycle terminates and grants"
+            (acl-hd-p? self-member (quote a) (quote read) (quote r))
+            true)
+          (acl-hd-check!
+            "self-child cycle terminates and grants"
+            (acl-hd-p? self-child (quote u) (quote read) (quote r))
+            true)
+          (acl-hd-check!
+            "two-node membership cycle terminates"
+            (acl-hd-p? two-cycle (quote x) (quote read) (quote r))
+            true)))
+      (let
+        ((db (acl-build-db (list (acl-trust (quote alpha) (quote full)) (acl-level-covers (quote full) (quote read)) (acl-member-of (quote alice) (quote team)) (acl-delegate (quote alpha) (quote team) (quote read) (quote doc)) (acl-deny (quote alice) (quote read) (quote doc))))))
+        (acl-hd-check!
+          "federated group grant, local member deny -> deny wins"
+          (acl-hd-p? db (quote alice) (quote read) (quote doc))
+          false))
+      (let
+        ((db (acl-build-db (list (acl-trust (quote alpha) (quote full)) (acl-level-covers (quote full) (quote read)) (acl-delegate (quote alpha) (quote bob) (quote read) (quote doc)) (acl-delegate (quote beta) (quote bob) (quote read) (quote doc))))))
+        (acl-hd-check!
+          "two peers delegate, one trusted -> permit"
+          (acl-hd-p? db (quote bob) (quote read) (quote doc))
+          true))
+      (let
+        ((db (acl-build-db (list (acl-trust (quote alpha) (quote full)) (acl-trust (quote beta) (quote full)) (acl-level-covers (quote full) (quote read)) (acl-delegate (quote alpha) (quote bob) (quote read) (quote doc)) (acl-delegate (quote beta) (quote bob) (quote read) (quote doc))))))
+        (acl-hd-check!
+          "two peers both trusted -> permit"
+          (acl-hd-p? db (quote bob) (quote read) (quote doc))
+          true))
+      (let
+        ((empty (acl-build-db (list))))
+        (acl-hd-check!
+          "empty db: nothing permitted"
+          (acl-hd-p? empty (quote u) (quote read) (quote r))
+          false))
+      (do
+        (acl-hd-check!
+          "validate: clean set has no bad facts"
+          (len
+            (acl-validate-facts
+              (list
+                (acl-grant (quote u) (quote read) (quote p))
+                (acl-member-of (quote u) (quote g))
+                (acl-delegate (quote pe) (quote u) (quote read) (quote p)))))
+          0)
+        (acl-hd-check!
+          "validate: facts-valid? true on clean set"
+          (acl-facts-valid?
+            (list (acl-grant (quote u) (quote read) (quote p))))
+          true)
+        (acl-hd-check!
+          "validate: surfaces wrong-arity and unknown predicate"
+          (len
+            (acl-validate-facts
+              (list
+                (acl-grant (quote u) (quote read) (quote p))
+                (list (quote grant) (quote u))
+                (list (quote bogus) (quote x) (quote y)))))
+          2)
+        (acl-hd-check!
+          "validate: empty set is valid"
+          (acl-facts-valid? (list))
+          true))
+      (let
+        ((db (acl-build-db (list (acl-grant (quote u) (quote read) (quote p)) (acl-deny (quote u) (quote edit) (quote p))))))
+        (do
+          (acl-audit-clear!)
+          (acl-audit-decide! db (quote u) (quote read) (quote p))
+          (acl-audit-decide! db (quote u) (quote edit) (quote p))
+          (let
+            ((snap (acl-audit-snapshot)))
+            (do
+              (acl-audit-clear!)
+              (acl-hd-check!
+                "audit: cleared count is 0"
+                (acl-audit-count)
+                0)
+              (acl-audit-restore! snap)
+              (acl-hd-check!
+                "audit: restored count"
+                (acl-audit-count)
+                2)
+              (acl-hd-check!
+                "audit: restored last act"
+                (get (first (acl-audit-tail 1)) :act)
+                (quote edit))
+              (acl-audit-decide! db (quote u) (quote comment) (quote p))
+              (acl-hd-check!
+                "audit: seq continues after restore"
+                (get (first (acl-audit-tail 1)) :seq)
+                2)
+              (acl-hd-check!
+                "audit: snapshot is an immutable copy"
+                (len (get snap :entries))
+                2)
+              (acl-audit-clear!))))))))
+
+(define
+  acl-harden-tests-run!
+  (fn
+    ()
+    (do
+      (set! acl-hd-pass 0)
+      (set! acl-hd-fail 0)
+      (set! acl-hd-failures (list))
+      (acl-hd-run-all!)
+      {:failures acl-hd-failures :total (+ acl-hd-pass acl-hd-fail) :passed acl-hd-pass :failed acl-hd-fail})))

lib/acl/tests/inherit.sx

@@ -0,0 +1,202 @@
+;; lib/acl/tests/inherit.sx — Phase 2: inheritance (groups, resource trees,
+;; role expansion) with deny-overrides.
+
+(define acl-it-pass 0)
+(define acl-it-fail 0)
+(define acl-it-failures (list))
+
+(define
+  acl-it-check!
+  (fn
+    (name got expected)
+    (if
+      (= got expected)
+      (set! acl-it-pass (+ acl-it-pass 1))
+      (do
+        (set! acl-it-fail (+ acl-it-fail 1))
+        (append!
+          acl-it-failures
+          (str name "\n    expected: " expected "\n    got:      " got))))))
+
+(define acl-it-p? (fn (db s a r) (acl-permit? db s a r)))
+
+(define
+  acl-it-run-all!
+  (fn
+    ()
+    (do
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote alice) (quote team)) (acl-grant (quote team) (quote read) (quote doc))))))
+        (do
+          (acl-it-check!
+            "group grant reaches member"
+            (acl-it-p? db (quote alice) (quote read) (quote doc))
+            true)
+          (acl-it-check!
+            "group grant: non-member excluded"
+            (acl-it-p? db (quote bob) (quote read) (quote doc))
+            false)
+          (acl-it-check!
+            "group grant: wrong action"
+            (acl-it-p? db (quote alice) (quote edit) (quote doc))
+            false)))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote alice) (quote team)) (acl-member-of (quote team) (quote org)) (acl-member-of (quote org) (quote company)) (acl-grant (quote company) (quote read) (quote doc))))))
+        (do
+          (acl-it-check!
+            "deep nested group grant reaches leaf member"
+            (acl-it-p? db (quote alice) (quote read) (quote doc))
+            true)
+          (acl-it-check!
+            "intermediate group also covered"
+            (acl-it-p? db (quote team) (quote read) (quote doc))
+            true)
+          (acl-it-check!
+            "mid group org covered"
+            (acl-it-p? db (quote org) (quote read) (quote doc))
+            true)))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote a) (quote b)) (acl-member-of (quote b) (quote a)) (acl-grant (quote b) (quote read) (quote r))))))
+        (do
+          (acl-it-check!
+            "cyclic membership terminates and grants"
+            (acl-it-p? db (quote a) (quote read) (quote r))
+            true)
+          (acl-it-check!
+            "cyclic membership covers both"
+            (acl-it-p? db (quote b) (quote read) (quote r))
+            true)))
+      (let
+        ((db (acl-build-db (list (acl-child-of (quote sec) (quote chap)) (acl-child-of (quote chap) (quote book)) (acl-grant (quote u) (quote read) (quote book))))))
+        (do
+          (acl-it-check!
+            "parent grant reaches direct child"
+            (acl-it-p? db (quote u) (quote read) (quote chap))
+            true)
+          (acl-it-check!
+            "parent grant reaches deep descendant"
+            (acl-it-p? db (quote u) (quote read) (quote sec))
+            true)
+          (acl-it-check!
+            "parent grant covers parent itself"
+            (acl-it-p? db (quote u) (quote read) (quote book))
+            true)
+          (acl-it-check!
+            "child grant does not climb to parent"
+            (acl-it-p?
+              (acl-build-db
+                (list
+                  (acl-child-of (quote sec) (quote book))
+                  (acl-grant (quote u) (quote read) (quote sec))))
+              (quote u)
+              (quote read)
+              (quote book))
+            false)))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote alice) (quote team)) (acl-child-of (quote post1) (quote board)) (acl-grant (quote team) (quote comment) (quote board))))))
+        (do
+          (acl-it-check!
+            "group + resource: member on child resource"
+            (acl-it-p? db (quote alice) (quote comment) (quote post1))
+            true)
+          (acl-it-check!
+            "group + resource: member on parent resource"
+            (acl-it-p? db (quote alice) (quote comment) (quote board))
+            true)))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote bob) (quote editor)) (acl-role-grant (quote editor) (quote edit) (quote page1)) (acl-role-grant (quote editor) (quote read) (quote page1))))))
+        (do
+          (acl-it-check!
+            "role confers edit to member"
+            (acl-it-p? db (quote bob) (quote edit) (quote page1))
+            true)
+          (acl-it-check!
+            "role confers read to member"
+            (acl-it-p? db (quote bob) (quote read) (quote page1))
+            true)
+          (acl-it-check!
+            "role: capability not in tuple denied"
+            (acl-it-p? db (quote bob) (quote moderate) (quote page1))
+            false)
+          (acl-it-check!
+            "role: non-member excluded"
+            (acl-it-p? db (quote eve) (quote edit) (quote page1))
+            false)))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote bob) (quote editor)) (acl-child-of (quote draft) (quote page1)) (acl-role-grant (quote editor) (quote edit) (quote page1))))))
+        (acl-it-check!
+          "role grant flows to child resource"
+          (acl-it-p? db (quote bob) (quote edit) (quote draft))
+          true))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote alice) (quote team)) (acl-grant (quote team) (quote read) (quote doc)) (acl-deny (quote alice) (quote read) (quote doc))))))
+        (acl-it-check!
+          "explicit deny beats inherited group allow"
+          (acl-it-p? db (quote alice) (quote read) (quote doc))
+          false))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote alice) (quote team)) (acl-grant (quote alice) (quote read) (quote doc)) (acl-deny (quote team) (quote read) (quote doc))))))
+        (do
+          (acl-it-check!
+            "group deny inherits and overrides direct grant"
+            (acl-it-p? db (quote alice) (quote read) (quote doc))
+            false)
+          (acl-it-check!
+            "group deny: another member also blocked"
+            (acl-it-p? db (quote team) (quote read) (quote doc))
+            false)))
+      (let
+        ((db (acl-build-db (list (acl-child-of (quote sec) (quote book)) (acl-grant (quote u) (quote read) (quote sec)) (acl-deny (quote u) (quote read) (quote book))))))
+        (acl-it-check!
+          "ancestor deny overrides descendant grant"
+          (acl-it-p? db (quote u) (quote read) (quote sec))
+          false))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote alice) (quote team)) (acl-grant (quote team) (quote read) (quote doc)) (acl-grant (quote team) (quote edit) (quote doc)) (acl-deny (quote alice) (quote edit) (quote doc))))))
+        (do
+          (acl-it-check!
+            "deny on edit leaves inherited read intact"
+            (acl-it-p? db (quote alice) (quote read) (quote doc))
+            true)
+          (acl-it-check!
+            "deny on edit blocks edit"
+            (acl-it-p? db (quote alice) (quote edit) (quote doc))
+            false)))
+      (let
+        ((db (acl-build-db (list (acl-member-of (quote alice) (quote team)) (acl-deny (quote team) (quote read) (quote doc))))))
+        (acl-it-check!
+          "inherited deny, no grant: denied"
+          (acl-it-p? db (quote alice) (quote read) (quote doc))
+          false))
+      (let
+        ((db (acl-build-db (list (acl-child-of (quote a) (quote root)) (acl-child-of (quote b) (quote root)) (acl-grant (quote u) (quote read) (quote root)) (acl-deny (quote u) (quote read) (quote a))))))
+        (do
+          (acl-it-check!
+            "deny on sibling a blocks a"
+            (acl-it-p? db (quote u) (quote read) (quote a))
+            false)
+          (acl-it-check!
+            "deny on sibling a leaves b permitted"
+            (acl-it-p? db (quote u) (quote read) (quote b))
+            true)
+          (acl-it-check!
+            "root itself still permitted"
+            (acl-it-p? db (quote u) (quote read) (quote root))
+            true)))
+      (let
+        ((db (acl-build-db (list (acl-grant (quote x) (quote read) (quote y))))))
+        (acl-it-check!
+          "direct grant under inheritance ruleset"
+          (acl-it-p? db (quote x) (quote read) (quote y))
+          true)))))
+
+(define
+  acl-inherit-tests-run!
+  (fn
+    ()
+    (do
+      (set! acl-it-pass 0)
+      (set! acl-it-fail 0)
+      (set! acl-it-failures (list))
+      (acl-it-run-all!)
+      {:failures acl-it-failures :total (+ acl-it-pass acl-it-fail) :passed acl-it-pass :failed acl-it-fail})))

lib/apl/conformance.conf

@@ -0,0 +1,63 @@
+# APL conformance config — sourced by lib/guest/conformance.sh.
+
+LANG_NAME=apl
+MODE=counters
+COUNTERS_PASS=apl-test-pass
+COUNTERS_FAIL=apl-test-fail
+TIMEOUT_PER_SUITE=300
+
+PRELOADS=(
+  spec/stdlib.sx
+  lib/r7rs.sx
+  lib/apl/runtime.sx
+  lib/apl/tokenizer.sx
+  lib/apl/parser.sx
+  lib/apl/transpile.sx
+  lib/apl/test-harness.sx
+)
+
+SUITES=(
+  "structural:lib/apl/tests/structural.sx"
+  "operators:lib/apl/tests/operators.sx"
+  "dfn:lib/apl/tests/dfn.sx"
+  "tradfn:lib/apl/tests/tradfn.sx"
+  "valence:lib/apl/tests/valence.sx"
+  "programs:lib/apl/tests/programs.sx"
+  "system:lib/apl/tests/system.sx"
+  "idioms:lib/apl/tests/idioms.sx"
+  "eval-ops:lib/apl/tests/eval-ops.sx"
+  "pipeline:lib/apl/tests/pipeline.sx"
+)
+
+emit_scoreboard_json() {
+  local n=${#GC_NAMES[@]} i sep
+  printf '{\n'
+  printf '  "suites": {\n'
+  for ((i=0; i<n; i++)); do
+    sep=","; [ $i -eq $((n-1)) ] && sep=""
+    printf '    "%s": {"pass": %d, "fail": %d}%s\n' \
+      "${GC_NAMES[$i]}" "${GC_PASS[$i]}" "${GC_FAIL[$i]}" "$sep"
+  done
+  printf '  },\n'
+  printf '  "total_pass": %d,\n' "$GC_TOTAL_PASS"
+  printf '  "total_fail": %d,\n' "$GC_TOTAL_FAIL"
+  printf '  "total": %d\n' "$GC_TOTAL"
+  printf '}\n'
+}
+
+emit_scoreboard_md() {
+  local n=${#GC_NAMES[@]} i
+  printf '# APL Conformance Scoreboard\n\n'
+  printf '_Generated by `lib/apl/conformance.sh`_\n\n'
+  printf '| Suite | Pass | Fail | Total |\n'
+  printf '|-------|-----:|-----:|------:|\n'
+  for ((i=0; i<n; i++)); do
+    printf '| %s | %d | %d | %d |\n' \
+      "${GC_NAMES[$i]}" "${GC_PASS[$i]}" "${GC_FAIL[$i]}" "${GC_TOTAL_S[$i]}"
+  done
+  printf '| **Total** | **%d** | **%d** | **%d** |\n' "$GC_TOTAL_PASS" "$GC_TOTAL_FAIL" "$GC_TOTAL"
+  printf '\n'
+  printf '## Notes\n\n'
+  printf '%s\n' '- Suites use the standard `apl-test name got expected` framework loaded against `lib/apl/runtime.sx` + `lib/apl/transpile.sx`.'
+  printf '%s\n' '- `lib/apl/tests/parse.sx` and `lib/apl/tests/scalar.sx` use their own self-contained frameworks and are excluded from this scoreboard.'
+}

lib/apl/conformance.sh

@@ -1,116 +1,5 @@
 #!/usr/bin/env bash
-# lib/apl/conformance.sh — run APL test suites, emit scoreboard.json + scoreboard.md.
-
-set -uo pipefail
-cd "$(git rev-parse --show-toplevel)"
-
-SX_SERVER="${SX_SERVER:-/root/rose-ash/hosts/ocaml/_build/default/bin/sx_server.exe}"
-if [ ! -x "$SX_SERVER" ]; then
-  SX_SERVER="hosts/ocaml/_build/default/bin/sx_server.exe"
-fi
-if [ ! -x "$SX_SERVER" ]; then
-  echo "ERROR: sx_server.exe not found." >&2
-  exit 1
-fi
-
-SUITES=(structural operators dfn tradfn valence programs system idioms eval-ops pipeline)
-
-OUT_JSON="lib/apl/scoreboard.json"
-OUT_MD="lib/apl/scoreboard.md"
-
-run_suite() {
-  local suite=$1
-  local file="lib/apl/tests/${suite}.sx"
-  local TMP
-  TMP=$(mktemp)
-  cat > "$TMP" << EPOCHS
-(epoch 1)
-(load "spec/stdlib.sx")
-(load "lib/r7rs.sx")
-(load "lib/apl/runtime.sx")
-(load "lib/apl/tokenizer.sx")
-(load "lib/apl/parser.sx")
-(load "lib/apl/transpile.sx")
-(epoch 2)
-(eval "(define apl-test-pass 0)")
-(eval "(define apl-test-fail 0)")
-(eval "(define apl-test (fn (name got expected) (if (= got expected) (set! apl-test-pass (+ apl-test-pass 1)) (set! apl-test-fail (+ apl-test-fail 1)))))")
-(epoch 3)
-(load "${file}")
-(epoch 4)
-(eval "(list apl-test-pass apl-test-fail)")
-EPOCHS
-
-  local OUTPUT
-  OUTPUT=$(timeout 300 "$SX_SERVER" < "$TMP" 2>/dev/null)
-  rm -f "$TMP"
-
-  local LINE
-  LINE=$(echo "$OUTPUT" | awk '/^\(ok-len 4 / {getline; print; exit}')
-  if [ -z "$LINE" ]; then
-    LINE=$(echo "$OUTPUT" | grep -E '^\(ok 4 \([0-9]+ [0-9]+\)\)' | tail -1 \
-            | sed -E 's/^\(ok 4 //; s/\)$//')
-  fi
-
-  local P F
-  P=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\).*/\1/')
-  F=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\).*/\2/')
-  P=${P:-0}
-  F=${F:-0}
-  echo "${P} ${F}"
-}
-
-declare -A SUITE_PASS
-declare -A SUITE_FAIL
-TOTAL_PASS=0
-TOTAL_FAIL=0
-
-echo "Running APL conformance suite..." >&2
-for s in "${SUITES[@]}"; do
-  read -r p f < <(run_suite "$s")
-  SUITE_PASS[$s]=$p
-  SUITE_FAIL[$s]=$f
-  TOTAL_PASS=$((TOTAL_PASS + p))
-  TOTAL_FAIL=$((TOTAL_FAIL + f))
-  printf "  %-12s %d/%d\n" "$s" "$p" "$((p+f))" >&2
-done
-
-# scoreboard.json
-{
-  printf '{\n'
-  printf '  "suites": {\n'
-  first=1
-  for s in "${SUITES[@]}"; do
-    if [ $first -eq 0 ]; then printf ',\n'; fi
-    printf '    "%s": {"pass": %d, "fail": %d}' "$s" "${SUITE_PASS[$s]}" "${SUITE_FAIL[$s]}"
-    first=0
-  done
-  printf '\n  },\n'
-  printf '  "total_pass": %d,\n' "$TOTAL_PASS"
-  printf '  "total_fail": %d,\n' "$TOTAL_FAIL"
-  printf '  "total": %d\n' "$((TOTAL_PASS + TOTAL_FAIL))"
-  printf '}\n'
-} > "$OUT_JSON"
-
-# scoreboard.md
-{
-  printf '# APL Conformance Scoreboard\n\n'
-  printf '_Generated by `lib/apl/conformance.sh`_\n\n'
-  printf '| Suite | Pass | Fail | Total |\n'
-  printf '|-------|-----:|-----:|------:|\n'
-  for s in "${SUITES[@]}"; do
-    p=${SUITE_PASS[$s]}
-    f=${SUITE_FAIL[$s]}
-    printf '| %s | %d | %d | %d |\n' "$s" "$p" "$f" "$((p+f))"
-  done
-  printf '| **Total** | **%d** | **%d** | **%d** |\n' "$TOTAL_PASS" "$TOTAL_FAIL" "$((TOTAL_PASS + TOTAL_FAIL))"
-  printf '\n'
-  printf '## Notes\n\n'
-  printf '%s\n' '- Suites use the standard `apl-test name got expected` framework loaded against `lib/apl/runtime.sx` + `lib/apl/transpile.sx`.'
-  printf '%s\n' '- `lib/apl/tests/parse.sx` and `lib/apl/tests/scalar.sx` use their own self-contained frameworks and are excluded from this scoreboard.'
-} > "$OUT_MD"
-
-echo "Wrote $OUT_JSON and $OUT_MD" >&2
-echo "Total: $TOTAL_PASS pass, $TOTAL_FAIL fail" >&2
-
-[ "$TOTAL_FAIL" -eq 0 ]
+# lib/apl/conformance.sh — APL conformance via the shared guest driver.
+# Config lives in lib/apl/conformance.conf (MODE=counters). Override the binary
+# with SX_SERVER=path/to/sx_server.exe bash lib/apl/conformance.sh
+exec bash "$(dirname "$0")/../guest/conformance.sh" "$(dirname "$0")/conformance.conf" "$@"

lib/apl/scoreboard.json

@@ -9,9 +9,9 @@
     "system": {"pass": 13, "fail": 0},
     "idioms": {"pass": 64, "fail": 0},
     "eval-ops": {"pass": 14, "fail": 0},
-    "pipeline": {"pass": 40, "fail": 0}
+    "pipeline": {"pass": 152, "fail": 0}
   },
-  "total_pass": 450,
+  "total_pass": 562,
   "total_fail": 0,
-  "total": 450
+  "total": 562
 }

lib/apl/scoreboard.md

@@ -13,8 +13,8 @@ _Generated by `lib/apl/conformance.sh`_
 | system | 13 | 0 | 13 |
 | idioms | 64 | 0 | 64 |
 | eval-ops | 14 | 0 | 14 |
-| pipeline | 40 | 0 | 40 |
-| **Total** | **450** | **0** | **450** |
+| pipeline | 152 | 0 | 152 |
+| **Total** | **562** | **0** | **562** |
 
 ## Notes
 

lib/apl/test-harness.sx

@@ -0,0 +1,15 @@
+; lib/apl/test-harness.sx — counters + assertion fn for the shared conformance
+; driver (lib/guest/conformance.sh, MODE=counters). Loaded as a PRELOAD so each
+; suite starts from a fresh 0/0; suites call (apl-test name got expected).
+
+(define apl-test-pass 0)
+(define apl-test-fail 0)
+
+(define
+  apl-test
+  (fn
+    (name got expected)
+    (if
+      (= got expected)
+      (set! apl-test-pass (+ apl-test-pass 1))
+      (set! apl-test-fail (+ apl-test-fail 1)))))

lib/feed/acl.sx

@@ -0,0 +1,38 @@
+; feed/acl — per-viewer visibility filtering. The same candidate stream yields
+; different timelines for different viewers, so ACL is applied per request and
+; pre-ACL timelines are never cached.
+;
+; permit? is injected: (permit? viewer activity) -> bool. Wire a real acl-sx
+; predicate here; feed/permit-acl? is a self-contained default that reads an
+; optional :visible-to allowlist on the activity.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/-elem?), lib/feed/rank.sx (feed/top).
+
+; default permit: actor always sees own activity; absent/nil :visible-to is
+; public; otherwise viewer must be in the allowlist.
+(define
+  feed/permit-acl?
+  (fn
+    (viewer a)
+    (or
+      (equal? viewer (get a :actor))
+      (let
+        ((allowed (get a :visible-to nil)))
+        (if (= allowed nil) true (feed/-elem? viewer allowed))))))
+
+(define feed/permit-public? (fn (viewer a) true))
+
+; filter a stream to what viewer may read
+(define
+  feed/visible
+  (fn
+    (stream viewer permit?)
+    (feed/filter stream (fn (a) (permit? viewer a)))))
+
+; the capstone: candidate stream -> ACL for viewer -> rank -> top-N
+(define
+  feed/timeline
+  (fn
+    (stream viewer permit? score-fn n)
+    (feed/top (feed/visible stream viewer permit?) score-fn n)))

lib/feed/aggregate.sx

@@ -0,0 +1,62 @@
+; feed/aggregate — group-by / counting via key-reduce. Keys must be strings
+; (dict keys), so composite keys (actor, day) are joined into one string.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx.
+
+; group activities into a dict: key-string -> (list of activities), order-preserving
+(define
+  feed/group-by
+  (fn
+    (stream key-fn)
+    (reduce
+      (fn
+        (g a)
+        (let
+          ((k (key-fn a)))
+          (assoc g k (append (get g k (list)) (list a)))))
+      {}
+      (feed/items stream))))
+
+; key-string -> count
+(define
+  feed/group-count
+  (fn
+    (stream key-fn)
+    (reduce
+      (fn
+        (g a)
+        (let
+          ((k (key-fn a)))
+          (assoc g k (+ (get g k 0) 1))))
+      {}
+      (feed/items stream))))
+
+; --- composite keys ---------------------------------------------------------
+
+(define feed/day (fn (at window) (floor (/ at window))))
+
+; (actor, day-bucket) -> "actor#day"
+(define
+  feed/actor-day-key
+  (fn
+    (window)
+    (fn
+      (a)
+      (string-append
+        (get a :actor)
+        "#"
+        (number->string (feed/day (get a :at) window))))))
+
+(define
+  feed/by-actor-day
+  (fn (stream window) (feed/group-count stream (feed/actor-day-key window))))
+
+; per-actor activity counts
+(define
+  feed/actor-counts
+  (fn (stream) (feed/group-count stream feed/actor)))
+
+; per-object activity counts (engagement)
+(define
+  feed/object-counts
+  (fn (stream) (feed/group-count stream feed/object)))

lib/feed/api.sx

@@ -0,0 +1,24 @@
+; feed/api — ergonomic API over the stream layer for non-APL callers.
+; A single mutable activity log; post appends, all returns it as a stream.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx (loaded by harness).
+
+(define feed/-log (list))
+
+; post — normalize then append. Returns the stored activity.
+(define
+  feed/post
+  (fn
+    (raw)
+    (let
+      ((a (feed/normalize raw)))
+      (begin (set! feed/-log (append feed/-log (list a))) a))))
+
+; all — the whole log as a stream (insertion order)
+(define feed/all (fn () (feed/stream feed/-log)))
+
+; reset! — clear the log (test hygiene)
+(define feed/reset! (fn () (begin (set! feed/-log (list)) nil)))
+
+; size — number of posted activities
+(define feed/size (fn () (len feed/-log)))

lib/feed/conformance.sh

@@ -0,0 +1,125 @@
+#!/usr/bin/env bash
+# lib/feed/conformance.sh — run feed test suites, emit scoreboard.json + scoreboard.md.
+
+set -uo pipefail
+cd "$(git rev-parse --show-toplevel)"
+
+SX_SERVER="${SX_SERVER:-/root/rose-ash/hosts/ocaml/_build/default/bin/sx_server.exe}"
+if [ ! -x "$SX_SERVER" ]; then
+  SX_SERVER="hosts/ocaml/_build/default/bin/sx_server.exe"
+fi
+if [ ! -x "$SX_SERVER" ]; then
+  echo "ERROR: sx_server.exe not found." >&2
+  exit 1
+fi
+
+SUITES=(basic fanout rank integration content notify home dedupe trending mute page thread)
+
+OUT_JSON="lib/feed/scoreboard.json"
+OUT_MD="lib/feed/scoreboard.md"
+
+run_suite() {
+  local suite=$1
+  local file="lib/feed/tests/${suite}.sx"
+  local TMP
+  TMP=$(mktemp)
+  cat > "$TMP" << EPOCHS
+(epoch 1)
+(load "spec/stdlib.sx")
+(load "lib/r7rs.sx")
+(load "lib/apl/runtime.sx")
+(load "lib/feed/normalize.sx")
+(load "lib/feed/stream.sx")
+(load "lib/feed/api.sx")
+(load "lib/feed/fanout.sx")
+(load "lib/feed/dedupe.sx")
+(load "lib/feed/aggregate.sx")
+(load "lib/feed/rank.sx")
+(load "lib/feed/acl.sx")
+(load "lib/feed/fed.sx")
+(load "lib/feed/content.sx")
+(load "lib/feed/notify.sx")
+(load "lib/feed/home.sx")
+(load "lib/feed/trending.sx")
+(load "lib/feed/mute.sx")
+(load "lib/feed/page.sx")
+(load "lib/feed/thread.sx")
+(epoch 2)
+(eval "(define feed-test-pass 0)")
+(eval "(define feed-test-fail 0)")
+(eval "(define feed-test (fn (name got expected) (if (= got expected) (set! feed-test-pass (+ feed-test-pass 1)) (set! feed-test-fail (+ feed-test-fail 1)))))")
+(epoch 3)
+(load "${file}")
+(epoch 4)
+(eval "(list feed-test-pass feed-test-fail)")
+EPOCHS
+
+  local OUTPUT
+  OUTPUT=$(timeout 300 "$SX_SERVER" < "$TMP" 2>/dev/null)
+  rm -f "$TMP"
+
+  local LINE
+  LINE=$(echo "$OUTPUT" | awk '/^\(ok-len 4 / {getline; print; exit}')
+  if [ -z "$LINE" ]; then
+    LINE=$(echo "$OUTPUT" | grep -E '^\(ok 4 \([0-9]+ [0-9]+\)\)' | tail -1 \
+            | sed -E 's/^\(ok 4 //; s/\)$//')
+  fi
+
+  local P F
+  P=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\).*/\1/')
+  F=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\).*/\2/')
+  P=${P:-0}
+  F=${F:-0}
+  echo "${P} ${F}"
+}
+
+declare -A SUITE_PASS
+declare -A SUITE_FAIL
+TOTAL_PASS=0
+TOTAL_FAIL=0
+
+echo "Running feed conformance suite..." >&2
+for s in "${SUITES[@]}"; do
+  read -r p f < <(run_suite "$s")
+  SUITE_PASS[$s]=$p
+  SUITE_FAIL[$s]=$f
+  TOTAL_PASS=$((TOTAL_PASS + p))
+  TOTAL_FAIL=$((TOTAL_FAIL + f))
+  printf "  %-12s %d/%d\n" "$s" "$p" "$((p+f))" >&2
+done
+
+# scoreboard.json
+{
+  printf '{\n'
+  printf '  "suites": {\n'
+  first=1
+  for s in "${SUITES[@]}"; do
+    if [ $first -eq 0 ]; then printf ',\n'; fi
+    printf '    "%s": {"pass": %d, "fail": %d}' "$s" "${SUITE_PASS[$s]}" "${SUITE_FAIL[$s]}"
+    first=0
+  done
+  printf '\n  },\n'
+  printf '  "total_pass": %d,\n' "$TOTAL_PASS"
+  printf '  "total_fail": %d,\n' "$TOTAL_FAIL"
+  printf '  "total": %d\n' "$((TOTAL_PASS + TOTAL_FAIL))"
+  printf '}\n'
+} > "$OUT_JSON"
+
+# scoreboard.md
+{
+  printf '# feed Conformance Scoreboard\n\n'
+  printf '_Generated by `lib/feed/conformance.sh`_\n\n'
+  printf '| Suite | Pass | Fail | Total |\n'
+  printf '|-------|-----:|-----:|------:|\n'
+  for s in "${SUITES[@]}"; do
+    p=${SUITE_PASS[$s]}
+    f=${SUITE_FAIL[$s]}
+    printf '| %s | %d | %d | %d |\n' "$s" "$p" "$f" "$((p+f))"
+  done
+  printf '| **Total** | **%d** | **%d** | **%d** |\n' "$TOTAL_PASS" "$TOTAL_FAIL" "$((TOTAL_PASS + TOTAL_FAIL))"
+} > "$OUT_MD"
+
+echo "Wrote $OUT_JSON and $OUT_MD" >&2
+echo "Total: $TOTAL_PASS pass, $TOTAL_FAIL fail" >&2
+
+[ "$TOTAL_FAIL" -eq 0 ]

lib/feed/content.sx

@@ -0,0 +1,68 @@
+; feed/content — TF-IDF relevance over activity :tags. Rare tags carry more
+; signal, so an activity matching an uncommon tag ranks above one matching a
+; common tag. Composes with rank.sx: feed/tfidf-score is just another scorer.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/-distinct), lib/feed/rank.sx (feed/rank).
+
+; document frequency: tag -> number of activities whose :tags contain it
+; (a tag repeated within one activity counts once toward df)
+(define
+  feed/tag-df
+  (fn
+    (stream)
+    (reduce
+      (fn
+        (df a)
+        (reduce
+          (fn (d t) (assoc d t (+ (get d t 0) 1)))
+          df
+          (feed/-distinct (get a :tags))))
+      {}
+      (feed/items stream))))
+
+; inverse document frequency: tag -> log(N / df)
+(define
+  feed/tag-idf
+  (fn
+    (stream)
+    (let
+      ((n (feed/count stream)) (df (feed/tag-df stream)))
+      (reduce
+        (fn (idf t) (assoc idf t (log (/ n (get df t)))))
+        {}
+        (keys df)))))
+
+; term frequency within one activity: tag -> occurrence count
+(define
+  feed/-tf
+  (fn
+    (a)
+    (reduce
+      (fn (tf t) (assoc tf t (+ (get tf t 0) 1)))
+      {}
+      (get a :tags))))
+
+; relevance of an activity to a query (list of tags) given precomputed idf:
+; sum over query tags of tf(tag in activity) * idf(tag in corpus)
+(define
+  feed/tfidf-score
+  (fn
+    (idf query)
+    (fn
+      (a)
+      (let
+        ((tf (feed/-tf a)))
+        (reduce
+          (fn
+            (acc t)
+            (+ acc (* (get tf t 0) (get idf t 0))))
+          0
+          query)))))
+
+; rank a stream by relevance to query tags (idf computed over the stream itself)
+(define
+  feed/by-relevance
+  (fn
+    (stream query)
+    (feed/rank stream (feed/tfidf-score (feed/tag-idf stream) query))))

lib/feed/dedupe.sx

@@ -0,0 +1,76 @@
+; feed/dedupe — collapse duplicate items, keeping first occurrence per key.
+; Each verb may want its own key (see briefing): "alice posted X" keys on
+; (actor verb object) — distinct per actor; "alice liked X / bob liked X"
+; collapse on (verb object) so the cross-actor likes fold into one.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/-elem? lives in fanout.sx).
+
+; generic: dedupe a stream by key-fn, first occurrence wins (stable)
+(define
+  feed/-dedup-by
+  (fn
+    (items key-fn)
+    (get
+      (reduce
+        (fn
+          (st x)
+          (let
+            ((k (key-fn x)))
+            (if (feed/-elem? k (get st :seen)) st {:seen (append (get st :seen) (list k)) :out (append (get st :out) (list x))})))
+        {:seen (list) :out (list)}
+        items)
+      :out)))
+
+(define
+  feed/dedupe
+  (fn
+    (stream key-fn)
+    (feed/stream (feed/-dedup-by (feed/items stream) key-fn))))
+
+; --- keys -------------------------------------------------------------------
+
+(define
+  feed/activity-key
+  (fn (a) (list (get a :actor) (get a :verb) (get a :object))))
+
+; collapse cross-actor duplicates of the same verb+object (e.g. likes)
+(define feed/collapse-key (fn (a) (list (get a :verb) (get a :object))))
+
+; per-receiver inbox key — one inbox event per (receiver, actor, verb, object)
+(define
+  feed/event-key
+  (fn
+    (ev)
+    (let
+      ((a (get ev :activity)))
+      (list (get ev :to) (get a :actor) (get a :verb) (get a :object)))))
+
+; verbs whose duplicates collapse across actors (reactions, not authorship).
+; rebindable: callers can (set! feed/collapse-verbs ...) to tune the policy.
+(define
+  feed/collapse-verbs
+  (list "like" "favourite" "follow" "boost" "repost"))
+
+; per-verb key: collapse-verbs fold on (verb object); the rest key on
+; (actor verb object).
+(define
+  feed/smart-key
+  (fn
+    (a)
+    (if
+      (feed/-elem? (get a :verb) feed/collapse-verbs)
+      (feed/collapse-key a)
+      (feed/activity-key a))))
+
+; --- ready-made dedupers ----------------------------------------------------
+
+(define feed/dedupe-activities (fn (s) (feed/dedupe s feed/activity-key)))
+
+(define feed/dedupe-collapse (fn (s) (feed/dedupe s feed/collapse-key)))
+
+; verb-aware: reactions collapse cross-actor, posts stay distinct per actor
+(define feed/dedupe-smart (fn (s) (feed/dedupe s feed/smart-key)))
+
+; dedupe an inbox: at most one event per receiver per (actor verb object)
+(define feed/dedupe-inbox (fn (inbox) (feed/dedupe inbox feed/event-key)))

