flow: reference host driver flow-drive-host/flow-run-host + 4 tests

Completes the host ABI from work-queue to driver loop: the host supplies only a
(kind payload) -> answer dispatch fn; flow-drive-host services one tick of pending
requests, flow-run-host ticks until quiescent (bounded). Tested via the art-dag
render -> human-review -> publish pipeline driven entirely by flow-run-host. The
art-dag integration is now: define dispatch, call flow-run-host. 166/166, 11 suites.

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

lib/acl/api.sx

@@ -1,45 +0,0 @@
-;; 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

@@ -1,110 +0,0 @@
-;; 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

@@ -1,32 +0,0 @@
-# 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

@@ -1,3 +0,0 @@
-#!/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

@@ -1,72 +0,0 @@
-;; 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

@@ -1,125 +0,0 @@
-;; 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

@@ -1,47 +0,0 @@
-;; 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

@@ -1,61 +0,0 @@
-;; 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

@@ -1,71 +0,0 @@
-;; 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

@@ -1,14 +0,0 @@
-{
-  "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

@@ -1,11 +0,0 @@
-# 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

@@ -1,170 +0,0 @@
-;; 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

@@ -1,316 +0,0 @@
-;; 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

@@ -1,273 +0,0 @@
-;; 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

@@ -1,228 +0,0 @@
-;; 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

@@ -1,202 +0,0 @@
-;; 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/flow/README.md

@@ -0,0 +1,141 @@
+# flow — durable DAG workflows on Scheme
+
+`flow` is a workflow engine for rose-ash: content pipelines (write → review →
+publish → federate), scheduled jobs, and multi-step user flows (signup, confirm,
+onboard) that **survive process restarts**. It is a thin Scheme prelude over the
+Scheme-on-SX guest (`lib/scheme/`); a flow runs *inside* the interpreter.
+
+Run the suite: `bash lib/flow/conformance.sh` → **151/151 across 10 suites**.
+
+## Model
+
+A **flow** is just a Scheme procedure of one argument — the upstream value:
+
+```
+node : input -> output
+```
+
+Combinators build composite nodes out of child nodes. A node that ignores its
+argument is effectively a thunk. There is no separate "graph" object: composition
+*is* function composition, so flows are values you can name, pass, and nest.
+
+```scheme
+(defflow publish
+  (sequence
+    (lambda (draft) (string-append draft "!"))
+    (branch (lambda (post) (>= (string-length post) 3))
+            (remote-node 'fed 'publish)
+            (flow-const 'rejected))))
+
+(flow/start publish "hello")   ; => federated, or a (flow-suspended id tag) state
+```
+
+## Building blocks (`spec.sx`)
+
+| Combinator | Meaning |
+|---|---|
+| `(flow-node f)` / `(flow-id x)` / `(flow-const v)` | leaf nodes |
+| `(sequence n ...)` | thread input left-to-right |
+| `(parallel n ...)` | fan input to every child, join results into a list (sequential eval) |
+| `(map-flow node)` | run `node` over each item of a list input, join results |
+| `(flow-while pred body max)` / `(flow-until ...)` | bounded iteration (cap `max` steps) |
+| `(defflow name body)` | bind + register a named flow (so it survives restart) |
+
+## Control flow + errors (`spec.sx`)
+
+| Combinator | Meaning |
+|---|---|
+| `(branch pred then else)` | `pred` on input selects `then`/`else` (`cond` is a Scheme special form) |
+| `(retry n node)` | re-run on a *raised exception*, up to `n` attempts |
+| `(timeout budget node)` | cooperative **step budget**: nodes call `(tick)`; the `(budget+1)`-th tick raises `flow-timeout` |
+| `(try-catch node handler)` | catch a raised exception → `(handler error)` |
+| `(fail reason)` / `(failed? x)` / `(fail-reason x)` | explicit failure *values* (flow downstream as data) |
+| `(recover node handler)` | the fail-VALUE counterpart of try-catch |
+| `(attempt n ...)` | railway sequence: stop at the first node returning a `(fail ...)` |
+| `(tap effect)` | run a side effect, return input unchanged |
+
+**Two error channels, on purpose.** Raised exceptions are for *bugs/transients*
+(caught by `retry`/`try-catch`). `(fail reason)` values are for *expected business
+outcomes* (validation rejected, declined) and compose via `attempt`/`recover`.
+
+## Suspend / resume — the durable core (`spec.sx`, `store.sx`)
+
+The guest Scheme's `call/cc` is **escape-only** — re-invoking a captured
+continuation after it returns *hangs* the runtime. So flow does **not** serialize
+continuations. Instead it uses **deterministic replay**:
+
+- `(suspend tag)` — if `tag` is already in the replay log, return its logged value;
+  otherwise escape to the driver as `(flow-suspended tag)`.
+- `resume` appends `(tag value)` to the log and **re-runs the flow from the start**.
+  Already-resolved suspends replay their values; the first unresolved one escapes
+  again (or the flow completes).
+
+The entire persisted state is the replay log — plain data. No live continuation is
+ever stored, so flows survive process restarts and even moves between instances.
+
+> **Author contract:** suspend `tag`s must be unique and deterministic across
+> replays, and **all** non-determinism / side effects must go through suspend
+> points (so their results are logged) — otherwise they re-run on every replay.
+
+### Lifecycle (`store.sx`)
+
+```scheme
+(flow/start flow input)   ; raw result if it completes, else (flow-suspended id tag)
+(flow/resume id value)    ; inject value at the waiting tag, continue
+(flow/cancel id)          ; terminate; a later resume is rejected
+```
+
+### Introspection & hygiene
+
+```scheme
+(flow/status id)   ; done | suspended | cancelled | unknown
+(flow/result id)   ; result if done, else (flow-error reason)
+(flow/list)        ; ((id status) ...)
+(flow/pending)     ; ((id waiting-tag) ...) — what each suspended flow awaits
+(flow/gc)          ; drop terminal records, keep live ones; returns count removed
+(flow/forget id)   ; drop one terminal record (refuses live flows)
+```
+
+### Crash recovery
+
+```scheme
+(flow-store-export)      ; the store as plain data (live procs nulled)
+(flow-store-import! d)   ; restore the store from exported data
+(flow-resumable-ids)     ; ids of suspended flows to wake on restart
+```
+
+On restart the flow definitions are reloaded (`defflow` re-registers names) and the
+exported store reimported; `resume` re-resolves each flow's procedure **by name**.
+
+## Distribution via fed-sx (`remote.sx`)
+
+```scheme
+(flow-peer-register! addr table)      ; mock a peer's exposed functions (fed-sx boundary)
+(remote-node addr fn)                 ; run a node on a peer
+(remote-failover addrs fn local)      ; try peers in order, fall through to a local node
+(flow-replicate-to addr)              ; copy this store to a peer's replica slot
+(flow-restore-from addr)              ; import a peer's replica (handoff)
+```
+
+**Handoff** is crash recovery across instances: replicate → local instance dies →
+peer restores the (plain-data) store and resumes. The replay log carries over, so
+all resolved suspends survive the move.
+
+## Files
+
+| File | Contents |
+|---|---|
+| `spec.sx` | combinators (flow-combinators-src / flow-control-src / flow-suspend-src) |
+| `store.sx` | durable store, lifecycle, crash recovery, introspection, hygiene |
+| `remote.sx` | fed-sx transport (mock peer registry), failover, replication |
+| `api.sx` | `flow-make-env` / `flow-run` SX helpers (one cached env, per-test reset) |
+| `tests/*.sx` | 10 suites, 151 cases |
+| `conformance.sh` | loads substrate + flow layer, runs every suite |
+
+## Notes on the substrate
+
+The guest Scheme (`lib/scheme/`, imported read-only) lacks dotted-rest params
+`(a . rest)` and named `let`; combinators use `(lambda args ...)` variadics + top-
+level recursion. `cons` is list-only (no dotted pairs), so log/assoc entries are
+2-element lists. Strings box as `{:scm-string "..."}`. Timeout is a step budget
+because there is no wall clock; `parallel` is sequential for the same reason.