lib/feed/fanout.sx

@@ -0,0 +1,114 @@
+; feed/fanout — THE SHOWCASE. Fan activities out to followers via the APL outer
+; product (∘.×). activities ∘.× audience → an (activity × follower) matrix of
+; inbox events; flatten to a vector; guard-keep only real follow edges.
+;
+; Requires: lib/apl/runtime.sx, lib/feed/normalize.sx, lib/feed/stream.sx.
+;
+; NOTE: apl-outer's combiner result is run through (if (scalar? r) (disclose r) r).
+; A bare dict counts as a scalar (shape ()) and disclose nils it — so the combiner
+; must (enclose ...) its event dict; apl-outer then discloses it back intact.
+
+; --- graph: {followee -> (list of followers)} -------------------------------
+
+(define feed/followers (fn (graph user) (get graph user (list))))
+
+; build a graph from (follower followee) edges: "follower follows followee"
+(define
+  feed/follow-graph
+  (fn
+    (edges)
+    (reduce
+      (fn
+        (g e)
+        (let
+          ((follower (first e)) (followee (nth e 1)))
+          (assoc
+            g
+            followee
+            (append (feed/followers g followee) (list follower)))))
+      {}
+      edges)))
+
+; --- helpers ----------------------------------------------------------------
+
+; unwrap an apl-scalar (has :ravel) back to its value; pass activities through
+(define
+  feed/-val
+  (fn
+    (x)
+    (if (and (= (type-of x) "dict") (has-key? x :ravel)) (disclose x) x)))
+
+(define feed/-elem? (fn (x lst) (some (fn (y) (equal? x y)) lst)))
+
+(define
+  feed/-distinct
+  (fn
+    (lst)
+    (if
+      (= (len lst) 0)
+      (list)
+      (get (apl-unique (make-array (list (len lst)) lst)) :ravel))))
+
+; rank-2 matrix -> rank-1 stream of its ravel
+(define feed/-flatten (fn (arr) (feed/stream (get arr :ravel))))
+
+; distinct receivers across the whole graph, sorted for determinism
+; (dict key order is unspecified, so sort to pin audience/recipient ordering)
+(define
+  feed/audience
+  (fn
+    (graph)
+    (sort
+      (feed/-distinct
+        (reduce
+          (fn (acc k) (append acc (feed/followers graph k)))
+          (list)
+          (keys graph))))))
+
+; --- the outer product ------------------------------------------------------
+
+; one (activity, follower) inbox event, enclosed so apl-outer keeps the dict
+(define feed/-mk-event (fn (a f) (enclose {:activity (feed/-val a) :to (feed/-val f)})))
+
+; keep events where :to actually follows the activity's actor
+(define
+  feed/-edge?
+  (fn
+    (graph)
+    (fn
+      (ev)
+      (feed/-elem?
+        (get ev :to)
+        (feed/followers graph (get (get ev :activity) :actor))))))
+
+; fanout — activities ∘.× audience, flatten, guard-keep real edges
+(define
+  feed/fanout
+  (fn
+    (stream graph)
+    (let
+      ((matrix (apl-outer feed/-mk-event stream (feed/stream (feed/audience graph)))))
+      (feed/filter (feed/-flatten matrix) (feed/-edge? graph)))))
+
+; --- inbox queries ----------------------------------------------------------
+
+(define
+  feed/inbox-for
+  (fn
+    (inbox user)
+    (feed/filter inbox (fn (ev) (equal? (get ev :to) user)))))
+
+(define
+  feed/recipients
+  (fn
+    (inbox)
+    (feed/-distinct (map (fn (ev) (get ev :to)) (feed/items inbox)))))
+
+; the activities (unwrapped) destined for a user
+(define
+  feed/inbox-activities
+  (fn
+    (inbox user)
+    (map
+      (fn (ev) (get ev :activity))
+      (feed/items (feed/inbox-for inbox user)))))

lib/feed/fed.sx

@@ -0,0 +1,60 @@
+; feed/fed — federation. Outbound: a local post fans out, then splits into local
+; vs remote inboxes; remote events are handed to an injected send-fn. Inbound:
+; peer activities merge into the local stream, deduped. Backfill: pull peer
+; history via an injected fetch-fn and merge.
+;
+; remote? / send-fn / fetch-fn are injected so real fed-sx transport wires in here
+; without feed depending on it.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx,
+; lib/feed/dedupe.sx.
+
+; --- merge / ingest ---------------------------------------------------------
+
+(define
+  feed/merge
+  (fn (s1 s2) (feed/stream (append (feed/items s1) (feed/items s2)))))
+
+; merge a peer stream into local, dropping (actor verb object) duplicates
+(define
+  feed/ingest
+  (fn (local peer) (feed/dedupe-activities (feed/merge local peer))))
+
+; --- inbound ----------------------------------------------------------------
+
+; peer pushes raw activities to the local inbox; normalize + ingest
+(define
+  feed/inbound
+  (fn
+    (local raw-activities)
+    (feed/ingest local (feed/stream (map feed/normalize raw-activities)))))
+
+; backfill on subscribe: pull peer history via fetch-fn, normalize, ingest
+(define
+  feed/backfill
+  (fn (local fetch-fn peer-id) (feed/inbound local (fetch-fn peer-id))))
+
+; --- outbound ---------------------------------------------------------------
+
+; split an inbox into local vs remote deliveries by viewer-id predicate
+(define feed/partition-inbox (fn (inbox remote?) {:local (feed/filter inbox (fn (ev) (not (remote? (get ev :to))))) :remote (feed/filter inbox (fn (ev) (remote? (get ev :to))))}))
+
+; fan a stream out over the graph, then partition by locality
+(define
+  feed/federate
+  (fn
+    (stream graph remote?)
+    (feed/partition-inbox (feed/fanout stream graph) remote?)))
+
+; deliver: hand each remote event to send-fn, return the local inbox to enqueue
+(define
+  feed/deliver
+  (fn
+    (stream graph remote? send-fn)
+    (let
+      ((parts (feed/federate stream graph remote?)))
+      (begin
+        (for-each
+          (fn (ev) (send-fn (get ev :to) (get ev :activity)))
+          (feed/items (get parts :remote)))
+        (get parts :local)))))

lib/feed/home.sx

@@ -0,0 +1,23 @@
+; feed/home — the capstone. A user's home timeline is the whole pipeline as one
+; line: fan all activities out over the follow graph, take the events landing in
+; the viewer's inbox, dedupe cross-posts, apply the viewer's ACL, rank, take N.
+;
+; Requires: fanout.sx, dedupe.sx, acl.sx (feed/timeline), rank.sx, stream.sx.
+
+; the activities in a user's inbox, as a stream
+(define
+  feed/inbox-stream
+  (fn (inbox user) (feed/stream (feed/inbox-activities inbox user))))
+
+; fanout ∘ inbox ∘ dedupe ∘ ACL ∘ rank ∘ take
+(define
+  feed/home
+  (fn
+    (stream graph viewer permit? score-fn n)
+    (feed/timeline
+      (feed/dedupe-activities
+        (feed/inbox-stream (feed/fanout stream graph) viewer))
+      viewer
+      permit?
+      score-fn
+      n)))

lib/feed/mute.sx

@@ -0,0 +1,44 @@
+; feed/mute — viewer-controlled filtering. ACL (acl.sx) is author-controlled
+; visibility; mute is the reader's own preference: hide muted actors or tags.
+; Like ACL it is per-viewer and applied per request, never cached.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/-elem?).
+
+; drop activities authored by a muted actor
+(define
+  feed/mute-actors
+  (fn
+    (stream actors)
+    (feed/filter
+      stream
+      (fn (a) (not (feed/-elem? (get a :actor) actors))))))
+
+; drop activities carrying any muted tag
+(define
+  feed/mute-tags
+  (fn
+    (stream tags)
+    (feed/filter
+      stream
+      (fn (a) (not (some (fn (t) (feed/-elem? t tags)) (get a :tags)))))))
+
+; drop activities about a muted object (thread mute)
+(define
+  feed/mute-objects
+  (fn
+    (stream objects)
+    (feed/filter
+      stream
+      (fn (a) (not (feed/-elem? (get a :object) objects))))))
+
+; apply a viewer preference bag: {:mute-actors (...) :mute-tags (...) :mute-objects (...)}
+(define
+  feed/apply-prefs
+  (fn
+    (stream prefs)
+    (feed/mute-objects
+      (feed/mute-tags
+        (feed/mute-actors stream (get prefs :mute-actors (list)))
+        (get prefs :mute-tags (list)))
+      (get prefs :mute-objects (list)))))

lib/feed/normalize.sx

@@ -0,0 +1,31 @@
+; feed/normalize — coerce arbitrary input into the canonical activity record.
+; An activity is a small dict {:actor :verb :object :at :tags}; a stream is an
+; APL vector of such dicts (see stream.sx). Extra keys on the raw input survive
+; (e.g. :visible-to for ACL, peer metadata for federation) — :tags is the
+; flexible bag but the record is not closed.
+
+(define feed/activity-keys (list :actor :verb :object :at :tags))
+
+(define
+  feed/normalize
+  (fn
+    (raw)
+    (let
+      ((d (if (= (type-of raw) "dict") raw {})))
+      (merge d {:actor (get d :actor "") :object (get d :object nil) :at (get d :at 0) :tags (let ((t (get d :tags (list)))) (if (list? t) t (list t))) :verb (get d :verb "post")}))))
+
+(define
+  feed/activity
+  (fn (actor verb object at tags) (feed/normalize {:actor actor :object object :at at :tags tags :verb verb})))
+
+(define feed/actor (fn (a) (get a :actor)))
+(define feed/verb (fn (a) (get a :verb)))
+(define feed/object (fn (a) (get a :object)))
+(define feed/at (fn (a) (get a :at)))
+(define feed/tags (fn (a) (get a :tags)))
+
+(define
+  feed/activity?
+  (fn
+    (a)
+    (and (= (type-of a) "dict") (has-key? a :actor) (has-key? a :verb))))

lib/feed/notify.sx

@@ -0,0 +1,45 @@
+; feed/notify — a notification feed is a thin layer over a recipient's inbox:
+; the events directed at a user, optionally verb-filtered, and a digest that
+; collapses "alice, bob and 1 other liked X" by (verb, object).
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/inbox-for, feed/-elem?).
+
+; all inbox events for a user (their raw notifications)
+(define feed/notifications (fn (inbox user) (feed/inbox-for inbox user)))
+
+; restrict to notification-worthy verbs (e.g. (list "like" "reply" "follow"))
+(define
+  feed/notify-verbs
+  (fn
+    (inbox user verbs)
+    (feed/filter
+      (feed/inbox-for inbox user)
+      (fn (ev) (feed/-elem? (get (get ev :activity) :verb) verbs)))))
+
+; group key "verb|object" — deterministic, sortable
+(define
+  feed/-notify-key
+  (fn
+    (ev)
+    (let
+      ((a (get ev :activity)))
+      (string-append (get a :verb) "|" (get a :object)))))
+
+; digest: one entry per (verb, object) with the distinct actors and a count,
+; ordered by key for determinism.
+(define
+  feed/notify-digest
+  (fn
+    (inbox user)
+    (let
+      ((events (feed/items (feed/inbox-for inbox user))))
+      (let
+        ((groups (reduce (fn (g ev) (let ((a (get ev :activity)) (k (feed/-notify-key ev))) (let ((cur (get g k {:object (get a :object) :actors (list) :verb (get a :verb)}))) (assoc g k (assoc cur :actors (append (get cur :actors) (list (get a :actor)))))))) {} events)))
+        (map
+          (fn
+            (k)
+            (let
+              ((grp (get groups k)))
+              (assoc grp :count (len (get grp :actors)))))
+          (sort (keys groups)))))))

lib/feed/page.sx

@@ -0,0 +1,50 @@
+; feed/page — pagination. Offset/limit for indexed access, and cursor-based
+; (by :at) for recency feeds, which is stable under inserts: a cursor is the
+; :at of the last item seen, and the next page is the newest items older than it.
+;
+; Requires: lib/feed/stream.sx (feed/recent, feed/take, feed/filter).
+
+; --- offset / limit ---------------------------------------------------------
+
+(define
+  feed/page
+  (fn
+    (stream offset limit)
+    (feed/stream (take (drop (feed/items stream) offset) limit))))
+
+(define
+  feed/page-count
+  (fn (stream limit) (ceil (/ (feed/count stream) limit))))
+
+; --- cursor (recency feeds) -------------------------------------------------
+
+; activities strictly older than cursor (scroll down / load older)
+(define
+  feed/before
+  (fn
+    (stream cursor)
+    (feed/filter stream (fn (a) (< (get a :at) cursor)))))
+
+; activities strictly newer than cursor (load newer / "N new posts")
+(define
+  feed/after
+  (fn
+    (stream cursor)
+    (feed/filter stream (fn (a) (> (get a :at) cursor)))))
+
+; one page: the `limit` newest activities older than cursor, newest first
+(define
+  feed/page-before
+  (fn
+    (stream cursor limit)
+    (feed/take (feed/recent (feed/before stream cursor)) limit)))
+
+; cursor to fetch the next (older) page: :at of the last item of a page,
+; or nil when the page is empty (end of feed)
+(define
+  feed/next-cursor
+  (fn
+    (page)
+    (let
+      ((items (feed/items page)))
+      (if (= (len items) 0) nil (get (last items) :at)))))

lib/feed/rank.sx

@@ -0,0 +1,92 @@
+; feed/rank — scoring + ranking. Scorers are (activity -> number). Ranking is a
+; stable two-pass grade-down: first by :at descending (the tiebreak), then by
+; score descending — so ties resolve by recency, then by input order. Fully
+; deterministic on ties.
+;
+; Requires: lib/apl/runtime.sx, lib/feed/normalize.sx, lib/feed/stream.sx.
+
+; --- scorers ----------------------------------------------------------------
+
+; recency: half-life decay. score = 0.5 ^ (age / half-life). at==now -> 1.0.
+(define
+  feed/recency
+  (fn
+    (now half-life)
+    (fn (a) (expt 0.5 (/ (- now (get a :at)) half-life)))))
+
+; velocity: how many of this actor's activities fall in (at-window, at] —
+; a burst of recent activity scores higher.
+(define
+  feed/velocity
+  (fn
+    (stream window)
+    (fn
+      (a)
+      (len
+        (filter
+          (fn
+            (b)
+            (and
+              (equal? (get b :actor) (get a :actor))
+              (<= (get b :at) (get a :at))
+              (> (get b :at) (- (get a :at) window))))
+          (feed/items stream))))))
+
+; engagement: how many activities in the stream touch this activity's :object
+(define
+  feed/engagement
+  (fn
+    (stream)
+    (fn
+      (a)
+      (len
+        (filter
+          (fn (b) (equal? (get b :object) (get a :object)))
+          (feed/items stream))))))
+
+; composite: weighted sum. parts = (list (list weight scorer) ...)
+(define
+  feed/composite
+  (fn
+    (parts)
+    (fn
+      (a)
+      (reduce
+        (fn (acc p) (+ acc (* (first p) ((nth p 1) a))))
+        0
+        parts))))
+
+; --- ranking ----------------------------------------------------------------
+
+; stable reorder of items by key-fn, descending (grade-down is stable)
+(define
+  feed/-desc-by
+  (fn
+    (items key-fn)
+    (let
+      ((keys (make-array (list (len items)) (map key-fn items))))
+      (let
+        ((order (get (apl-grade-down keys) :ravel)))
+        (map (fn (i) (nth items (- i 1))) order)))))
+
+; rank by score descending; ties -> :at descending -> input order
+(define
+  feed/rank
+  (fn
+    (stream score-fn)
+    (let
+      ((by-at (feed/-desc-by (feed/items stream) feed/at)))
+      (feed/stream (feed/-desc-by by-at score-fn)))))
+
+; attach a :score to each activity (for inspection / debugging)
+(define
+  feed/with-scores
+  (fn
+    (stream score-fn)
+    (feed/stream
+      (map (fn (a) (assoc a :score (score-fn a))) (feed/items stream)))))
+
+; top-N ranked timeline
+(define
+  feed/top
+  (fn (stream score-fn n) (feed/take (feed/rank stream score-fn) n)))

lib/feed/scoreboard.json

@@ -0,0 +1,19 @@
+{
+  "suites": {
+    "basic": {"pass": 30, "fail": 0},
+    "fanout": {"pass": 29, "fail": 0},
+    "rank": {"pass": 24, "fail": 0},
+    "integration": {"pass": 22, "fail": 0},
+    "content": {"pass": 15, "fail": 0},
+    "notify": {"pass": 8, "fail": 0},
+    "home": {"pass": 6, "fail": 0},
+    "dedupe": {"pass": 9, "fail": 0},
+    "trending": {"pass": 11, "fail": 0},
+    "mute": {"pass": 9, "fail": 0},
+    "page": {"pass": 14, "fail": 0},
+    "thread": {"pass": 12, "fail": 0}
+  },
+  "total_pass": 189,
+  "total_fail": 0,
+  "total": 189
+}

lib/feed/scoreboard.md

@@ -0,0 +1,19 @@
+# feed Conformance Scoreboard
+
+_Generated by `lib/feed/conformance.sh`_
+
+| Suite | Pass | Fail | Total |
+|-------|-----:|-----:|------:|
+| basic | 30 | 0 | 30 |
+| fanout | 29 | 0 | 29 |
+| rank | 24 | 0 | 24 |
+| integration | 22 | 0 | 22 |
+| content | 15 | 0 | 15 |
+| notify | 8 | 0 | 8 |
+| home | 6 | 0 | 6 |
+| dedupe | 9 | 0 | 9 |
+| trending | 11 | 0 | 11 |
+| mute | 9 | 0 | 9 |
+| page | 14 | 0 | 14 |
+| thread | 12 | 0 | 12 |
+| **Total** | **189** | **0** | **189** |

lib/feed/stream.sx

@@ -0,0 +1,75 @@
+; feed/stream — a stream is an APL vector (rank-1 array) whose ravel holds
+; activity dicts. Operations lift APL primitives onto this shape: filter via
+; compress (/), sort via grade (⍋), take via ↑, reverse via ⌽.
+;
+; Requires: lib/apl/runtime.sx, lib/feed/normalize.sx (loaded by harness).
+
+(define feed/stream (fn (acts) (make-array (list (len acts)) acts)))
+
+(define feed/items (fn (s) (get s :ravel)))
+
+(define feed/count (fn (s) (len (get s :ravel))))
+
+(define feed/empty (feed/stream (list)))
+
+(define feed/empty? (fn (s) (= (feed/count s) 0)))
+
+; filter — bool mask ∘ compress. pred : activity -> truthy
+(define
+  feed/filter
+  (fn
+    (s pred)
+    (let
+      ((items (get s :ravel)))
+      (let
+        ((mask (make-array (list (len items)) (map (fn (a) (if (pred a) 1 0)) items))))
+        (apl-compress mask s)))))
+
+; sort-by — ascending, stable on ties (grade-up is stable). key-fn : activity -> number
+(define
+  feed/sort-by
+  (fn
+    (s key-fn)
+    (let
+      ((items (get s :ravel)))
+      (let
+        ((keys (make-array (list (len items)) (map key-fn items))))
+        (let
+          ((order (get (apl-grade-up keys) :ravel)))
+          (feed/stream (map (fn (i) (nth items (- i 1))) order)))))))
+
+(define feed/sort-by-at (fn (s) (feed/sort-by s feed/at)))
+
+; newest-first: ascending sort then reverse (⌽)
+(define feed/recent (fn (s) (apl-reverse (feed/sort-by-at s))))
+
+; take N (↑), clamped to stream length so it never over-takes/pads
+(define
+  feed/take
+  (fn
+    (s n)
+    (let
+      ((c (feed/count s)))
+      (if (>= n c) s (apl-take (apl-scalar n) s)))))
+
+(define feed/reverse (fn (s) (apl-reverse s)))
+
+; common predicates
+(define
+  feed/by-actor
+  (fn (s actor) (feed/filter s (fn (a) (equal? (get a :actor) actor)))))
+
+(define
+  feed/by-verb
+  (fn (s verb) (feed/filter s (fn (a) (equal? (get a :verb) verb)))))
+
+(define
+  feed/by-object
+  (fn
+    (s object)
+    (feed/filter s (fn (a) (equal? (get a :object) object)))))
+
+; activities at or after timestamp t
+(define
+  feed/since
+  (fn (s t) (feed/filter s (fn (a) (>= (get a :at) t)))))

lib/feed/tests/basic.sx

@@ -0,0 +1,118 @@
+; Phase 1 — normalize, stream ops, api. Uses the feed-test harness
+; (feed-test name got expected) provided by conformance.sh.
+
+; ---------- normalize ----------
+
+(feed-test
+  "normalize default actor"
+  (feed/actor (feed/normalize {}))
+  "")
+(feed-test
+  "normalize default verb"
+  (feed/verb (feed/normalize {}))
+  "post")
+(feed-test
+  "normalize default at"
+  (feed/at (feed/normalize {}))
+  0)
+(feed-test
+  "normalize default object"
+  (feed/object (feed/normalize {}))
+  nil)
+(feed-test
+  "normalize default tags"
+  (feed/tags (feed/normalize {}))
+  (list))
+(feed-test
+  "normalize keeps actor"
+  (feed/actor (feed/normalize {:actor "alice"}))
+  "alice")
+(feed-test
+  "normalize keeps verb"
+  (feed/verb (feed/normalize {:verb "like"}))
+  "like")
+(feed-test
+  "normalize scalar tag -> list"
+  (feed/tags (feed/normalize {:tags "x"}))
+  (list "x"))
+(feed-test
+  "normalize list tags kept"
+  (feed/tags (feed/normalize {:tags (list "a" "b")}))
+  (list "a" "b"))
+(feed-test
+  "activity constructor at"
+  (feed/at (feed/activity "a" "post" "o" 5 (list)))
+  5)
+(feed-test
+  "activity? on activity"
+  (feed/activity? (feed/normalize {:actor "a"}))
+  true)
+(feed-test "activity? on number" (feed/activity? 5) false)
+(feed-test "activity? on bare dict" (feed/activity? {:foo 1}) false)
+
+; ---------- stream ----------
+
+(define
+  S
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 30 (list))
+      (feed/activity "bob" "like" "p1" 10 (list))
+      (feed/activity "alice" "post" "p2" 20 (list)))))
+
+(feed-test "stream count" (feed/count S) 3)
+(feed-test "stream items len" (len (feed/items S)) 3)
+(feed-test
+  "sort-by-at actors asc"
+  (map feed/actor (feed/items (feed/sort-by-at S)))
+  (list "bob" "alice" "alice"))
+(feed-test
+  "recent newest first"
+  (map feed/at (feed/items (feed/recent S)))
+  (list 30 20 10))
+(feed-test
+  "take 2 of recent"
+  (feed/count (feed/take (feed/recent S) 2))
+  2)
+(feed-test
+  "take clamps past end"
+  (feed/count (feed/take S 10))
+  3)
+(feed-test
+  "by-actor alice count"
+  (feed/count (feed/by-actor S "alice"))
+  2)
+(feed-test
+  "by-verb like actor"
+  (map feed/actor (feed/items (feed/by-verb S "like")))
+  (list "bob"))
+(feed-test
+  "by-object p1 count"
+  (feed/count (feed/by-object S "p1"))
+  2)
+(feed-test
+  "since 20 count"
+  (feed/count (feed/since S 20))
+  2)
+(feed-test
+  "reverse ats"
+  (map feed/at (feed/items (feed/reverse S)))
+  (list 20 10 30))
+(feed-test "empty? on empty" (feed/empty? feed/empty) true)
+(feed-test
+  "empty? on filtered-out"
+  (feed/empty? (feed/by-actor S "zzz"))
+  true)
+
+; ---------- api ----------
+
+(feed/reset!)
+(feed/post {:actor "x" :at 1 :verb "post"})
+(feed/post {:actor "y" :at 2 :verb "like"})
+(feed-test "api size after posts" (feed/size) 2)
+(feed-test "api all count" (feed/count (feed/all)) 2)
+(feed-test
+  "post returns normalized verb"
+  (feed/verb (feed/post {:actor "z"}))
+  "post")
+(feed-test "api size after third post" (feed/size) 3)

lib/feed/tests/content.sx

@@ -0,0 +1,85 @@
+; Follow-up — TF-IDF content ranking over :tags. (feed-test name got expected)
+
+(define
+  corpus
+  (feed/stream
+    (list
+      (feed/normalize {:actor "u" :object "o1" :at 10 :tags (list "cats" "funny")})
+      (feed/normalize {:actor "u" :object "o2" :at 20 :tags (list "cats" "news")})
+      (feed/normalize {:actor "u" :object "o3" :at 30 :tags (list "politics" "news")})
+      (feed/normalize {:actor "u" :object "o4" :at 40 :tags (list "cats")}))))
+
+; ---------- document frequency ----------
+
+(feed-test "df cats" (get (feed/tag-df corpus) "cats") 3)
+(feed-test "df news" (get (feed/tag-df corpus) "news") 2)
+(feed-test "df funny" (get (feed/tag-df corpus) "funny") 1)
+(feed-test "df politics" (get (feed/tag-df corpus) "politics") 1)
+(feed-test "df full" (feed/tag-df corpus) {:news 2 :funny 1 :politics 1 :cats 3})
+
+; ---------- inverse document frequency ----------
+
+(feed-test
+  "idf news = log(4/2)"
+  (get (feed/tag-idf corpus) "news")
+  (log 2))
+(feed-test
+  "idf funny = log(4/1)"
+  (get (feed/tag-idf corpus) "funny")
+  (log 4))
+(feed-test
+  "rarer tag has higher idf"
+  (>
+    (get (feed/tag-idf corpus) "funny")
+    (get (feed/tag-idf corpus) "cats"))
+  true)
+
+; ---------- tf-idf scoring ----------
+
+(define idf (feed/tag-idf corpus))
+
+(feed-test
+  "score query funny on o1"
+  ((feed/tfidf-score idf (list "funny")) (feed/normalize {:actor "u" :object "x" :tags (list "cats" "funny")}))
+  (log 4))
+(feed-test
+  "score query funny on non-match"
+  ((feed/tfidf-score idf (list "funny")) (feed/normalize {:actor "u" :object "x" :tags (list "cats")}))
+  0)
+(feed-test
+  "unknown query tag scores 0"
+  ((feed/tfidf-score idf (list "zzz")) (feed/normalize {:actor "u" :object "x" :tags (list "cats")}))
+  0)
+
+; ---------- ranking by relevance ----------
+
+; query news: o2,o3 match (score log2), o1,o4 don't (0); ties break by :at desc
+(feed-test
+  "by-relevance news order"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/by-relevance corpus (list "news"))))
+  (list "o3" "o2" "o4" "o1"))
+
+; query funny: only o1 matches -> ranks first
+(feed-test
+  "by-relevance funny first"
+  (get
+    (nth (feed/items (feed/by-relevance corpus (list "funny"))) 0)
+    :object)
+  "o1")
+
+; query (cats news): o2 carries both tags -> highest combined tf-idf
+(feed-test
+  "by-relevance cats+news top"
+  (get
+    (nth
+      (feed/items (feed/by-relevance corpus (list "cats" "news")))
+      0)
+    :object)
+  "o2")
+
+(feed-test
+  "by-relevance preserves count"
+  (feed/count (feed/by-relevance corpus (list "cats")))
+  4)

lib/feed/tests/dedupe.sx

@@ -0,0 +1,56 @@
+; Follow-up — verb-aware (smart) dedupe. (feed-test name got expected)
+
+; reactions (like/follow) collapse cross-actor; posts stay distinct per actor
+(define
+  M
+  (feed/stream
+    (list
+      (feed/activity "alice" "like" "X" 1 (list))
+      (feed/activity "bob" "like" "X" 2 (list))
+      (feed/activity "alice" "post" "P" 3 (list))
+      (feed/activity "bob" "post" "P" 4 (list))
+      (feed/activity "alice" "follow" "C" 5 (list))
+      (feed/activity "bob" "follow" "C" 6 (list))))) ; collapses
+
+(feed-test
+  "smart dedupe total"
+  (feed/count (feed/dedupe-smart M))
+  4)
+(feed-test
+  "smart keeps both posts"
+  (feed/count (feed/by-verb (feed/dedupe-smart M) "post"))
+  2)
+(feed-test
+  "smart collapses likes to one"
+  (feed/count (feed/by-verb (feed/dedupe-smart M) "like"))
+  1)
+(feed-test
+  "smart collapses follows to one"
+  (feed/count (feed/by-verb (feed/dedupe-smart M) "follow"))
+  1)
+(feed-test
+  "collapsed like keeps first actor"
+  (map feed/actor (feed/items (feed/by-verb (feed/dedupe-smart M) "like")))
+  (list "alice"))
+
+; contrast: plain activity dedupe keeps cross-actor likes distinct
+(feed-test
+  "activity dedupe keeps both likes"
+  (feed/count (feed/by-verb (feed/dedupe-activities M) "like"))
+  2)
+
+; contrast: blanket collapse folds the two posts (same verb+object) too
+(feed-test
+  "collapse dedupe folds posts"
+  (feed/count (feed/by-verb (feed/dedupe-collapse M) "post"))
+  1)
+
+; smart-key dispatch
+(feed-test
+  "smart-key reaction -> (verb object)"
+  (feed/smart-key (feed/activity "alice" "like" "X" 0 (list)))
+  (list "like" "X"))
+(feed-test
+  "smart-key post -> (actor verb object)"
+  (feed/smart-key (feed/activity "alice" "post" "P" 0 (list)))
+  (list "alice" "post" "P"))

lib/feed/tests/fanout.sx

@@ -0,0 +1,187 @@
+; Phase 2 — fanout via outer product + dedupe. (feed-test name got expected)
+
+; ---------- graph ----------
+
+; edges: (follower followee). bob,carol follow alice; carol,dave follow bob.
+(define
+  G
+  (feed/follow-graph
+    (list
+      (list "bob" "alice")
+      (list "carol" "alice")
+      (list "carol" "bob")
+      (list "dave" "bob"))))
+
+(feed-test "followers alice" (feed/followers G "alice") (list "bob" "carol"))
+(feed-test "followers bob" (feed/followers G "bob") (list "carol" "dave"))
+(feed-test "followers unknown" (feed/followers G "zzz") (list))
+(feed-test "audience distinct" (feed/audience G) (list "bob" "carol" "dave"))
+
+; ---------- fanout ----------
+
+(define
+  S
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 10 (list))
+      (feed/activity "alice" "post" "p2" 20 (list))
+      (feed/activity "bob" "like" "p1" 30 (list)))))
+
+(define IB (feed/fanout S G))
+
+(feed-test "fanout total edges" (feed/count IB) 6)
+(feed-test
+  "inbox bob count"
+  (feed/count (feed/inbox-for IB "bob"))
+  2)
+(feed-test
+  "inbox carol count"
+  (feed/count (feed/inbox-for IB "carol"))
+  3)
+(feed-test
+  "inbox dave count"
+  (feed/count (feed/inbox-for IB "dave"))
+  1)
+(feed-test
+  "inbox alice (follows none)"
+  (feed/count (feed/inbox-for IB "alice"))
+  0)
+(feed-test
+  "recipients order"
+  (feed/recipients IB)
+  (list "bob" "carol" "dave"))
+(feed-test
+  "bob inbox objects"
+  (map (fn (a) (get a :object)) (feed/inbox-activities IB "bob"))
+  (list "p1" "p2"))
+(feed-test
+  "dave inbox objects"
+  (map (fn (a) (get a :object)) (feed/inbox-activities IB "dave"))
+  (list "p1"))
+(feed-test
+  "dave inbox verb"
+  (map (fn (a) (get a :verb)) (feed/inbox-activities IB "dave"))
+  (list "like"))
+
+; empty graph → no audience → no edges
+(feed-test
+  "empty graph fanout"
+  (feed/count (feed/fanout S {}))
+  0)
+
+; actor nobody follows produces no edges
+(define
+  Sghost
+  (feed/stream (list (feed/activity "ghost" "post" "g1" 5 (list)))))
+(feed-test
+  "unfollowed actor fanout"
+  (feed/count (feed/fanout Sghost G))
+  0)
+
+; ---------- high fanout (popular actor) ----------
+
+(define
+  Gstar
+  (feed/follow-graph
+    (list
+      (list "u1" "star")
+      (list "u2" "star")
+      (list "u3" "star")
+      (list "u4" "star")
+      (list "u5" "star"))))
+(define
+  Sstar
+  (feed/stream (list (feed/activity "star" "post" "s1" 1 (list)))))
+(feed-test
+  "star fanout count"
+  (feed/count (feed/fanout Sstar Gstar))
+  5)
+(feed-test "star audience size" (len (feed/audience Gstar)) 5)
+
+; ---------- mutual follow ----------
+
+(define Gmut (feed/follow-graph (list (list "a" "b") (list "b" "a"))))
+(define
+  Smut
+  (feed/stream
+    (list
+      (feed/activity "a" "post" "pa" 1 (list))
+      (feed/activity "b" "post" "pb" 2 (list)))))
+(define IBmut (feed/fanout Smut Gmut))
+(feed-test "mutual total" (feed/count IBmut) 2)
+(feed-test
+  "mutual a gets pb"
+  (map (fn (x) (get x :object)) (feed/inbox-activities IBmut "a"))
+  (list "pb"))
+(feed-test
+  "mutual b gets pa"
+  (map (fn (x) (get x :object)) (feed/inbox-activities IBmut "b"))
+  (list "pa"))
+
+; ---------- dedupe ----------
+
+(define
+  Sdup2
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 1 (list))
+      (feed/activity "alice" "post" "p1" 9 (list))
+      (feed/activity "alice" "post" "p2" 2 (list)))))
+(feed-test
+  "dedupe-activities collapses dup"
+  (feed/count (feed/dedupe-activities Sdup2))
+  2)
+(feed-test
+  "dedupe-activities keeps distinct"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/dedupe-activities Sdup2)))
+  (list "p1" "p2"))
+
+(define
+  Slikes
+  (feed/stream
+    (list
+      (feed/activity "alice" "like" "X" 1 (list))
+      (feed/activity "bob" "like" "X" 2 (list))
+      (feed/activity "carol" "like" "Y" 3 (list)))))
+(feed-test
+  "collapse cross-actor likes"
+  (feed/count (feed/dedupe-collapse Slikes))
+  2)
+(feed-test
+  "collapse keeps distinct objects"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/dedupe-collapse Slikes)))
+  (list "X" "Y"))
+
+(feed-test
+  "activity-key shape"
+  (feed/activity-key (feed/activity "a" "post" "o" 0 (list)))
+  (list "a" "post" "o"))
+(feed-test
+  "collapse-key shape"
+  (feed/collapse-key (feed/activity "a" "like" "o" 0 (list)))
+  (list "like" "o"))
+
+; cross-post: alice posts p1 twice → bob's inbox has it twice → dedupe-inbox → once
+(define
+  Scross
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 1 (list))
+      (feed/activity "alice" "post" "p1" 5 (list)))))
+(define IBcross (feed/fanout Scross G))
+(feed-test
+  "cross-post raw bob count"
+  (feed/count (feed/inbox-for IBcross "bob"))
+  2)
+(feed-test
+  "cross-post deduped bob count"
+  (feed/count (feed/inbox-for (feed/dedupe-inbox IBcross) "bob"))
+  1)
+(feed-test
+  "dedupe-inbox keeps distinct receivers"
+  (feed/count (feed/dedupe-inbox IBcross))
+  2)

lib/feed/tests/home.sx

@@ -0,0 +1,73 @@
+; Follow-up — feed/home capstone pipeline. (feed-test name got expected)
+
+; alice follows star and bob (edges: follower followee)
+(define
+  G
+  (feed/follow-graph (list (list "alice" "star") (list "alice" "bob"))))
+
+; star posts s1 then s2; bob posts b1; star re-posts s1 (cross-post dup);
+; zoe posts z1 (alice does NOT follow zoe)
+(define
+  S
+  (feed/stream
+    (list
+      (feed/activity "star" "post" "s1" 10 (list))
+      (feed/activity "star" "post" "s2" 20 (list))
+      (feed/activity "bob" "post" "b1" 15 (list))
+      (feed/activity "star" "post" "s1" 5 (list))
+      (feed/activity "zoe" "post" "z1" 30 (list)))))
+
+(define rec (feed/recency 100 10))
+
+(feed-test
+  "home count (deduped, followed only)"
+  (feed/count (feed/home S G "alice" feed/permit-public? rec 10))
+  3)
+
+(feed-test
+  "home order by recency"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/home S G "alice" feed/permit-public? rec 10)))
+  (list "s2" "b1" "s1"))
+
+(feed-test
+  "home excludes unfollowed zoe"
+  (feed/-elem?
+    "z1"
+    (map
+      (fn (a) (get a :object))
+      (feed/items (feed/home S G "alice" feed/permit-public? rec 10))))
+  false)
+
+(feed-test
+  "home top-2"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/home S G "alice" feed/permit-public? rec 2)))
+  (list "s2" "b1"))
+
+(feed-test
+  "home dedupes cross-post (one s1)"
+  (len
+    (filter
+      (fn (o) (equal? o "s1"))
+      (map
+        (fn (a) (get a :object))
+        (feed/items
+          (feed/home S G "alice" feed/permit-public? rec 10)))))
+  1)
+
+; ACL applied per-viewer in the home pipeline
+(define
+  Sacl
+  (feed/stream
+    (list (feed/normalize {:actor "star" :object "pub" :at 20}) (feed/normalize {:actor "star" :object "sec" :visible-to (list "carol") :at 25}))))
+(define Gacl (feed/follow-graph (list (list "alice" "star"))))
+
+(feed-test
+  "home hides activity alice not permitted"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/home Sacl Gacl "alice" feed/permit-acl? rec 10)))
+  (list "pub"))

lib/feed/tests/integration.sx

@@ -0,0 +1,155 @@
+; Phase 4 — visibility (ACL) + federation, and the end-to-end timeline.
+; (feed-test name got expected)
+
+; ---------- ACL visibility ----------
+; pub: public. sec: bob, allows carol. dm: frank, allows dave.
+
+(define
+  C
+  (feed/stream
+    (list
+      (feed/normalize {:actor "alice" :object "pub" :at 10})
+      (feed/normalize {:actor "bob" :object "sec" :visible-to (list "carol") :at 20})
+      (feed/normalize {:actor "frank" :object "dm" :visible-to (list "dave") :at 30}))))
+
+(feed-test
+  "public visible to anyone"
+  (feed/count (feed/visible C "zoe" feed/permit-acl?))
+  1)
+(feed-test
+  "carol sees allowlisted + public"
+  (feed/count (feed/visible C "carol" feed/permit-acl?))
+  2)
+(feed-test
+  "dave sees dm + public"
+  (feed/count (feed/visible C "dave" feed/permit-acl?))
+  2)
+(feed-test
+  "author always sees own private"
+  (feed/count (feed/visible C "frank" feed/permit-acl?))
+  2)
+(feed-test
+  "permit-public? lets all through"
+  (feed/count (feed/visible C "zoe" feed/permit-public?))
+  3)
+(feed-test
+  "visible objects for dave"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/visible C "dave" feed/permit-acl?)))
+  (list "pub" "dm"))
+
+; per-viewer: same stream, different timelines
+(feed-test
+  "zoe timeline differs from carol"
+  (not
+    (=
+      (feed/count (feed/visible C "zoe" feed/permit-acl?))
+      (feed/count (feed/visible C "carol" feed/permit-acl?))))
+  true)
+
+; ---------- federation: merge / ingest ----------
+
+(define
+  L
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 10 (list))
+      (feed/activity "alice" "post" "p2" 20 (list)))))
+(define
+  P
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p2" 20 (list))
+      (feed/activity "peer" "post" "p9" 25 (list)))))
+
+(feed-test "merge concatenates" (feed/count (feed/merge L P)) 4)
+(feed-test
+  "ingest dedupes overlap"
+  (feed/count (feed/ingest L P))
+  3)
+
+(feed-test
+  "inbound normalizes + ingests"
+  (feed/count (feed/inbound L (list {:actor "peer" :object "p9" :at 25} {:actor "alice" :object "p1" :at 10})))
+  3)
+
+; backfill via injected fetch-fn
+(define peer-history (fn (peer-id) (list {:actor peer-id :object "h1" :at 1} {:actor peer-id :object "h2" :at 2})))
+(feed-test
+  "backfill merges peer history"
+  (feed/count (feed/backfill L peer-history "remote"))
+  4)
+(feed-test
+  "backfill objects present"
+  (map
+    (fn (a) (get a :object))
+    (feed/items
+      (feed/by-actor (feed/backfill L peer-history "remote") "remote")))
+  (list "h1" "h2"))
+
+; ---------- federation: outbound partition ----------
+
+; bob (local), alice@remote + carol@remote (remote) follow star
+(define
+  Gf
+  (feed/follow-graph
+    (list
+      (list "bob" "star")
+      (list "alice@remote" "star")
+      (list "carol@remote" "star"))))
+(define
+  Sf
+  (feed/stream (list (feed/activity "star" "post" "s1" 1 (list)))))
+(define
+  remote?
+  (fn (id) (feed/-elem? id (list "alice@remote" "carol@remote"))))
+(define parts (feed/federate Sf Gf remote?))
+
+(feed-test "local deliveries" (feed/count (get parts :local)) 1)
+(feed-test "remote deliveries" (feed/count (get parts :remote)) 2)
+(feed-test
+  "local recipient is bob"
+  (feed/recipients (get parts :local))
+  (list "bob"))
+
+; deliver: send-fn receives each remote event, local inbox returned
+(define sent (list))
+(define send-fn (fn (to act) (set! sent (append sent (list to)))))
+(define local-inbox (feed/deliver Sf Gf remote? send-fn))
+(feed-test "deliver returns local inbox" (feed/count local-inbox) 1)
+(feed-test "deliver sent to both remotes" (len sent) 2)
+(feed-test "deliver remote targets" sent (list "alice@remote" "carol@remote"))
+
+; ---------- end-to-end: federated, ACL-filtered, ranked timeline ----------
+
+(define
+  base
+  (feed/stream
+    (list
+      (feed/normalize {:actor "alice" :object "a1" :at 100})
+      (feed/normalize {:actor "bob" :object "b1" :visible-to (list "carol") :at 90})
+      (feed/normalize {:actor "eve" :object "e1" :visible-to (list "dave") :at 80}))))
+(define federated (feed/inbound base (list {:actor "peer" :object "x1" :at 110})))
+(define rec (feed/recency 120 10))
+(define
+  carol-tl
+  (feed/timeline federated "carol" feed/permit-acl? rec 3))
+
+; eve's :visible-to excludes carol -> filtered out; peer/alice public, bob allows carol
+(feed-test "carol federated timeline count" (feed/count carol-tl) 3)
+(feed-test
+  "carol timeline order (recency)"
+  (map (fn (a) (get a :object)) (feed/items carol-tl))
+  (list "x1" "a1" "b1"))
+(feed-test
+  "eve dm excluded from carol"
+  (feed/-elem? "e1" (map (fn (a) (get a :object)) (feed/items carol-tl)))
+  false)
+(feed-test
+  "dave sees eve dm not bob"
+  (map
+    (fn (a) (get a :object))
+    (feed/items
+      (feed/timeline federated "dave" feed/permit-acl? rec 5)))
+  (list "x1" "a1" "e1"))

lib/feed/tests/mute.sx

@@ -0,0 +1,68 @@
+; Follow-up — viewer mute/block filtering. (feed-test name got expected)
+
+(define
+  S
+  (feed/stream
+    (list
+      (feed/normalize {:actor "alice" :object "P1" :at 1 :tags (list "news")})
+      (feed/normalize {:actor "bob" :object "P2" :at 2 :tags (list "spam")})
+      (feed/normalize {:actor "alice" :object "P3" :at 3 :tags (list "cats")})
+      (feed/normalize {:actor "carol" :object "P4" :at 4 :tags (list "news" "spam")}))))
+
+; ---------- mute actors ----------
+
+(feed-test
+  "mute bob drops his post"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/mute-actors S (list "bob"))))
+  (list "P1" "P3" "P4"))
+(feed-test
+  "mute alice drops two"
+  (feed/count (feed/mute-actors S (list "alice")))
+  2)
+(feed-test
+  "mute nobody keeps all"
+  (feed/count (feed/mute-actors S (list)))
+  4)
+
+; ---------- mute tags ----------
+
+(feed-test
+  "mute spam tag drops two"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/mute-tags S (list "spam"))))
+  (list "P1" "P3"))
+(feed-test
+  "mute news+cats leaves spam-only"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/mute-tags S (list "news" "cats"))))
+  (list "P2"))
+
+; ---------- mute objects ----------
+
+(feed-test
+  "mute object P3 (thread mute)"
+  (feed/count (feed/mute-objects S (list "P3")))
+  3)
+
+; ---------- combined prefs ----------
+
+(feed-test
+  "apply-prefs actors + tags"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/apply-prefs S {:mute-actors (list "bob") :mute-tags (list "cats")})))
+  (list "P1" "P4"))
+(feed-test
+  "apply-prefs empty keeps all"
+  (feed/count (feed/apply-prefs S {}))
+  4)
+(feed-test
+  "apply-prefs all three filters"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/apply-prefs S {:mute-objects (list "P3") :mute-actors (list "carol") :mute-tags (list "spam")})))
+  (list "P1"))

lib/feed/tests/notify.sx

@@ -0,0 +1,69 @@
+; Follow-up — notification feed over an inbox. (feed-test name got expected)
+
+; an inbox is a stream of {:to receiver :activity act} events
+(define mk-ev (fn (to act) {:activity act :to to}))
+
+(define
+  IB
+  (feed/stream
+    (list
+      (mk-ev "alice" (feed/activity "bob" "like" "P" 10 (list)))
+      (mk-ev "alice" (feed/activity "carol" "like" "P" 20 (list)))
+      (mk-ev "alice" (feed/activity "dave" "reply" "Q" 30 (list)))
+      (mk-ev "bob" (feed/activity "eve" "like" "R" 40 (list))))))
+
+; ---------- raw notifications ----------
+
+(feed-test
+  "alice notification count"
+  (feed/count (feed/notifications IB "alice"))
+  3)
+(feed-test
+  "bob notification count"
+  (feed/count (feed/notifications IB "bob"))
+  1)
+(feed-test
+  "zoe no notifications"
+  (feed/count (feed/notifications IB "zoe"))
+  0)
+
+; ---------- verb filtering ----------
+
+(feed-test
+  "alice likes only"
+  (feed/count (feed/notify-verbs IB "alice" (list "like")))
+  2)
+(feed-test
+  "alice replies only"
+  (feed/count (feed/notify-verbs IB "alice" (list "reply")))
+  1)
+(feed-test
+  "alice like+reply"
+  (feed/count (feed/notify-verbs IB "alice" (list "like" "reply")))
+  3)
+(feed-test
+  "alice follow (none)"
+  (feed/count (feed/notify-verbs IB "alice" (list "follow")))
+  0)
+
+; ---------- digest ----------
+
+(define dig (feed/notify-digest IB "alice"))
+
+(feed-test "digest group count" (len dig) 2)
+(feed-test
+  "digest sorted by key (like|P before reply|Q)"
+  (map (fn (g) (get g :object)) dig)
+  (list "P" "Q"))
+(feed-test
+  "like group actors"
+  (get (nth dig 0) :actors)
+  (list "bob" "carol"))
+(feed-test "like group count" (get (nth dig 0) :count) 2)
+(feed-test "like group verb" (get (nth dig 0) :verb) "like")
+(feed-test "reply group count" (get (nth dig 1) :count) 1)
+(feed-test
+  "reply group actors"
+  (get (nth dig 1) :actors)
+  (list "dave"))
+(feed-test "empty digest for zoe" (feed/notify-digest IB "zoe") (list))

lib/feed/tests/page.sx

@@ -0,0 +1,86 @@
+; Follow-up — pagination (offset + cursor). (feed-test name got expected)
+
+; ---------- offset / limit ----------
+
+(define
+  O
+  (feed/stream
+    (list
+      (feed/activity "u" "post" "o1" 1 (list))
+      (feed/activity "u" "post" "o2" 2 (list))
+      (feed/activity "u" "post" "o3" 3 (list))
+      (feed/activity "u" "post" "o4" 4 (list))
+      (feed/activity "u" "post" "o5" 5 (list)))))
+
+(feed-test
+  "page 1"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/page O 0 2)))
+  (list "o1" "o2"))
+(feed-test
+  "page 2"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/page O 2 2)))
+  (list "o3" "o4"))
+(feed-test
+  "page 3 (partial)"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/page O 4 2)))
+  (list "o5"))
+(feed-test
+  "page past end empty"
+  (feed/count (feed/page O 10 2))
+  0)
+(feed-test "page-count 5/2 = 3" (feed/page-count O 2) 3)
+(feed-test "page-count 5/5 = 1" (feed/page-count O 5) 1)
+
+; ---------- cursor (recency) ----------
+
+(define
+  R
+  (feed/stream
+    (list
+      (feed/activity "u" "post" "a" 50 (list))
+      (feed/activity "u" "post" "b" 40 (list))
+      (feed/activity "u" "post" "c" 30 (list))
+      (feed/activity "u" "post" "d" 20 (list))
+      (feed/activity "u" "post" "e" 10 (list)))))
+
+(define p1 (feed/page-before R 100 2))
+(feed-test
+  "cursor page 1 newest first"
+  (map (fn (a) (get a :object)) (feed/items p1))
+  (list "a" "b"))
+(feed-test "next cursor after page 1" (feed/next-cursor p1) 40)
+
+(define p2 (feed/page-before R (feed/next-cursor p1) 2))
+(feed-test
+  "cursor page 2"
+  (map (fn (a) (get a :object)) (feed/items p2))
+  (list "c" "d"))
+(feed-test "next cursor after page 2" (feed/next-cursor p2) 20)
+
+(define p3 (feed/page-before R (feed/next-cursor p2) 2))
+(feed-test
+  "cursor page 3 (partial)"
+  (map (fn (a) (get a :object)) (feed/items p3))
+  (list "e"))
+
+(feed-test
+  "empty page nil cursor"
+  (feed/next-cursor (feed/page-before R 5 2))
+  nil)
+
+(feed-test
+  "after cursor loads newer"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/recent (feed/after R 30))))
+  (list "a" "b"))
+(feed-test
+  "before cursor count"
+  (feed/count (feed/before R 30))
+  2)

lib/feed/tests/rank.sx

@@ -0,0 +1,160 @@
+; Phase 3 — aggregation + ranking. (feed-test name got expected)
+
+; ---------- aggregation ----------
+
+(define
+  A
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 5 (list))
+      (feed/activity "alice" "post" "p2" 15 (list))
+      (feed/activity "bob" "post" "p3" 25 (list))
+      (feed/activity "alice" "like" "p1" 35 (list)))))
+
+(feed-test "actor-counts" (feed/actor-counts A) {:alice 3 :bob 1})
+(feed-test "object-counts" (feed/object-counts A) {:p2 1 :p3 1 :p1 2})
+(feed-test
+  "group-by actor alice len"
+  (len (get (feed/group-by A feed/actor) "alice"))
+  3)
+(feed-test
+  "group-count empty"
+  (feed/group-count feed/empty feed/actor)
+  {})
+
+; day bucketing
+(define
+  D
+  (feed/stream
+    (list
+      (feed/activity "alice" "post" "p1" 5 (list))
+      (feed/activity "alice" "post" "p2" 8 (list))
+      (feed/activity "alice" "post" "p3" 12 (list)))))
+
+(feed-test "feed/day floor" (feed/day 12 10) 1)
+(feed-test "feed/day same bucket" (feed/day 8 10) 0)
+(feed-test "by-actor-day" (feed/by-actor-day D 10) {:alice#0 2 :alice#1 1})
+
+; ---------- recency ----------
+
+(define rec (feed/recency 100 10))
+(feed-test
+  "recency at=now -> 1"
+  (rec (feed/activity "x" "post" "o" 100 (list)))
+  1)
+(feed-test
+  "recency age=hl -> .5"
+  (rec (feed/activity "x" "post" "o" 90 (list)))
+  0.5)
+(feed-test
+  "recency age=2hl -> .25"
+  (rec (feed/activity "x" "post" "o" 80 (list)))
+  0.25)
+
+; ---------- velocity ----------
+
+(define vel (feed/velocity D 10))
+(feed-test
+  "velocity burst (at=12)"
+  (vel (feed/activity "alice" "post" "z" 12 (list)))
+  3)
+(feed-test
+  "velocity mid (at=8)"
+  (vel (feed/activity "alice" "post" "z" 8 (list)))
+  2)
+(feed-test
+  "velocity first (at=5)"
+  (vel (feed/activity "alice" "post" "z" 5 (list)))
+  1)
+(feed-test
+  "velocity other actor"
+  (vel (feed/activity "bob" "post" "z" 12 (list)))
+  0)
+
+; ---------- engagement ----------
+
+(define eng (feed/engagement A))
+(feed-test
+  "engagement p1"
+  (eng (feed/activity "x" "post" "p1" 0 (list)))
+  2)
+(feed-test
+  "engagement p2"
+  (eng (feed/activity "x" "post" "p2" 0 (list)))
+  1)
+
+; ---------- composite ----------
+
+(define
+  cmp1
+  (feed/composite (list (list 2 (fn (a) (get a :at))))))
+(feed-test
+  "composite single part"
+  (cmp1 (feed/activity "x" "post" "o" 5 (list)))
+  10)
+(define
+  cmp2
+  (feed/composite
+    (list
+      (list 2 (fn (a) (get a :at)))
+      (list 3 (fn (a) 1)))))
+(feed-test
+  "composite two parts"
+  (cmp2 (feed/activity "x" "post" "o" 5 (list)))
+  13)
+
+; ---------- ranking ----------
+
+(define
+  R
+  (feed/stream
+    (list
+      (feed/activity "u" "post" "oC" 80 (list))
+      (feed/activity "u" "post" "oA" 100 (list))
+      (feed/activity "u" "post" "oB" 90 (list)))))
+
+(feed-test
+  "rank by recency objects"
+  (map (fn (a) (get a :object)) (feed/items (feed/rank R rec)))
+  (list "oA" "oB" "oC"))
+(feed-test
+  "top-2 by recency"
+  (map (fn (a) (get a :object)) (feed/items (feed/top R rec 2)))
+  (list "oA" "oB"))
+(feed-test "top-2 count" (feed/count (feed/top R rec 2)) 2)
+
+; constant score -> tiebreak by :at descending
+(define
+  T
+  (feed/stream
+    (list
+      (feed/activity "u" "post" "f" 10 (list))
+      (feed/activity "u" "post" "g" 30 (list))
+      (feed/activity "u" "post" "h" 20 (list)))))
+(feed-test
+  "tiebreak at-desc"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/rank T (fn (a) 0))))
+  (list "g" "h" "f"))
+
+; equal score AND equal :at -> stable input order
+(define
+  E
+  (feed/stream
+    (list
+      (feed/activity "u" "post" "first" 50 (list))
+      (feed/activity "u" "post" "second" 50 (list)))))
+(feed-test
+  "stable equal-key input order"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/rank E (fn (a) 0))))
+  (list "first" "second"))
+
+(feed-test
+  "with-scores attaches score"
+  (get (nth (feed/items (feed/with-scores R rec)) 1) :score)
+  1)
+
+(feed-test "rank preserves count" (feed/count (feed/rank A rec)) 4)

lib/feed/tests/thread.sx

@@ -0,0 +1,49 @@
+; Follow-up — conversation threading via :reply-to closure. (feed-test name got expected)
+
+(define
+  S
+  (feed/stream
+    (list
+      (feed/normalize {:actor "a" :object "root" :at 1})
+      (feed/normalize {:actor "b" :object "r1" :at 2 :verb "reply" :reply-to "root"})
+      (feed/normalize {:actor "c" :object "r2" :at 3 :verb "reply" :reply-to "root"})
+      (feed/normalize {:actor "d" :object "r3" :at 4 :verb "reply" :reply-to "r1"})
+      (feed/normalize {:actor "e" :object "x" :at 5}))))
+
+; ---------- direct replies ----------
+
+(feed-test "direct replies to root" (feed/reply-count S "root") 2)
+(feed-test "direct replies to r1" (feed/reply-count S "r1") 1)
+(feed-test "no replies to r3" (feed/reply-count S "r3") 0)
+(feed-test
+  "replies objects to root"
+  (map (fn (a) (get a :object)) (feed/items (feed/replies S "root")))
+  (list "r1" "r2"))
+
+; ---------- thread closure ----------
+
+(feed-test
+  "thread objects root (transitive)"
+  (feed/thread-objects S "root")
+  (list "root" "r1" "r2" "r3"))
+(feed-test
+  "thread root chronological"
+  (map (fn (a) (get a :object)) (feed/items (feed/thread S "root")))
+  (list "root" "r1" "r2" "r3"))
+(feed-test "thread size root" (feed/thread-size S "root") 4)
+(feed-test
+  "thread excludes unrelated x"
+  (feed/-elem?
+    "x"
+    (map (fn (a) (get a :object)) (feed/items (feed/thread S "root"))))
+  false)
+
+; ---------- sub-thread ----------
+
+(feed-test
+  "thread from r1 (sub-tree)"
+  (map (fn (a) (get a :object)) (feed/items (feed/thread S "r1")))
+  (list "r1" "r3"))
+(feed-test "thread size r1" (feed/thread-size S "r1") 2)
+(feed-test "leaf thread is itself" (feed/thread-size S "r3") 1)
+(feed-test "unrelated thread is itself" (feed/thread-size S "x") 1)

lib/feed/tests/trending.sx

@@ -0,0 +1,82 @@
+; Follow-up — trending objects/actors by recent activity. (feed-test name got expected)
+
+; window (50,100]: X@60,X@70 (a), Y@80 (b), Z@90 (c); W@40 is too old
+(define
+  S
+  (feed/stream
+    (list
+      (feed/activity "a" "post" "X" 60 (list))
+      (feed/activity "a" "post" "X" 70 (list))
+      (feed/activity "b" "post" "Y" 80 (list))
+      (feed/activity "c" "post" "Z" 90 (list))
+      (feed/activity "d" "post" "W" 40 (list)))))
+
+; ---------- trending objects ----------
+
+(feed-test
+  "trending count (3 in window)"
+  (len (feed/trending S 100 50 10))
+  3)
+(feed-test
+  "trending top object"
+  (get
+    (nth (feed/trending S 100 50 10) 0)
+    :object)
+  "X")
+(feed-test
+  "trending top count"
+  (get
+    (nth (feed/trending S 100 50 10) 0)
+    :count)
+  2)
+(feed-test
+  "trending order (count desc, key asc tiebreak)"
+  (map
+    (fn (e) (get e :object))
+    (feed/trending S 100 50 10))
+  (list "X" "Y" "Z"))
+(feed-test
+  "trending top-2"
+  (map
+    (fn (e) (get e :object))
+    (feed/trending S 100 50 2))
+  (list "X" "Y"))
+(feed-test
+  "old object W excluded"
+  (feed/-elem?
+    "W"
+    (map
+      (fn (e) (get e :object))
+      (feed/trending S 100 50 10)))
+  false)
+(feed-test
+  "narrow window keeps only newest"
+  (map
+    (fn (e) (get e :object))
+    (feed/trending S 100 15 10))
+  (list "Z"))
+(feed-test
+  "empty window -> nothing"
+  (feed/trending S 100 5 10)
+  (list))
+
+; ---------- trending actors ----------
+
+(feed-test
+  "trending actor top"
+  (get
+    (nth (feed/trending-actors S 100 50 10) 0)
+    :actor)
+  "a")
+(feed-test
+  "trending actor count"
+  (get
+    (nth (feed/trending-actors S 100 50 10) 0)
+    :count)
+  2)
+(feed-test
+  "trending actors order"
+  (map
+    (fn (e) (get e :actor))
+    (feed/trending-actors S 100 50 10))
+  (list "a" "b" "c"))

lib/feed/thread.sx

@@ -0,0 +1,59 @@
+; feed/thread — conversation threading. A reply carries :reply-to <parent-object>
+; (normalize preserves it). A thread is the transitive closure over :reply-to from
+; a root object: root + replies + replies-to-replies, gathered chronologically.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/-elem?, feed/-distinct).
+
+; direct replies to an object
+(define
+  feed/replies
+  (fn
+    (stream object)
+    (feed/filter stream (fn (a) (equal? (get a :reply-to) object)))))
+
+(define
+  feed/reply-count
+  (fn (stream object) (feed/count (feed/replies stream object))))
+
+; iterate f from x until the result stops growing (set-closure fixpoint)
+(define
+  feed/-fixpoint
+  (fn
+    (f x)
+    (let
+      ((nx (f x)))
+      (if (= (len nx) (len x)) x (feed/-fixpoint f nx)))))
+
+; the set of object-ids in the thread rooted at `root`
+(define
+  feed/thread-objects
+  (fn
+    (stream root)
+    (let
+      ((all (feed/items stream)))
+      (feed/-fixpoint
+        (fn
+          (acc)
+          (feed/-distinct
+            (append
+              acc
+              (map
+                (fn (a) (get a :object))
+                (filter (fn (a) (feed/-elem? (get a :reply-to) acc)) all)))))
+        (list root)))))
+
+; the full thread as a chronological stream (root + all descendants)
+(define
+  feed/thread
+  (fn
+    (stream root)
+    (let
+      ((objs (feed/thread-objects stream root)))
+      (feed/sort-by-at
+        (feed/filter stream (fn (a) (feed/-elem? (get a :object) objs)))))))
+
+; how many activities are in the thread (root counts as 1)
+(define
+  feed/thread-size
+  (fn (stream root) (feed/count (feed/thread stream root))))

lib/feed/trending.sx

@@ -0,0 +1,42 @@
+; feed/trending — what's hot right now: objects (or actors) ranked by activity
+; count within a recency window. Deterministic: count descending, ties broken by
+; key ascending (entries are pre-sorted by key, then stable grade-down by count).
+;
+; Requires: lib/feed/stream.sx, lib/feed/aggregate.sx (object/actor-counts),
+; lib/feed/rank.sx (feed/-desc-by).
+
+; activities within (now-window, now]
+(define
+  feed/-recent
+  (fn
+    (stream now window)
+    (feed/filter
+      stream
+      (fn (a) (and (<= (get a :at) now) (> (get a :at) (- now window)))))))
+
+; counts dict -> top-N entries {label key, :count n}, count desc, key asc
+(define
+  feed/-top-counts
+  (fn
+    (counts label n)
+    (let
+      ((entries (map (fn (k) (assoc {:count (get counts k)} label k)) (sort (keys counts)))))
+      (take (feed/-desc-by entries (fn (e) (get e :count))) n))))
+
+; top-N trending objects in the window
+(define
+  feed/trending
+  (fn
+    (stream now window n)
+    (feed/-top-counts
+      (feed/object-counts (feed/-recent stream now window))
+      :object n)))
+
+; top-N most active actors in the window
+(define
+  feed/trending-actors
+  (fn
+    (stream now window n)
+    (feed/-top-counts
+      (feed/actor-counts (feed/-recent stream now window))
+      :actor n)))

lib/identity/audit.sx

@@ -0,0 +1,27 @@
+;; identity/audit.sx — the grant audit ledger.
+;;
+;; Every transition that changes a grant — issue, refresh, revoke (and,
+;; wired from oauth, consent) — appends an immutable event to this
+;; append-only process. The ledger is queryable by subject, which is what
+;; `(identity/audit subject)` answers. This is the in-memory realisation
+;; of the event stream; a persist-backed stream is a later substrate
+;; concern (Erlang↔persist bridge), kept out of scope here per the loop's
+;; \"in-memory log until persist lands\" allowance — the queryable
+;; semantics are identical.
+;;
+;; Events are {Seq, Subject, Action}; Seq is a monotonic sequence number.
+;; Reads return chronological (oldest-first) order:
+;;
+;;   record(A, Subject, Action)  -> ok       (one-way; FIFO-ordered)
+;;   audit(A, Subject)           -> [{Seq, Subject, Action}, ...]
+;;   actions(A, Subject)         -> [Action, ...]
+;;   count(A, Subject)           -> N
+;;   all(A)                      -> [{Seq, Subject, Action}, ...]
+
+(define
+  identity-audit-source
+  "-module(identity_audit).\n\n   start() ->\n     spawn(fun () -> loop([], 0) end).\n\n   record(A, Subject, Action) ->\n     A ! {event, Subject, Action},\n     ok.\n\n   audit(A, Subject) ->\n     A ! {audit, Subject, self()},\n     receive {audit_reply, R} -> R end.\n\n   actions(A, Subject) ->\n     A ! {actions, Subject, self()},\n     receive {audit_reply, R} -> R end.\n\n   count(A, Subject) ->\n     A ! {count, Subject, self()},\n     receive {audit_reply, R} -> R end.\n\n   all(A) ->\n     A ! {all, self()},\n     receive {audit_reply, R} -> R end.\n\n   loop(Events, Seq) ->\n     receive\n       {event, Subject, Action} ->\n         loop([{Seq, Subject, Action} | Events], Seq + 1);\n       {audit, Subject, From} ->\n         From ! {audit_reply, collect(Subject, Events, [])},\n         loop(Events, Seq);\n       {actions, Subject, From} ->\n         From ! {audit_reply, action_list(Subject, Events, [])},\n         loop(Events, Seq);\n       {count, Subject, From} ->\n         From ! {audit_reply, count_subj(Subject, Events, 0)},\n         loop(Events, Seq);\n       {all, From} ->\n         From ! {audit_reply, reverse(Events, [])},\n         loop(Events, Seq);\n       {stop, From} ->\n         From ! {audit_reply, ok}\n     end.\n\n   collect(_, [], Acc) -> Acc;\n   collect(Subject, [{Seq, S, A} | Rest], Acc) ->\n     case S =:= Subject of\n       true -> collect(Subject, Rest, [{Seq, S, A} | Acc]);\n       false -> collect(Subject, Rest, Acc)\n     end.\n\n   action_list(_, [], Acc) -> Acc;\n   action_list(Subject, [{_, S, A} | Rest], Acc) ->\n     case S =:= Subject of\n       true -> action_list(Subject, Rest, [A | Acc]);\n       false -> action_list(Subject, Rest, Acc)\n     end.\n\n   count_subj(_, [], N) -> N;\n   count_subj(Subject, [{_, S, _} | Rest], N) ->\n     case S =:= Subject of\n       true -> count_subj(Subject, Rest, N + 1);\n       false -> count_subj(Subject, Rest, N)\n     end.\n\n   reverse([], Acc) -> Acc;\n   reverse([H | T], Acc) -> reverse(T, [H | Acc]).")
+
+(define
+  identity-load-audit!
+  (fn () (erlang-load-module identity-audit-source)))

lib/identity/cache.sx

@@ -0,0 +1,29 @@
+;; identity/cache.sx — a delegated grant-verification cache, mirroring the
+;; Redis-cache pattern apps use in front of grant verification.
+;;
+;; The cache is a process wrapping a token registry. introspect() is
+;; memoised; issue/issue_grant/refresh/revoke pass through. The danger
+;; with any cache is staleness: a revoked token must NOT keep reading
+;; valid out of the cache, not even for a millisecond (the loop's hard
+;; rule). We get that for free with GENERATION invalidation:
+;;
+;;   - each cache entry records the generation it was written at;
+;;   - a hit requires entry.generation == current generation;
+;;   - any state-changing op that can invalidate an existing token
+;;     (revoke — which cascades to a grant; refresh — whose reuse cascades)
+;;     bumps the generation.
+;;
+;; So a single revoke instantly invalidates every cached positive: the
+;; next introspect is a miss and re-validates against the live registry,
+;; which returns {inactive}. Revocation stays real; the cache only ever
+;; accelerates the steady state, never overrides a revocation.
+;;
+;; stats() -> {Hits, Misses} so callers can see the cache is live.
+
+(define
+  identity-cache-source
+  "-module(identity_grant_cache).\n\n   start() ->\n     spawn(fun () ->\n       Reg = identity_tokens:start(),\n       loop(Reg, 1, [], 0, 0)\n     end).\n\n   issue(C, Subject, Client, Scope) ->\n     C ! {issue, Subject, Client, Scope, self()},\n     receive {cache_reply, R} -> R end.\n\n   issue_grant(C, Subject, Client, Scope) ->\n     C ! {issue_grant, Subject, Client, Scope, self()},\n     receive {cache_reply, R} -> R end.\n\n   refresh(C, RefreshTok) ->\n     C ! {refresh, RefreshTok, self()},\n     receive {cache_reply, R} -> R end.\n\n   introspect(C, Token) ->\n     C ! {introspect, Token, self()},\n     receive {cache_reply, R} -> R end.\n\n   revoke(C, Token) ->\n     C ! {revoke, Token, self()},\n     receive {cache_reply, R} -> R end.\n\n   stats(C) ->\n     C ! {stats, self()},\n     receive {cache_reply, R} -> R end.\n\n   loop(Reg, Gen, Entries, Hits, Misses) ->\n     receive\n       {introspect, Tok, From} ->\n         case lookup_fresh(Tok, Gen, Entries) of\n           {hit, Result} ->\n             From ! {cache_reply, Result},\n             loop(Reg, Gen, Entries, Hits + 1, Misses);\n           miss ->\n             Result = identity_tokens:introspect(Reg, Tok),\n             From ! {cache_reply, Result},\n             loop(Reg, Gen, put_entry(Tok, Result, Gen, Entries), Hits, Misses + 1)\n         end;\n       {issue, Subject, Client, Scope, From} ->\n         From ! {cache_reply, identity_tokens:issue(Reg, Subject, Client, Scope)},\n         loop(Reg, Gen, Entries, Hits, Misses);\n       {issue_grant, Subject, Client, Scope, From} ->\n         From ! {cache_reply, identity_tokens:issue_grant(Reg, Subject, Client, Scope)},\n         loop(Reg, Gen, Entries, Hits, Misses);\n       {refresh, RTok, From} ->\n         From ! {cache_reply, identity_tokens:refresh(Reg, RTok)},\n         loop(Reg, Gen + 1, Entries, Hits, Misses);\n       {revoke, Tok, From} ->\n         identity_tokens:revoke(Reg, Tok),\n         From ! {cache_reply, ok},\n         loop(Reg, Gen + 1, Entries, Hits, Misses);\n       {stats, From} ->\n         From ! {cache_reply, {Hits, Misses}},\n         loop(Reg, Gen, Entries, Hits, Misses)\n     end.\n\n   lookup_fresh(_, _, []) -> miss;\n   lookup_fresh(Tok, Gen, [{T, {Result, G}} | Rest]) ->\n     case T =:= Tok of\n       true ->\n         case G =:= Gen of\n           true -> {hit, Result};\n           false -> miss\n         end;\n       false -> lookup_fresh(Tok, Gen, Rest)\n     end.\n\n   put_entry(Tok, Result, Gen, Entries) ->\n     [{Tok, {Result, Gen}} | remove(Tok, Entries)].\n\n   remove(_, []) -> [];\n   remove(Tok, [{T, V} | Rest]) ->\n     case T =:= Tok of\n       true -> remove(Tok, Rest);\n       false -> [{T, V} | remove(Tok, Rest)]\n     end.")
+
+(define
+  identity-load-cache!
+  (fn () (erlang-load-module identity-cache-source)))