lib/flow/api.sx

@@ -0,0 +1,65 @@
+;; lib/flow/api.sx — flow runtime entry points.
+;;
+;; Builds a Scheme env preloaded with the flow combinators (lib/flow/spec.sx),
+;; the durable store + lifecycle (lib/flow/store.sx), the fed-sx remote layer
+;; (lib/flow/remote.sx), and the host integration ABI (lib/flow/host.sx), and
+;; provides SX helpers to run flow programs.
+;;
+;; Scheme-level API (available inside flow programs):
+;;   (flow/start flow input) — run a flow; raw result if it completes, else
+;;                             (flow-suspended id tag). Defined in store.sx.
+;;   (flow/resume id value)  — resume a suspended flow (store.sx)
+;;   (flow/cancel id)        — cancel a flow (store.sx)
+;;   (suspend tag)           — suspension point (spec.sx)
+;;   (request kind payload)  — host request envelope over suspend (host.sx)
+;;   (remote-node addr fn)   — node executed on a federation peer (remote.sx)
+;;
+;; SX-level helpers (for hosts and tests):
+;;   (flow-make-env)        — fresh standard env + combinators + store + remote + host
+;;   (flow-run src)         — eval a Scheme program string in a reset shared env
+;;   (flow-run-in env src)  — eval a Scheme program string in a given env
+;;
+;; flow-run reuses ONE env (building the full standard env is expensive) and
+;; resets the mutable flow globals before each program, so tests stay isolated
+;; without paying for a fresh standard env each time. flow-registry persists (it
+;; models reloaded flow definitions surviving a restart).
+
+(define
+  flow-make-env
+  (fn
+    ()
+    (let
+      ((env (scheme-standard-env)))
+      (flow-load-combinators! env)
+      (flow-load-store! env)
+      (flow-load-remote! env)
+      (flow-load-host! env)
+      env)))
+
+(define
+  flow-run-in
+  (fn (env src) (scheme-eval-program (scheme-parse-all src) env)))
+
+(define
+  flow-reset-src
+  "(set! flow-store (list)) (set! flow-next-id 0) (set! flow-replay-log (list)) (set! flow-suspend-k #f) (set! flow-timeout-budget -1) (set! flow-peers (list)) (set! flow-replicas (list))")
+
+(define flow-env-cache false)
+
+(define
+  flow-shared-env
+  (fn
+    ()
+    (begin
+      (if flow-env-cache nil (set! flow-env-cache (flow-make-env)))
+      flow-env-cache)))
+
+(define
+  flow-run
+  (fn
+    (src)
+    (let
+      ((env (flow-shared-env)))
+      (begin
+        (scheme-eval-program (scheme-parse-all flow-reset-src) env)
+        (scheme-eval-program (scheme-parse-all src) env)))))

lib/flow/conformance.sh

@@ -0,0 +1,103 @@
+#!/usr/bin/env bash
+# flow-on-sx conformance runner — runs all flow test suites in one sx_server process.
+#
+# Usage:
+#   bash lib/flow/conformance.sh        # run all suites
+#   bash lib/flow/conformance.sh -v     # verbose (list each 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="${1:-}"
+
+# Suites: NAME RUNNER-FN PATH
+SUITES=(
+  "basic       flow-basic-tests-run!     lib/flow/tests/basic.sx"
+  "control     flow-ctl-tests-run!       lib/flow/tests/control.sx"
+  "suspend     flow-sus-tests-run!       lib/flow/tests/suspend.sx"
+  "recovery    flow-rec-tests-run!       lib/flow/tests/recovery.sx"
+  "distributed flow-dist-tests-run!      lib/flow/tests/distributed.sx"
+  "api         flow-api-tests-run!       lib/flow/tests/api.sx"
+  "combinators flow-cmb-tests-run!       lib/flow/tests/combinators.sx"
+  "railway     flow-rail-tests-run!      lib/flow/tests/railway.sx"
+  "integration flow-int-tests-run!       lib/flow/tests/integration.sx"
+  "hygiene     flow-hyg-tests-run!       lib/flow/tests/hygiene.sx"
+  "host        flow-hst-tests-run!       lib/flow/tests/host.sx"
+)
+
+TMPFILE=$(mktemp); trap "rm -f $TMPFILE" EXIT
+EPOCH=1
+
+emit_load () { echo "(epoch $EPOCH)"; echo "(load \"$1\")"; EPOCH=$((EPOCH+1)); }
+emit_eval () { echo "(epoch $EPOCH)"; echo "(eval \"$1\")"; EPOCH=$((EPOCH+1)); }
+
+{
+  emit_load "lib/guest/lex.sx"
+  emit_load "lib/guest/reflective/env.sx"
+  emit_load "lib/guest/reflective/quoting.sx"
+  emit_load "lib/scheme/parser.sx"
+  emit_load "lib/scheme/eval.sx"
+  emit_load "lib/scheme/runtime.sx"
+  emit_load "lib/flow/spec.sx"
+  emit_load "lib/flow/store.sx"
+  emit_load "lib/flow/remote.sx"
+  emit_load "lib/flow/host.sx"
+  emit_load "lib/flow/api.sx"
+  for SUITE in "${SUITES[@]}"; do
+    read -r _NAME _RUNNER FILE <<< "$SUITE"
+    emit_load "$FILE"
+    emit_eval "($_RUNNER)"
+  done
+} > "$TMPFILE"
+
+OUTPUT=$(timeout 540 "$SX_SERVER" < "$TMPFILE" 2>&1 || true)
+
+TOTAL_PASS=0
+TOTAL_FAIL=0
+FAILED_SUITES=()
+
+LAST_DICT_LINES=$(echo "$OUTPUT" | grep -E '^\{:' || true)
+
+I=0
+while read -r LINE; do
+  [ -z "$LINE" ] && continue
+  P=$(echo "$LINE" | grep -oE ':passed [0-9]+' | awk '{print $2}')
+  F=$(echo "$LINE" | grep -oE ':failed [0-9]+' | awk '{print $2}')
+  [ -z "$P" ] && P=0
+  [ -z "$F" ] && F=0
+  SUITE_INFO="${SUITES[$I]}"
+  SUITE_NAME=$(echo "$SUITE_INFO" | awk '{print $1}')
+  TOTAL_PASS=$((TOTAL_PASS + P))
+  TOTAL_FAIL=$((TOTAL_FAIL + F))
+  if [ "$F" -gt 0 ]; then
+    FAILED_SUITES+=("$SUITE_NAME: $P/$((P+F))")
+    printf 'X %-12s %d/%d\n' "$SUITE_NAME" "$P" "$((P+F))"
+    echo "$LINE" | grep -oE ':name "[^"]*"' | sed 's/:name /    fail: /'
+  elif [ "$VERBOSE" = "-v" ]; then
+    printf 'ok %-12s %d passed\n' "$SUITE_NAME" "$P"
+  fi
+  I=$((I+1))
+done <<< "$LAST_DICT_LINES"
+
+TOTAL=$((TOTAL_PASS + TOTAL_FAIL))
+if [ "$TOTAL" -eq 0 ]; then
+  echo "ERROR: no suite results parsed. Raw output:" >&2
+  echo "$OUTPUT" >&2
+  exit 1
+fi
+if [ $TOTAL_FAIL -eq 0 ]; then
+  echo "ok $TOTAL_PASS/$TOTAL flow-on-sx tests passed (${#SUITES[@]} suites)"
+else
+  echo "FAIL $TOTAL_PASS/$TOTAL passed, $TOTAL_FAIL failed:"
+  for S in "${FAILED_SUITES[@]}"; do echo "  $S"; done
+  exit 1
+fi

lib/flow/host.sx

@@ -0,0 +1,42 @@
+;; lib/flow/host.sx — the host integration ABI (Phase 8).
+;;
+;; `suspend` is flow's seam to the outside world, but a bare (suspend tag) is just a
+;; signal — every author would invent their own tag shape. This layer defines a
+;; stable request/response contract so a host (e.g. an art-dag driver, or a human
+;; review UI) can hook in WITHOUT reverse-engineering ad-hoc tags.
+;;
+;; A flow asks the host to do something and waits for the answer:
+;;   (request kind payload)  — suspend with a typed envelope (flow-request kind
+;;     payload); evaluates to the host's resume value.
+;;   (await-human prompt)    — request kind=human (a decision point)
+;;   (await-render recipe)   — request kind=render (e.g. an art-dag job)
+;;   (await-effect kind p)   — request of an arbitrary kind
+;;
+;; The host drives flows by polling its work queue and resuming:
+;;   (flow-host-requests)    — ((id kind payload) ...) for every SUSPENDED flow whose
+;;     waiting tag is a host request. The host dispatches by kind (render -> submit a
+;;     Celery job; human -> show UI), then calls (flow/resume id answer).
+;;   (request? tag) / (request-kind tag) / (request-payload tag) — parse one tag.
+;;
+;; Reference driver — the host only supplies `dispatch`, a (kind payload) -> answer:
+;;   (flow-drive-host dispatch)        — one tick: service every CURRENTLY pending
+;;     request (snapshot), resuming each with (dispatch kind payload); returns the
+;;     count serviced. Resumes may create new requests — serviced on the next tick.
+;;   (flow-run-host dispatch maxticks) — tick until quiescent (no pending requests)
+;;     or maxticks reached; returns total requests serviced. Bounded for determinism.
+;;
+;; Contract: the host owns IO and persistence. flow stays deterministic — a flow
+;; never performs IO itself, it only `request`s; the host performs the effect and
+;; feeds the result back via resume (which the replay log records, so the effect is
+;; not re-run on recovery). Persist with flow-store-export after each transition and
+;; flow-store-import! on boot.
+
+(define
+  flow-host-src
+  "(define (request kind payload) (suspend (list (quote flow-request) kind payload)))\n   (define (request? tag) (and (pair? tag) (eq? (car tag) (quote flow-request))))\n   (define (request-kind tag) (car (cdr tag)))\n   (define (request-payload tag) (car (cdr (cdr tag))))\n   (define (await-human prompt) (request (quote human) prompt))\n   (define (await-render recipe) (request (quote render) recipe))\n   (define (await-effect kind payload) (request kind payload))\n   (define (flow-host-req-step pend)\n     (if (null? pend)\n         (list)\n         (let ((id (car (car pend))) (tag (car (cdr (car pend)))))\n           (if (request? tag)\n               (cons (list id (request-kind tag) (request-payload tag))\n                     (flow-host-req-step (cdr pend)))\n               (flow-host-req-step (cdr pend))))))\n   (define (flow-host-requests) (flow-host-req-step (flow/pending)))\n   (define (flow-drive-host-step reqs dispatch)\n     (if (null? reqs)\n         0\n         (begin\n           (flow/resume (car (car reqs)) (dispatch (car (cdr (car reqs))) (car (cdr (cdr (car reqs))))))\n           (+ 1 (flow-drive-host-step (cdr reqs) dispatch)))))\n   (define (flow-drive-host dispatch) (flow-drive-host-step (flow-host-requests) dispatch))\n   (define (flow-run-host dispatch maxticks)\n     (if (<= maxticks 0)\n         0\n         (let ((n (flow-drive-host dispatch)))\n           (if (= n 0) 0 (+ n (flow-run-host dispatch (- maxticks 1)))))))")
+
+(define
+  flow-load-host!
+  (fn
+    (env)
+    (begin (scheme-eval-program (scheme-parse-all flow-host-src) env) env)))