lib/identity/clients.sx

@@ -0,0 +1,28 @@
+;; identity/clients.sx — the OAuth client registry (RFC 6749 §2).
+;;
+;; A client is registered with a type, a secret, and its allow-listed
+;; redirect_uris:
+;;
+;;   public        — cannot keep a secret (SPAs, native apps, §2.1);
+;;                   identified but not authenticated.
+;;   confidential  — can authenticate; MUST present its secret at the token
+;;                   endpoint (§3.2.1, §4.1.3). A wrong secret is
+;;                   invalid_client — never a soft pass.
+;;
+;; Redirect URIs must be pre-registered (§3.1.2.2 + OAuth Security BCP):
+;; valid_redirect/3 is the exact-match check the authorize/exchange steps
+;; consult so an attacker cannot redirect the code to an unregistered URI.
+;;
+;;   register(C, ClientId, Type, Secret, RedirectUris) -> ok | {error, exists}
+;;   lookup(C, ClientId)            -> {ok, Type, RedirectUris} | {error, unknown_client}
+;;   authenticate(C, ClientId, Sec) -> {ok, public} | {ok, confidential}
+;;                                   | {error, invalid_client} | {error, unknown_client}
+;;   valid_redirect(C, ClientId, U) -> true | false
+
+(define
+  identity-clients-source
+  "-module(identity_clients).\n\n   start() ->\n     spawn(fun () -> loop([]) end).\n\n   register(C, ClientId, Type, Secret, RedirectUris) ->\n     C ! {register, ClientId, Type, Secret, RedirectUris, self()},\n     receive {client_reply, R} -> R end.\n\n   lookup(C, ClientId) ->\n     C ! {lookup, ClientId, self()},\n     receive {client_reply, R} -> R end.\n\n   authenticate(C, ClientId, Secret) ->\n     C ! {authenticate, ClientId, Secret, self()},\n     receive {client_reply, R} -> R end.\n\n   valid_redirect(C, ClientId, Uri) ->\n     C ! {valid_redirect, ClientId, Uri, self()},\n     receive {client_reply, R} -> R end.\n\n   loop(Clients) ->\n     receive\n       {register, ClientId, Type, Secret, RedirectUris, From} ->\n         case find(ClientId, Clients) of\n           {ok, _} ->\n             From ! {client_reply, {error, exists}},\n             loop(Clients);\n           none ->\n             From ! {client_reply, ok},\n             loop([{ClientId, {Type, Secret, RedirectUris}} | Clients])\n         end;\n       {lookup, ClientId, From} ->\n         case find(ClientId, Clients) of\n           none -> From ! {client_reply, {error, unknown_client}};\n           {ok, {Type, _, Uris}} -> From ! {client_reply, {ok, Type, Uris}}\n         end,\n         loop(Clients);\n       {authenticate, ClientId, Secret, From} ->\n         case find(ClientId, Clients) of\n           none ->\n             From ! {client_reply, {error, unknown_client}};\n           {ok, {public, _, _}} ->\n             From ! {client_reply, {ok, public}};\n           {ok, {confidential, S, _}} ->\n             case S =:= Secret of\n               true -> From ! {client_reply, {ok, confidential}};\n               false -> From ! {client_reply, {error, invalid_client}}\n             end\n         end,\n         loop(Clients);\n       {valid_redirect, ClientId, Uri, From} ->\n         case find(ClientId, Clients) of\n           none -> From ! {client_reply, false};\n           {ok, {_, _, Uris}} -> From ! {client_reply, member(Uri, Uris)}\n         end,\n         loop(Clients);\n       {stop, From} ->\n         From ! {client_reply, ok}\n     end.\n\n   member(_, []) -> false;\n   member(X, [Y | Rest]) ->\n     case X =:= Y of\n       true -> true;\n       false -> member(X, Rest)\n     end.\n\n   find(_, []) -> none;\n   find(Key, [{K, V} | Rest]) ->\n     case K =:= Key of\n       true -> {ok, V};\n       false -> find(Key, Rest)\n     end.")
+
+(define
+  identity-load-clients!
+  (fn () (erlang-load-module identity-clients-source)))

lib/identity/conformance.sh

@@ -0,0 +1,215 @@
+#!/usr/bin/env bash
+# identity-on-sx conformance runner.
+#
+# Loads the Erlang-on-SX substrate, the identity library, and every
+# identity test suite via the epoch protocol, collects pass/fail counts,
+# and writes lib/identity/scoreboard.json + .md.
+#
+# Usage:
+#   bash lib/identity/conformance.sh        # run all suites
+#   bash lib/identity/conformance.sh -v     # verbose per-suite
+
+set -uo pipefail
+cd "$(git rev-parse --show-toplevel)"
+
+SX_SERVER="${SX_SERVER:-hosts/ocaml/_build/default/bin/sx_server.exe}"
+if [ ! -x "$SX_SERVER" ]; then
+  SX_SERVER="/root/rose-ash/hosts/ocaml/_build/default/bin/sx_server.exe"
+fi
+if [ ! -x "$SX_SERVER" ]; then
+  echo "ERROR: sx_server.exe not found." >&2
+  exit 1
+fi
+
+VERBOSE="${1:-}"
+TMPFILE=$(mktemp)
+OUTFILE=$(mktemp)
+trap "rm -f $TMPFILE $OUTFILE" EXIT
+
+# Each suite: name | counter pass | counter total
+SUITES=(
+  "session|id-session-test-pass|id-session-test-count"
+  "token|id-token-test-pass|id-token-test-count"
+  "registry|id-registry-test-pass|id-registry-test-count"
+  "api|id-api-test-pass|id-api-test-count"
+  "oauth|id-oauth-test-pass|id-oauth-test-count"
+  "sso|id-sso-test-pass|id-sso-test-count"
+  "membership|id-membership-test-pass|id-membership-test-count"
+  "cache|id-cache-test-pass|id-cache-test-count"
+  "audit|id-audit-test-pass|id-audit-test-count"
+  "federation|id-fed-test-pass|id-fed-test-count"
+  "expiry|id-expiry-test-pass|id-expiry-test-count"
+  "clients|id-clients-test-pass|id-clients-test-count"
+  "grants|id-grants-test-pass|id-grants-test-count"
+  "device|id-device-test-pass|id-device-test-count"
+  "facade|id-facade-test-pass|id-facade-test-count"
+  "delegation|id-deleg-test-pass|id-deleg-test-count"
+  "session-mgmt|id-smgmt-test-pass|id-smgmt-test-count"
+  "exchange|id-xchg-test-pass|id-xchg-test-count"
+  "introspect|id-intr-test-pass|id-intr-test-count"
+  "par|id-par-test-pass|id-par-test-count"
+  "dynreg|id-dyn-test-pass|id-dyn-test-count"
+  "account|id-acct-test-pass|id-acct-test-count"
+)
+
+cat > "$TMPFILE" << 'EPOCHS'
+(epoch 1)
+(load "lib/erlang/tokenizer.sx")
+(load "lib/erlang/parser.sx")
+(load "lib/erlang/parser-core.sx")
+(load "lib/erlang/parser-expr.sx")
+(load "lib/erlang/parser-module.sx")
+(load "lib/erlang/transpile.sx")
+(load "lib/erlang/runtime.sx")
+(load "lib/identity/session.sx")
+(load "lib/identity/token.sx")
+(load "lib/identity/registry.sx")
+(load "lib/identity/api.sx")
+(load "lib/identity/oauth.sx")
+(load "lib/identity/membership.sx")
+(load "lib/identity/cache.sx")
+(load "lib/identity/audit.sx")
+(load "lib/identity/federation.sx")
+(load "lib/identity/clients.sx")
+(load "lib/identity/device.sx")
+(load "lib/identity/delegation.sx")
+(load "lib/identity/tests/session.sx")
+(load "lib/identity/tests/token.sx")
+(load "lib/identity/tests/registry.sx")
+(load "lib/identity/tests/api.sx")
+(load "lib/identity/tests/oauth.sx")
+(load "lib/identity/tests/sso.sx")
+(load "lib/identity/tests/membership.sx")
+(load "lib/identity/tests/cache.sx")
+(load "lib/identity/tests/audit.sx")
+(load "lib/identity/tests/federation.sx")
+(load "lib/identity/tests/expiry.sx")
+(load "lib/identity/tests/clients.sx")
+(load "lib/identity/tests/grants.sx")
+(load "lib/identity/tests/device.sx")
+(load "lib/identity/tests/facade.sx")
+(load "lib/identity/tests/delegation.sx")
+(load "lib/identity/tests/session_mgmt.sx")
+(load "lib/identity/tests/exchange.sx")
+(load "lib/identity/tests/introspect.sx")
+(load "lib/identity/tests/par.sx")
+(load "lib/identity/tests/dynreg.sx")
+(load "lib/identity/tests/account.sx")
+(epoch 100)
+(eval "(list id-session-test-pass id-session-test-count)")
+(epoch 101)
+(eval "(list id-token-test-pass id-token-test-count)")
+(epoch 102)
+(eval "(list id-registry-test-pass id-registry-test-count)")
+(epoch 103)
+(eval "(list id-api-test-pass id-api-test-count)")
+(epoch 104)
+(eval "(list id-oauth-test-pass id-oauth-test-count)")
+(epoch 105)
+(eval "(list id-sso-test-pass id-sso-test-count)")
+(epoch 106)
+(eval "(list id-membership-test-pass id-membership-test-count)")
+(epoch 107)
+(eval "(list id-cache-test-pass id-cache-test-count)")
+(epoch 108)
+(eval "(list id-audit-test-pass id-audit-test-count)")
+(epoch 109)
+(eval "(list id-fed-test-pass id-fed-test-count)")
+(epoch 110)
+(eval "(list id-expiry-test-pass id-expiry-test-count)")
+(epoch 111)
+(eval "(list id-clients-test-pass id-clients-test-count)")
+(epoch 112)
+(eval "(list id-grants-test-pass id-grants-test-count)")
+(epoch 113)
+(eval "(list id-device-test-pass id-device-test-count)")
+(epoch 114)
+(eval "(list id-facade-test-pass id-facade-test-count)")
+(epoch 115)
+(eval "(list id-deleg-test-pass id-deleg-test-count)")
+(epoch 116)
+(eval "(list id-smgmt-test-pass id-smgmt-test-count)")
+(epoch 117)
+(eval "(list id-xchg-test-pass id-xchg-test-count)")
+(epoch 118)
+(eval "(list id-intr-test-pass id-intr-test-count)")
+(epoch 119)
+(eval "(list id-par-test-pass id-par-test-count)")
+(epoch 120)
+(eval "(list id-dyn-test-pass id-dyn-test-count)")
+(epoch 121)
+(eval "(list id-acct-test-pass id-acct-test-count)")
+EPOCHS
+
+timeout 1200 "$SX_SERVER" < "$TMPFILE" > "$OUTFILE" 2>&1
+
+parse_pair() {
+  local epoch="$1"
+  local line
+  line=$(grep -A1 "^(ok-len $epoch " "$OUTFILE" | tail -1)
+  echo "$line" | sed -E 's/[()]//g'
+}
+
+TOTAL_PASS=0
+TOTAL_COUNT=0
+JSON_SUITES=""
+MD_ROWS=""
+
+idx=0
+for entry in "${SUITES[@]}"; do
+  name="${entry%%|*}"
+  epoch=$((100 + idx))
+  pair=$(parse_pair "$epoch")
+  pass=$(echo "$pair" | awk '{print $1}')
+  count=$(echo "$pair" | awk '{print $2}')
+  if [ -z "$pass" ] || [ -z "$count" ]; then
+    pass=0
+    count=0
+  fi
+  TOTAL_PASS=$((TOTAL_PASS + pass))
+  TOTAL_COUNT=$((TOTAL_COUNT + count))
+  status="ok"
+  marker="✅"
+  if [ "$pass" != "$count" ]; then
+    status="fail"
+    marker="❌"
+  fi
+  if [ "$VERBOSE" = "-v" ]; then
+    printf "  %-12s %s/%s\n" "$name" "$pass" "$count"
+  fi
+  if [ -n "$JSON_SUITES" ]; then JSON_SUITES+=","; fi
+  JSON_SUITES+=$'\n    '
+  JSON_SUITES+="{\"name\":\"$name\",\"pass\":$pass,\"total\":$count,\"status\":\"$status\"}"
+  MD_ROWS+="| $marker | $name | $pass | $count |"$'\n'
+  idx=$((idx + 1))
+done
+
+printf '\nidentity-on-sx conformance: %d / %d\n' "$TOTAL_PASS" "$TOTAL_COUNT"
+
+cat > lib/identity/scoreboard.json <<JSON
+{
+  "language": "identity",
+  "total_pass": $TOTAL_PASS,
+  "total": $TOTAL_COUNT,
+  "suites": [$JSON_SUITES
+  ]
+}
+JSON
+
+cat > lib/identity/scoreboard.md <<MD
+# identity-on-sx Scoreboard
+
+**Total: ${TOTAL_PASS} / ${TOTAL_COUNT} tests passing**
+
+|  | Suite | Pass | Total |
+|---|---|---|---|
+$MD_ROWS
+
+Generated by \`lib/identity/conformance.sh\`.
+MD
+
+if [ "$TOTAL_PASS" -eq "$TOTAL_COUNT" ]; then
+  exit 0
+else
+  exit 1
+fi

lib/identity/delegation.sx

@@ -0,0 +1,34 @@
+;; identity/delegation.sx — the identity -> acl delegation boundary.
+;;
+;; This is the loop's central architectural rule made concrete:
+;; AUTHENTICATION is identity's job; AUTHORIZATION is acl's. A request is
+;; checked in two stages, and the order matters:
+;;
+;;   1. identity proves WHO via the opaque token (introspect). If the token
+;;      is inactive, the answer is {error, unauthenticated} — a 401. acl is
+;;      NEVER consulted; \"I don't know who you are\" is not a permission
+;;      question.
+;;   2. only for an authenticated subject does identity construct the
+;;      permission query {Subject, Scope, Action, Resource} and HAND IT OFF
+;;      to acl. acl returns permit | deny; deny is {error, forbidden} — a
+;;      403. identity itself never decides permission.
+;;
+;; The real decider is acl-on-sx (Datalog), which runs as a different
+;; guest language on SX and is wired in at the integration layer. Here the
+;; acl side is a labelled STUB process so the boundary is exercised: it
+;; permits when the Action is within the token's granted Scope. Swap the
+;; stub pid for the acl adapter and the boundary is unchanged.
+;;
+;;   check(TokReg, Acl, Token, Action, Resource) ->
+;;     {ok, Subject} | {error, unauthenticated} | {error, forbidden}
+
+(define
+  identity-delegation-source
+  "-module(identity_delegation).\n\n   check(TokReg, Acl, Token, Action, Resource) ->\n     case identity_tokens:introspect(TokReg, Token) of\n       {inactive} ->\n         {error, unauthenticated};\n       {active, Subject, _Client, Scope} ->\n         Acl ! {acl_query, Subject, Scope, Action, Resource, self()},\n         receive {acl_verdict, V} ->\n           case V of\n             permit -> {ok, Subject};\n             deny -> {error, forbidden}\n           end\n         end\n     end.\n\n   %% --- stub acl decider (stands in for acl-on-sx / Datalog) ---\n   %% Permits iff the Action is one of the token's granted scopes. The real\n   %% acl decides on rules + facts; this only exercises the handoff shape.\n   stub_acl() ->\n     spawn(fun () -> acl_loop() end).\n\n   acl_loop() ->\n     receive\n       {acl_query, _Subject, Scope, Action, _Resource, From} ->\n         From ! {acl_verdict, decide(Action, Scope)},\n         acl_loop();\n       stop ->\n         ok\n     end.\n\n   decide(Action, Scope) ->\n     case member(Action, Scope) of\n       true -> permit;\n       false -> deny\n     end.\n\n   member(_, []) -> false;\n   member(X, [Y | Rest]) ->\n     case X =:= Y of\n       true -> true;\n       false -> member(X, Rest)\n     end.")
+
+(define
+  identity-load-delegation!
+  (fn
+    ()
+    (identity-load-token!)
+    (erlang-load-module identity-delegation-source)))

lib/identity/device.sx

@@ -0,0 +1,33 @@
+;; identity/device.sx — the device authorization grant (RFC 8628).
+;;
+;; For input-constrained devices (TVs, CLIs): the device gets a device_code
+;; + user_code, the user approves out-of-band on another device, and the
+;; device polls the token endpoint until it flips. The poll status machine
+;; is RFC 8628 §3.5:
+;;
+;;   authorize(ClientId, Scope) -> {ok, DeviceCode, UserCode}
+;;   approve(UserCode, Subject) -> ok | {error, ...}   (the human's browser)
+;;   deny(UserCode)             -> ok | {error, ...}
+;;   poll(DeviceCode) ->
+;;     pending  -> {error, authorization_pending}
+;;     denied   -> {error, access_denied}
+;;     approved -> {ok, Token}        (device code is then single-use)
+;;     consumed -> {error, invalid_grant}
+;;     unknown  -> {error, invalid_grant}
+;;
+;; Tokens are grant-backed (token.sx) so revocation stays real. Device-code
+;; expiry and slow_down (poll-rate limiting) are deferred — the substrate
+;; has no wall clock and the core status machine is the security-relevant
+;; part; introspect via token.sx already honours token TTL.
+;;
+;; State: loop(TokReg, Requests) where Requests is
+;;   [{DeviceCode, UserCode, ClientId, Scope, Status}]
+;;   Status :: pending | {approved, Subject} | denied | consumed
+
+(define
+  identity-device-source
+  "-module(identity_device).\n\n   start() ->\n     spawn(fun () ->\n       TokReg = identity_tokens:start(),\n       loop(TokReg, [])\n     end).\n\n   authorize(D, ClientId, Scope) ->\n     D ! {authorize, ClientId, Scope, self()},\n     receive {device_reply, R} -> R end.\n\n   approve(D, UserCode, Subject) ->\n     D ! {approve, UserCode, Subject, self()},\n     receive {device_reply, R} -> R end.\n\n   deny(D, UserCode) ->\n     D ! {deny, UserCode, self()},\n     receive {device_reply, R} -> R end.\n\n   poll(D, DeviceCode) ->\n     D ! {poll, DeviceCode, self()},\n     receive {device_reply, R} -> R end.\n\n   introspect(D, Token) ->\n     D ! {introspect, Token, self()},\n     receive {device_reply, R} -> R end.\n\n   loop(TokReg, Requests) ->\n     receive\n       {authorize, ClientId, Scope, From} ->\n         DeviceCode = make_ref(),\n         UserCode = make_ref(),\n         From ! {device_reply, {ok, DeviceCode, UserCode}},\n         loop(TokReg, [{DeviceCode, UserCode, ClientId, Scope, pending} | Requests]);\n       {approve, UserCode, Subject, From} ->\n         case find_user(UserCode, Requests) of\n           none ->\n             From ! {device_reply, {error, unknown_code}},\n             loop(TokReg, Requests);\n           {ok, {_, _, _, _, pending}} ->\n             From ! {device_reply, ok},\n             loop(TokReg, set_user(UserCode, {approved, Subject}, Requests));\n           {ok, {_, _, _, _, St}} ->\n             From ! {device_reply, {error, St}},\n             loop(TokReg, Requests)\n         end;\n       {deny, UserCode, From} ->\n         case find_user(UserCode, Requests) of\n           none ->\n             From ! {device_reply, {error, unknown_code}},\n             loop(TokReg, Requests);\n           {ok, {_, _, _, _, pending}} ->\n             From ! {device_reply, ok},\n             loop(TokReg, set_user(UserCode, denied, Requests));\n           {ok, {_, _, _, _, St}} ->\n             From ! {device_reply, {error, St}},\n             loop(TokReg, Requests)\n         end;\n       {poll, DeviceCode, From} ->\n         case find_device(DeviceCode, Requests) of\n           none ->\n             From ! {device_reply, {error, invalid_grant}},\n             loop(TokReg, Requests);\n           {ok, {_, _, _, _, pending}} ->\n             From ! {device_reply, {error, authorization_pending}},\n             loop(TokReg, Requests);\n           {ok, {_, _, _, _, denied}} ->\n             From ! {device_reply, {error, access_denied}},\n             loop(TokReg, Requests);\n           {ok, {_, _, _, _, consumed}} ->\n             From ! {device_reply, {error, invalid_grant}},\n             loop(TokReg, Requests);\n           {ok, {_, _, ClientId, Scope, {approved, Subject}}} ->\n             {ok, Token} = identity_tokens:issue(TokReg, Subject, ClientId, Scope),\n             From ! {device_reply, {ok, Token}},\n             loop(TokReg, set_device(DeviceCode, consumed, Requests))\n         end;\n       {introspect, Token, From} ->\n         From ! {device_reply, identity_tokens:introspect(TokReg, Token)},\n         loop(TokReg, Requests);\n       {stop, From} ->\n         From ! {device_reply, ok}\n     end.\n\n   find_device(_, []) -> none;\n   find_device(DCode, [{D, U, C, S, St} | Rest]) ->\n     case D =:= DCode of\n       true -> {ok, {D, U, C, S, St}};\n       false -> find_device(DCode, Rest)\n     end.\n\n   find_user(_, []) -> none;\n   find_user(UCode, [{D, U, C, S, St} | Rest]) ->\n     case U =:= UCode of\n       true -> {ok, {D, U, C, S, St}};\n       false -> find_user(UCode, Rest)\n     end.\n\n   set_device(_, _, []) -> [];\n   set_device(DCode, NewSt, [{D, U, C, S, St} | Rest]) ->\n     case D =:= DCode of\n       true -> [{D, U, C, S, NewSt} | Rest];\n       false -> [{D, U, C, S, St} | set_device(DCode, NewSt, Rest)]\n     end.\n\n   set_user(_, _, []) -> [];\n   set_user(UCode, NewSt, [{D, U, C, S, St} | Rest]) ->\n     case U =:= UCode of\n       true -> [{D, U, C, S, NewSt} | Rest];\n       false -> [{D, U, C, S, St} | set_user(UCode, NewSt, Rest)]\n     end.")
+
+(define
+  identity-load-device!
+  (fn () (identity-load-token!) (erlang-load-module identity-device-source)))

lib/identity/federation.sx

@@ -0,0 +1,30 @@
+;; identity/federation.sx — federated identity: peer-asserted subjects,
+;; advisory and trust-gated.
+;;
+;; A peer instance can assert \"this remote subject authenticated with me\".
+;; We accept such an assertion ONLY from a peer we explicitly trust
+;; (trust-gated); an assertion from an unknown peer is {error, untrusted},
+;; never silently honoured. Even when accepted, the resulting identity is
+;; ADVISORY: it is flagged peer_asserted with its origin peer, never
+;; promoted to local authority. Downstream (acl) decides how much a
+;; peer-asserted identity may do; identity only records who asserted it.
+;;
+;; Cross-instance subject mapping turns a (Peer, RemoteSubject) pair into a
+;; stable local subject. By default it is namespaced — {federated, Peer,
+;; RemoteSubject} — so two peers' \"alice\" never collide; an explicit map
+;; can alias a remote subject to a local one.
+;;
+;;   trust(F, Peer) / untrust(F, Peer) / trusted(F, Peer)
+;;   map(F, Peer, Remote, Local)            -> ok    (optional alias)
+;;   resolve(F, Peer, Remote)               -> {ok, LocalSubject}
+;;   assert_id(F, Peer, Remote)             -> {ok, LocalSubject}
+;;                                           | {error, untrusted}
+;;   provenance(F, LocalSubject)            -> {peer_asserted, Peer} | {local}
+
+(define
+  identity-federation-source
+  "-module(identity_federation).\n\n   start() ->\n     spawn(fun () -> loop([], [], []) end).\n\n   trust(F, Peer) ->\n     F ! {trust, Peer, self()},\n     receive {fed_reply, R} -> R end.\n\n   untrust(F, Peer) ->\n     F ! {untrust, Peer, self()},\n     receive {fed_reply, R} -> R end.\n\n   trusted(F, Peer) ->\n     F ! {trusted, Peer, self()},\n     receive {fed_reply, R} -> R end.\n\n   map(F, Peer, Remote, Local) ->\n     F ! {map, Peer, Remote, Local, self()},\n     receive {fed_reply, R} -> R end.\n\n   resolve(F, Peer, Remote) ->\n     F ! {resolve, Peer, Remote, self()},\n     receive {fed_reply, R} -> R end.\n\n   assert_id(F, Peer, Remote) ->\n     F ! {assert_id, Peer, Remote, self()},\n     receive {fed_reply, R} -> R end.\n\n   provenance(F, Local) ->\n     F ! {provenance, Local, self()},\n     receive {fed_reply, R} -> R end.\n\n   loop(Trusted, Maps, Asserted) ->\n     receive\n       {trust, Peer, From} ->\n         From ! {fed_reply, ok},\n         loop(add_unique(Peer, Trusted), Maps, Asserted);\n       {untrust, Peer, From} ->\n         From ! {fed_reply, ok},\n         loop(drop(Peer, Trusted), Maps, Asserted);\n       {trusted, Peer, From} ->\n         From ! {fed_reply, member(Peer, Trusted)},\n         loop(Trusted, Maps, Asserted);\n       {map, Peer, Remote, Local, From} ->\n         From ! {fed_reply, ok},\n         loop(Trusted, [{{Peer, Remote}, Local} | drop_map(Peer, Remote, Maps)], Asserted);\n       {resolve, Peer, Remote, From} ->\n         From ! {fed_reply, {ok, resolve_local(Peer, Remote, Maps)}},\n         loop(Trusted, Maps, Asserted);\n       {assert_id, Peer, Remote, From} ->\n         case member(Peer, Trusted) of\n           false ->\n             From ! {fed_reply, {error, untrusted}},\n             loop(Trusted, Maps, Asserted);\n           true ->\n             Local = resolve_local(Peer, Remote, Maps),\n             From ! {fed_reply, {ok, Local}},\n             loop(Trusted, Maps, [{Local, Peer} | drop_assert(Local, Asserted)])\n         end;\n       {provenance, Local, From} ->\n         case find_assert(Local, Asserted) of\n           {ok, Peer} -> From ! {fed_reply, {peer_asserted, Peer}};\n           none -> From ! {fed_reply, {local}}\n         end,\n         loop(Trusted, Maps, Asserted);\n       {stop, From} ->\n         From ! {fed_reply, ok}\n     end.\n\n   resolve_local(Peer, Remote, Maps) ->\n     case find_map(Peer, Remote, Maps) of\n       {ok, Local} -> Local;\n       none -> {federated, Peer, Remote}\n     end.\n\n   find_map(_, _, []) -> none;\n   find_map(Peer, Remote, [{{P, R}, Local} | Rest]) ->\n     case same(P, Peer, R, Remote) of\n       true -> {ok, Local};\n       false -> find_map(Peer, Remote, Rest)\n     end.\n\n   drop_map(_, _, []) -> [];\n   drop_map(Peer, Remote, [{{P, R}, Local} | Rest]) ->\n     case same(P, Peer, R, Remote) of\n       true -> drop_map(Peer, Remote, Rest);\n       false -> [{{P, R}, Local} | drop_map(Peer, Remote, Rest)]\n     end.\n\n   same(P, Peer, R, Remote) ->\n     case P =:= Peer of\n       true -> R =:= Remote;\n       false -> false\n     end.\n\n   find_assert(_, []) -> none;\n   find_assert(Local, [{L, Peer} | Rest]) ->\n     case L =:= Local of\n       true -> {ok, Peer};\n       false -> find_assert(Local, Rest)\n     end.\n\n   drop_assert(_, []) -> [];\n   drop_assert(Local, [{L, Peer} | Rest]) ->\n     case L =:= Local of\n       true -> drop_assert(Local, Rest);\n       false -> [{L, Peer} | drop_assert(Local, Rest)]\n     end.\n\n   add_unique(X, Xs) ->\n     case member(X, Xs) of\n       true -> Xs;\n       false -> [X | Xs]\n     end.\n\n   drop(_, []) -> [];\n   drop(X, [Y | Rest]) ->\n     case X =:= Y of\n       true -> drop(X, Rest);\n       false -> [Y | drop(X, Rest)]\n     end.\n\n   member(_, []) -> false;\n   member(X, [Y | Rest]) ->\n     case X =:= Y of\n       true -> true;\n       false -> member(X, Rest)\n     end.")
+
+(define
+  identity-load-federation!
+  (fn () (erlang-load-module identity-federation-source)))

lib/identity/membership.sx

@@ -0,0 +1,31 @@
+;; identity/membership.sx — coop membership state + per-app projection.
+;;
+;; Membership is canonical subject state held by one process, a guarded
+;; state machine (invalid transitions are explicit errors, never silent
+;; no-ops):
+;;
+;;   none --request--> pending --approve--> active
+;;   active --lapse--> lapsed --reinstate--> active
+;;   {pending|active|lapsed} --revoke--> revoked   (terminal)
+;;
+;; A per-app GRANT PROJECTION renders that one canonical state into the
+;; view a given client app consumes — mirroring rose-ash's per-app grant
+;; verification. The projection is pure identity: it reports WHAT the
+;; subject's membership is for that app; it does NOT decide whether the
+;; app should let them in. That permission question is acl's, keyed off
+;; this projection.
+;;
+;;   project(Subject, App) ->
+;;     active  -> {member, Tier, App}
+;;     pending -> {pending, App}
+;;     lapsed  -> {lapsed, App}
+;;     revoked -> {denied, App}
+;;     none    -> {non_member, App}
+
+(define
+  identity-membership-source
+  "-module(identity_membership).\n\n   start() ->\n     spawn(fun () -> loop([]) end).\n\n   request(M, Subject, Tier) ->\n     M ! {request, Subject, Tier, self()},\n     receive {membership_reply, R} -> R end.\n\n   approve(M, Subject) ->\n     M ! {approve, Subject, self()},\n     receive {membership_reply, R} -> R end.\n\n   lapse(M, Subject) ->\n     M ! {lapse, Subject, self()},\n     receive {membership_reply, R} -> R end.\n\n   reinstate(M, Subject) ->\n     M ! {reinstate, Subject, self()},\n     receive {membership_reply, R} -> R end.\n\n   revoke(M, Subject) ->\n     M ! {revoke, Subject, self()},\n     receive {membership_reply, R} -> R end.\n\n   status(M, Subject) ->\n     M ! {status, Subject, self()},\n     receive {membership_reply, R} -> R end.\n\n   project(M, Subject, App) ->\n     M ! {project, Subject, App, self()},\n     receive {membership_reply, R} -> R end.\n\n   loop(Members) ->\n     receive\n       {request, Subject, Tier, From} ->\n         case find(Subject, Members) of\n           none ->\n             From ! {membership_reply, ok},\n             loop([{Subject, {pending, Tier}} | Members]);\n           {ok, _} ->\n             From ! {membership_reply, {error, exists}},\n             loop(Members)\n         end;\n       {approve, Subject, From} ->\n         case find(Subject, Members) of\n           none ->\n             From ! {membership_reply, {error, not_found}},\n             loop(Members);\n           {ok, {pending, Tier}} ->\n             From ! {membership_reply, ok},\n             loop(set_record(Subject, {active, Tier}, Members));\n           {ok, {St, _}} ->\n             From ! {membership_reply, {error, St}},\n             loop(Members)\n         end;\n       {lapse, Subject, From} ->\n         case find(Subject, Members) of\n           none ->\n             From ! {membership_reply, {error, not_found}},\n             loop(Members);\n           {ok, {active, Tier}} ->\n             From ! {membership_reply, ok},\n             loop(set_record(Subject, {lapsed, Tier}, Members));\n           {ok, {St, _}} ->\n             From ! {membership_reply, {error, St}},\n             loop(Members)\n         end;\n       {reinstate, Subject, From} ->\n         case find(Subject, Members) of\n           none ->\n             From ! {membership_reply, {error, not_found}},\n             loop(Members);\n           {ok, {lapsed, Tier}} ->\n             From ! {membership_reply, ok},\n             loop(set_record(Subject, {active, Tier}, Members));\n           {ok, {St, _}} ->\n             From ! {membership_reply, {error, St}},\n             loop(Members)\n         end;\n       {revoke, Subject, From} ->\n         case find(Subject, Members) of\n           none ->\n             From ! {membership_reply, {error, not_found}},\n             loop(Members);\n           {ok, {_, Tier}} ->\n             From ! {membership_reply, ok},\n             loop(set_record(Subject, {revoked, Tier}, Members))\n         end;\n       {status, Subject, From} ->\n         case find(Subject, Members) of\n           none -> From ! {membership_reply, {none}};\n           {ok, {St, Tier}} -> From ! {membership_reply, {ok, St, Tier}}\n         end,\n         loop(Members);\n       {project, Subject, App, From} ->\n         From ! {membership_reply, project_view(Subject, App, Members)},\n         loop(Members);\n       {stop, From} ->\n         From ! {membership_reply, ok}\n     end.\n\n   project_view(Subject, App, Members) ->\n     case find(Subject, Members) of\n       none -> {non_member, App};\n       {ok, {active, Tier}} -> {member, Tier, App};\n       {ok, {pending, _}} -> {pending, App};\n       {ok, {lapsed, _}} -> {lapsed, App};\n       {ok, {revoked, _}} -> {denied, App}\n     end.\n\n   set_record(_, _, []) -> [];\n   set_record(Subject, Rec, [{S, Old} | Rest]) ->\n     case S =:= Subject of\n       true -> [{S, Rec} | Rest];\n       false -> [{S, Old} | set_record(Subject, Rec, Rest)]\n     end.\n\n   find(_, []) -> none;\n   find(Key, [{K, V} | Rest]) ->\n     case K =:= Key of\n       true -> {ok, V};\n       false -> find(Key, Rest)\n     end.")
+
+(define
+  identity-load-membership!
+  (fn () (erlang-load-module identity-membership-source)))

lib/identity/registry.sx

@@ -0,0 +1,22 @@
+;; identity/registry.sx — routes sessions by id and by (subject, client).
+;;
+;; The registry is the directory that makes SSO possible: one subject can
+;; hold many sessions (one per client), and the OAuth machine asks it the
+;; single question that drives silent login — \"is there a live session
+;; for this subject + this client?\". It stores (SessionId, Subject,
+;; Client, Pid) rows and answers:
+;;
+;;   whereis_session(Id)      -> {ok, Pid} | {error, not_found}
+;;   lookup(Subject, Client)  -> {ok, Pid} | {error, not_found}   (SSO probe)
+;;   sessions_for(Subject)    -> {ok, [SessionId, ...]}           (fan-out)
+;;
+;; The registry only routes — it holds no grant state and decides nothing.
+;; Liveness of the routed-to session is that session process's own affair.
+
+(define
+  identity-registry-source
+  "-module(identity_registry).\n\n   start() ->\n     spawn(fun () -> loop([]) end).\n\n   register(Reg, SessionId, Subject, Client, Pid) ->\n     Reg ! {register, SessionId, Subject, Client, Pid, self()},\n     receive {registry_reply, R} -> R end.\n\n   whereis_session(Reg, SessionId) ->\n     Reg ! {whereis_session, SessionId, self()},\n     receive {registry_reply, R} -> R end.\n\n   lookup(Reg, Subject, Client) ->\n     Reg ! {lookup, Subject, Client, self()},\n     receive {registry_reply, R} -> R end.\n\n   sessions_for(Reg, Subject) ->\n     Reg ! {sessions_for, Subject, self()},\n     receive {registry_reply, R} -> R end.\n\n   deregister(Reg, SessionId) ->\n     Reg ! {deregister, SessionId, self()},\n     receive {registry_reply, R} -> R end.\n\n   stop(Reg) ->\n     Reg ! {stop, self()},\n     receive {registry_reply, R} -> R end.\n\n   loop(Entries) ->\n     receive\n       {register, SessionId, Subject, Client, Pid, From} ->\n         From ! {registry_reply, ok},\n         loop([{SessionId, Subject, Client, Pid} | remove_id(SessionId, Entries)]);\n       {whereis_session, SessionId, From} ->\n         From ! {registry_reply, find_id(SessionId, Entries)},\n         loop(Entries);\n       {lookup, Subject, Client, From} ->\n         From ! {registry_reply, find_sc(Subject, Client, Entries)},\n         loop(Entries);\n       {sessions_for, Subject, From} ->\n         From ! {registry_reply, {ok, collect_subject(Subject, Entries)}},\n         loop(Entries);\n       {deregister, SessionId, From} ->\n         From ! {registry_reply, ok},\n         loop(remove_id(SessionId, Entries));\n       {stop, From} ->\n         From ! {registry_reply, ok}\n     end.\n\n   find_id(_, []) -> {error, not_found};\n   find_id(Id, [{Sid, _, _, Pid} | Rest]) ->\n     case Sid =:= Id of\n       true -> {ok, Pid};\n       false -> find_id(Id, Rest)\n     end.\n\n   find_sc(_, _, []) -> {error, not_found};\n   find_sc(Subject, Client, [{_, Su, Cl, Pid} | Rest]) ->\n     case Su =:= Subject of\n       true ->\n         case Cl =:= Client of\n           true -> {ok, Pid};\n           false -> find_sc(Subject, Client, Rest)\n         end;\n       false -> find_sc(Subject, Client, Rest)\n     end.\n\n   collect_subject(_, []) -> [];\n   collect_subject(Subject, [{Sid, Su, _, _} | Rest]) ->\n     case Su =:= Subject of\n       true -> [Sid | collect_subject(Subject, Rest)];\n       false -> collect_subject(Subject, Rest)\n     end.\n\n   remove_id(_, []) -> [];\n   remove_id(Id, [{Sid, Su, Cl, Pid} | Rest]) ->\n     case Sid =:= Id of\n       true -> remove_id(Id, Rest);\n       false -> [{Sid, Su, Cl, Pid} | remove_id(Id, Rest)]\n     end.")
+
+(define
+  identity-load-registry!
+  (fn () (erlang-load-module identity-registry-source)))

lib/identity/scoreboard.json

@@ -0,0 +1,29 @@
+{
+  "language": "identity",
+  "total_pass": 233,
+  "total": 233,
+  "suites": [
+    {"name":"session","pass":11,"total":11,"status":"ok"},
+    {"name":"token","pass":24,"total":24,"status":"ok"},
+    {"name":"registry","pass":9,"total":9,"status":"ok"},
+    {"name":"api","pass":10,"total":10,"status":"ok"},
+    {"name":"oauth","pass":17,"total":17,"status":"ok"},
+    {"name":"sso","pass":10,"total":10,"status":"ok"},
+    {"name":"membership","pass":17,"total":17,"status":"ok"},
+    {"name":"cache","pass":9,"total":9,"status":"ok"},
+    {"name":"audit","pass":11,"total":11,"status":"ok"},
+    {"name":"federation","pass":12,"total":12,"status":"ok"},
+    {"name":"expiry","pass":8,"total":8,"status":"ok"},
+    {"name":"clients","pass":11,"total":11,"status":"ok"},
+    {"name":"grants","pass":9,"total":9,"status":"ok"},
+    {"name":"device","pass":10,"total":10,"status":"ok"},
+    {"name":"facade","pass":9,"total":9,"status":"ok"},
+    {"name":"delegation","pass":8,"total":8,"status":"ok"},
+    {"name":"session-mgmt","pass":8,"total":8,"status":"ok"},
+    {"name":"exchange","pass":8,"total":8,"status":"ok"},
+    {"name":"introspect","pass":9,"total":9,"status":"ok"},
+    {"name":"par","pass":7,"total":7,"status":"ok"},
+    {"name":"dynreg","pass":5,"total":5,"status":"ok"},
+    {"name":"account","pass":11,"total":11,"status":"ok"}
+  ]
+}

lib/identity/scoreboard.md

@@ -0,0 +1,31 @@
+# identity-on-sx Scoreboard
+
+**Total: 233 / 233 tests passing**
+
+|  | Suite | Pass | Total |
+|---|---|---|---|
+| ✅ | session | 11 | 11 |
+| ✅ | token | 24 | 24 |
+| ✅ | registry | 9 | 9 |
+| ✅ | api | 10 | 10 |
+| ✅ | oauth | 17 | 17 |
+| ✅ | sso | 10 | 10 |
+| ✅ | membership | 17 | 17 |
+| ✅ | cache | 9 | 9 |
+| ✅ | audit | 11 | 11 |
+| ✅ | federation | 12 | 12 |
+| ✅ | expiry | 8 | 8 |
+| ✅ | clients | 11 | 11 |
+| ✅ | grants | 9 | 9 |
+| ✅ | device | 10 | 10 |
+| ✅ | facade | 9 | 9 |
+| ✅ | delegation | 8 | 8 |
+| ✅ | session-mgmt | 8 | 8 |
+| ✅ | exchange | 8 | 8 |
+| ✅ | introspect | 9 | 9 |
+| ✅ | par | 7 | 7 |
+| ✅ | dynreg | 5 | 5 |
+| ✅ | account | 11 | 11 |
+
+
+Generated by `lib/identity/conformance.sh`.