lib/flow/remote.sx

@@ -0,0 +1,34 @@
+;; lib/flow/remote.sx — distributed nodes via fed-sx (Phase 4).
+;;
+;; A node can execute on a federation peer. The transport is the fed-sx boundary;
+;; it is MOCKED in tests by a peer registry mapping addr -> function table. In
+;; production flow-transport would issue a fed-sx call; here it dispatches locally.
+;;
+;;   (flow-peer-register! addr table) — register a mock peer. table is a list of
+;;     (fn-name proc) entries — the functions that peer exposes.
+;;   (flow-transport addr fn input)   — invoke fn on the peer with input. Raises
+;;     (flow-remote-unreachable) if the addr is unknown, (flow-remote-no-fn) if the
+;;     peer does not expose fn.
+;;   (remote-node addr fn)            — a node that runs fn on the peer at addr.
+;;   (remote-failover addrs fn local) — try fn on each peer in addrs in order; on a
+;;     raised error move to the next peer; if every peer fails, run the `local`
+;;     node as a fallback.
+;;
+;; Persistence across instances + handoff. Each instance runs the same flow
+;; definitions, so the only thing that needs to cross the wire is the (plain-data)
+;; store — exactly flow-store-export from store.sx. Replication pushes that export
+;; to a peer's replica slot; handoff = restore the replica on the peer and resume.
+;;
+;;   (flow-replicate-to addr) — copy this instance's store to peer addr's replica
+;;   (flow-restore-from addr) — import the replica from peer addr (#t / #f)
+;;   (flow-replica-get addr)  — the raw replicated store at addr (or #f)
+
+(define
+  flow-remote-src
+  "(define flow-peers (list))\n   (define (flow-assoc key alist)\n     (if (null? alist)\n         #f\n         (if (eq? (car (car alist)) key) (car (cdr (car alist))) (flow-assoc key (cdr alist)))))\n   (define (flow-peer-register! addr table) (set! flow-peers (cons (list addr table) flow-peers)))\n   (define (flow-transport addr fn input)\n     (let ((table (flow-assoc addr flow-peers)))\n       (if table\n           (let ((proc (flow-assoc fn table)))\n             (if proc (proc input) (raise (quote flow-remote-no-fn))))\n           (raise (quote flow-remote-unreachable)))))\n   (define (remote-node addr fn) (lambda (input) (flow-transport addr fn input)))\n   (define (flow-failover-step addrs fn input local)\n     (if (null? addrs)\n         (local input)\n         (guard (e (#t (flow-failover-step (cdr addrs) fn input local)))\n           (flow-transport (car addrs) fn input))))\n   (define (remote-failover addrs fn local)\n     (lambda (input) (flow-failover-step addrs fn input local)))\n\n   (define flow-replicas (list))\n   (define (flow-replicas-remove addr reps)\n     (if (null? reps)\n         (list)\n         (if (eq? (car (car reps)) addr)\n             (flow-replicas-remove addr (cdr reps))\n             (cons (car reps) (flow-replicas-remove addr (cdr reps))))))\n   (define (flow-replicate-to addr)\n     (set! flow-replicas (cons (list addr (flow-store-export)) (flow-replicas-remove addr flow-replicas))))\n   (define (flow-replica-get addr) (flow-assoc addr flow-replicas))\n   (define (flow-restore-from addr)\n     (let ((data (flow-replica-get addr)))\n       (if data (begin (flow-store-import! data) #t) #f)))")
+
+(define
+  flow-load-remote!
+  (fn
+    (env)
+    (begin (scheme-eval-program (scheme-parse-all flow-remote-src) env) env)))

lib/flow/scoreboard.json

@@ -0,0 +1,19 @@
+{
+  "total": 166,
+  "passed": 166,
+  "failed": 0,
+  "suites": {
+    "basic": { "passed": 18, "total": 18 },
+    "control": { "passed": 31, "total": 31 },
+    "suspend": { "passed": 17, "total": 17 },
+    "recovery": { "passed": 8, "total": 8 },
+    "distributed": { "passed": 19, "total": 19 },
+    "api": { "passed": 12, "total": 12 },
+    "combinators": { "passed": 17, "total": 17 },
+    "railway": { "passed": 10, "total": 10 },
+    "integration": { "passed": 10, "total": 10 },
+    "hygiene": { "passed": 9, "total": 9 },
+    "host": { "passed": 15, "total": 15 }
+  },
+  "phases": { "phase1": "done", "phase2": "done", "phase3": "done", "phase4": "done", "phase5": "done", "phase6": "done", "phase7": "done", "phase8": "done" }
+}

lib/flow/scoreboard.md

@@ -0,0 +1,53 @@
+# flow-on-sx Scoreboard
+
+**All tests pass: 166 / 166 across 11 suites. Phases 1-8 complete.**
+
+`bash lib/flow/conformance.sh`
+
+## Per-suite breakdown
+
+| Suite | Passing | Covers |
+|-------|--------:|--------|
+| basic |     18  | Phase 1: single nodes, linear sequence, data-flow threading, defflow, parallel fan/join, nested composition, publish-shaped flow |
+| control |  31  | Phase 2: `branch` (6); error model `fail`/`failed?`/`fail-reason` (6); `try-catch` (6); `retry n` (6); `timeout` cooperative step budget (7) |
+| suspend |  17  | Phase 3: suspend/resume/cancel via deterministic replay; multi-step, replay determinism, lifecycle guards, suspend-in-branch |
+| recovery |  8  | Phase 3: crash recovery — store export/import, resumable scan, restart-at-every-step, replay-log survival |
+| distributed | 19 | Phase 4: `remote-node` (7); `remote-failover` (6); replication + handoff across instances (6) |
+| api |  12  | Phase 5: introspection — `flow/status`, `flow/result`, `flow/list`, `flow/pending` |
+| combinators | 17 | Phase 5: `tap`, `recover` (fail-value), `map-flow` fan-over-list, `flow-while`/`flow-until` bounded iteration |
+| railway | 10 | Phase 6: `attempt` — fail-value short-circuiting sequence + recover rejoin |
+| integration | 10 | Phase 7: end-to-end order + onboarding flows composing every phase (suspend, branch, federation, crash recovery, handoff, introspection) |
+| hygiene | 9 | Phase 5: `flow/gc` (prune terminal flows), `flow/forget` (drop one terminal record) |
+| host | 15 | Phase 8: host ABI — `request`/`await-human`/`await-render`, `flow-host-requests` queue, `flow-run-host` reference driver; art-dag-shaped render→review→publish loop |
+
+## Architecture
+
+Flow combinators are a **Scheme prelude** (`lib/flow/spec.sx`) loaded onto
+`scheme-standard-env`. A flow is a Scheme procedure `input -> output`. The whole
+flow executes inside the Scheme interpreter, so Phase 3's `suspend` (call/cc) will
+capture the flow continuation directly.
+
+- `lib/flow/spec.sx` — combinators: `flow-node`, `flow-id`, `flow-const`,
+  `sequence`, `parallel`, `defflow`; `flow-load-combinators!`.
+- `lib/flow/api.sx` — `flow/start` (Scheme); `flow-make-env`, `flow-run`,
+  `flow-run-in` (SX helpers).
+- `lib/flow/tests/basic.sx` — 18 cases.
+- `lib/flow/conformance.sh` — loads substrate + flow layer, runs suites.
+
+## Semantics notes
+
+- **node** = 1-arg Scheme procedure; the upstream value is the argument. A node
+  ignoring its argument is effectively a thunk.
+- **sequence** threads left-to-right; empty sequence = identity.
+- **parallel** fans the same input to every branch and joins results into a list.
+  Evaluation is **sequential** for now; true concurrency arrives in Phase 3.
+
+## Phases
+
+- [x] Phase 1 — Declarative DAG + sequential execution (combinators + 18 tests, `flow/start`)
+- [x] Phase 2 — Control flow + error handling (branch, error model, try-catch, retry, timeout)
+- [x] Phase 3 — Suspend/resume (suspend/resume/cancel + crash recovery via deterministic replay)
+- [x] Phase 4 — Distributed nodes via fed-sx (remote-node, failover, replication + handoff)
+- [x] Phase 5 — Operational API + combinators (introspection, tap, recover, map-flow)
+- [ ] Phase 3 — Suspend / resume (the showcase)
+- [ ] Phase 4 — Distributed nodes via fed-sx