lib/identity/session.sx

@@ -0,0 +1,20 @@
+;; identity/session.sx — a session is an Erlang process.
+;;
+;; create  = spawn a session process holding {subject, client, status}
+;; lookup  = a message; the live process answers {ok, ...} or {error, S}
+;; expire  = explicit message OR an idle timeout the process arms itself
+;; revoke  = explicit message; the grant tombstones immediately
+;;
+;; Expiry is the process's own `receive ... after Ttl` timeout, never a
+;; global sweep. On timeout the process notifies its Owner and becomes a
+;; tombstone that still answers lookups — with {error, expired}, never a
+;; silent dead mailbox. A revoked or expired session is an explicit
+;; negative state, not the absence of a positive one.
+
+(define
+  identity-session-source
+  "-module(identity_session).\n\n   start(SessionId, Subject, Client, Owner, Ttl) ->\n     spawn(fun () -> active(SessionId, Subject, Client, Owner, Ttl) end).\n\n   lookup(Pid) ->\n     Pid ! {lookup, self()},\n     receive {session_reply, R} -> R end.\n\n   touch(Pid) ->\n     Pid ! {touch, self()},\n     receive {session_reply, R} -> R end.\n\n   expire(Pid) ->\n     Pid ! {expire, self()},\n     receive {session_reply, R} -> R end.\n\n   revoke(Pid) ->\n     Pid ! {revoke, self()},\n     receive {session_reply, R} -> R end.\n\n   stop(Pid) ->\n     Pid ! {stop, self()},\n     receive {session_reply, R} -> R end.\n\n   active(SessionId, Subject, Client, Owner, Ttl) ->\n     receive\n       {lookup, From} ->\n         From ! {session_reply, {ok, {SessionId, Subject, Client, active}}},\n         active(SessionId, Subject, Client, Owner, Ttl);\n       {touch, From} ->\n         From ! {session_reply, ok},\n         active(SessionId, Subject, Client, Owner, Ttl);\n       {expire, From} ->\n         From ! {session_reply, ok},\n         tombstone(SessionId, Subject, Client, expired);\n       {revoke, From} ->\n         From ! {session_reply, ok},\n         tombstone(SessionId, Subject, Client, revoked);\n       {stop, From} ->\n         From ! {session_reply, ok}\n     after Ttl ->\n       Owner ! {session_expired, SessionId},\n       tombstone(SessionId, Subject, Client, expired)\n     end.\n\n   tombstone(SessionId, Subject, Client, Status) ->\n     receive\n       {lookup, From} ->\n         From ! {session_reply, {error, Status}},\n         tombstone(SessionId, Subject, Client, Status);\n       {touch, From} ->\n         From ! {session_reply, {error, Status}},\n         tombstone(SessionId, Subject, Client, Status);\n       {expire, From} ->\n         From ! {session_reply, ok},\n         tombstone(SessionId, Subject, Client, Status);\n       {revoke, From} ->\n         From ! {session_reply, ok},\n         tombstone(SessionId, Subject, Client, revoked);\n       {stop, From} ->\n         From ! {session_reply, ok}\n     end.")
+
+(define
+  identity-load-session!
+  (fn () (erlang-load-module identity-session-source)))

lib/identity/tests/account.sx

@@ -0,0 +1,102 @@
+;; identity/tests/account.sx — the account-security surface: \"apps with
+;; access\" (grants_for / identity:grants) plus \"disconnect this app\"
+;; (revoke_app / identity:revoke_app). Completes the per-subject view+action
+;; pair alongside sessions and history.
+
+(define id-acct-test-count 0)
+(define id-acct-test-pass 0)
+(define id-acct-test-fails (list))
+
+(define
+  id-acct-test
+  (fn
+    (name actual expected)
+    (set! id-acct-test-count (+ id-acct-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-acct-test-pass (+ id-acct-test-pass 1))
+      (append! id-acct-test-fails {:name name :expected expected :actual actual}))))
+
+(define ida-ev erlang-eval-ast)
+(define idanm (fn (v) (get v :name)))
+
+(identity-load-all!)
+
+;; ── token-level grants_for ───────────────────────────────────────
+
+(id-acct-test
+  "grants_for lists a subject's active grants"
+  (ida-ev
+    "R = identity_tokens:start(),\n     identity_tokens:issue(R, alice, web, read),\n     identity_tokens:issue(R, alice, cli, write),\n     identity_tokens:issue(R, bob, web, read),\n     length(identity_tokens:grants_for(R, alice))")
+  2)
+
+(id-acct-test
+  "grants_for excludes revoked grants"
+  (ida-ev
+    "R = identity_tokens:start(),\n     {ok, A} = identity_tokens:issue(R, alice, web, read),\n     identity_tokens:issue(R, alice, cli, write),\n     identity_tokens:revoke(R, A),\n     length(identity_tokens:grants_for(R, alice))")
+  1)
+
+(id-acct-test
+  "grants_for is empty for a subject with none"
+  (ida-ev
+    "R = identity_tokens:start(),\n     identity_tokens:issue(R, alice, web, read),\n     length(identity_tokens:grants_for(R, ghost))")
+  0)
+
+(id-acct-test
+  "each grant entry carries the client"
+  (idanm
+    (ida-ev
+      "R = identity_tokens:start(),\n       identity_tokens:issue(R, alice, web, read),\n       case identity_tokens:grants_for(R, alice) of\n         [{Client, _Scope}] -> Client;\n         _ -> other\n       end"))
+  "web")
+
+;; ── token-level revoke_app (\"disconnect this app\") ────────────────
+
+(id-acct-test
+  "revoke_app revokes all of a subject's grants for one client"
+  (ida-ev
+    "R = identity_tokens:start(),\n     identity_tokens:issue(R, alice, web, read),\n     identity_tokens:issue(R, alice, web, write),\n     identity_tokens:issue(R, alice, cli, read),\n     identity_tokens:revoke_app(R, alice, web),\n     length(identity_tokens:grants_for(R, alice))")
+  1)
+
+(id-acct-test
+  "revoke_app deactivates that client's tokens"
+  (idanm
+    (ida-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, web, read),\n       identity_tokens:revoke_app(R, alice, web),\n       case identity_tokens:introspect(R, T) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(id-acct-test
+  "revoke_app leaves another subject's same-client grant intact"
+  (ida-ev
+    "R = identity_tokens:start(),\n     identity_tokens:issue(R, alice, web, read),\n     identity_tokens:issue(R, bob, web, read),\n     identity_tokens:revoke_app(R, alice, web),\n     length(identity_tokens:grants_for(R, bob))")
+  1)
+
+;; ── facade-level grants + revoke_app ─────────────────────────────
+
+(id-acct-test
+  "identity:grants lists apps a subject has logged into"
+  (ida-ev
+    "Svc = identity:start(),\n     identity:login(Svc, alice, web, read),\n     identity:login(Svc, alice, mobile, read),\n     length(identity:grants(Svc, alice))")
+  2)
+
+(id-acct-test
+  "identity:revoke_app disconnects one app, leaving the rest"
+  (ida-ev
+    "Svc = identity:start(),\n     identity:login(Svc, alice, web, read),\n     identity:login(Svc, alice, mobile, read),\n     identity:revoke_app(Svc, alice, web),\n     length(identity:grants(Svc, alice))")
+  1)
+
+(id-acct-test
+  "identity:grants is per-subject"
+  (ida-ev
+    "Svc = identity:start(),\n     identity:login(Svc, alice, web, read),\n     identity:login(Svc, bob, web, read),\n     length(identity:grants(Svc, bob))")
+  1)
+
+(id-acct-test
+  "revoke_app is audited as a revoke"
+  (idanm
+    (ida-ev
+      "Svc = identity:start(),\n       identity:login(Svc, alice, web, read),\n       identity:revoke_app(Svc, alice, web),\n       case identity:history(Svc, alice) of\n         [login, issue, revoke] -> audited;\n         Other -> Other\n       end"))
+  "audited")
+
+(define
+  id-acct-test-summary
+  (str "account " id-acct-test-pass "/" id-acct-test-count))

lib/identity/tests/api.sx

@@ -0,0 +1,111 @@
+;; identity/tests/api.sx — the service facade end-to-end: login issues a
+;; session + token, verify proves identity, revoke and logout take effect
+;; immediately. Exercises session + token + registry through one door.
+
+(define id-api-test-count 0)
+(define id-api-test-pass 0)
+(define id-api-test-fails (list))
+
+(define
+  id-api-test
+  (fn
+    (name actual expected)
+    (set! id-api-test-count (+ id-api-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-api-test-pass (+ id-api-test-pass 1))
+      (append! id-api-test-fails {:name name :expected expected :actual actual}))))
+
+(define ida-ev erlang-eval-ast)
+(define idanm (fn (v) (get v :name)))
+
+(identity-load-all!)
+
+;; ── login + verify (happy path) ──────────────────────────────────
+
+(id-api-test
+  "login then verify is active"
+  (idanm
+    (ida-ev
+      "Svc = identity:start(),\n       {ok, _Sid, Tok} = identity:login(Svc, alice, web, read),\n       case identity:verify(Svc, Tok) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+(id-api-test
+  "verify returns the logged-in subject"
+  (idanm
+    (ida-ev
+      "Svc = identity:start(),\n       {ok, _Sid, Tok} = identity:login(Svc, alice, web, read),\n       case identity:verify(Svc, Tok) of\n         {active, Subject, _, _} -> Subject\n       end"))
+  "alice")
+
+(id-api-test
+  "verify returns the granted scope"
+  (idanm
+    (ida-ev
+      "Svc = identity:start(),\n       {ok, _Sid, Tok} = identity:login(Svc, bob, cli, write),\n       case identity:verify(Svc, Tok) of\n         {active, _, _, Scope} -> Scope\n       end"))
+  "write")
+
+;; ── revoke is real through the facade ────────────────────────────
+
+(id-api-test
+  "revoked token verifies inactive immediately"
+  (idanm
+    (ida-ev
+      "Svc = identity:start(),\n       {ok, _Sid, Tok} = identity:login(Svc, alice, web, read),\n       identity:revoke(Svc, Tok),\n       case identity:verify(Svc, Tok) of\n         {active, _, _, _} -> still_valid;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+;; ── session lifecycle through the facade ─────────────────────────
+
+(id-api-test
+  "fresh session reports active"
+  (idanm
+    (ida-ev
+      "Svc = identity:start(),\n       {ok, Sid, _Tok} = identity:login(Svc, alice, web, read),\n       identity:session_status(Svc, Sid)"))
+  "active")
+
+(id-api-test
+  "logout makes the session gone"
+  (idanm
+    (ida-ev
+      "Svc = identity:start(),\n       {ok, Sid, _Tok} = identity:login(Svc, alice, web, read),\n       identity:logout(Svc, Sid),\n       identity:session_status(Svc, Sid)"))
+  "gone")
+
+(id-api-test
+  "status of an unknown session is gone"
+  (idanm
+    (ida-ev "Svc = identity:start(),\n       identity:session_status(Svc, 999)"))
+  "gone")
+
+;; ── independence: logins do not bleed into each other ────────────
+
+(id-api-test
+  "revoking one login leaves the other active"
+  (idanm
+    (ida-ev
+      "Svc = identity:start(),\n       {ok, _S1, T1} = identity:login(Svc, alice, web, read),\n       {ok, _S2, T2} = identity:login(Svc, bob, cli, write),\n       identity:revoke(Svc, T1),\n       case identity:verify(Svc, T2) of\n         {active, Subject, _, _} -> Subject;\n         {inactive} -> inactive\n       end"))
+  "bob")
+
+(id-api-test
+  "logging out one session leaves the other active"
+  (idanm
+    (ida-ev
+      "Svc = identity:start(),\n       {ok, S1, _T1} = identity:login(Svc, alice, web, read),\n       {ok, S2, _T2} = identity:login(Svc, alice, cli, read),\n       identity:logout(Svc, S1),\n       identity:session_status(Svc, S2)"))
+  "active")
+
+;; ── coordinator deregisters on a session_expired notification ────
+;; A live idle session fires its own `after` timeout and notifies its
+;; owner (the coordinator), which then deregisters it — timeout-driven,
+;; never swept. The owner-internal path can't be observed by driving the
+;; scheduler idle from the test's main process, so we assert the handler
+;; directly: the mailbox is FIFO, so the expiry notification is processed
+;; before the following status query.
+
+(id-api-test
+  "session_expired notification deregisters the session"
+  (idanm
+    (ida-ev
+      "Svc = identity:start(),\n       {ok, Sid, _Tok} = identity:login(Svc, alice, web, read, 50),\n       active = identity:session_status(Svc, Sid),\n       Svc ! {session_expired, Sid},\n       identity:session_status(Svc, Sid)"))
+  "gone")
+
+(define
+  id-api-test-summary
+  (str "api " id-api-test-pass "/" id-api-test-count))

lib/identity/tests/audit.sx

@@ -0,0 +1,117 @@
+;; identity/tests/audit.sx — the grant audit ledger. Every grant
+;; transition is recorded; the ledger is queryable per subject and
+;; chronological. Covers issue/refresh/revoke wiring through the token
+;; registry, reuse-triggered revoke, per-subject isolation, completeness,
+;; and direct ledger use.
+
+(define id-audit-test-count 0)
+(define id-audit-test-pass 0)
+(define id-audit-test-fails (list))
+
+(define
+  id-audit-test
+  (fn
+    (name actual expected)
+    (set! id-audit-test-count (+ id-audit-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-audit-test-pass (+ id-audit-test-pass 1))
+      (append! id-audit-test-fails {:name name :expected expected :actual actual}))))
+
+(define ida-ev erlang-eval-ast)
+(define idanm (fn (v) (get v :name)))
+
+(identity-load-audit!)
+(identity-load-token!)
+
+;; ── issue is audited ─────────────────────────────────────────────
+
+(id-audit-test
+  "issue records one event for the subject"
+  (ida-ev
+    "A = identity_audit:start(),\n     Reg = identity_tokens:start(A),\n     identity_tokens:issue(Reg, alice, web, read),\n     identity_audit:count(A, alice)")
+  1)
+
+(id-audit-test
+  "the recorded action is issue"
+  (idanm
+    (ida-ev
+      "A = identity_audit:start(),\n       Reg = identity_tokens:start(A),\n       identity_tokens:issue(Reg, alice, web, read),\n       case identity_audit:actions(A, alice) of\n         [issue] -> matched;\n         _ -> nomatch\n       end"))
+  "matched")
+
+;; ── full grant lifecycle is audited in order ─────────────────────
+
+(id-audit-test
+  "issue, refresh, revoke are recorded in order"
+  (idanm
+    (ida-ev
+      "A = identity_audit:start(),\n       Reg = identity_tokens:start(A),\n       {ok, G, R} = identity_tokens:issue_grant(Reg, alice, web, read),\n       identity_tokens:refresh(Reg, R),\n       identity_tokens:revoke(Reg, G),\n       case identity_audit:actions(A, alice) of\n         [issue, refresh, revoke] -> matched;\n         _ -> nomatch\n       end"))
+  "matched")
+
+;; ── reuse-triggered revoke is audited ────────────────────────────
+
+(id-audit-test
+  "a refresh-reuse cascade records a revoke event"
+  (idanm
+    (ida-ev
+      "A = identity_audit:start(),\n       Reg = identity_tokens:start(A),\n       {ok, _G, R} = identity_tokens:issue_grant(Reg, alice, web, read),\n       identity_tokens:refresh(Reg, R),\n       identity_tokens:refresh(Reg, R),\n       case identity_audit:actions(A, alice) of\n         [issue, refresh, revoke] -> matched;\n         _ -> nomatch\n       end"))
+  "matched")
+
+;; ── per-subject isolation ────────────────────────────────────────
+
+(id-audit-test
+  "the ledger separates subjects"
+  (ida-ev
+    "A = identity_audit:start(),\n     Reg = identity_tokens:start(A),\n     identity_tokens:issue(Reg, alice, web, read),\n     identity_tokens:issue(Reg, bob, cli, write),\n     identity_tokens:issue(Reg, alice, mobile, read),\n     identity_audit:count(A, alice)")
+  2)
+
+(id-audit-test
+  "an unaudited subject has zero events"
+  (ida-ev
+    "A = identity_audit:start(),\n     Reg = identity_tokens:start(A),\n     identity_tokens:issue(Reg, alice, web, read),\n     identity_audit:count(A, ghost)")
+  0)
+
+;; ── the full log accumulates across subjects ─────────────────────
+
+(id-audit-test
+  "all events accumulate in the ledger"
+  (ida-ev
+    "A = identity_audit:start(),\n     Reg = identity_tokens:start(A),\n     identity_tokens:issue(Reg, alice, web, read),\n     identity_tokens:issue(Reg, bob, cli, write),\n     length(identity_audit:all(A))")
+  2)
+
+;; ── completeness: no grant transition is dropped ─────────────────
+
+(id-audit-test
+  "the ledger is complete across a mixed transition stream"
+  (ida-ev
+    "A = identity_audit:start(),\n     Reg = identity_tokens:start(A),\n     identity_tokens:issue(Reg, alice, web, read),\n     {ok, _G, R} = identity_tokens:issue_grant(Reg, alice, cli, read),\n     identity_tokens:refresh(Reg, R),\n     {ok, B} = identity_tokens:issue(Reg, bob, web, read),\n     identity_tokens:revoke(Reg, B),\n     length(identity_audit:all(A))")
+  5)
+
+;; ── start/0 stays unaudited (no regression) ──────────────────────
+
+(id-audit-test
+  "an unaudited registry still issues working tokens"
+  (idanm
+    (ida-ev
+      "Reg = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(Reg, alice, web, read),\n       case identity_tokens:introspect(Reg, T) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+;; ── direct ledger use (e.g. login/consent events) ────────────────
+
+(id-audit-test
+  "events can be recorded directly on the ledger"
+  (idanm
+    (ida-ev
+      "A = identity_audit:start(),\n       identity_audit:record(A, alice, login),\n       identity_audit:record(A, alice, consent),\n       case identity_audit:actions(A, alice) of\n         [login, consent] -> matched;\n         _ -> nomatch\n       end"))
+  "matched")
+
+(id-audit-test
+  "an audit entry carries its subject"
+  (idanm
+    (ida-ev
+      "A = identity_audit:start(),\n       identity_audit:record(A, alice, login),\n       case identity_audit:audit(A, alice) of\n         [{_, Subject, _}] -> Subject;\n         _ -> nomatch\n       end"))
+  "alice")
+
+(define
+  id-audit-test-summary
+  (str "audit " id-audit-test-pass "/" id-audit-test-count))

lib/identity/tests/cache.sx

@@ -0,0 +1,102 @@
+;; identity/tests/cache.sx — delegated grant-verification cache. Proves
+;; the cache is live (hits/misses) AND that revocation stays real: a
+;; revoked token never reads valid out of the cache, because any revoke
+;; bumps the generation and forces re-validation.
+
+(define id-cache-test-count 0)
+(define id-cache-test-pass 0)
+(define id-cache-test-fails (list))
+
+(define
+  id-cache-test
+  (fn
+    (name actual expected)
+    (set! id-cache-test-count (+ id-cache-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-cache-test-pass (+ id-cache-test-pass 1))
+      (append! id-cache-test-fails {:name name :expected expected :actual actual}))))
+
+(define idc-ev erlang-eval-ast)
+(define idcnm (fn (v) (get v :name)))
+
+(identity-load-token!)
+(identity-load-cache!)
+
+;; ── delegation: cache forwards to the registry ───────────────────
+
+(id-cache-test
+  "introspect through the cache returns active"
+  (idcnm
+    (idc-ev
+      "C = identity_grant_cache:start(),\n       {ok, T} = identity_grant_cache:issue(C, alice, web, read),\n       case identity_grant_cache:introspect(C, T) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+;; ── the cache is actually caching ────────────────────────────────
+
+(id-cache-test
+  "a repeated introspect is a cache hit"
+  (idc-ev
+    "C = identity_grant_cache:start(),\n     {ok, T} = identity_grant_cache:issue(C, alice, web, read),\n     identity_grant_cache:introspect(C, T),\n     identity_grant_cache:introspect(C, T),\n     case identity_grant_cache:stats(C) of {H, _} -> H end")
+  1)
+
+(id-cache-test
+  "the first introspect of a token is a miss"
+  (idc-ev
+    "C = identity_grant_cache:start(),\n     {ok, T} = identity_grant_cache:issue(C, alice, web, read),\n     identity_grant_cache:introspect(C, T),\n     identity_grant_cache:introspect(C, T),\n     case identity_grant_cache:stats(C) of {_, M} -> M end")
+  1)
+
+;; ── revocation stays real through the cache (the centrepiece) ─────
+
+(id-cache-test
+  "a revoked token introspects inactive through the cache"
+  (idcnm
+    (idc-ev
+      "C = identity_grant_cache:start(),\n       {ok, T} = identity_grant_cache:issue(C, alice, web, read),\n       identity_grant_cache:introspect(C, T),\n       identity_grant_cache:revoke(C, T),\n       case identity_grant_cache:introspect(C, T) of\n         {active, _, _, _} -> still_valid;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(id-cache-test
+  "revoke invalidates the cache (post-revoke read re-validates)"
+  (idc-ev
+    "C = identity_grant_cache:start(),\n     {ok, T} = identity_grant_cache:issue(C, alice, web, read),\n     identity_grant_cache:introspect(C, T),\n     identity_grant_cache:revoke(C, T),\n     identity_grant_cache:introspect(C, T),\n     case identity_grant_cache:stats(C) of {_, M} -> M end")
+  2)
+
+;; ── cascade visibility through the cache ──────────────────────────
+
+(id-cache-test
+  "cascade revocation is visible through the cache"
+  (idcnm
+    (idc-ev
+      "C = identity_grant_cache:start(),\n       {ok, A, R} = identity_grant_cache:issue_grant(C, alice, web, read),\n       identity_grant_cache:introspect(C, A),\n       identity_grant_cache:revoke(C, R),\n       case identity_grant_cache:introspect(C, A) of\n         {active, _, _, _} -> still_valid;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+;; ── a sibling token re-validates correctly after a revoke ────────
+
+(id-cache-test
+  "revoking one token leaves an independent token valid"
+  (idcnm
+    (idc-ev
+      "C = identity_grant_cache:start(),\n       {ok, A} = identity_grant_cache:issue(C, alice, web, read),\n       {ok, B} = identity_grant_cache:issue(C, bob, cli, write),\n       identity_grant_cache:introspect(C, A),\n       identity_grant_cache:introspect(C, B),\n       identity_grant_cache:revoke(C, A),\n       case identity_grant_cache:introspect(C, B) of\n         {active, Subject, _, _} -> Subject;\n         {inactive} -> inactive\n       end"))
+  "bob")
+
+;; ── refresh flows through the cache and stays correct ────────────
+
+(id-cache-test
+  "a refreshed token introspects active through the cache"
+  (idcnm
+    (idc-ev
+      "C = identity_grant_cache:start(),\n       {ok, _A, R} = identity_grant_cache:issue_grant(C, alice, web, read),\n       {ok, A2, _R2} = identity_grant_cache:refresh(C, R),\n       case identity_grant_cache:introspect(C, A2) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+;; ── unknown token is inactive, and cached as such ────────────────
+
+(id-cache-test
+  "an unknown token introspects inactive through the cache"
+  (idcnm
+    (idc-ev
+      "C = identity_grant_cache:start(),\n       Bogus = make_ref(),\n       case identity_grant_cache:introspect(C, Bogus) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(define
+  id-cache-test-summary
+  (str "cache " id-cache-test-pass "/" id-cache-test-count))

lib/identity/tests/clients.sx

@@ -0,0 +1,108 @@
+;; identity/tests/clients.sx — OAuth client registry: registration,
+;; public vs confidential authentication, and redirect_uri allow-listing.
+
+(define id-clients-test-count 0)
+(define id-clients-test-pass 0)
+(define id-clients-test-fails (list))
+
+(define
+  id-clients-test
+  (fn
+    (name actual expected)
+    (set! id-clients-test-count (+ id-clients-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-clients-test-pass (+ id-clients-test-pass 1))
+      (append! id-clients-test-fails {:name name :expected expected :actual actual}))))
+
+(define idc-ev erlang-eval-ast)
+(define idcnm (fn (v) (get v :name)))
+
+(identity-load-clients!)
+
+;; ── registration + lookup ────────────────────────────────────────
+
+(id-clients-test
+  "a registered client looks up its type"
+  (idcnm
+    (idc-ev
+      "C = identity_clients:start(),\n       identity_clients:register(C, app1, confidential, s3cret, [uri1]),\n       case identity_clients:lookup(C, app1) of\n         {ok, Type, _} -> Type;\n         {error, W} -> W\n       end"))
+  "confidential")
+
+(id-clients-test
+  "registering the same client twice is an error"
+  (idcnm
+    (idc-ev
+      "C = identity_clients:start(),\n       identity_clients:register(C, app1, confidential, s3cret, [uri1]),\n       case identity_clients:register(C, app1, public, none, [uri1]) of\n         ok -> ok;\n         {error, W} -> W\n       end"))
+  "exists")
+
+(id-clients-test
+  "looking up an unregistered client is unknown_client"
+  (idcnm
+    (idc-ev
+      "C = identity_clients:start(),\n       case identity_clients:lookup(C, ghost) of\n         {ok, _, _} -> found;\n         {error, W} -> W\n       end"))
+  "unknown_client")
+
+;; ── confidential client authentication ───────────────────────────
+
+(id-clients-test
+  "a confidential client authenticates with the right secret"
+  (idcnm
+    (idc-ev
+      "C = identity_clients:start(),\n       identity_clients:register(C, app1, confidential, s3cret, [uri1]),\n       case identity_clients:authenticate(C, app1, s3cret) of\n         {ok, Kind} -> Kind;\n         {error, W} -> W\n       end"))
+  "confidential")
+
+(id-clients-test
+  "a confidential client with the wrong secret is invalid_client"
+  (idcnm
+    (idc-ev
+      "C = identity_clients:start(),\n       identity_clients:register(C, app1, confidential, s3cret, [uri1]),\n       case identity_clients:authenticate(C, app1, wrongsecret) of\n         {ok, _} -> accepted;\n         {error, W} -> W\n       end"))
+  "invalid_client")
+
+(id-clients-test
+  "a public client needs no secret to authenticate"
+  (idcnm
+    (idc-ev
+      "C = identity_clients:start(),\n       identity_clients:register(C, spa, public, none, [uri1]),\n       case identity_clients:authenticate(C, spa, anything) of\n         {ok, Kind} -> Kind;\n         {error, W} -> W\n       end"))
+  "public")
+
+(id-clients-test
+  "authenticating an unknown client is unknown_client"
+  (idcnm
+    (idc-ev
+      "C = identity_clients:start(),\n       case identity_clients:authenticate(C, ghost, x) of\n         {ok, _} -> accepted;\n         {error, W} -> W\n       end"))
+  "unknown_client")
+
+;; ── redirect_uri allow-listing ───────────────────────────────────
+
+(id-clients-test
+  "a registered redirect_uri is valid"
+  (idcnm
+    (idc-ev
+      "C = identity_clients:start(),\n       identity_clients:register(C, app1, confidential, s3cret, [uri1, uri2]),\n       case identity_clients:valid_redirect(C, app1, uri1) of\n         true -> yes;\n         false -> no\n       end"))
+  "yes")
+
+(id-clients-test
+  "a second registered redirect_uri is also valid"
+  (idcnm
+    (idc-ev
+      "C = identity_clients:start(),\n       identity_clients:register(C, app1, confidential, s3cret, [uri1, uri2]),\n       case identity_clients:valid_redirect(C, app1, uri2) of\n         true -> yes;\n         false -> no\n       end"))
+  "yes")
+
+(id-clients-test
+  "an unregistered redirect_uri is rejected"
+  (idcnm
+    (idc-ev
+      "C = identity_clients:start(),\n       identity_clients:register(C, app1, confidential, s3cret, [uri1]),\n       case identity_clients:valid_redirect(C, app1, evil_uri) of\n         true -> yes;\n         false -> no\n       end"))
+  "no")
+
+(id-clients-test
+  "redirect validation for an unknown client is rejected"
+  (idcnm
+    (idc-ev
+      "C = identity_clients:start(),\n       case identity_clients:valid_redirect(C, ghost, uri1) of\n         true -> yes;\n         false -> no\n       end"))
+  "no")
+
+(define
+  id-clients-test-summary
+  (str "clients " id-clients-test-pass "/" id-clients-test-count))

lib/identity/tests/delegation.sx

@@ -0,0 +1,102 @@
+;; identity/tests/delegation.sx — the identity -> acl boundary.
+;; Authentication (identity) gates BEFORE authorization (acl): an inactive
+;; token is unauthenticated (401) and acl is never consulted; only an
+;; authenticated subject's request is delegated to acl for permit/deny.
+
+(define id-deleg-test-count 0)
+(define id-deleg-test-pass 0)
+(define id-deleg-test-fails (list))
+
+(define
+  id-deleg-test
+  (fn
+    (name actual expected)
+    (set! id-deleg-test-count (+ id-deleg-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-deleg-test-pass (+ id-deleg-test-pass 1))
+      (append! id-deleg-test-fails {:name name :expected expected :actual actual}))))
+
+(define idl-ev erlang-eval-ast)
+(define idlnm (fn (v) (get v :name)))
+
+(identity-load-delegation!)
+
+;; Shared prelude: a token registry, a stub acl, and a token granting
+;; [read, write] to alice, all bound.
+(define
+  idl-setup
+  "R = identity_tokens:start(),\n   A = identity_delegation:stub_acl(),\n   {ok, T} = identity_tokens:issue(R, alice, web, [read, write])")
+
+;; ── authenticated + acl permits ──────────────────────────────────
+
+(id-deleg-test
+  "an authenticated, permitted request returns the subject"
+  (idlnm
+    (idl-ev
+      (str
+        idl-setup
+        ", case identity_delegation:check(R, A, T, read, doc1) of\n             {ok, S} -> S;\n             {error, W} -> W\n           end")))
+  "alice")
+
+;; ── authenticated + acl denies → 403 ─────────────────────────────
+
+(id-deleg-test
+  "an authenticated but unpermitted request is forbidden"
+  (idlnm
+    (idl-ev
+      "R = identity_tokens:start(),\n       A = identity_delegation:stub_acl(),\n       {ok, T} = identity_tokens:issue(R, alice, web, [read]),\n       case identity_delegation:check(R, A, T, write, doc1) of\n         {ok, _} -> permitted;\n         {error, W} -> W\n       end"))
+  "forbidden")
+
+;; ── unauthenticated → 401, acl never consulted ───────────────────
+
+(id-deleg-test
+  "a revoked token is unauthenticated, not forbidden"
+  (idlnm
+    (idl-ev
+      (str
+        idl-setup
+        ", identity_tokens:revoke(R, T),\n           case identity_delegation:check(R, A, T, read, doc1) of\n             {ok, _} -> permitted;\n             {error, W} -> W\n           end")))
+  "unauthenticated")
+
+(id-deleg-test
+  "an unknown token is unauthenticated"
+  (idlnm
+    (idl-ev
+      "R = identity_tokens:start(),\n       A = identity_delegation:stub_acl(),\n       Bogus = make_ref(),\n       case identity_delegation:check(R, A, Bogus, read, doc1) of\n         {ok, _} -> permitted;\n         {error, W} -> W\n       end"))
+  "unauthenticated")
+
+(id-deleg-test
+  "an expired token is unauthenticated"
+  (idlnm
+    (idl-ev
+      "R = identity_tokens:start(),\n       A = identity_delegation:stub_acl(),\n       {ok, T} = identity_tokens:issue(R, alice, web, [read], 100),\n       identity_tokens:advance(R, 100),\n       case identity_delegation:check(R, A, T, read, doc1) of\n         {ok, _} -> permitted;\n         {error, W} -> W\n       end"))
+  "unauthenticated")
+
+;; ── 401 takes precedence over 403 (identity gates first) ─────────
+
+(id-deleg-test
+  "a revoked token with no matching scope is still unauthenticated"
+  (idlnm
+    (idl-ev
+      "R = identity_tokens:start(),\n       A = identity_delegation:stub_acl(),\n       {ok, T} = identity_tokens:issue(R, alice, web, [admin]),\n       identity_tokens:revoke(R, T),\n       case identity_delegation:check(R, A, T, read, doc1) of\n         {ok, _} -> permitted;\n         {error, W} -> W\n       end"))
+  "unauthenticated")
+
+;; ── acl is what decides for an authenticated subject ─────────────
+
+(id-deleg-test
+  "the same subject is permitted one action and denied another"
+  (idl-ev
+    "R = identity_tokens:start(),\n     A = identity_delegation:stub_acl(),\n     {ok, T} = identity_tokens:issue(R, alice, web, [read]),\n     Allowed = case identity_delegation:check(R, A, T, read, doc1) of\n       {ok, _} -> 1; {error, _} -> 0 end,\n     Denied = case identity_delegation:check(R, A, T, write, doc1) of\n       {ok, _} -> 1; {error, _} -> 0 end,\n     Allowed - Denied")
+  1)
+
+(id-deleg-test
+  "identity does not widen permission beyond the token scope"
+  (idlnm
+    (idl-ev
+      "R = identity_tokens:start(),\n       A = identity_delegation:stub_acl(),\n       {ok, T} = identity_tokens:issue(R, alice, web, [read, write]),\n       case identity_delegation:check(R, A, T, delete, doc1) of\n         {ok, _} -> permitted;\n         {error, W} -> W\n       end"))
+  "forbidden")
+
+(define
+  id-deleg-test-summary
+  (str "delegation " id-deleg-test-pass "/" id-deleg-test-count))

lib/identity/tests/device.sx

@@ -0,0 +1,109 @@
+;; identity/tests/device.sx — device authorization grant (RFC 8628):
+;; authorize → poll(pending) → approve/deny out-of-band → poll(token/denied).
+
+(define id-device-test-count 0)
+(define id-device-test-pass 0)
+(define id-device-test-fails (list))
+
+(define
+  id-device-test
+  (fn
+    (name actual expected)
+    (set! id-device-test-count (+ id-device-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-device-test-pass (+ id-device-test-pass 1))
+      (append! id-device-test-fails {:name name :expected expected :actual actual}))))
+
+(define idd-ev erlang-eval-ast)
+(define iddnm (fn (v) (get v :name)))
+
+(identity-load-device!)
+
+;; ── polling before approval ──────────────────────────────────────
+
+(id-device-test
+  "polling a pending device code is authorization_pending"
+  (iddnm
+    (idd-ev
+      "D = identity_device:start(),\n       {ok, Dc, _Uc} = identity_device:authorize(D, tv, watch),\n       case identity_device:poll(D, Dc) of\n         {ok, _} -> got;\n         {error, W} -> W\n       end"))
+  "authorization_pending")
+
+;; ── approve → token ──────────────────────────────────────────────
+
+(id-device-test
+  "after approval, polling yields a working token"
+  (iddnm
+    (idd-ev
+      "D = identity_device:start(),\n       {ok, Dc, Uc} = identity_device:authorize(D, tv, watch),\n       identity_device:approve(D, Uc, alice),\n       {ok, T} = identity_device:poll(D, Dc),\n       case identity_device:introspect(D, T) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+(id-device-test
+  "the device token carries the approving subject"
+  (iddnm
+    (idd-ev
+      "D = identity_device:start(),\n       {ok, Dc, Uc} = identity_device:authorize(D, tv, watch),\n       identity_device:approve(D, Uc, alice),\n       {ok, T} = identity_device:poll(D, Dc),\n       case identity_device:introspect(D, T) of\n         {active, Subject, _, _} -> Subject\n       end"))
+  "alice")
+
+(id-device-test
+  "the device token carries the requested scope"
+  (iddnm
+    (idd-ev
+      "D = identity_device:start(),\n       {ok, Dc, Uc} = identity_device:authorize(D, tv, stream),\n       identity_device:approve(D, Uc, alice),\n       {ok, T} = identity_device:poll(D, Dc),\n       case identity_device:introspect(D, T) of\n         {active, _, _, Scope} -> Scope\n       end"))
+  "stream")
+
+;; ── deny ─────────────────────────────────────────────────────────
+
+(id-device-test
+  "after denial, polling is access_denied"
+  (iddnm
+    (idd-ev
+      "D = identity_device:start(),\n       {ok, Dc, Uc} = identity_device:authorize(D, tv, watch),\n       identity_device:deny(D, Uc),\n       case identity_device:poll(D, Dc) of\n         {ok, _} -> got;\n         {error, W} -> W\n       end"))
+  "access_denied")
+
+;; ── unknown codes ────────────────────────────────────────────────
+
+(id-device-test
+  "polling an unknown device code is invalid_grant"
+  (iddnm
+    (idd-ev
+      "D = identity_device:start(),\n       Bogus = make_ref(),\n       case identity_device:poll(D, Bogus) of\n         {ok, _} -> got;\n         {error, W} -> W\n       end"))
+  "invalid_grant")
+
+(id-device-test
+  "approving an unknown user code is unknown_code"
+  (iddnm
+    (idd-ev
+      "D = identity_device:start(),\n       Bogus = make_ref(),\n       case identity_device:approve(D, Bogus, alice) of\n         ok -> ok;\n         {error, W} -> W\n       end"))
+  "unknown_code")
+
+;; ── single-use device code ───────────────────────────────────────
+
+(id-device-test
+  "the device code is single-use after issuing a token"
+  (iddnm
+    (idd-ev
+      "D = identity_device:start(),\n       {ok, Dc, Uc} = identity_device:authorize(D, tv, watch),\n       identity_device:approve(D, Uc, alice),\n       identity_device:poll(D, Dc),\n       case identity_device:poll(D, Dc) of\n         {ok, _} -> got;\n         {error, W} -> W\n       end"))
+  "invalid_grant")
+
+;; ── guarded transitions ──────────────────────────────────────────
+
+(id-device-test
+  "approving an already-denied request is rejected"
+  (iddnm
+    (idd-ev
+      "D = identity_device:start(),\n       {ok, _Dc, Uc} = identity_device:authorize(D, tv, watch),\n       identity_device:deny(D, Uc),\n       case identity_device:approve(D, Uc, alice) of\n         ok -> ok;\n         {error, W} -> W\n       end"))
+  "denied")
+
+;; ── independence ─────────────────────────────────────────────────
+
+(id-device-test
+  "two device requests are independent"
+  (iddnm
+    (idd-ev
+      "D = identity_device:start(),\n       {ok, Dc1, Uc1} = identity_device:authorize(D, tv, watch),\n       {ok, Dc2, _Uc2} = identity_device:authorize(D, cli, deploy),\n       identity_device:approve(D, Uc1, alice),\n       case identity_device:poll(D, Dc2) of\n         {ok, _} -> got;\n         {error, W} -> W\n       end"))
+  "authorization_pending")
+
+(define
+  id-device-test-summary
+  (str "device " id-device-test-pass "/" id-device-test-count))

lib/identity/tests/dynreg.sx

@@ -0,0 +1,68 @@
+;; identity/tests/dynreg.sx — dynamic client registration (RFC 7591): the
+;; server generates the client_id + secret for self-service onboarding.
+
+(define id-dyn-test-count 0)
+(define id-dyn-test-pass 0)
+(define id-dyn-test-fails (list))
+
+(define
+  id-dyn-test
+  (fn
+    (name actual expected)
+    (set! id-dyn-test-count (+ id-dyn-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-dyn-test-pass (+ id-dyn-test-pass 1))
+      (append! id-dyn-test-fails {:name name :expected expected :actual actual}))))
+
+(define idd-ev erlang-eval-ast)
+(define iddnm (fn (v) (get v :name)))
+
+(identity-load-oauth!)
+
+;; ── self-service registration yields usable credentials ──────────
+
+(id-dyn-test
+  "a dynamically registered confidential client can get a token"
+  (iddnm
+    (idd-ev
+      "O = identity_oauth:start(),\n       {ok, Cid, Sec} = identity_oauth:register_dynamic(O, confidential, [uri1]),\n       {ok, T} = identity_oauth:client_credentials(O, Cid, Sec, batch),\n       case identity_oauth:introspect(O, T) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+(id-dyn-test
+  "the token's subject is the generated client id"
+  (iddnm
+    (idd-ev
+      "O = identity_oauth:start(),\n       {ok, Cid, Sec} = identity_oauth:register_dynamic(O, confidential, [uri1]),\n       {ok, T} = identity_oauth:client_credentials(O, Cid, Sec, batch),\n       case identity_oauth:introspect(O, T) of\n         {active, Sub, _, _} ->\n           case Sub =:= Cid of true -> matches; false -> mismatch end;\n         {inactive} -> inactive\n       end"))
+  "matches")
+
+;; ── the generated secret is required ─────────────────────────────
+
+(id-dyn-test
+  "a wrong secret for a dynamic client is invalid_client"
+  (iddnm
+    (idd-ev
+      "O = identity_oauth:start(),\n       {ok, Cid, _Sec} = identity_oauth:register_dynamic(O, confidential, [uri1]),\n       case identity_oauth:client_credentials(O, Cid, wrongsecret, batch) of\n         {ok, _} -> issued;\n         {error, W} -> W\n       end"))
+  "invalid_client")
+
+;; ── uniqueness ───────────────────────────────────────────────────
+
+(id-dyn-test
+  "two registrations yield distinct client ids"
+  (iddnm
+    (idd-ev
+      "O = identity_oauth:start(),\n       {ok, C1, _} = identity_oauth:register_dynamic(O, confidential, [uri1]),\n       {ok, C2, _} = identity_oauth:register_dynamic(O, confidential, [uri1]),\n       case C1 =:= C2 of true -> collision; false -> distinct end"))
+  "distinct")
+
+;; ── a dynamic public client still cannot use client-credentials ──
+
+(id-dyn-test
+  "a dynamic public client is unauthorized for client-credentials"
+  (iddnm
+    (idd-ev
+      "O = identity_oauth:start(),\n       {ok, Cid, Sec} = identity_oauth:register_dynamic(O, public, [uri1]),\n       case identity_oauth:client_credentials(O, Cid, Sec, batch) of\n         {ok, _} -> issued;\n         {error, W} -> W\n       end"))
+  "unauthorized_client")
+
+(define
+  id-dyn-test-summary
+  (str "dynreg " id-dyn-test-pass "/" id-dyn-test-count))

lib/identity/tests/exchange.sx

@@ -0,0 +1,110 @@
+;; identity/tests/exchange.sx — token exchange (RFC 8693 §2.1): downscope a
+;; valid access token into a new independent token for a downstream service.
+
+(define id-xchg-test-count 0)
+(define id-xchg-test-pass 0)
+(define id-xchg-test-fails (list))
+
+(define
+  id-xchg-test
+  (fn
+    (name actual expected)
+    (set! id-xchg-test-count (+ id-xchg-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-xchg-test-pass (+ id-xchg-test-pass 1))
+      (append! id-xchg-test-fails {:name name :expected expected :actual actual}))))
+
+(define idx-ev erlang-eval-ast)
+(define idxnm (fn (v) (get v :name)))
+
+(identity-load-oauth!)
+
+;; Shared prelude: an access token A for alice with scope [read, write].
+(define
+  idx-token
+  "O = identity_oauth:start(),\n   {consent_required, Rq} = identity_oauth:authorize(O, web, uri1, [read, write], alice, v),\n   {code, Cd} = identity_oauth:consent(O, Rq, allow),\n   {ok, A, _R} = identity_oauth:exchange(O, Cd, web, uri1, v)")
+
+;; ── downscoping ──────────────────────────────────────────────────
+
+(id-xchg-test
+  "exchange downscopes to a subset"
+  (idxnm
+    (idx-ev
+      (str
+        idx-token
+        ", {ok, X} = identity_oauth:token_exchange(O, A, [read]),\n           case identity_oauth:introspect(O, X) of\n             {active, _, _, [read]} -> downscoped;\n             {active, _, _, _} -> other;\n             {inactive} -> inactive\n           end")))
+  "downscoped")
+
+(id-xchg-test
+  "the exchanged token keeps the subject"
+  (idxnm
+    (idx-ev
+      (str
+        idx-token
+        ", {ok, X} = identity_oauth:token_exchange(O, A, [read]),\n           case identity_oauth:introspect(O, X) of\n             {active, Subject, _, _} -> Subject\n           end")))
+  "alice")
+
+(id-xchg-test
+  "exchange to the same scope is allowed"
+  (idxnm
+    (idx-ev
+      (str
+        idx-token
+        ", {ok, X} = identity_oauth:token_exchange(O, A, [read, write]),\n           case identity_oauth:introspect(O, X) of\n             {active, _, _, [read, write]} -> full;\n             {active, _, _, _} -> other;\n             {inactive} -> inactive\n           end")))
+  "full")
+
+;; ── scope cannot be widened ──────────────────────────────────────
+
+(id-xchg-test
+  "exchange cannot widen beyond the subject token's scope"
+  (idxnm
+    (idx-ev
+      "O = identity_oauth:start(),\n       {consent_required, Rq} = identity_oauth:authorize(O, web, uri1, [read], alice, v),\n       {code, Cd} = identity_oauth:consent(O, Rq, allow),\n       {ok, A, _R} = identity_oauth:exchange(O, Cd, web, uri1, v),\n       case identity_oauth:token_exchange(O, A, [read, write]) of\n         {ok, _} -> widened;\n         {error, W} -> W\n       end"))
+  "invalid_scope")
+
+;; ── inactive subject token cannot be exchanged ───────────────────
+
+(id-xchg-test
+  "exchanging a revoked subject token is invalid_grant"
+  (idxnm
+    (idx-ev
+      (str
+        idx-token
+        ", identity_oauth:revoke(O, A),\n           case identity_oauth:token_exchange(O, A, [read]) of\n             {ok, _} -> issued;\n             {error, W} -> W\n           end")))
+  "invalid_grant")
+
+;; ── independent lifecycles ───────────────────────────────────────
+
+(id-xchg-test
+  "revoking the subject token does not revoke the exchanged token"
+  (idxnm
+    (idx-ev
+      (str
+        idx-token
+        ", {ok, X} = identity_oauth:token_exchange(O, A, [read]),\n           identity_oauth:revoke(O, A),\n           case identity_oauth:introspect(O, X) of\n             {active, _, _, _} -> still_active;\n             {inactive} -> inactive\n           end")))
+  "still_active")
+
+(id-xchg-test
+  "revoking the exchanged token does not revoke the subject token"
+  (idxnm
+    (idx-ev
+      (str
+        idx-token
+        ", {ok, X} = identity_oauth:token_exchange(O, A, [read]),\n           identity_oauth:revoke(O, X),\n           case identity_oauth:introspect(O, A) of\n             {active, _, _, _} -> still_active;\n             {inactive} -> inactive\n           end")))
+  "still_active")
+
+;; ── chained downscoping ──────────────────────────────────────────
+
+(id-xchg-test
+  "an exchanged token can itself be exchanged (chain)"
+  (idxnm
+    (idx-ev
+      (str
+        idx-token
+        ", {ok, X1} = identity_oauth:token_exchange(O, A, [read, write]),\n           {ok, X2} = identity_oauth:token_exchange(O, X1, [read]),\n           case identity_oauth:introspect(O, X2) of\n             {active, _, _, [read]} -> chained;\n             {active, _, _, _} -> other;\n             {inactive} -> inactive\n           end")))
+  "chained")
+
+(define
+  id-xchg-test-summary
+  (str "exchange " id-xchg-test-pass "/" id-xchg-test-count))

lib/identity/tests/expiry.sx

@@ -0,0 +1,92 @@
+;; identity/tests/expiry.sx — access-token expiry on a logical clock
+;; (RFC 6749 §4.2.2 expires_in). `advance` stands in for time passing;
+;; introspect returns inactive once the clock reaches a token's expiry.
+;; Refresh mints a fresh short-lived access token — the point of refresh.
+
+(define id-expiry-test-count 0)
+(define id-expiry-test-pass 0)
+(define id-expiry-test-fails (list))
+
+(define
+  id-expiry-test
+  (fn
+    (name actual expected)
+    (set! id-expiry-test-count (+ id-expiry-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-expiry-test-pass (+ id-expiry-test-pass 1))
+      (append! id-expiry-test-fails {:name name :expected expected :actual actual}))))
+
+(define ide-ev erlang-eval-ast)
+(define idenm (fn (v) (get v :name)))
+
+(identity-load-token!)
+
+;; ── within TTL is active; past TTL is inactive ───────────────────
+
+(id-expiry-test
+  "a token within its TTL is active"
+  (idenm
+    (ide-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, web, read, 100),\n       identity_tokens:advance(R, 50),\n       case identity_tokens:introspect(R, T) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+(id-expiry-test
+  "a token at its TTL boundary is expired"
+  (idenm
+    (ide-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, web, read, 100),\n       identity_tokens:advance(R, 100),\n       case identity_tokens:introspect(R, T) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(id-expiry-test
+  "a token just before its TTL is still active"
+  (idenm
+    (ide-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, web, read, 100),\n       identity_tokens:advance(R, 99),\n       case identity_tokens:introspect(R, T) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+;; ── no TTL (infinity) never expires ──────────────────────────────
+
+(id-expiry-test
+  "a token issued without a TTL never expires"
+  (idenm
+    (ide-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, web, read),\n       identity_tokens:advance(R, 100000),\n       case identity_tokens:introspect(R, T) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+;; ── refresh mints a fresh short-lived token ──────────────────────
+
+(id-expiry-test
+  "refresh renews access after the old token expired"
+  (idenm
+    (ide-ev
+      "R = identity_tokens:start(),\n       {ok, A, Rt} = identity_tokens:issue_grant(R, alice, web, read, 100),\n       identity_tokens:advance(R, 100),\n       inactive = case identity_tokens:introspect(R, A) of\n         {active, _, _, _} -> active; {inactive} -> inactive end,\n       {ok, A2, _R2} = identity_tokens:refresh(R, Rt),\n       case identity_tokens:introspect(R, A2) of\n         {active, _, _, _} -> renewed;\n         {inactive} -> inactive\n       end"))
+  "renewed")
+
+(id-expiry-test
+  "the renewed token also expires after its own TTL"
+  (idenm
+    (ide-ev
+      "R = identity_tokens:start(),\n       {ok, _A, Rt} = identity_tokens:issue_grant(R, alice, web, read, 100),\n       identity_tokens:advance(R, 100),\n       {ok, A2, _R2} = identity_tokens:refresh(R, Rt),\n       identity_tokens:advance(R, 100),\n       case identity_tokens:introspect(R, A2) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+;; ── the logical clock ────────────────────────────────────────────
+
+(id-expiry-test
+  "the clock starts at zero and advances"
+  (ide-ev
+    "R = identity_tokens:start(),\n     identity_tokens:advance(R, 7),\n     identity_tokens:advance(R, 35),\n     identity_tokens:now(R)")
+  42)
+
+;; ── expiry composes with revocation ──────────────────────────────
+
+(id-expiry-test
+  "an expired token is also inactive after revoke (no contradiction)"
+  (idenm
+    (ide-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, web, read, 100),\n       identity_tokens:advance(R, 200),\n       identity_tokens:revoke(R, T),\n       case identity_tokens:introspect(R, T) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(define
+  id-expiry-test-summary
+  (str "expiry " id-expiry-test-pass "/" id-expiry-test-count))

lib/identity/tests/facade.sx

@@ -0,0 +1,97 @@
+;; identity/tests/facade.sx — the unified facade: one coordinator wiring
+;; sessions+tokens, the audit ledger, and membership. Exercises the
+;; cross-module integration (login/logout auditing, audit history, member
+;; enrollment + projection) through the single `identity` door.
+
+(define id-facade-test-count 0)
+(define id-facade-test-pass 0)
+(define id-facade-test-fails (list))
+
+(define
+  id-facade-test
+  (fn
+    (name actual expected)
+    (set! id-facade-test-count (+ id-facade-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-facade-test-pass (+ id-facade-test-pass 1))
+      (append! id-facade-test-fails {:name name :expected expected :actual actual}))))
+
+(define idfc-ev erlang-eval-ast)
+(define idfcnm (fn (v) (get v :name)))
+
+(identity-load-all!)
+
+;; ── login + logout are audited through the ledger ────────────────
+
+(id-facade-test
+  "login then logout records login, issue, logout in order"
+  (idfcnm
+    (idfc-ev
+      "Svc = identity:start(),\n       {ok, Sid, _Tok} = identity:login(Svc, alice, web, read),\n       identity:logout(Svc, Sid),\n       case identity:history(Svc, alice) of\n         [login, issue, logout] -> ordered;\n         Other -> Other\n       end"))
+  "ordered")
+
+(id-facade-test
+  "revoking a token is audited"
+  (idfcnm
+    (idfc-ev
+      "Svc = identity:start(),\n       {ok, _Sid, Tok} = identity:login(Svc, alice, web, read),\n       identity:revoke(Svc, Tok),\n       case identity:history(Svc, alice) of\n         [login, issue, revoke] -> ordered;\n         Other -> Other\n       end"))
+  "ordered")
+
+(id-facade-test
+  "history is per-subject"
+  (idfc-ev
+    "Svc = identity:start(),\n     identity:login(Svc, alice, web, read),\n     identity:login(Svc, bob, cli, read),\n     identity:login(Svc, alice, mobile, read),\n     length(identity:history(Svc, alice))")
+  4)
+
+;; ── membership through the facade ────────────────────────────────
+
+(id-facade-test
+  "enroll makes the subject an active member"
+  (idfcnm
+    (idfc-ev
+      "Svc = identity:start(),\n       identity:enroll(Svc, alice, supporter),\n       case identity:member_status(Svc, alice) of\n         {ok, St, _} -> St;\n         {none} -> none\n       end"))
+  "active")
+
+(id-facade-test
+  "enroll keeps the tier"
+  (idfcnm
+    (idfc-ev
+      "Svc = identity:start(),\n       identity:enroll(Svc, alice, supporter),\n       case identity:member_status(Svc, alice) of\n         {ok, _, Tier} -> Tier\n       end"))
+  "supporter")
+
+(id-facade-test
+  "an enrolled member projects per-app"
+  (idfcnm
+    (idfc-ev
+      "Svc = identity:start(),\n       identity:enroll(Svc, alice, basic),\n       case identity:member_project(Svc, alice, market) of\n         {member, _, App} -> App;\n         {Tag, _} -> Tag\n       end"))
+  "market")
+
+(id-facade-test
+  "a non-member projects as non_member"
+  (idfcnm
+    (idfc-ev
+      "Svc = identity:start(),\n       case identity:member_project(Svc, stranger, blog) of\n         {member, _, _} -> member;\n         {Tag, _} -> Tag\n       end"))
+  "non_member")
+
+;; ── the facade still proves identity ─────────────────────────────
+
+(id-facade-test
+  "verify still returns the subject after login"
+  (idfcnm
+    (idfc-ev
+      "Svc = identity:start(),\n       {ok, _Sid, Tok} = identity:login(Svc, alice, web, read),\n       case identity:verify(Svc, Tok) of\n         {active, Subject, _, _} -> Subject;\n         {inactive} -> inactive\n       end"))
+  "alice")
+
+;; ── identity and membership are distinct axes ────────────────────
+
+(id-facade-test
+  "logging in does not enroll membership"
+  (idfcnm
+    (idfc-ev
+      "Svc = identity:start(),\n       identity:login(Svc, alice, web, read),\n       case identity:member_status(Svc, alice) of\n         {ok, St, _} -> St;\n         {none} -> none\n       end"))
+  "none")
+
+(define
+  id-facade-test-summary
+  (str "facade " id-facade-test-pass "/" id-facade-test-count))

lib/identity/tests/federation.sx

@@ -0,0 +1,115 @@
+;; identity/tests/federation.sx — federated identity: trust-gated,
+;; advisory peer assertions + cross-instance subject mapping.
+
+(define id-fed-test-count 0)
+(define id-fed-test-pass 0)
+(define id-fed-test-fails (list))
+
+(define
+  id-fed-test
+  (fn
+    (name actual expected)
+    (set! id-fed-test-count (+ id-fed-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-fed-test-pass (+ id-fed-test-pass 1))
+      (append! id-fed-test-fails {:name name :expected expected :actual actual}))))
+
+(define idf-ev erlang-eval-ast)
+(define idfnm (fn (v) (get v :name)))
+
+(identity-load-federation!)
+
+;; ── trust gating ─────────────────────────────────────────────────
+
+(id-fed-test
+  "an assertion from an untrusted peer is rejected"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       case identity_federation:assert_id(F, peer1, alice) of\n         {ok, _} -> accepted;\n         {error, Why} -> Why\n       end"))
+  "untrusted")
+
+(id-fed-test
+  "a trusted peer's assertion is accepted"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       identity_federation:trust(F, peer1),\n       case identity_federation:assert_id(F, peer1, alice) of\n         {ok, _} -> accepted;\n         {error, Why} -> Why\n       end"))
+  "accepted")
+
+(id-fed-test
+  "untrust closes the door to future assertions"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       identity_federation:trust(F, peer1),\n       identity_federation:untrust(F, peer1),\n       case identity_federation:assert_id(F, peer1, alice) of\n         {ok, _} -> accepted;\n         {error, Why} -> Why\n       end"))
+  "untrusted")
+
+(id-fed-test
+  "trusted? is true for a trusted peer"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       identity_federation:trust(F, peer1),\n       case identity_federation:trusted(F, peer1) of\n         true -> yes;\n         false -> no\n       end"))
+  "yes")
+
+(id-fed-test
+  "trusted? is false for an unknown peer"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       identity_federation:trust(F, peer1),\n       case identity_federation:trusted(F, peer2) of\n         true -> yes;\n         false -> no\n       end"))
+  "no")
+
+;; ── advisory provenance ──────────────────────────────────────────
+
+(id-fed-test
+  "an asserted identity is flagged peer_asserted with its origin"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       identity_federation:trust(F, peer1),\n       {ok, L} = identity_federation:assert_id(F, peer1, alice),\n       case identity_federation:provenance(F, L) of\n         {peer_asserted, P} -> P;\n         {local} -> local\n       end"))
+  "peer1")
+
+(id-fed-test
+  "a non-federated subject has local provenance"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       case identity_federation:provenance(F, alice) of\n         {peer_asserted, _} -> peer_asserted;\n         {local} -> local\n       end"))
+  "local")
+
+;; ── cross-instance subject mapping ───────────────────────────────
+
+(id-fed-test
+  "remote subjects are namespaced by peer by default"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       case identity_federation:resolve(F, peer1, alice) of\n         {ok, {federated, _, Remote}} -> Remote;\n         _ -> other\n       end"))
+  "alice")
+
+(id-fed-test
+  "the same remote name from two peers maps to distinct subjects"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       {ok, L1} = identity_federation:resolve(F, peer1, alice),\n       {ok, L2} = identity_federation:resolve(F, peer2, alice),\n       case L1 =:= L2 of\n         true -> collision;\n         false -> distinct\n       end"))
+  "distinct")
+
+(id-fed-test
+  "an explicit map aliases a remote subject to a local one"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       identity_federation:trust(F, peer1),\n       identity_federation:map(F, peer1, alice, alice_local),\n       case identity_federation:assert_id(F, peer1, alice) of\n         {ok, alice_local} -> mapped;\n         {ok, _} -> unmapped;\n         {error, W} -> W\n       end"))
+  "mapped")
+
+(id-fed-test
+  "a mapped subject keeps peer_asserted provenance"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       identity_federation:trust(F, peer1),\n       identity_federation:map(F, peer1, alice, alice_local),\n       identity_federation:assert_id(F, peer1, alice),\n       case identity_federation:provenance(F, alice_local) of\n         {peer_asserted, P} -> P;\n         {local} -> local\n       end"))
+  "peer1")
+
+(id-fed-test
+  "two peers asserting same name keep separate provenance"
+  (idfnm
+    (idf-ev
+      "F = identity_federation:start(),\n       identity_federation:trust(F, peer1),\n       identity_federation:trust(F, peer2),\n       {ok, L1} = identity_federation:assert_id(F, peer1, alice),\n       {ok, _L2} = identity_federation:assert_id(F, peer2, alice),\n       case identity_federation:provenance(F, L1) of\n         {peer_asserted, P} -> P;\n         {local} -> local\n       end"))
+  "peer1")
+
+(define
+  id-fed-test-summary
+  (str "federation " id-fed-test-pass "/" id-fed-test-count))

lib/identity/tests/grants.sx

@@ -0,0 +1,96 @@
+;; identity/tests/grants.sx — the client-credentials grant (RFC 6749
+;; §4.4): a confidential client authenticates and gets a token acting on
+;; its own behalf — no end-user, no refresh token (§4.4.3). Public clients
+;; cannot use it.
+
+(define id-grants-test-count 0)
+(define id-grants-test-pass 0)
+(define id-grants-test-fails (list))
+
+(define
+  id-grants-test
+  (fn
+    (name actual expected)
+    (set! id-grants-test-count (+ id-grants-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-grants-test-pass (+ id-grants-test-pass 1))
+      (append! id-grants-test-fails {:name name :expected expected :actual actual}))))
+
+(define idg-ev erlang-eval-ast)
+(define idgnm (fn (v) (get v :name)))
+
+(identity-load-oauth!)
+
+;; ── confidential client-credentials happy path ───────────────────
+
+(id-grants-test
+  "a confidential client obtains a working token"
+  (idgnm
+    (idg-ev
+      "O = identity_oauth:start(),\n       identity_oauth:register_client(O, svc, confidential, sk, [uri1]),\n       {ok, T} = identity_oauth:client_credentials(O, svc, sk, batch),\n       case identity_oauth:introspect(O, T) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+(id-grants-test
+  "the client-credentials token's subject is the client itself"
+  (idgnm
+    (idg-ev
+      "O = identity_oauth:start(),\n       identity_oauth:register_client(O, svc, confidential, sk, [uri1]),\n       {ok, T} = identity_oauth:client_credentials(O, svc, sk, batch),\n       case identity_oauth:introspect(O, T) of\n         {active, Subject, _, _} -> Subject\n       end"))
+  "svc")
+
+(id-grants-test
+  "the client-credentials token carries the requested scope"
+  (idgnm
+    (idg-ev
+      "O = identity_oauth:start(),\n       identity_oauth:register_client(O, svc, confidential, sk, [uri1]),\n       {ok, T} = identity_oauth:client_credentials(O, svc, sk, reports),\n       case identity_oauth:introspect(O, T) of\n         {active, _, _, Scope} -> Scope\n       end"))
+  "reports")
+
+(id-grants-test
+  "client-credentials issues no refresh token (single value)"
+  (idgnm
+    (idg-ev
+      "O = identity_oauth:start(),\n       identity_oauth:register_client(O, svc, confidential, sk, [uri1]),\n       case identity_oauth:client_credentials(O, svc, sk, batch) of\n         {ok, _, _} -> pair;\n         {ok, _} -> single;\n         {error, W} -> W\n       end"))
+  "single")
+
+;; ── authentication failures ──────────────────────────────────────
+
+(id-grants-test
+  "a wrong client secret is invalid_client"
+  (idgnm
+    (idg-ev
+      "O = identity_oauth:start(),\n       identity_oauth:register_client(O, svc, confidential, sk, [uri1]),\n       case identity_oauth:client_credentials(O, svc, wrong, batch) of\n         {ok, _} -> issued;\n         {error, W} -> W\n       end"))
+  "invalid_client")
+
+(id-grants-test
+  "a public client cannot use client-credentials"
+  (idgnm
+    (idg-ev
+      "O = identity_oauth:start(),\n       identity_oauth:register_client(O, spa, public, none, [uri1]),\n       case identity_oauth:client_credentials(O, spa, none, batch) of\n         {ok, _} -> issued;\n         {error, W} -> W\n       end"))
+  "unauthorized_client")
+
+(id-grants-test
+  "an unregistered client cannot use client-credentials"
+  (idgnm
+    (idg-ev
+      "O = identity_oauth:start(),\n       case identity_oauth:client_credentials(O, ghost, x, batch) of\n         {ok, _} -> issued;\n         {error, W} -> W\n       end"))
+  "invalid_client")
+
+;; ── independence + real revocation for client tokens ─────────────
+
+(id-grants-test
+  "two confidential clients get independent tokens"
+  (idgnm
+    (idg-ev
+      "O = identity_oauth:start(),\n       identity_oauth:register_client(O, svc1, confidential, k1, [uri1]),\n       identity_oauth:register_client(O, svc2, confidential, k2, [uri1]),\n       {ok, _T1} = identity_oauth:client_credentials(O, svc1, k1, batch),\n       {ok, T2} = identity_oauth:client_credentials(O, svc2, k2, batch),\n       case identity_oauth:introspect(O, T2) of\n         {active, Subject, _, _} -> Subject\n       end"))
+  "svc2")
+
+(id-grants-test
+  "a client-credentials token can be revoked"
+  (idgnm
+    (idg-ev
+      "O = identity_oauth:start(),\n       identity_oauth:register_client(O, svc, confidential, sk, [uri1]),\n       {ok, T} = identity_oauth:client_credentials(O, svc, sk, batch),\n       identity_oauth:revoke(O, T),\n       case identity_oauth:introspect(O, T) of\n         {active, _, _, _} -> still_valid;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(define
+  id-grants-test-summary
+  (str "grants " id-grants-test-pass "/" id-grants-test-count))

lib/identity/tests/introspect.sx

@@ -0,0 +1,93 @@
+;; identity/tests/introspect.sx — RFC 7662 §2.2 full introspection metadata
+;; (sub, client_id, scope, exp, iat, token_type) alongside the live-lookup
+;; active/inactive semantics.
+
+(define id-intr-test-count 0)
+(define id-intr-test-pass 0)
+(define id-intr-test-fails (list))
+
+(define
+  id-intr-test
+  (fn
+    (name actual expected)
+    (set! id-intr-test-count (+ id-intr-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-intr-test-pass (+ id-intr-test-pass 1))
+      (append! id-intr-test-fails {:name name :expected expected :actual actual}))))
+
+(define idi-ev erlang-eval-ast)
+(define idinm (fn (v) (get v :name)))
+
+(identity-load-token!)
+
+;; ── metadata fields ──────────────────────────────────────────────
+
+(id-intr-test
+  "introspect_full reports token_type bearer"
+  (idinm
+    (idi-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, web, read, 100),\n       case identity_tokens:introspect_full(R, T) of\n         {active, _, _, _, _, _, Tt} -> Tt;\n         {inactive} -> inactive\n       end"))
+  "bearer")
+
+(id-intr-test
+  "introspect_full reports the subject"
+  (idinm
+    (idi-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, web, read, 100),\n       case identity_tokens:introspect_full(R, T) of\n         {active, Sub, _, _, _, _, _} -> Sub\n       end"))
+  "alice")
+
+(id-intr-test
+  "introspect_full reports the client_id"
+  (idinm
+    (idi-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, mobile, read, 100),\n       case identity_tokens:introspect_full(R, T) of\n         {active, _, Cl, _, _, _, _} -> Cl\n       end"))
+  "mobile")
+
+(id-intr-test
+  "introspect_full reports the scope"
+  (idinm
+    (idi-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, web, write, 100),\n       case identity_tokens:introspect_full(R, T) of\n         {active, _, _, Sc, _, _, _} -> Sc\n       end"))
+  "write")
+
+;; ── exp / iat reflect the logical clock ──────────────────────────
+
+(id-intr-test
+  "iat is the clock value at issue"
+  (idi-ev
+    "R = identity_tokens:start(),\n     identity_tokens:advance(R, 7),\n     {ok, T} = identity_tokens:issue(R, alice, web, read, 100),\n     case identity_tokens:introspect_full(R, T) of\n       {active, _, _, _, _, Iat, _} -> Iat\n     end")
+  7)
+
+(id-intr-test
+  "exp is iat plus the ttl"
+  (idi-ev
+    "R = identity_tokens:start(),\n     identity_tokens:advance(R, 7),\n     {ok, T} = identity_tokens:issue(R, alice, web, read, 100),\n     case identity_tokens:introspect_full(R, T) of\n       {active, _, _, _, Exp, Iat, _} -> Exp - Iat\n     end")
+  100)
+
+;; ── inactive / expired / revoked ─────────────────────────────────
+
+(id-intr-test
+  "an expired token introspects inactive in full mode too"
+  (idinm
+    (idi-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, web, read, 100),\n       identity_tokens:advance(R, 100),\n       case identity_tokens:introspect_full(R, T) of\n         {active, _, _, _, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(id-intr-test
+  "a revoked token introspects inactive in full mode"
+  (idinm
+    (idi-ev
+      "R = identity_tokens:start(),\n       {ok, T} = identity_tokens:issue(R, alice, web, read),\n       identity_tokens:revoke(R, T),\n       case identity_tokens:introspect_full(R, T) of\n         {active, _, _, _, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(id-intr-test
+  "an unknown token introspects inactive in full mode"
+  (idinm
+    (idi-ev
+      "R = identity_tokens:start(),\n       Bogus = make_ref(),\n       case identity_tokens:introspect_full(R, Bogus) of\n         {active, _, _, _, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(define
+  id-intr-test-summary
+  (str "introspect " id-intr-test-pass "/" id-intr-test-count))