lib/flow/spec.sx

@@ -0,0 +1,61 @@
+;; lib/flow/spec.sx — flow combinators as a Scheme prelude.
+;;
+;; A flow is a Scheme procedure of one argument: the upstream value.
+;;   node : input -> output
+;; A leaf node ignoring its argument is effectively a thunk. Combinators
+;; build composite nodes out of child nodes. The whole flow runs INSIDE the
+;; Scheme interpreter.
+;;
+;; Phase 1 combinators (flow-combinators-src):
+;;   flow-node / flow-id / flow-const / sequence / parallel / defflow
+;;   defflow both binds the flow and registers it by name (flow-register!, in
+;;   store.sx) so it can be re-resolved after a process restart.
+;;   map-flow (Phase 5): run a node over each item of a list input, join results.
+;;   flow-while / flow-until (Phase 5): bounded iteration — re-run body, threading
+;;   the value, while/until pred holds, up to `max` steps (deterministic bound; no
+;;   unbounded loops in pure SX).
+;;
+;; Phase 2 combinators (flow-control-src):
+;;   branch / fail / failed? / fail-reason / try-catch / retry / timeout / tick
+;;   tap (Phase 5): side-effecting pass-through (returns input unchanged).
+;;   recover (Phase 5): the fail-VALUE counterpart of try-catch.
+;;   attempt (Phase 6): railway sequence — thread nodes left-to-right but stop at
+;;     the first node that returns a (fail ...) value, returning that failure.
+;;
+;; Phase 3 suspend core (flow-suspend-src):
+;;   The guest Scheme's call/cc is ESCAPE-ONLY (re-invoking a captured k after it
+;;   returns hangs the runtime), so suspend/resume CANNOT re-enter a continuation.
+;;   Instead, durability uses DETERMINISTIC REPLAY: a flow re-runs from the start
+;;   on each resume; suspend points that have already been resolved replay their
+;;   logged value, and the first unresolved suspend escapes back to the driver.
+;;   The entire persisted state is the replay log (plain (tag value) data), which
+;;   survives process restart — no live continuation is ever serialized.
+;;
+;;   (suspend tag)  — if tag is in the replay log, return its value; else escape
+;;     to the driver as (flow-suspended tag). tags must be unique & deterministic
+;;     across replays. ALL effects/non-determinism must go through suspend so their
+;;     results are logged (otherwise they re-run on every replay).
+;;   (flow-drive flow input log) — run flow with the given replay log; returns
+;;     (flow-done result) or (flow-suspended tag).
+
+(define
+  flow-combinators-src
+  "(define (flow-node f) f)\n   (define (flow-id input) input)\n   (define (flow-const v) (lambda (input) v))\n   (define (flow-seq-step ns v)\n     (if (null? ns) v (flow-seq-step (cdr ns) ((car ns) v))))\n   (define sequence (lambda ns (lambda (input) (flow-seq-step ns input))))\n   (define parallel (lambda ns (lambda (input) (map (lambda (n) (n input)) ns))))\n   (define (map-flow node) (lambda (items) (map node items)))\n   (define (flow-while-step pred body input n)\n     (if (<= n 0)\n         input\n         (if (pred input) (flow-while-step pred body (body input) (- n 1)) input)))\n   (define (flow-while pred body max) (lambda (input) (flow-while-step pred body input max)))\n   (define (flow-until-step pred body input n)\n     (if (<= n 0)\n         input\n         (if (pred input) input (flow-until-step pred body (body input) (- n 1)))))\n   (define (flow-until pred body max) (lambda (input) (flow-until-step pred body input max)))\n   (define-syntax defflow\n     (syntax-rules ()\n       ((defflow nm body)\n        (begin (define nm body) (flow-register! (quote nm) nm)))))")
+
+(define
+  flow-control-src
+  "(define (branch pred then else)\n     (lambda (input) (if (pred input) (then input) (else input))))\n   (define (fail reason) (list (quote flow-fail) reason))\n   (define (failed? x) (and (pair? x) (eq? (car x) (quote flow-fail))))\n   (define (fail-reason x) (car (cdr x)))\n   (define (recover node handler)\n     (lambda (input)\n       (let ((r (node input)))\n         (if (failed? r) (handler (fail-reason r)) r))))\n   (define (tap effect)\n     (lambda (input) (begin (effect input) input)))\n   (define (flow-attempt-step ns v)\n     (if (failed? v)\n         v\n         (if (null? ns) v (flow-attempt-step (cdr ns) ((car ns) v)))))\n   (define attempt (lambda ns (lambda (input) (flow-attempt-step ns input))))\n   (define (try-catch node handler)\n     (lambda (input) (guard (e (#t (handler e))) (node input))))\n   (define (flow-retry-step n node input)\n     (guard (e (#t (if (<= n 1) (raise e) (flow-retry-step (- n 1) node input))))\n       (node input)))\n   (define (retry n node) (lambda (input) (flow-retry-step n node input)))\n   (define flow-timeout-budget -1)\n   (define (tick)\n     (if (< flow-timeout-budget 0)\n         0\n         (begin\n           (set! flow-timeout-budget (- flow-timeout-budget 1))\n           (if (< flow-timeout-budget 0)\n               (raise (quote flow-timeout))\n               flow-timeout-budget))))\n   (define (timeout budget node)\n     (lambda (input)\n       (let ((saved flow-timeout-budget))\n         (set! flow-timeout-budget budget)\n         (guard (e (#t (begin (set! flow-timeout-budget saved) (raise e))))\n           (let ((result (node input)))\n             (set! flow-timeout-budget saved)\n             result)))))")
+
+(define
+  flow-suspend-src
+  "(define flow-replay-log (list))\n   (define flow-suspend-k #f)\n   (define (flow-log-lookup tag log)\n     (if (null? log)\n         (list #f #f)\n         (if (eq? (car (car log)) tag)\n             (list #t (car (cdr (car log))))\n             (flow-log-lookup tag (cdr log)))))\n   (define (suspend tag)\n     (let ((hit (flow-log-lookup tag flow-replay-log)))\n       (if (car hit)\n           (car (cdr hit))\n           (flow-suspend-k (list (quote flow-suspended) tag)))))\n   (define (flow-drive flow input log)\n     (set! flow-replay-log log)\n     (call/cc\n       (lambda (k)\n         (set! flow-suspend-k k)\n         (list (quote flow-done) (flow input)))))")
+
+(define
+  flow-load-combinators!
+  (fn
+    (env)
+    (begin
+      (scheme-eval-program (scheme-parse-all flow-combinators-src) env)
+      (scheme-eval-program (scheme-parse-all flow-control-src) env)
+      (scheme-eval-program (scheme-parse-all flow-suspend-src) env)
+      env)))

lib/flow/tests/api.sx

@@ -0,0 +1,79 @@
+;; lib/flow/tests/api.sx — Phase 5: operational introspection API.
+
+(define flow-api-pass 0)
+(define flow-api-fail 0)
+(define flow-api-fails (list))
+
+(define
+  flow-api-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! flow-api-pass (+ flow-api-pass 1))
+      (begin
+        (set! flow-api-fail (+ flow-api-fail 1))
+        (append! flow-api-fails {:name name :expected expected :actual actual})))))
+
+(define flow-a (fn (src) (flow-run src)))
+
+;; ── flow/status ─────────────────────────────────────────────────
+(flow-api-test "status: unknown id" (flow-a "(flow/status 999)") "unknown")
+(flow-api-test
+  "status: suspended flow"
+  (flow-a
+    "(defflow w (lambda (x) (suspend (quote q)))) (define id (car (cdr (flow/start w 0)))) (flow/status id)")
+  "suspended")
+(flow-api-test
+  "status: completed flow"
+  (flow-a
+    "(defflow w (sequence (lambda (x) (suspend (quote q))) (lambda (v) v))) (define id (car (cdr (flow/start w 0)))) (flow/resume id 5) (flow/status id)")
+  "done")
+(flow-api-test
+  "status: cancelled flow"
+  (flow-a
+    "(defflow w (lambda (x) (suspend (quote q)))) (define id (car (cdr (flow/start w 0)))) (flow/cancel id) (flow/status id)")
+  "cancelled")
+
+;; ── flow/result ─────────────────────────────────────────────────
+(flow-api-test
+  "result: returns the value of a completed flow"
+  (flow-a
+    "(defflow w (sequence (lambda (x) (suspend (quote q))) (lambda (v) (list (quote got) v)))) (define id (car (cdr (flow/start w 0)))) (flow/resume id 9) (flow/result id)")
+  (list "got" 9))
+(flow-api-test
+  "result: a still-suspended flow has no result"
+  (flow-a
+    "(defflow w (lambda (x) (suspend (quote q)))) (define id (car (cdr (flow/start w 0)))) (flow/result id)")
+  (list "flow-error" "not-done"))
+(flow-api-test
+  "result: unknown id errors"
+  (flow-a "(flow/result 999)")
+  (list "flow-error" "no-such-flow"))
+
+;; ── flow/list ───────────────────────────────────────────────────
+(flow-api-test "list: empty store" (flow-a "(flow/list)") (list))
+(flow-api-test
+  "list: reports id + status for each flow (newest first)"
+  (flow-a
+    "(defflow w (lambda (x) (suspend (quote q)))) (flow/start w 0) (flow/start (lambda (x) (* x 2)) 5) (flow/list)")
+  (list (list 2 "done") (list 1 "suspended")))
+
+;; ── flow/pending ────────────────────────────────────────────────
+(flow-api-test
+  "pending: lists suspended flows with their waiting tag"
+  (flow-a
+    "(defflow w (lambda (x) (suspend (quote review)))) (flow/start w 0) (flow/pending)")
+  (list (list 1 "review")))
+(flow-api-test
+  "pending: excludes completed and cancelled flows"
+  (flow-a
+    "(defflow w (lambda (x) (suspend (quote q)))) (defflow v (sequence (lambda (x) (suspend (quote r))) (lambda (y) y))) (define i1 (car (cdr (flow/start w 0)))) (define i2 (car (cdr (flow/start v 0)))) (define i3 (car (cdr (flow/start w 0)))) (flow/resume i2 1) (flow/cancel i3) (flow/pending)")
+  (list (list 1 "q")))
+(flow-api-test
+  "pending: operator can drain all pending flows"
+  (flow-a
+    "(defflow w (sequence (lambda (x) (suspend (quote q))) (lambda (v) (* v 10)))) (flow/start w 0) (flow/start w 0) (define ps (flow/pending)) (flow/resume (car (car ps)) 1) (flow/resume (car (car (cdr ps))) 2) (flow/list)")
+  (list (list 1 "done") (list 2 "done")))
+
+(define flow-api-tests-run! (fn () {:total (+ flow-api-pass flow-api-fail) :passed flow-api-pass :failed flow-api-fail :fails flow-api-fails}))