lib/identity/tests/membership.sx

@@ -0,0 +1,155 @@
+;; identity/tests/membership.sx — membership state machine + per-app
+;; grant projection. Valid transitions advance state; invalid ones are
+;; explicit errors. The projection renders one canonical state per app.
+
+(define id-membership-test-count 0)
+(define id-membership-test-pass 0)
+(define id-membership-test-fails (list))
+
+(define
+  id-membership-test
+  (fn
+    (name actual expected)
+    (set! id-membership-test-count (+ id-membership-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-membership-test-pass (+ id-membership-test-pass 1))
+      (append! id-membership-test-fails {:name name :expected expected :actual actual}))))
+
+(define idm-ev erlang-eval-ast)
+(define idmnm (fn (v) (get v :name)))
+
+(identity-load-membership!)
+
+;; ── request → pending → approve → active ─────────────────────────
+
+(id-membership-test
+  "request leaves the subject pending"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       case identity_membership:status(M, alice) of\n         {ok, St, _} -> St;\n         {none} -> none\n       end"))
+  "pending")
+
+(id-membership-test
+  "approve activates a pending membership"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       identity_membership:approve(M, alice),\n       case identity_membership:status(M, alice) of\n         {ok, St, _} -> St;\n         {none} -> none\n       end"))
+  "active")
+
+(id-membership-test
+  "status keeps the requested tier"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, supporter),\n       identity_membership:approve(M, alice),\n       case identity_membership:status(M, alice) of\n         {ok, _, Tier} -> Tier\n       end"))
+  "supporter")
+
+;; ── guarded transitions: invalid moves are explicit errors ───────
+
+(id-membership-test
+  "requesting twice is an error"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       case identity_membership:request(M, alice, basic) of\n         ok -> ok;\n         {error, Why} -> Why\n       end"))
+  "exists")
+
+(id-membership-test
+  "approving an unknown subject is not_found"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       case identity_membership:approve(M, ghost) of\n         ok -> ok;\n         {error, Why} -> Why\n       end"))
+  "not_found")
+
+(id-membership-test
+  "approving an already-active membership is an error"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       identity_membership:approve(M, alice),\n       case identity_membership:approve(M, alice) of\n         ok -> ok;\n         {error, Why} -> Why\n       end"))
+  "active")
+
+;; ── lapse / reinstate ────────────────────────────────────────────
+
+(id-membership-test
+  "active member can lapse"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       identity_membership:approve(M, alice),\n       identity_membership:lapse(M, alice),\n       case identity_membership:status(M, alice) of\n         {ok, St, _} -> St\n       end"))
+  "lapsed")
+
+(id-membership-test
+  "lapsing a pending membership is an error"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       case identity_membership:lapse(M, alice) of\n         ok -> ok;\n         {error, Why} -> Why\n       end"))
+  "pending")
+
+(id-membership-test
+  "lapsed member can reinstate to active"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       identity_membership:approve(M, alice),\n       identity_membership:lapse(M, alice),\n       identity_membership:reinstate(M, alice),\n       case identity_membership:status(M, alice) of\n         {ok, St, _} -> St\n       end"))
+  "active")
+
+;; ── revoke is terminal ───────────────────────────────────────────
+
+(id-membership-test
+  "any member can be revoked"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       identity_membership:approve(M, alice),\n       identity_membership:revoke(M, alice),\n       case identity_membership:status(M, alice) of\n         {ok, St, _} -> St\n       end"))
+  "revoked")
+
+(id-membership-test
+  "a revoked membership cannot be reinstated"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       identity_membership:approve(M, alice),\n       identity_membership:revoke(M, alice),\n       case identity_membership:reinstate(M, alice) of\n         ok -> ok;\n         {error, Why} -> Why\n       end"))
+  "revoked")
+
+;; ── per-app grant projection ─────────────────────────────────────
+
+(id-membership-test
+  "active member projects as member"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       identity_membership:approve(M, alice),\n       case identity_membership:project(M, alice, blog) of\n         {member, _, _} -> member;\n         {Tag, _} -> Tag\n       end"))
+  "member")
+
+(id-membership-test
+  "projection carries the requesting app"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       identity_membership:approve(M, alice),\n       case identity_membership:project(M, alice, market) of\n         {member, _, App} -> App\n       end"))
+  "market")
+
+(id-membership-test
+  "the same subject projects consistently across apps"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, supporter),\n       identity_membership:approve(M, alice),\n       {member, T1, blog} = identity_membership:project(M, alice, blog),\n       {member, T2, events} = identity_membership:project(M, alice, events),\n       case T1 =:= T2 of\n         true -> T1;\n         false -> mismatch\n       end"))
+  "supporter")
+
+(id-membership-test
+  "unknown subject projects as non_member"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       case identity_membership:project(M, ghost, blog) of\n         {Tag, _} -> Tag;\n         {Tag, _, _} -> Tag\n       end"))
+  "non_member")
+
+(id-membership-test
+  "lapsed member projects as lapsed"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       identity_membership:approve(M, alice),\n       identity_membership:lapse(M, alice),\n       case identity_membership:project(M, alice, blog) of\n         {Tag, _} -> Tag;\n         {Tag, _, _} -> Tag\n       end"))
+  "lapsed")
+
+(id-membership-test
+  "revoked member projects as denied"
+  (idmnm
+    (idm-ev
+      "M = identity_membership:start(),\n       identity_membership:request(M, alice, basic),\n       identity_membership:approve(M, alice),\n       identity_membership:revoke(M, alice),\n       case identity_membership:project(M, alice, blog) of\n         {Tag, _} -> Tag;\n         {Tag, _, _} -> Tag\n       end"))
+  "denied")
+
+(define
+  id-membership-test-summary
+  (str "membership " id-membership-test-pass "/" id-membership-test-count))

lib/identity/tests/oauth.sx

@@ -0,0 +1,192 @@
+;; identity/tests/oauth.sx — OAuth2 authorization-code flow (RFC 6749
+;; §4.1) + PKCE (RFC 7636) + refresh grant (§6). Covers the full happy
+;; path end-to-end (code exchange → access+refresh → refresh rotation) and
+;; every rejection: denied consent, single-use codes, client/redirect
+;; binding, PKCE mismatch, unknown code/request, refresh-token reuse, and
+;; revoke-then-use (which must fail).
+
+(define id-oauth-test-count 0)
+(define id-oauth-test-pass 0)
+(define id-oauth-test-fails (list))
+
+(define
+  id-oauth-test
+  (fn
+    (name actual expected)
+    (set! id-oauth-test-count (+ id-oauth-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-oauth-test-pass (+ id-oauth-test-pass 1))
+      (append! id-oauth-test-fails {:name name :expected expected :actual actual}))))
+
+(define ido-ev erlang-eval-ast)
+(define idonm (fn (v) (get v :name)))
+
+(identity-load-token!)
+(identity-load-oauth!)
+
+;; Shared prelude: authorize + consent(allow) leaving Code bound.
+(define
+  ido-granted
+  "O = identity_oauth:start(),\n   {consent_required, ReqId} =\n     identity_oauth:authorize(O, webapp, uri1, read, alice, verif1),\n   {code, Code} = identity_oauth:consent(O, ReqId, allow)")
+
+;; ── full happy path ──────────────────────────────────────────────
+
+(id-oauth-test
+  "authorize asks for consent"
+  (idonm
+    (ido-ev
+      "O = identity_oauth:start(),\n       case identity_oauth:authorize(O, webapp, uri1, read, alice, verif1) of\n         {consent_required, _} -> consent_required;\n         Other -> Other\n       end"))
+  "consent_required")
+
+(id-oauth-test
+  "consent(allow) returns a code"
+  (idonm (ido-ev (str ido-granted ", case Code of _ -> issued end")))
+  "issued")
+
+(id-oauth-test
+  "exchanged access token introspects active"
+  (idonm
+    (ido-ev
+      (str
+        ido-granted
+        ", {ok, Tok, _R} = identity_oauth:exchange(O, Code, webapp, uri1, verif1),\n           case identity_oauth:introspect(O, Tok) of\n             {active, _, _, _} -> active;\n             {inactive} -> inactive\n           end")))
+  "active")
+
+(id-oauth-test
+  "exchanged token carries the authorized subject"
+  (idonm
+    (ido-ev
+      (str
+        ido-granted
+        ", {ok, Tok, _R} = identity_oauth:exchange(O, Code, webapp, uri1, verif1),\n           case identity_oauth:introspect(O, Tok) of\n             {active, Subject, _, _} -> Subject\n           end")))
+  "alice")
+
+(id-oauth-test
+  "exchanged token carries the authorized scope"
+  (idonm
+    (ido-ev
+      (str
+        ido-granted
+        ", {ok, Tok, _R} = identity_oauth:exchange(O, Code, webapp, uri1, verif1),\n           case identity_oauth:introspect(O, Tok) of\n             {active, _, _, Scope} -> Scope\n           end")))
+  "read")
+
+;; ── refresh grant (RFC 6749 §6) end-to-end ───────────────────────
+
+(id-oauth-test
+  "refresh after exchange yields a working access token"
+  (idonm
+    (ido-ev
+      (str
+        ido-granted
+        ", {ok, _A, R} = identity_oauth:exchange(O, Code, webapp, uri1, verif1),\n           {ok, A2, _R2} = identity_oauth:refresh(O, R),\n           case identity_oauth:introspect(O, A2) of\n             {active, _, _, _} -> active;\n             {inactive} -> inactive\n           end")))
+  "active")
+
+(id-oauth-test
+  "reusing a rotated refresh token is invalid_grant"
+  (idonm
+    (ido-ev
+      (str
+        ido-granted
+        ", {ok, _A, R} = identity_oauth:exchange(O, Code, webapp, uri1, verif1),\n           {ok, _A2, _R2} = identity_oauth:refresh(O, R),\n           case identity_oauth:refresh(O, R) of\n             {ok, _, _} -> rotated;\n             {error, Why} -> Why\n           end")))
+  "invalid_grant")
+
+;; ── consent denied (§4.1.2.1) ────────────────────────────────────
+
+(id-oauth-test
+  "denied consent yields access_denied"
+  (idonm
+    (ido-ev
+      "O = identity_oauth:start(),\n       {consent_required, ReqId} =\n         identity_oauth:authorize(O, webapp, uri1, read, alice, verif1),\n       case identity_oauth:consent(O, ReqId, deny) of\n         {error, Why} -> Why;\n         {code, _} -> issued\n       end"))
+  "access_denied")
+
+;; ── single-use codes (§10.5) ─────────────────────────────────────
+
+(id-oauth-test
+  "code cannot be exchanged twice"
+  (idonm
+    (ido-ev
+      (str
+        ido-granted
+        ", identity_oauth:exchange(O, Code, webapp, uri1, verif1),\n           case identity_oauth:exchange(O, Code, webapp, uri1, verif1) of\n             {ok, _, _} -> replayed;\n             {error, Why} -> Why\n           end")))
+  "invalid_grant")
+
+;; ── code binding to client + redirect_uri (§4.1.3) ───────────────
+
+(id-oauth-test
+  "exchange with wrong client is invalid_grant"
+  (idonm
+    (ido-ev
+      (str
+        ido-granted
+        ", case identity_oauth:exchange(O, Code, attacker, uri1, verif1) of\n             {ok, _, _} -> ok;\n             {error, Why} -> Why\n           end")))
+  "invalid_grant")
+
+(id-oauth-test
+  "exchange with wrong redirect_uri is invalid_grant"
+  (idonm
+    (ido-ev
+      (str
+        ido-granted
+        ", case identity_oauth:exchange(O, Code, webapp, evil_uri, verif1) of\n             {ok, _, _} -> ok;\n             {error, Why} -> Why\n           end")))
+  "invalid_grant")
+
+;; ── PKCE verifier mismatch (RFC 7636) ────────────────────────────
+
+(id-oauth-test
+  "exchange with wrong PKCE verifier is invalid_grant"
+  (idonm
+    (ido-ev
+      (str
+        ido-granted
+        ", case identity_oauth:exchange(O, Code, webapp, uri1, badverif) of\n             {ok, _, _} -> ok;\n             {error, Why} -> Why\n           end")))
+  "invalid_grant")
+
+;; ── unknown code / request ───────────────────────────────────────
+
+(id-oauth-test
+  "exchanging an unknown code is invalid_grant"
+  (idonm
+    (ido-ev
+      "O = identity_oauth:start(),\n       Bogus = make_ref(),\n       case identity_oauth:exchange(O, Bogus, webapp, uri1, verif1) of\n         {ok, _, _} -> ok;\n         {error, Why} -> Why\n       end"))
+  "invalid_grant")
+
+(id-oauth-test
+  "consent on an unknown request is unknown_request"
+  (idonm
+    (ido-ev
+      "O = identity_oauth:start(),\n       Bogus = make_ref(),\n       case identity_oauth:consent(O, Bogus, allow) of\n         {code, _} -> issued;\n         {error, Why} -> Why\n       end"))
+  "unknown_request")
+
+;; ── revoke-then-use must fail (RFC 7009) ─────────────────────────
+
+(id-oauth-test
+  "revoked exchanged token introspects inactive"
+  (idonm
+    (ido-ev
+      (str
+        ido-granted
+        ", {ok, Tok, _R} = identity_oauth:exchange(O, Code, webapp, uri1, verif1),\n           identity_oauth:revoke(O, Tok),\n           case identity_oauth:introspect(O, Tok) of\n             {active, _, _, _} -> still_valid;\n             {inactive} -> inactive\n           end")))
+  "inactive")
+
+(id-oauth-test
+  "revoking the access token blocks a later refresh (cascade)"
+  (idonm
+    (ido-ev
+      (str
+        ido-granted
+        ", {ok, A, R} = identity_oauth:exchange(O, Code, webapp, uri1, verif1),\n           identity_oauth:revoke(O, A),\n           case identity_oauth:refresh(O, R) of\n             {ok, _, _} -> refreshed;\n             {error, Why} -> Why\n           end")))
+  "invalid_grant")
+
+;; ── independence: two concurrent authorizations don't collide ────
+
+(id-oauth-test
+  "two authorizations issue independent grants"
+  (idonm
+    (ido-ev
+      "O = identity_oauth:start(),\n       {consent_required, R1} =\n         identity_oauth:authorize(O, webapp, uri1, read, alice, va),\n       {consent_required, R2} =\n         identity_oauth:authorize(O, cli, uri2, write, bob, vb),\n       {code, C1} = identity_oauth:consent(O, R1, allow),\n       {code, C2} = identity_oauth:consent(O, R2, allow),\n       {ok, _A1, _RR1} = identity_oauth:exchange(O, C1, webapp, uri1, va),\n       {ok, A2, _RR2} = identity_oauth:exchange(O, C2, cli, uri2, vb),\n       case identity_oauth:introspect(O, A2) of\n         {active, Subject, _, _} -> Subject\n       end"))
+  "bob")
+
+(define
+  id-oauth-test-summary
+  (str "oauth " id-oauth-test-pass "/" id-oauth-test-count))

lib/identity/tests/par.sx

@@ -0,0 +1,84 @@
+;; identity/tests/par.sx — pushed authorization requests (PAR, RFC 9126):
+;; lodge the authorization params up front under a single-use request_uri,
+;; then redeem it into the normal consent flow. The binding (client,
+;; redirect, PKCE) carried by the pushed request is enforced at exchange.
+
+(define id-par-test-count 0)
+(define id-par-test-pass 0)
+(define id-par-test-fails (list))
+
+(define
+  id-par-test
+  (fn
+    (name actual expected)
+    (set! id-par-test-count (+ id-par-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-par-test-pass (+ id-par-test-pass 1))
+      (append! id-par-test-fails {:name name :expected expected :actual actual}))))
+
+(define idp-ev erlang-eval-ast)
+(define idpnm (fn (v) (get v :name)))
+
+(identity-load-oauth!)
+
+;; ── pushed request redeems into consent ──────────────────────────
+
+(id-par-test
+  "authorize_pushed on a fresh request_uri asks for consent"
+  (idpnm
+    (idp-ev
+      "O = identity_oauth:start(),\n       {ok, Ru} = identity_oauth:push_authorization_request(O, web, uri1, read, alice, v),\n       case identity_oauth:authorize_pushed(O, Ru) of\n         {consent_required, _} -> consent_required;\n         {error, W} -> W\n       end"))
+  "consent_required")
+
+;; ── full PAR flow ────────────────────────────────────────────────
+
+(id-par-test
+  "the full PAR flow yields a working token"
+  (idpnm
+    (idp-ev
+      "O = identity_oauth:start(),\n       {ok, Ru} = identity_oauth:push_authorization_request(O, web, uri1, read, alice, v),\n       {consent_required, Rq} = identity_oauth:authorize_pushed(O, Ru),\n       {code, Cd} = identity_oauth:consent(O, Rq, allow),\n       {ok, A, _R} = identity_oauth:exchange(O, Cd, web, uri1, v),\n       case identity_oauth:introspect(O, A) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+(id-par-test
+  "the PAR token carries the pushed subject"
+  (idpnm
+    (idp-ev
+      "O = identity_oauth:start(),\n       {ok, Ru} = identity_oauth:push_authorization_request(O, web, uri1, read, alice, v),\n       {consent_required, Rq} = identity_oauth:authorize_pushed(O, Ru),\n       {code, Cd} = identity_oauth:consent(O, Rq, allow),\n       {ok, A, _R} = identity_oauth:exchange(O, Cd, web, uri1, v),\n       case identity_oauth:introspect(O, A) of\n         {active, Subject, _, _} -> Subject\n       end"))
+  "alice")
+
+;; ── request_uri is single-use ────────────────────────────────────
+
+(id-par-test
+  "a request_uri cannot be redeemed twice"
+  (idpnm
+    (idp-ev
+      "O = identity_oauth:start(),\n       {ok, Ru} = identity_oauth:push_authorization_request(O, web, uri1, read, alice, v),\n       identity_oauth:authorize_pushed(O, Ru),\n       case identity_oauth:authorize_pushed(O, Ru) of\n         {consent_required, _} -> reused;\n         {error, W} -> W\n       end"))
+  "invalid_request_uri")
+
+(id-par-test
+  "an unknown request_uri is rejected"
+  (idpnm
+    (idp-ev
+      "O = identity_oauth:start(),\n       Bogus = make_ref(),\n       case identity_oauth:authorize_pushed(O, Bogus) of\n         {consent_required, _} -> ok;\n         {error, W} -> W\n       end"))
+  "invalid_request_uri")
+
+;; ── the pushed binding is still enforced at exchange ─────────────
+
+(id-par-test
+  "a PAR-issued code still enforces PKCE"
+  (idpnm
+    (idp-ev
+      "O = identity_oauth:start(),\n       {ok, Ru} = identity_oauth:push_authorization_request(O, web, uri1, read, alice, v),\n       {consent_required, Rq} = identity_oauth:authorize_pushed(O, Ru),\n       {code, Cd} = identity_oauth:consent(O, Rq, allow),\n       case identity_oauth:exchange(O, Cd, web, uri1, wrongverif) of\n         {ok, _, _} -> ok;\n         {error, W} -> W\n       end"))
+  "invalid_grant")
+
+(id-par-test
+  "a PAR-issued code still enforces client binding"
+  (idpnm
+    (idp-ev
+      "O = identity_oauth:start(),\n       {ok, Ru} = identity_oauth:push_authorization_request(O, web, uri1, read, alice, v),\n       {consent_required, Rq} = identity_oauth:authorize_pushed(O, Ru),\n       {code, Cd} = identity_oauth:consent(O, Rq, allow),\n       case identity_oauth:exchange(O, Cd, attacker, uri1, v) of\n         {ok, _, _} -> ok;\n         {error, W} -> W\n       end"))
+  "invalid_grant")
+
+(define
+  id-par-test-summary
+  (str "par " id-par-test-pass "/" id-par-test-count))

lib/identity/tests/registry.sx

@@ -0,0 +1,99 @@
+;; identity/tests/registry.sx — routing by id and by (subject, client),
+;; SSO fan-out (one subject, many clients), and integration with live
+;; session processes routed through the registry.
+
+(define id-registry-test-count 0)
+(define id-registry-test-pass 0)
+(define id-registry-test-fails (list))
+
+(define
+  id-registry-test
+  (fn
+    (name actual expected)
+    (set! id-registry-test-count (+ id-registry-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-registry-test-pass (+ id-registry-test-pass 1))
+      (append! id-registry-test-fails {:name name :expected expected :actual actual}))))
+
+(define idr-ev erlang-eval-ast)
+(define idrnm (fn (v) (get v :name)))
+
+(identity-load-session!)
+(identity-load-registry!)
+
+;; ── whereis by session id ────────────────────────────────────────
+
+(id-registry-test
+  "registered session is found by id"
+  (idrnm
+    (idr-ev
+      "Me = self(),\n       Reg = identity_registry:start(),\n       identity_registry:register(Reg, s1, alice, web, Me),\n       case identity_registry:whereis_session(Reg, s1) of\n         {ok, _} -> found;\n         {error, _} -> missing\n       end"))
+  "found")
+
+(id-registry-test
+  "unknown session id is not_found, not a crash"
+  (idrnm
+    (idr-ev
+      "Reg = identity_registry:start(),\n       case identity_registry:whereis_session(Reg, nope) of\n         {ok, _} -> found;\n         {error, Why} -> Why\n       end"))
+  "not_found")
+
+;; ── lookup by (subject, client) — the SSO probe ──────────────────
+
+(id-registry-test
+  "lookup finds a session for subject+client"
+  (idrnm
+    (idr-ev
+      "Me = self(),\n       Reg = identity_registry:start(),\n       identity_registry:register(Reg, s1, alice, web, Me),\n       case identity_registry:lookup(Reg, alice, web) of\n         {ok, _} -> found;\n         {error, _} -> missing\n       end"))
+  "found")
+
+(id-registry-test
+  "lookup is precise: right subject, wrong client misses"
+  (idrnm
+    (idr-ev
+      "Me = self(),\n       Reg = identity_registry:start(),\n       identity_registry:register(Reg, s1, alice, web, Me),\n       case identity_registry:lookup(Reg, alice, cli) of\n         {ok, _} -> found;\n         {error, _} -> missing\n       end"))
+  "missing")
+
+;; ── SSO fan-out: one subject, many clients ───────────────────────
+
+(id-registry-test
+  "sessions_for returns all of a subject's sessions"
+  (idr-ev
+    "Me = self(),\n     Reg = identity_registry:start(),\n     identity_registry:register(Reg, s1, alice, web, Me),\n     identity_registry:register(Reg, s2, alice, cli, Me),\n     identity_registry:register(Reg, s3, bob, web, Me),\n     case identity_registry:sessions_for(Reg, alice) of\n       {ok, L} -> length(L)\n     end")
+  2)
+
+(id-registry-test
+  "sessions_for an unknown subject is empty"
+  (idr-ev
+    "Reg = identity_registry:start(),\n     case identity_registry:sessions_for(Reg, ghost) of\n       {ok, L} -> length(L)\n     end")
+  0)
+
+;; ── re-register replaces the row for that id (no duplicates) ──────
+
+(id-registry-test
+  "re-registering an id does not duplicate it"
+  (idr-ev
+    "Me = self(),\n     Reg = identity_registry:start(),\n     identity_registry:register(Reg, s1, alice, web, Me),\n     identity_registry:register(Reg, s1, alice, web, Me),\n     case identity_registry:sessions_for(Reg, alice) of\n       {ok, L} -> length(L)\n     end")
+  1)
+
+;; ── deregister removes routing ───────────────────────────────────
+
+(id-registry-test
+  "deregistered session is no longer found"
+  (idrnm
+    (idr-ev
+      "Me = self(),\n       Reg = identity_registry:start(),\n       identity_registry:register(Reg, s1, alice, web, Me),\n       identity_registry:deregister(Reg, s1),\n       case identity_registry:whereis_session(Reg, s1) of\n         {ok, _} -> found;\n         {error, _} -> missing\n       end"))
+  "missing")
+
+;; ── integration: route to a live session and look it up ──────────
+
+(id-registry-test
+  "routed-to session answers lookup as active"
+  (idrnm
+    (idr-ev
+      "Me = self(),\n       Reg = identity_registry:start(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       identity_registry:register(Reg, s1, alice, web, S),\n       {ok, Pid} = identity_registry:lookup(Reg, alice, web),\n       case identity_session:lookup(Pid) of\n         {ok, {_,_,_,St}} -> St;\n         {error, St} -> St\n       end"))
+  "active")
+
+(define
+  id-registry-test-summary
+  (str "registry " id-registry-test-pass "/" id-registry-test-count))

lib/identity/tests/session.sx

@@ -0,0 +1,118 @@
+;; identity/tests/session.sx — session-as-process: create, lookup,
+;; touch, explicit expire, revoke, and idle-timeout self-expiry.
+;; Negative paths are tested as first-class: a tombstoned session
+;; answers {error, Status}, it does not go silent.
+
+(define id-session-test-count 0)
+(define id-session-test-pass 0)
+(define id-session-test-fails (list))
+
+(define
+  id-session-test
+  (fn
+    (name actual expected)
+    (set! id-session-test-count (+ id-session-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-session-test-pass (+ id-session-test-pass 1))
+      (append! id-session-test-fails {:name name :expected expected :actual actual}))))
+
+(define id-ev erlang-eval-ast)
+(define idnm (fn (v) (get v :name)))
+
+(identity-load-session!)
+
+;; ── create + lookup ──────────────────────────────────────────────
+
+(id-session-test
+  "lookup of live session is active"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       case identity_session:lookup(S) of {ok, {_,_,_,St}} -> St end"))
+  "active")
+
+(id-session-test
+  "lookup preserves subject"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       case identity_session:lookup(S) of {ok, {_,Subject,_,_}} -> Subject end"))
+  "alice")
+
+(id-session-test
+  "lookup preserves client"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       case identity_session:lookup(S) of {ok, {_,_,Client,_}} -> Client end"))
+  "web")
+
+;; ── touch keeps a live session ───────────────────────────────────
+
+(id-session-test
+  "touch on live session is ok"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       identity_session:touch(S)"))
+  "ok")
+
+;; ── explicit expire ──────────────────────────────────────────────
+
+(id-session-test
+  "expire then lookup is error expired"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       identity_session:expire(S),\n       case identity_session:lookup(S) of {error, St} -> St end"))
+  "expired")
+
+(id-session-test
+  "touch on expired session is error"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       identity_session:expire(S),\n       case identity_session:touch(S) of {error, St} -> St end"))
+  "expired")
+
+;; ── revoke is immediate ──────────────────────────────────────────
+
+(id-session-test
+  "revoke then lookup is error revoked"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       identity_session:revoke(S),\n       case identity_session:lookup(S) of {error, St} -> St end"))
+  "revoked")
+
+;; ── idle-timeout self-expiry ─────────────────────────────────────
+
+(id-session-test
+  "idle timeout notifies owner"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, 50),\n       _ = identity_session:lookup(S),\n       receive {session_expired, Sid} -> Sid end"))
+  "s1")
+
+(id-session-test
+  "lookup after idle timeout is error expired"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, 50),\n       _ = identity_session:lookup(S),\n       receive {session_expired, _} -> ok end,\n       case identity_session:lookup(S) of {error, St} -> St end"))
+  "expired")
+
+;; ── isolation: sessions are independent processes ────────────────
+
+(id-session-test
+  "expiring one session leaves the other active"
+  (idnm
+    (id-ev
+      "Me = self(),\n       A = identity_session:start(s1, alice, web, Me, infinity),\n       B = identity_session:start(s2, bob, web, Me, infinity),\n       identity_session:expire(A),\n       case identity_session:lookup(B) of {ok, {_,_,_,St}} -> St end"))
+  "active")
+
+;; ── clean stop ───────────────────────────────────────────────────
+
+(id-session-test
+  "stop returns ok"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       identity_session:stop(S)"))
+  "ok")
+
+(define
+  id-session-test-summary
+  (str "session " id-session-test-pass "/" id-session-test-count))

lib/identity/tests/session_mgmt.sx

@@ -0,0 +1,81 @@
+;; identity/tests/session_mgmt.sx — subject-wide session management:
+;; enumerate a subject's sessions and \"log out everywhere\".
+
+(define id-smgmt-test-count 0)
+(define id-smgmt-test-pass 0)
+(define id-smgmt-test-fails (list))
+
+(define
+  id-smgmt-test
+  (fn
+    (name actual expected)
+    (set! id-smgmt-test-count (+ id-smgmt-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-smgmt-test-pass (+ id-smgmt-test-pass 1))
+      (append! id-smgmt-test-fails {:name name :expected expected :actual actual}))))
+
+(define idsm-ev erlang-eval-ast)
+(define idsmnm (fn (v) (get v :name)))
+
+(identity-load-all!)
+
+;; ── enumerate a subject's sessions ───────────────────────────────
+
+(id-smgmt-test
+  "sessions lists all of a subject's sessions"
+  (idsm-ev
+    "Svc = identity:start(),\n     identity:login(Svc, alice, web, read),\n     identity:login(Svc, alice, cli, read),\n     length(identity:sessions(Svc, alice))")
+  2)
+
+(id-smgmt-test
+  "sessions is empty for a subject with none"
+  (idsm-ev
+    "Svc = identity:start(),\n     length(identity:sessions(Svc, stranger))")
+  0)
+
+;; ── log out everywhere ───────────────────────────────────────────
+
+(id-smgmt-test
+  "logout_all ends every session of the subject"
+  (idsmnm
+    (idsm-ev
+      "Svc = identity:start(),\n       {ok, S1, _} = identity:login(Svc, alice, web, read),\n       {ok, S2, _} = identity:login(Svc, alice, cli, read),\n       identity:logout_all(Svc, alice),\n       case {identity:session_status(Svc, S1), identity:session_status(Svc, S2)} of\n         {gone, gone} -> both_gone;\n         _ -> some_left\n       end"))
+  "both_gone")
+
+(id-smgmt-test
+  "after logout_all the subject has no sessions"
+  (idsm-ev
+    "Svc = identity:start(),\n     identity:login(Svc, alice, web, read),\n     identity:login(Svc, alice, cli, read),\n     identity:logout_all(Svc, alice),\n     length(identity:sessions(Svc, alice))")
+  0)
+
+(id-smgmt-test
+  "logout_all leaves other subjects' sessions intact"
+  (idsm-ev
+    "Svc = identity:start(),\n     identity:login(Svc, alice, web, read),\n     identity:login(Svc, bob, web, read),\n     identity:logout_all(Svc, alice),\n     length(identity:sessions(Svc, bob))")
+  1)
+
+(id-smgmt-test
+  "logout_all on an unknown subject is ok, not a crash"
+  (idsmnm
+    (idsm-ev "Svc = identity:start(),\n       identity:logout_all(Svc, ghost)"))
+  "ok")
+
+;; ── logout_all is audited ────────────────────────────────────────
+
+(id-smgmt-test
+  "logout_all records a logout event"
+  (idsmnm
+    (idsm-ev
+      "Svc = identity:start(),\n       identity:login(Svc, alice, web, read),\n       identity:logout_all(Svc, alice),\n       case identity:history(Svc, alice) of\n         [login, issue, logout] -> audited;\n         Other -> Other\n       end"))
+  "audited")
+
+(id-smgmt-test
+  "logout_all audits each of several sessions"
+  (idsm-ev
+    "Svc = identity:start(),\n     identity:login(Svc, alice, web, read),\n     identity:login(Svc, alice, cli, read),\n     identity:logout_all(Svc, alice),\n     length(identity:history(Svc, alice))")
+  6)
+
+(define
+  id-smgmt-test-summary
+  (str "session-mgmt " id-smgmt-test-pass "/" id-smgmt-test-count))

lib/identity/tests/sso.sx

@@ -0,0 +1,115 @@
+;; identity/tests/sso.sx — silent SSO (prompt=none, OIDC §3.1.2.1) as a
+;; fast-path through the authorization-code machine. One subject session,
+;; many client apps; no session → login_required (a negative state, not a
+;; redirect). Silently-issued codes carry the same client/redirect/PKCE
+;; binding as consented codes.
+
+(define id-sso-test-count 0)
+(define id-sso-test-pass 0)
+(define id-sso-test-fails (list))
+
+(define
+  id-sso-test
+  (fn
+    (name actual expected)
+    (set! id-sso-test-count (+ id-sso-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-sso-test-pass (+ id-sso-test-pass 1))
+      (append! id-sso-test-fails {:name name :expected expected :actual actual}))))
+
+(define ids-ev erlang-eval-ast)
+(define idsnm (fn (v) (get v :name)))
+
+(identity-load-token!)
+(identity-load-session!)
+(identity-load-registry!)
+(identity-load-oauth!)
+
+;; ── no session → login_required ──────────────────────────────────
+
+(id-sso-test
+  "silent authorize without a session is login_required"
+  (idsnm
+    (ids-ev
+      "O = identity_oauth:start(),\n       case identity_oauth:silent_authorize(O, dashboard, uri2, read, alice, vv) of\n         {code, _} -> got_code;\n         {error, Why} -> Why\n       end"))
+  "login_required")
+
+;; ── established session → silent code ────────────────────────────
+
+(id-sso-test
+  "silent authorize for the same client returns a code"
+  (idsnm
+    (ids-ev
+      "O = identity_oauth:start(),\n       {ok, _Sid} = identity_oauth:establish(O, alice, web),\n       case identity_oauth:silent_authorize(O, web, uri1, read, alice, vv) of\n         {code, _} -> got_code;\n         {error, Why} -> Why\n       end"))
+  "got_code")
+
+;; ── one session, many clients ────────────────────────────────────
+
+(id-sso-test
+  "a different client gets a silent code off the same session"
+  (idsnm
+    (ids-ev
+      "O = identity_oauth:start(),\n       {ok, _Sid} = identity_oauth:establish(O, alice, web),\n       case identity_oauth:silent_authorize(O, dashboard, uri2, read, alice, vv) of\n         {code, _} -> got_code;\n         {error, Why} -> Why\n       end"))
+  "got_code")
+
+(id-sso-test
+  "many clients all silently authorize off one session"
+  (idsnm
+    (ids-ev
+      "O = identity_oauth:start(),\n       {ok, _Sid} = identity_oauth:establish(O, alice, web),\n       {code, _C1} = identity_oauth:silent_authorize(O, dashboard, uri2, read, alice, vv),\n       {code, _C2} = identity_oauth:silent_authorize(O, mobile, uri3, read, alice, vv),\n       case identity_oauth:silent_authorize(O, billing, uri4, read, alice, vv) of\n         {code, _} -> got_code;\n         {error, Why} -> Why\n       end"))
+  "got_code")
+
+;; ── full SSO → token ─────────────────────────────────────────────
+
+(id-sso-test
+  "silent code exchanges to a working token"
+  (idsnm
+    (ids-ev
+      "O = identity_oauth:start(),\n       {ok, _Sid} = identity_oauth:establish(O, alice, web),\n       {code, C} = identity_oauth:silent_authorize(O, dashboard, uri2, read, alice, vv),\n       {ok, A, _R} = identity_oauth:exchange(O, C, dashboard, uri2, vv),\n       case identity_oauth:introspect(O, A) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+(id-sso-test
+  "SSO token carries the subject"
+  (idsnm
+    (ids-ev
+      "O = identity_oauth:start(),\n       {ok, _Sid} = identity_oauth:establish(O, alice, web),\n       {code, C} = identity_oauth:silent_authorize(O, dashboard, uri2, read, alice, vv),\n       {ok, A, _R} = identity_oauth:exchange(O, C, dashboard, uri2, vv),\n       case identity_oauth:introspect(O, A) of\n         {active, Subject, _, _} -> Subject\n       end"))
+  "alice")
+
+;; ── silent codes keep the full binding ───────────────────────────
+
+(id-sso-test
+  "silent code still enforces PKCE at exchange"
+  (idsnm
+    (ids-ev
+      "O = identity_oauth:start(),\n       {ok, _Sid} = identity_oauth:establish(O, alice, web),\n       {code, C} = identity_oauth:silent_authorize(O, dashboard, uri2, read, alice, vv),\n       case identity_oauth:exchange(O, C, dashboard, uri2, wrongverif) of\n         {ok, _, _} -> ok;\n         {error, Why} -> Why\n       end"))
+  "invalid_grant")
+
+(id-sso-test
+  "silent code still enforces client binding at exchange"
+  (idsnm
+    (ids-ev
+      "O = identity_oauth:start(),\n       {ok, _Sid} = identity_oauth:establish(O, alice, web),\n       {code, C} = identity_oauth:silent_authorize(O, dashboard, uri2, read, alice, vv),\n       case identity_oauth:exchange(O, C, attacker, uri2, vv) of\n         {ok, _, _} -> ok;\n         {error, Why} -> Why\n       end"))
+  "invalid_grant")
+
+;; ── subject scoping: SSO is per subject ──────────────────────────
+
+(id-sso-test
+  "another subject is still login_required"
+  (idsnm
+    (ids-ev
+      "O = identity_oauth:start(),\n       {ok, _Sid} = identity_oauth:establish(O, alice, web),\n       case identity_oauth:silent_authorize(O, dashboard, uri2, read, bob, vv) of\n         {code, _} -> got_code;\n         {error, Why} -> Why\n       end"))
+  "login_required")
+
+;; ── ending the session closes the SSO fast-path ──────────────────
+
+(id-sso-test
+  "after end_session, silent authorize is login_required"
+  (idsnm
+    (ids-ev
+      "O = identity_oauth:start(),\n       {ok, Sid} = identity_oauth:establish(O, alice, web),\n       identity_oauth:end_session(O, Sid),\n       case identity_oauth:silent_authorize(O, dashboard, uri2, read, alice, vv) of\n         {code, _} -> got_code;\n         {error, Why} -> Why\n       end"))
+  "login_required")
+
+(define
+  id-sso-test-summary
+  (str "sso " id-sso-test-pass "/" id-sso-test-count))