lib/flow/tests/basic.sx

@@ -0,0 +1,121 @@
+;; lib/flow/tests/basic.sx — Phase 1: declarative DAG + sequential execution.
+
+(define flow-basic-pass 0)
+(define flow-basic-fail 0)
+(define flow-basic-fails (list))
+
+(define
+  flow-basic-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! flow-basic-pass (+ flow-basic-pass 1))
+      (begin
+        (set! flow-basic-fail (+ flow-basic-fail 1))
+        (append! flow-basic-fails {:name name :expected expected :actual actual})))))
+
+;; Run a Scheme flow-program string and return its final value.
+(define flow-b (fn (src) (flow-run src)))
+
+;; Scheme strings are boxed as {:scm-string "..."}; unwrap to a host string.
+(define flow-bs (fn (src) (get (flow-run src) :scm-string)))
+
+;; ── single node ─────────────────────────────────────────────────
+(flow-basic-test
+  "node: identity passes input through"
+  (flow-b "(flow/start flow-id 7)")
+  7)
+(flow-basic-test
+  "node: const ignores input"
+  (flow-b "(flow/start (flow-const 99) 1)")
+  99)
+(flow-basic-test
+  "node: bare lambda is a node"
+  (flow-b "(flow/start (lambda (x) (* x x)) 6)")
+  36)
+
+;; ── linear sequence ─────────────────────────────────────────────
+(flow-basic-test
+  "sequence: empty is identity"
+  (flow-b "(flow/start (sequence) 42)")
+  42)
+(flow-basic-test
+  "sequence: single child"
+  (flow-b "(flow/start (sequence (lambda (x) (+ x 1))) 41)")
+  42)
+(flow-basic-test
+  "sequence: two children thread"
+  (flow-b
+    "(flow/start (sequence (lambda (x) (+ x 1)) (lambda (x) (* x 10))) 4)")
+  50)
+(flow-basic-test
+  "sequence: three children thread"
+  (flow-b
+    "(flow/start (sequence (lambda (x) (+ x 1)) (lambda (x) (* x 2)) (lambda (x) (- x 3))) 5)")
+  9)
+
+;; ── data flow between nodes ─────────────────────────────────────
+(flow-basic-test
+  "data flow: string accumulation"
+  (flow-bs
+    "(flow/start (sequence (lambda (s) (string-append s \"-a\")) (lambda (s) (string-append s \"-b\"))) \"x\")")
+  "x-a-b")
+(flow-basic-test
+  "data flow: list build"
+  (flow-b
+    "(flow/start (sequence (lambda (x) (cons x (list))) (lambda (xs) (cons 0 xs))) 7)")
+  (list 0 7))
+
+;; ── defflow ─────────────────────────────────────────────────────
+(flow-basic-test
+  "defflow: names a flow"
+  (flow-b
+    "(defflow inc2 (sequence (lambda (x) (+ x 1)) (lambda (x) (+ x 1)))) (flow/start inc2 40)")
+  42)
+(flow-basic-test
+  "defflow: reusable"
+  (flow-b
+    "(defflow dbl (lambda (x) (* x 2))) (+ (flow/start dbl 3) (flow/start dbl 10))")
+  26)
+
+;; ── parallel (sequential semantics, join into list) ─────────────
+(flow-basic-test
+  "parallel: fans input to all branches"
+  (flow-b
+    "(flow/start (parallel (lambda (x) (+ x 1)) (lambda (x) (* x 2)) (lambda (x) (- x 3))) 10)")
+  (list 11 20 7))
+(flow-basic-test
+  "parallel: empty joins to empty list"
+  (flow-b "(flow/start (parallel) 5)")
+  (list))
+(flow-basic-test
+  "parallel: single branch"
+  (flow-b "(flow/start (parallel (lambda (x) (* x x))) 9)")
+  (list 81))
+
+;; ── nested composition ──────────────────────────────────────────
+(flow-basic-test
+  "nested: sequence of sequences"
+  (flow-b
+    "(flow/start (sequence (sequence (lambda (x) (+ x 1)) (lambda (x) (+ x 1))) (sequence (lambda (x) (* x 3)))) 0)")
+  6)
+(flow-basic-test
+  "nested: parallel inside sequence, join then reduce"
+  (flow-b
+    "(flow/start (sequence (parallel (lambda (x) (+ x 1)) (lambda (x) (* x 2))) (lambda (xs) (apply + xs))) 10)")
+  31)
+(flow-basic-test
+  "nested: sequence inside parallel branch"
+  (flow-b
+    "(flow/start (parallel (sequence (lambda (x) (+ x 1)) (lambda (x) (* x 2))) (lambda (x) x)) 5)")
+  (list 12 5))
+
+;; ── publish-shaped flow (the architecture sketch) ───────────────
+(flow-basic-test
+  "publish: write -> (review | spell) -> join lengths"
+  (flow-b
+    "(defflow publish (sequence (lambda (draft) (string-append draft \"!\")) (parallel (lambda (c) (string-length c)) (lambda (c) (string-length (string-append c \"?\")))))) (flow/start publish \"hi\")")
+  (list 3 4))
+
+(define flow-basic-tests-run! (fn () {:total (+ flow-basic-pass flow-basic-fail) :passed flow-basic-pass :failed flow-basic-fail :fails flow-basic-fails}))

lib/flow/tests/combinators.sx

@@ -0,0 +1,108 @@
+;; lib/flow/tests/combinators.sx — Phase 5: combinator library (tap, recover, map-flow, iteration).
+
+(define flow-cmb-pass 0)
+(define flow-cmb-fail 0)
+(define flow-cmb-fails (list))
+
+(define
+  flow-cmb-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! flow-cmb-pass (+ flow-cmb-pass 1))
+      (begin
+        (set! flow-cmb-fail (+ flow-cmb-fail 1))
+        (append! flow-cmb-fails {:name name :expected expected :actual actual})))))
+
+(define flow-m (fn (src) (flow-run src)))
+
+;; ── tap (side-effecting pass-through) ───────────────────────────
+(flow-cmb-test
+  "tap: returns input unchanged"
+  (flow-m "(flow/start (tap (lambda (x) (* x 999))) 7)")
+  7)
+(flow-cmb-test
+  "tap: runs the side effect"
+  (flow-m
+    "(define seen 0) (flow/start (tap (lambda (x) (set! seen x))) 42) seen")
+  42)
+(flow-cmb-test
+  "tap: value flows on while the effect observes it"
+  (flow-m
+    "(define log 0) (flow/start (sequence (lambda (x) (+ x 1)) (tap (lambda (x) (set! log x))) (lambda (x) (* x 2))) 10) (list log (flow/result 1))")
+  (list 11 22))
+
+;; ── recover (fail-value counterpart of try-catch) ───────────────
+(flow-cmb-test
+  "recover: passes a non-fail value through"
+  (flow-m "(flow/start (recover (lambda (x) (* x 2)) (lambda (r) -1)) 5)")
+  10)
+(flow-cmb-test
+  "recover: handles a fail value via the reason"
+  (flow-m
+    "(flow/start (recover (lambda (x) (fail (quote too-small))) (lambda (r) (list (quote recovered) r))) 1)")
+  (list "recovered" "too-small"))
+(flow-cmb-test
+  "recover: handler can supply a default value"
+  (flow-m
+    "(flow/start (sequence (recover (lambda (x) (if (> x 0) x (fail (quote neg))) ) (flow-const 0)) (lambda (x) (* x 10))) -3)")
+  0)
+(flow-cmb-test
+  "recover: does not catch raised exceptions (those are try-catch's job)"
+  (flow-m
+    "(flow/start (try-catch (recover (lambda (x) (raise (quote boom))) (flow-const 0)) (lambda (e) e)) 1)")
+  "boom")
+
+;; ── map-flow (run a node over a list, join) ─────────────────────
+(flow-cmb-test
+  "map-flow: applies the node to each item"
+  (flow-m "(flow/start (map-flow (lambda (x) (* x x))) (list 1 2 3 4))")
+  (list 1 4 9 16))
+(flow-cmb-test
+  "map-flow: empty list joins to empty"
+  (flow-m "(flow/start (map-flow (lambda (x) (+ x 1))) (list))")
+  (list))
+(flow-cmb-test
+  "map-flow: each item runs an independent sub-flow"
+  (flow-m
+    "(flow/start (map-flow (sequence (lambda (x) (+ x 1)) (lambda (x) (* x 2)))) (list 0 4 9))")
+  (list 2 10 20))
+(flow-cmb-test
+  "map-flow: composes — fan over a list then reduce the join"
+  (flow-m
+    "(flow/start (sequence (map-flow (lambda (x) (* x 10))) (lambda (xs) (apply + xs))) (list 1 2 3))")
+  60)
+
+;; ── flow-while / flow-until (bounded iteration) ─────────────────
+(flow-cmb-test
+  "flow-while: iterates while the predicate holds"
+  (flow-m
+    "(flow/start (flow-while (lambda (x) (< x 10)) (lambda (x) (+ x 1)) 100) 0)")
+  10)
+(flow-cmb-test
+  "flow-while: a false predicate leaves input unchanged"
+  (flow-m
+    "(flow/start (flow-while (lambda (x) (< x 0)) (lambda (x) (+ x 1)) 100) 5)")
+  5)
+(flow-cmb-test
+  "flow-while: respects the max-iteration bound"
+  (flow-m "(flow/start (flow-while (lambda (x) #t) (lambda (x) (+ x 1)) 3) 0)")
+  3)
+(flow-cmb-test
+  "flow-while: doubles until past a threshold"
+  (flow-m
+    "(flow/start (flow-while (lambda (x) (< x 50)) (lambda (x) (* x 2)) 100) 3)")
+  96)
+(flow-cmb-test
+  "flow-until: iterates until the predicate becomes true"
+  (flow-m
+    "(flow/start (flow-until (lambda (x) (>= x 10)) (lambda (x) (+ x 3)) 100) 0)")
+  12)
+(flow-cmb-test
+  "flow-until: composes inside a sequence"
+  (flow-m
+    "(flow/start (sequence (flow-until (lambda (x) (> x 100)) (lambda (x) (* x 3)) 100) (lambda (x) (- x 100))) 5)")
+  35)
+
+(define flow-cmb-tests-run! (fn () {:total (+ flow-cmb-pass flow-cmb-fail) :passed flow-cmb-pass :failed flow-cmb-fail :fails flow-cmb-fails}))