lib/identity/tests/token.sx

@@ -0,0 +1,215 @@
+;; identity/tests/token.sx — opaque tokens, grant-backed lookup, real
+;; revocation, refresh-token rotation, cascading revocation, and scope
+;; narrowing on refresh. The revoke-then-introspect and refresh-reuse
+;; paths are the security centrepieces.
+
+(define id-token-test-count 0)
+(define id-token-test-pass 0)
+(define id-token-test-fails (list))
+
+(define
+  id-token-test
+  (fn
+    (name actual expected)
+    (set! id-token-test-count (+ id-token-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-token-test-pass (+ id-token-test-pass 1))
+      (append! id-token-test-fails {:name name :expected expected :actual actual}))))
+
+(define idt-ev erlang-eval-ast)
+(define idtnm (fn (v) (get v :name)))
+
+(identity-load-token!)
+
+;; ── issue + introspect (happy path) ──────────────────────────────
+
+(id-token-test
+  "fresh token introspects active"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, Tok} = identity_tokens:issue(Reg, alice, web, read),\n       case identity_tokens:introspect(Reg, Tok) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+(id-token-test
+  "introspect returns the granted subject"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, Tok} = identity_tokens:issue(Reg, alice, web, read),\n       case identity_tokens:introspect(Reg, Tok) of\n         {active, Subject, _, _} -> Subject\n       end"))
+  "alice")
+
+(id-token-test
+  "introspect returns the granted scope"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, Tok} = identity_tokens:issue(Reg, alice, web, write),\n       case identity_tokens:introspect(Reg, Tok) of\n         {active, _, _, Scope} -> Scope\n       end"))
+  "write")
+
+;; ── opacity: distinct tokens, no cross-talk ──────────────────────
+
+(id-token-test
+  "two issues yield independent grants"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, A} = identity_tokens:issue(Reg, alice, web, read),\n       {ok, B} = identity_tokens:issue(Reg, bob, cli, write),\n       identity_tokens:revoke(Reg, A),\n       case identity_tokens:introspect(Reg, B) of\n         {active, Subject, _, _} -> Subject;\n         {inactive} -> inactive\n       end"))
+  "bob")
+
+;; ── revocation is real (RFC 7009) ────────────────────────────────
+
+(id-token-test
+  "revoked token introspects inactive immediately"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, Tok} = identity_tokens:issue(Reg, alice, web, read),\n       active = case identity_tokens:introspect(Reg, Tok) of\n         {active, _, _, _} -> active end,\n       identity_tokens:revoke(Reg, Tok),\n       case identity_tokens:introspect(Reg, Tok) of\n         {active, _, _, _} -> still_valid;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(id-token-test
+  "revoke is idempotent"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, Tok} = identity_tokens:issue(Reg, alice, web, read),\n       identity_tokens:revoke(Reg, Tok),\n       identity_tokens:revoke(Reg, Tok)"))
+  "ok")
+
+;; ── unknown tokens are inactive, never an error/crash ────────────
+
+(id-token-test
+  "introspecting an unknown token is inactive"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       Bogus = make_ref(),\n       case identity_tokens:introspect(Reg, Bogus) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(id-token-test
+  "revoking an unknown token is ok, not a crash"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       Bogus = make_ref(),\n       identity_tokens:revoke(Reg, Bogus)"))
+  "ok")
+
+;; ── one revocation does not affect a sibling token ───────────────
+
+(id-token-test
+  "revoking one token leaves the other active"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, A} = identity_tokens:issue(Reg, alice, web, read),\n       {ok, B} = identity_tokens:issue(Reg, alice, cli, read),\n       identity_tokens:revoke(Reg, A),\n       case identity_tokens:introspect(Reg, B) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+;; ── issue_grant: access + refresh pair (RFC 6749 §4.1.4 / §5.1) ───
+
+(id-token-test
+  "issue_grant access token introspects active"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, A, _R} = identity_tokens:issue_grant(Reg, alice, web, read),\n       case identity_tokens:introspect(Reg, A) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+;; ── refresh rotation (RFC 6749 §6) ───────────────────────────────
+
+(id-token-test
+  "refresh mints a working new access token"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, _A, R} = identity_tokens:issue_grant(Reg, alice, web, read),\n       {ok, A2, _R2} = identity_tokens:refresh(Reg, R),\n       case identity_tokens:introspect(Reg, A2) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+(id-token-test
+  "rotated token keeps the grant's subject"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, _A, R} = identity_tokens:issue_grant(Reg, alice, web, read),\n       {ok, A2, _R2} = identity_tokens:refresh(Reg, R),\n       case identity_tokens:introspect(Reg, A2) of\n         {active, Subject, _, _} -> Subject\n       end"))
+  "alice")
+
+(id-token-test
+  "refresh chains across rotations"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, _A, R} = identity_tokens:issue_grant(Reg, alice, web, read),\n       {ok, _A2, R2} = identity_tokens:refresh(Reg, R),\n       {ok, A3, _R3} = identity_tokens:refresh(Reg, R2),\n       case identity_tokens:introspect(Reg, A3) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "active")
+
+(id-token-test
+  "refreshing an unknown token is invalid_grant"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       Bogus = make_ref(),\n       case identity_tokens:refresh(Reg, Bogus) of\n         {ok, _, _} -> rotated;\n         {error, Why} -> Why\n       end"))
+  "invalid_grant")
+
+;; ── refresh-token reuse = theft → revoke the family (RFC 6819) ────
+
+(id-token-test
+  "reusing a superseded refresh token is invalid_grant"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, _A, R} = identity_tokens:issue_grant(Reg, alice, web, read),\n       {ok, _A2, _R2} = identity_tokens:refresh(Reg, R),\n       case identity_tokens:refresh(Reg, R) of\n         {ok, _, _} -> rotated;\n         {error, Why} -> Why\n       end"))
+  "invalid_grant")
+
+(id-token-test
+  "refresh reuse revokes the live descendant too"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, _A, R} = identity_tokens:issue_grant(Reg, alice, web, read),\n       {ok, A2, _R2} = identity_tokens:refresh(Reg, R),\n       identity_tokens:refresh(Reg, R),\n       case identity_tokens:introspect(Reg, A2) of\n         {active, _, _, _} -> still_valid;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+;; ── cascading revocation: revoke any token, the grant dies ───────
+
+(id-token-test
+  "revoking the access token blocks refresh"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, A, R} = identity_tokens:issue_grant(Reg, alice, web, read),\n       identity_tokens:revoke(Reg, A),\n       case identity_tokens:refresh(Reg, R) of\n         {ok, _, _} -> refreshed;\n         {error, Why} -> Why\n       end"))
+  "invalid_grant")
+
+(id-token-test
+  "revoking the refresh token deactivates the access token"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, A, R} = identity_tokens:issue_grant(Reg, alice, web, read),\n       identity_tokens:revoke(Reg, R),\n       case identity_tokens:introspect(Reg, A) of\n         {active, _, _, _} -> active;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+;; ── scope as a set + narrowing on refresh (RFC 6749 §6 / §3.3) ───
+
+(id-token-test
+  "a list scope round-trips through introspect"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, A, _R} = identity_tokens:issue_grant(Reg, alice, web, [read, write]),\n       case identity_tokens:introspect(Reg, A) of\n         {active, _, _, [read, write]} -> matched;\n         {active, _, _, _} -> other;\n         {inactive} -> inactive\n       end"))
+  "matched")
+
+(id-token-test
+  "refresh can narrow the scope to a subset"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, _A, R} = identity_tokens:issue_grant(Reg, alice, web, [read, write]),\n       {ok, A2, _R2} = identity_tokens:refresh(Reg, R, [read]),\n       case identity_tokens:introspect(Reg, A2) of\n         {active, _, _, [read]} -> narrowed;\n         {active, _, _, _} -> other;\n         {inactive} -> inactive\n       end"))
+  "narrowed")
+
+(id-token-test
+  "refresh cannot widen scope beyond the grant"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, _A, R} = identity_tokens:issue_grant(Reg, alice, web, [read]),\n       case identity_tokens:refresh(Reg, R, [read, write]) of\n         {ok, _, _} -> widened;\n         {error, Why} -> Why\n       end"))
+  "invalid_scope")
+
+(id-token-test
+  "an invalid_scope refresh does not consume the refresh token"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, _A, R} = identity_tokens:issue_grant(Reg, alice, web, [read, write]),\n       identity_tokens:refresh(Reg, R, [admin]),\n       case identity_tokens:refresh(Reg, R, [read]) of\n         {ok, _, _} -> still_usable;\n         {error, Why} -> Why\n       end"))
+  "still_usable")
+
+(id-token-test
+  "plain refresh keeps the full grant scope"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, _A, R} = identity_tokens:issue_grant(Reg, alice, web, [read, write]),\n       {ok, A2, _R2} = identity_tokens:refresh(Reg, R),\n       case identity_tokens:introspect(Reg, A2) of\n         {active, _, _, [read, write]} -> full;\n         {active, _, _, _} -> other;\n         {inactive} -> inactive\n       end"))
+  "full")
+
+(id-token-test
+  "a narrowed token still cascades on revoke"
+  (idtnm
+    (idt-ev
+      "Reg = identity_tokens:start(),\n       {ok, _A, R} = identity_tokens:issue_grant(Reg, alice, web, [read, write]),\n       {ok, A2, _R2} = identity_tokens:refresh(Reg, R, [read]),\n       identity_tokens:revoke(Reg, A2),\n       case identity_tokens:introspect(Reg, A2) of\n         {active, _, _, _} -> still_valid;\n         {inactive} -> inactive\n       end"))
+  "inactive")
+
+(define
+  id-token-test-summary
+  (str "token " id-token-test-pass "/" id-token-test-count))

lib/mod/activity.sx

@@ -0,0 +1,40 @@
+;; lib/mod/activity.sx — export decisions as ActivityPub-shaped events.
+;;
+;; The rose-ash platform propagates cross-domain effects as ActivityPub-shaped
+;; activities. A moderation decision maps to a moderation verb so the rest of the
+;; platform (and federated peers) can act on it: remove→Delete, ban→Block,
+;; hide/escalate→Flag, keep→no activity. The precise mod action is preserved in
+;; :action so a consumer can disambiguate (e.g. hide vs escalate, both Flag).
+
+(define
+  mod/action->verb
+  (fn
+    (action)
+    (cond
+      ((= action "remove") "Delete")
+      ((= action "ban") "Block")
+      ((= action "hide") "Flag")
+      ((= action "escalate") "Flag")
+      (true nil))))
+
+(define
+  mod/decision->activity
+  (fn
+    (d actor)
+    (let
+      ((verb (mod/action->verb (get d :action))))
+      (if (nil? verb) nil {:type verb :action (get d :action) :actor actor :summary (str "moderation/" (get d :action) " via " (get d :rule)) :object (get d :report-id) :rule (get d :rule)}))))
+
+;; map a batch of decisions to activities, dropping the no-op keeps
+(define
+  mod/decisions->activities
+  (fn
+    (decisions actor)
+    (reduce
+      (fn
+        (acc d)
+        (let
+          ((a (mod/decision->activity d actor)))
+          (if (nil? a) acc (append acc (list a)))))
+      (list)
+      decisions)))

lib/mod/api.sx

@@ -0,0 +1,163 @@
+;; lib/mod/api.sx — report registry + lifecycle façade + public entry points.
+;;
+;; mod/report files a report (assigning a sequential id) and opens a lifecycle
+;; case for it; mod/add-evidence accumulates evidence; mod/decide runs the engine
+;; and commits to the audit log. The lifecycle façade (mod/triage, mod/resolve,
+;; mod/review, mod/appeal, mod/finalize) drives the per-report case through its
+;; states, logging each committed decision to the audit trail.
+
+(define mod/*reports* (list))
+(define mod/*cases* (list))
+(define mod/*counter* 0)
+(define mod/*rules* mod/default-rules)
+
+(define
+  mod/reset!
+  (fn
+    ()
+    (begin
+      (set! mod/*reports* (list))
+      (set! mod/*cases* (list))
+      (set! mod/*counter* 0)
+      (mod/audit-reset!))))
+
+(define
+  mod/report
+  (fn
+    (by about reason)
+    (begin
+      (set! mod/*counter* (+ mod/*counter* 1))
+      (let
+        ((id (str "r" mod/*counter*)))
+        (let
+          ((r (mod/mk-report id by about reason)))
+          (begin
+            (append! mod/*reports* r)
+            (append! mod/*cases* {:id id :case (mod/mk-case r)})
+            r))))))
+
+(define
+  mod/get-report
+  (fn
+    (id)
+    (reduce
+      (fn (acc r) (if (= (mod/report-id r) id) r acc))
+      nil
+      mod/*reports*)))
+
+(define
+  mod/add-evidence
+  (fn
+    (id kind val)
+    (let
+      ((r (mod/get-report id)))
+      (if
+        (nil? r)
+        nil
+        (let
+          ((updated (mod/attach-evidence r (mod/mk-evidence kind val))))
+          (begin
+            (set!
+              mod/*reports*
+              (map
+                (fn (x) (if (= (mod/report-id x) id) updated x))
+                mod/*reports*))
+            updated))))))
+
+(define
+  mod/decide
+  (fn
+    (id)
+    (let
+      ((r (mod/get-report id)))
+      (if
+        (nil? r)
+        nil
+        (let
+          ((d (mod/decide-report r mod/*reports* mod/*rules*)))
+          (begin (mod/log-decision! d (mod/report-evidence r)) d))))))
+
+;; ── lifecycle façade over the case registry ──
+
+(define
+  mod/case-of
+  (fn
+    (id)
+    (reduce
+      (fn (acc rec) (if (= (get rec :id) id) (get rec :case) acc))
+      nil
+      mod/*cases*)))
+
+(define
+  mod/case-store!
+  (fn
+    (id c)
+    (set!
+      mod/*cases*
+      (map
+        (fn (rec) (if (= (get rec :id) id) {:id id :case c} rec))
+        mod/*cases*))))
+
+;; apply a lifecycle op to the stored case, persist it, and (when a decision was
+;; committed cleanly) append it to the audit log; returns the updated case
+(define
+  mod/case-apply!
+  (fn
+    (id op log?)
+    (let
+      ((c (mod/case-of id)))
+      (if
+        (nil? c)
+        nil
+        (let
+          ((c2 (op c)))
+          (begin
+            (mod/case-store! id c2)
+            (when
+              log?
+              (when
+                (nil? (mod/case-error c2))
+                (let
+                  ((d (mod/case-decision c2)))
+                  (if
+                    (nil? d)
+                    nil
+                    (mod/log-decision!
+                      d
+                      (mod/report-evidence (mod/case-report c2)))))))
+            c2))))))
+
+(define
+  mod/triage
+  (fn
+    (id)
+    (mod/case-apply!
+      id
+      (fn (c) (mod/case-triage c mod/*reports* mod/*rules*))
+      false)))
+
+(define
+  mod/resolve
+  (fn (id) (mod/case-apply! id (fn (c) (mod/case-resolve c)) true)))
+
+(define
+  mod/review
+  (fn
+    (id kind val)
+    (mod/case-apply!
+      id
+      (fn (c) (mod/case-review c kind val mod/*reports* mod/*rules*))
+      true)))
+
+(define
+  mod/appeal
+  (fn
+    (id kind val)
+    (mod/case-apply!
+      id
+      (fn (c) (mod/case-appeal c kind val mod/*reports* mod/*rules*))
+      true)))
+
+(define
+  mod/finalize
+  (fn (id) (mod/case-apply! id (fn (c) (mod/case-finalize c)) false)))

lib/mod/audit.sx

@@ -0,0 +1,54 @@
+;; lib/mod/audit.sx — append-only decision log.
+;;
+;; Every decision the api commits is recorded as an immutable audit entry holding
+;; the decision (action + matching rule), the proof tree (the derivation that
+;; justified it), and a snapshot of the evidence in force at decision time. The
+;; log is append-only: entries are never mutated or removed, only appended, each
+;; with a monotonic sequence number. Retrieval is by report id (full history) or
+;; by sequence.
+
+(define mod/*audit-log* (list))
+(define mod/*audit-seq* 0)
+
+(define
+  mod/audit-reset!
+  (fn
+    ()
+    (begin (set! mod/*audit-log* (list)) (set! mod/*audit-seq* 0))))
+
+(define mod/mk-audit-entry (fn (seq decision evidence-snapshot) {:action (get decision :action) :evidence evidence-snapshot :proof (get decision :proof) :rule (get decision :rule) :report-id (get decision :report-id) :seq seq}))
+
+(define
+  mod/log-decision!
+  (fn
+    (decision evidence-snapshot)
+    (begin
+      (set! mod/*audit-seq* (+ mod/*audit-seq* 1))
+      (let
+        ((entry (mod/mk-audit-entry mod/*audit-seq* decision evidence-snapshot)))
+        (begin (append! mod/*audit-log* entry) entry)))))
+
+;; entries for one report, in chronological (sequence) order
+(define
+  mod/audit
+  (fn
+    (id)
+    (reduce
+      (fn
+        (acc e)
+        (if (= (get e :report-id) id) (append acc (list e)) acc))
+      (list)
+      mod/*audit-log*)))
+
+(define mod/audit-all (fn () mod/*audit-log*))
+(define mod/audit-count (fn () (len mod/*audit-log*)))
+
+;; most recent decision logged for a report (nil if none)
+(define
+  mod/audit-latest
+  (fn
+    (id)
+    (reduce
+      (fn (acc e) (if (= (get e :report-id) id) e acc))
+      nil
+      mod/*audit-log*)))

lib/mod/batch.sx

@@ -0,0 +1,55 @@
+;; lib/mod/batch.sx — batch triage + corpus analytics.
+;;
+;; Operational layer: decide a whole queue of reports at once, summarize the
+;; outcomes by action, and measure which rules actually fire across a corpus.
+;; mod/never-fired is the empirical complement to lint's static unreachable check
+;; (Ext 5): lint finds rules that CAN'T fire by structure; never-fired finds rules
+;; that DIDN'T fire on real data.
+
+(define
+  mod/decide-batch
+  (fn
+    (reports rules)
+    (map (fn (r) (mod/decide-report r reports rules)) reports)))
+
+(define
+  mod/count-action
+  (fn
+    (decisions action)
+    (reduce
+      (fn (acc d) (if (= (get d :action) action) (+ acc 1) acc))
+      0
+      decisions)))
+
+(define mod/action-histogram (fn (decisions) {:keep (mod/count-action decisions "keep") :remove (mod/count-action decisions "remove") :escalate (mod/count-action decisions "escalate") :hide (mod/count-action decisions "hide") :ban (mod/count-action decisions "ban")}))
+
+(define
+  mod/rule-fire-count
+  (fn
+    (decisions rule-name)
+    (reduce
+      (fn (acc d) (if (= (get d :rule) rule-name) (+ acc 1) acc))
+      0
+      decisions)))
+
+(define
+  mod/rule-coverage
+  (fn
+    (reports rules)
+    (let
+      ((decisions (mod/decide-batch reports rules)))
+      (map (fn (rule) {:rule (mod/rule-name rule) :fired (mod/rule-fire-count decisions (mod/rule-name rule))}) rules))))
+
+(define
+  mod/never-fired
+  (fn
+    (reports rules)
+    (reduce
+      (fn
+        (acc c)
+        (if
+          (= (get c :fired) 0)
+          (append acc (list (get c :rule)))
+          acc))
+      (list)
+      (mod/rule-coverage reports rules))))

lib/mod/conformance.conf

@@ -0,0 +1,60 @@
+# Mod conformance config — sourced by lib/guest/conformance.sh.
+
+LANG_NAME=mod
+MODE=dict
+
+PRELOADS=(
+  lib/guest/pratt.sx
+  lib/prolog/tokenizer.sx
+  lib/prolog/parser.sx
+  lib/prolog/runtime.sx
+  lib/prolog/query.sx
+  lib/prolog/compiler.sx
+  lib/mod/schema.sx
+  lib/mod/policy.sx
+  lib/mod/defrule.sx
+  lib/mod/engine.sx
+  lib/mod/explain.sx
+  lib/mod/severity.sx
+  lib/mod/offenders.sx
+  lib/mod/quorum.sx
+  lib/mod/trace.sx
+  lib/mod/whatif.sx
+  lib/mod/batch.sx
+  lib/mod/temporal.sx
+  lib/mod/sla.sx
+  lib/mod/wire.sx
+  lib/mod/activity.sx
+  lib/mod/policies.sx
+  lib/mod/pipeline.sx
+  lib/mod/lifecycle.sx
+  lib/mod/audit.sx
+  lib/mod/api.sx
+  lib/mod/fed.sx
+  lib/mod/link.sx
+  lib/mod/lint.sx
+)
+
+SUITES=(
+  "decide:lib/mod/tests/decide.sx:(mod-decide-tests-run!)"
+  "audit:lib/mod/tests/audit.sx:(mod-audit-tests-run!)"
+  "escalation:lib/mod/tests/escalation.sx:(mod-escalation-tests-run!)"
+  "fed:lib/mod/tests/fed.sx:(mod-fed-tests-run!)"
+  "extensions:lib/mod/tests/extensions.sx:(mod-extensions-tests-run!)"
+  "link:lib/mod/tests/link.sx:(mod-link-tests-run!)"
+  "lint:lib/mod/tests/lint.sx:(mod-lint-tests-run!)"
+  "severity:lib/mod/tests/severity.sx:(mod-severity-tests-run!)"
+  "offenders:lib/mod/tests/offenders.sx:(mod-offenders-tests-run!)"
+  "quorum:lib/mod/tests/quorum.sx:(mod-quorum-tests-run!)"
+  "trace:lib/mod/tests/trace.sx:(mod-trace-tests-run!)"
+  "whatif:lib/mod/tests/whatif.sx:(mod-whatif-tests-run!)"
+  "batch:lib/mod/tests/batch.sx:(mod-batch-tests-run!)"
+  "temporal:lib/mod/tests/temporal.sx:(mod-temporal-tests-run!)"
+  "sla:lib/mod/tests/sla.sx:(mod-sla-tests-run!)"
+  "wire:lib/mod/tests/wire.sx:(mod-wire-tests-run!)"
+  "disjunction:lib/mod/tests/disjunction.sx:(mod-disjunction-tests-run!)"
+  "activity:lib/mod/tests/activity.sx:(mod-activity-tests-run!)"
+  "policies:lib/mod/tests/policies.sx:(mod-policies-tests-run!)"
+  "defrule:lib/mod/tests/defrule.sx:(mod-defrule-tests-run!)"
+  "pipeline:lib/mod/tests/pipeline.sx:(mod-pipeline-tests-run!)"
+)

lib/mod/conformance.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+# Thin wrapper — see lib/guest/conformance.sh and lib/mod/conformance.conf.
+exec bash "$(dirname "$0")/../guest/conformance.sh" "$(dirname "$0")/conformance.conf" "$@"

lib/mod/defrule.sx

@@ -0,0 +1,16 @@
+;; lib/mod/defrule.sx — ergonomic rule / ruleset construction.
+;;
+;; The roadmap sketched a (defrule action :when conditions) surface. Conditions
+;; already evaluate to plain data, so this needs no macro — variadic functions
+;; suffice: mod/defrule collects its trailing condition forms via &rest (dropping
+;; the explicit outer (list ...)), and mod/ruleset assembles rules the same way.
+;;
+;;   (mod/ruleset
+;;     (mod/defrule "spam-hide" :hide (list :classification "spam"))
+;;     (mod/defrule "default-keep" :keep))
+
+(define
+  mod/defrule
+  (fn (name action &rest conds) (mod/mk-rule name action conds)))
+
+(define mod/ruleset (fn (&rest rules) rules))

lib/mod/engine.sx

@@ -0,0 +1,64 @@
+;; lib/mod/engine.sx — decide a report by querying the policy program.
+;;
+;; build-program assembles the report's facts plus the compiled policy clauses;
+;; decide-report runs the Prolog query and returns a decision. A decision is a
+;; proof, not a bare keyword: it carries the matching rule, the conditions it
+;; required, the evidence that satisfied them, and a derivation — the proof tree.
+;;
+;; The proof tree is built constructively: for the matching rule, each body goal
+;; is re-queried against the same DB with the report id bound, recording the goal
+;; text, whether it was solved, and the bindings that satisfied it. That is a
+;; genuine derivation drawn from the Prolog database, ready for the audit trail.
+
+(define
+  mod/find-rule
+  (fn
+    (rules name)
+    (reduce
+      (fn
+        (acc r)
+        (if (nil? acc) (if (= (mod/rule-name r) name) r acc) acc))
+      nil
+      rules)))
+
+(define
+  mod/build-program
+  (fn
+    (r count rules)
+    (str (mod/report-facts r count) "\n" (mod/rules->program rules))))
+
+(define
+  mod/proof-goals
+  (fn
+    (db id conds)
+    (if
+      (empty? conds)
+      (list {:solved true :goal "true" :bindings {}})
+      (map
+        (fn
+          (c)
+          (let
+            ((g (mod/cond->goal c id)))
+            (let ((sols (pl-query-all db g))) {:solved (if (empty? sols) false true) :goal g :bindings (if (empty? sols) {} (first sols))})))
+        conds))))
+
+(define
+  mod/decide-report
+  (fn
+    (r reports rules)
+    (let
+      ((count (mod/report-count (mod/report-about r) reports))
+        (kinds (mod/classify-keywords r))
+        (id (mod/report-id r)))
+      (let
+        ((program (mod/build-program r count rules)))
+        (let
+          ((db (pl-load program)))
+          (let
+            ((sol (pl-query-one db (str "policy_action(" id ", Action, Rule)"))))
+            (if
+              (nil? sol)
+              {:action "keep" :proof {:goals (list) :evidence kinds :conditions (list) :rule "none" :count count} :report-id id :rule "none"}
+              (let
+                ((rname (dict-get sol "Rule")))
+                (let ((rule (mod/find-rule rules rname))) {:action (mod/rule-action rule) :proof {:goals (mod/proof-goals db id (mod/rule-when rule)) :evidence kinds :conditions (mod/rule-when rule) :rule rname :count count} :report-id id :rule rname})))))))))

lib/mod/explain.sx

@@ -0,0 +1,55 @@
+;; lib/mod/explain.sx — human-readable proof explanation.
+;;
+;; Turns a decision (from mod/decide-report, or any audit entry) into a readable
+;; multi-line "why": the action, the rule that fired, the evidence in play, and
+;; the derivation goal-by-goal with [proved]/[unproved] marks and the unification
+;; bindings that satisfied each goal. Pure SX over the Phase-2 proof tree.
+
+(define
+  mod/explain-binds
+  (fn
+    (binds)
+    (mod/join-with
+      ", "
+      (map (fn (k) (str k "=" (dict-get binds k))) (keys binds)))))
+
+(define
+  mod/explain-goal
+  (fn
+    (g)
+    (let
+      ((mark (if (get g :solved) "  [proved] " "  [unproved] "))
+        (binds (get g :bindings)))
+      (if
+        (empty? (keys binds))
+        (str mark (get g :goal))
+        (str mark (get g :goal) "  {" (mod/explain-binds binds) "}")))))
+
+(define
+  mod/explain-evidence
+  (fn
+    (evidence)
+    (if
+      (empty? evidence)
+      "Evidence: (none)"
+      (str "Evidence: " (mod/join-with ", " evidence)))))
+
+(define
+  mod/explain
+  (fn
+    (decision)
+    (let
+      ((id (get decision :report-id))
+        (action (get decision :action))
+        (rule (get decision :rule))
+        (proof (get decision :proof)))
+      (let
+        ((goals (get proof :goals)) (evidence (get proof :evidence)))
+        (mod/join-with
+          "\n"
+          (append
+            (list
+              (str "Report " id ": " action " (rule: " rule ")")
+              (mod/explain-evidence evidence)
+              "Because:")
+            (map mod/explain-goal goals)))))))

lib/mod/fed.sx

@@ -0,0 +1,145 @@
+;; lib/mod/fed.sx — federation: cross-instance reports, decision sharing, trust,
+;; revocation. fed-sx itself is mocked here (an in-memory outbox); the real wire
+;; transport would replace mod/fed-send!.
+;;
+;; Trust is advisory by default (the hard rule): a peer's decision only binds
+;; locally when (mod/trusted? peer :mod) holds. An untrusted peer's decision is
+;; recorded as a suggestion in the advisory log and is NOT applied. Local
+;; decisions propagate outward via the outbox. Revocation undoes a locally
+;; applied action when its proof is invalidated, notifying the origin peer.
+
+(define mod/*fed-trust* (list))     ;; {:peer :scope}
+(define mod/*fed-outbox* (list))    ;; {:to :type :payload}
+(define mod/*fed-advisory* (list))  ;; {:peer :decision} — received, not applied
+(define mod/*fed-applied* (list))   ;; {:report-id :action :origin :revoked}
+(define mod/*fed-origins* (list))   ;; {:id :origin}
+
+(define
+  mod/fed-reset!
+  (fn
+    ()
+    (begin
+      (set! mod/*fed-trust* (list))
+      (set! mod/*fed-outbox* (list))
+      (set! mod/*fed-advisory* (list))
+      (set! mod/*fed-applied* (list))
+      (set! mod/*fed-origins* (list)))))
+
+;; ── trust model ──
+
+(define
+  mod/trust-match?
+  (fn
+    (t peer scope)
+    (if (= (get t :peer) peer) (= (get t :scope) scope) false)))
+
+(define
+  mod/grant-trust
+  (fn (peer scope) (begin (append! mod/*fed-trust* {:scope scope :peer peer}) true)))
+
+(define
+  mod/revoke-trust
+  (fn
+    (peer scope)
+    (set!
+      mod/*fed-trust*
+      (reduce
+        (fn
+          (acc t)
+          (if (mod/trust-match? t peer scope) acc (append acc (list t))))
+        (list)
+        mod/*fed-trust*))))
+
+(define
+  mod/trusted?
+  (fn
+    (peer scope)
+    (mod/any? (fn (t) (mod/trust-match? t peer scope)) mod/*fed-trust*)))
+
+;; ── cross-instance reports ──
+
+(define
+  mod/fed-receive-report
+  (fn
+    (peer by about reason)
+    (let
+      ((r (mod/report by about reason)))
+      (begin (append! mod/*fed-origins* {:id (mod/report-id r) :origin peer}) r))))
+
+(define
+  mod/report-origin
+  (fn
+    (id)
+    (reduce
+      (fn (acc o) (if (= (get o :id) id) (get o :origin) acc))
+      "local"
+      mod/*fed-origins*)))
+
+;; ── decision sharing (mock fed-sx send) ──
+
+(define
+  mod/fed-send!
+  (fn (to type payload) (begin (append! mod/*fed-outbox* {:type type :to to :payload payload}) true)))
+
+(define mod/fed-outbox (fn () mod/*fed-outbox*))
+
+(define
+  mod/fed-share-decision
+  (fn
+    (decision peers)
+    (reduce
+      (fn
+        (acc p)
+        (begin (mod/fed-send! p "decision" decision) (append acc (list p))))
+      (list)
+      peers)))
+
+;; ── receiving a peer's decision (advisory unless trusted) ──
+
+(define
+  mod/fed-applied-action
+  (fn
+    (report-id)
+    (reduce
+      (fn (acc a) (if (= (get a :report-id) report-id) a acc))
+      nil
+      mod/*fed-applied*)))
+
+(define
+  mod/fed-receive-decision
+  (fn
+    (peer decision)
+    (if
+      (mod/trusted? peer :mod)
+      (begin (append! mod/*fed-applied* {:revoked false :action (get decision :action) :report-id (get decision :report-id) :origin peer}) {:advisory false :peer peer :applied true :decision decision})
+      (begin (append! mod/*fed-advisory* {:peer peer :decision decision}) {:advisory true :peer peer :applied false :decision decision}))))
+
+;; ── revocation ──
+
+(define
+  mod/fed-revoke!
+  (fn
+    (report-id reason)
+    (begin
+      (set!
+        mod/*fed-applied*
+        (map
+          (fn (a) (if (= (get a :report-id) report-id) {:revoked true :action (get a :action) :report-id (get a :report-id) :origin (get a :origin)} a))
+          mod/*fed-applied*))
+      (mod/fed-send! (mod/report-origin report-id) "revocation" {:report-id report-id :reason reason})
+      report-id)))
+
+;; re-run the engine; if the action no longer holds, the prior decision's proof
+;; is invalidated — revoke the applied moderation.
+(define
+  mod/fed-revoke-if-invalidated
+  (fn
+    (report decision reports rules)
+    (let
+      ((d2 (mod/decide-report report reports rules)))
+      (if
+        (= (get d2 :action) (get decision :action))
+        {:revoked false :decision d2}
+        (begin
+          (mod/fed-revoke! (get decision :report-id) "proof invalidated")
+          {:revoked true :decision d2})))))

lib/mod/lifecycle.sx

@@ -0,0 +1,160 @@
+;; lib/mod/lifecycle.sx — report lifecycle state machine (pure SX over the engine).
+;;
+;; Lifecycle state is deliberately separate from policy: the Prolog rules answer
+;; "what action?", this module answers "where in the process is this report?".
+;;
+;;   :open ──triage──▶ :triaged ──resolve/review──▶ :decided ──appeal──▶ :appealed
+;;                                                      │                    │
+;;                                                      └────finalize───▶ :final ◀┘
+;;
+;; A case is an immutable value {:report :state :decision :tier :error :history}.
+;; Every transition returns a NEW case; illegal transitions return the case
+;; unchanged with :error set. Tiers: triage runs the engine (auto-tier); a
+;; terminal action (hide/remove/keep) resolves immediately, an :escalate action
+;; flags the case for human review (human-tier) before it can be resolved.
+
+(define mod/case* (fn (report state decision tier err history) {:history history :state state :report report :error err :tier tier :decision decision}))
+
+(define
+  mod/mk-case
+  (fn (report) (mod/case* report "open" nil nil nil (list))))
+
+(define mod/case-report (fn (c) (get c :report)))
+(define mod/case-state (fn (c) (get c :state)))
+(define mod/case-decision (fn (c) (get c :decision)))
+(define mod/case-tier (fn (c) (get c :tier)))
+(define mod/case-error (fn (c) (get c :error)))
+(define mod/case-history (fn (c) (get c :history)))
+
+;; ── transition table ──
+
+(define mod/lc-transitions {:final (list) :appealed (list "final") :decided (list "appealed" "final") :open (list "triaged") :triaged (list "decided")})
+
+(define mod/member? (fn (x lst) (mod/any? (fn (y) (= y x)) lst)))
+
+(define
+  mod/lc-can-transition?
+  (fn
+    (from to)
+    (let
+      ((outs (get mod/lc-transitions from)))
+      (if (nil? outs) false (mod/member? to outs)))))
+
+;; ── core transition: validate, record history, or flag :error ──
+
+(define
+  mod/case-goto
+  (fn
+    (c to note report decision tier)
+    (let
+      ((from (mod/case-state c)))
+      (if
+        (mod/lc-can-transition? from to)
+        (mod/case*
+          report
+          to
+          decision
+          tier
+          nil
+          (append (mod/case-history c) (list {:note note :to to :from from})))
+        (mod/case*
+          (mod/case-report c)
+          from
+          (mod/case-decision c)
+          (mod/case-tier c)
+          (str "illegal transition: " from " -> " to)
+          (mod/case-history c))))))
+
+(define
+  mod/case-error-set
+  (fn
+    (c msg)
+    (mod/case*
+      (mod/case-report c)
+      (mod/case-state c)
+      (mod/case-decision c)
+      (mod/case-tier c)
+      msg
+      (mod/case-history c))))
+
+;; ── lifecycle operations ──
+
+;; :open → :triaged — run the auto-tier first pass.
+(define
+  mod/case-triage
+  (fn
+    (c reports rules)
+    (let
+      ((d (mod/decide-report (mod/case-report c) reports rules)))
+      (let
+        ((tier (if (= (get d :action) "escalate") "human" "auto")))
+        (mod/case-goto
+          c
+          "triaged"
+          "auto-tier first pass"
+          (mod/case-report c)
+          d
+          tier)))))
+
+;; :triaged → :decided — auto-tier resolves; human-tier is blocked until review.
+(define
+  mod/case-resolve
+  (fn
+    (c)
+    (if
+      (= (mod/case-tier c) "human")
+      (mod/case-error-set c "awaiting human review (escalated)")
+      (mod/case-goto
+        c
+        "decided"
+        "auto-tier resolved"
+        (mod/case-report c)
+        (mod/case-decision c)
+        (mod/case-tier c)))))
+
+;; :triaged → :decided — human review: attach evidence, re-decide, resolve.
+(define
+  mod/case-review
+  (fn
+    (c kind val reports rules)
+    (let
+      ((nr (mod/attach-evidence (mod/case-report c) (mod/mk-evidence kind val))))
+      (let
+        ((d (mod/decide-report nr reports rules)))
+        (mod/case-goto c "decided" (str "human review: " kind) nr d "human")))))
+
+;; :decided → :appealed — appeal: attach evidence, re-decide (may override).
+(define
+  mod/case-appeal
+  (fn
+    (c kind val reports rules)
+    (let
+      ((nr (mod/attach-evidence (mod/case-report c) (mod/mk-evidence kind val))))
+      (let
+        ((d (mod/decide-report nr reports rules)))
+        (mod/case-goto
+          c
+          "appealed"
+          (str "appeal: " kind)
+          nr
+          d
+          (mod/case-tier c))))))
+
+;; :decided | :appealed → :final
+(define
+  mod/case-finalize
+  (fn
+    (c)
+    (mod/case-goto
+      c
+      "final"
+      "finalized"
+      (mod/case-report c)
+      (mod/case-decision c)
+      (mod/case-tier c))))
+
+(define
+  mod/case-action
+  (fn
+    (c)
+    (let ((d (mod/case-decision c))) (if (nil? d) nil (get d :action)))))