lib/flow/tests/control.sx

@@ -0,0 +1,179 @@
+;; lib/flow/tests/control.sx — Phase 2: control flow + error handling.
+
+(define flow-ctl-pass 0)
+(define flow-ctl-fail 0)
+(define flow-ctl-fails (list))
+
+(define
+  flow-ctl-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! flow-ctl-pass (+ flow-ctl-pass 1))
+      (begin
+        (set! flow-ctl-fail (+ flow-ctl-fail 1))
+        (append! flow-ctl-fails {:name name :expected expected :actual actual})))))
+
+(define flow-c (fn (src) (flow-run src)))
+(define flow-cs (fn (src) (get (flow-run src) :scm-string)))
+
+;; ── branch ──────────────────────────────────────────────────────
+(flow-ctl-test
+  "branch: true selects then"
+  (flow-c
+    "(flow/start (branch (lambda (x) (> x 0)) (lambda (x) (* x 100)) (lambda (x) (- 0 x))) 5)")
+  500)
+(flow-ctl-test
+  "branch: false selects else"
+  (flow-c
+    "(flow/start (branch (lambda (x) (> x 0)) (lambda (x) (* x 100)) (lambda (x) (- 0 x))) -3)")
+  3)
+(flow-ctl-test
+  "branch: predicate sees the threaded input"
+  (flow-c
+    "(flow/start (sequence (lambda (x) (+ x 1)) (branch (lambda (x) (> x 3)) (flow-const 100) (flow-const 0))) 3)")
+  100)
+(flow-ctl-test
+  "branch: branches are full nodes (sequence inside)"
+  (flow-c
+    "(flow/start (branch (lambda (x) (< x 10)) (sequence (lambda (x) (+ x 1)) (lambda (x) (* x 2))) (flow-const 0)) 4)")
+  10)
+(flow-ctl-test
+  "branch: nested branch (3-way sign)"
+  (flow-c
+    "(defflow sign (branch (lambda (x) (> x 0)) (flow-const 1) (branch (lambda (x) (< x 0)) (flow-const -1) (flow-const 0)))) (list (flow/start sign 7) (flow/start sign -7) (flow/start sign 0))")
+  (list 1 -1 0))
+(flow-ctl-test
+  "branch: publish-shaped approval gate"
+  (flow-cs
+    "(defflow publish (branch (lambda (post) (>= (string-length post) 3)) (lambda (post) (string-append post \" [published]\")) (lambda (post) (string-append post \" [rejected]\")))) (flow/start publish \"ok\")")
+  "ok [rejected]")
+
+;; ── error model — explicit (fail reason) values ─────────────────
+(flow-ctl-test
+  "fail: failed? is true for a failure value"
+  (flow-c "(failed? (fail 404))")
+  true)
+(flow-ctl-test
+  "fail: fail-reason extracts the reason"
+  (flow-c "(fail-reason (fail 404))")
+  404)
+(flow-ctl-test
+  "fail: failed? is false for a plain value"
+  (flow-c "(failed? 7)")
+  false)
+(flow-ctl-test
+  "fail: failed? is false for an ordinary list"
+  (flow-c "(failed? (list 1 2 3))")
+  false)
+(flow-ctl-test
+  "fail: a node may emit a failure as data"
+  (flow-c
+    "(defflow validate (lambda (s) (if (>= (string-length s) 3) s (fail (quote too-short))))) (failed? (flow/start validate \"hi\"))")
+  true)
+(flow-ctl-test
+  "fail: failure flows downstream, branch recovers"
+  (flow-c
+    "(defflow guarded (sequence (lambda (s) (if (>= (string-length s) 3) (string-length s) (fail (quote too-short)))) (branch failed? (lambda (f) (list (quote recovered) (fail-reason f))) (lambda (n) (list (quote ok) n))))) (flow/start guarded \"hi\")")
+  (list "recovered" "too-short"))
+
+;; ── try-catch — reify raised exceptions ─────────────────────────
+(flow-ctl-test
+  "try-catch: no exception returns node result"
+  (flow-c "(flow/start (try-catch (lambda (x) (* x 2)) (lambda (e) -1)) 5)")
+  10)
+(flow-ctl-test
+  "try-catch: handler runs on raise"
+  (flow-c
+    "(flow/start (try-catch (lambda (x) (raise (quote boom))) (flow-const 99)) 1)")
+  99)
+(flow-ctl-test
+  "try-catch: handler receives the reified error"
+  (flow-c "(flow/start (try-catch (lambda (x) (raise 42)) (lambda (e) e)) 0)")
+  42)
+(flow-ctl-test
+  "try-catch: catches exception from deep inside a sequence"
+  (flow-c
+    "(flow/start (try-catch (sequence (lambda (x) (+ x 1)) (lambda (x) (raise (quote deep)))) (flow-const -99)) 5)")
+  -99)
+(flow-ctl-test
+  "try-catch: handler may convert to a failure value"
+  (flow-c
+    "(failed? (flow/start (try-catch (lambda (x) (raise (quote bad))) (lambda (e) (fail e))) 0))")
+  true)
+(flow-ctl-test
+  "try-catch: composes — recover then continue"
+  (flow-c
+    "(flow/start (sequence (try-catch (lambda (x) (raise (quote x))) (flow-const 10)) (lambda (n) (* n 5))) 0)")
+  50)
+
+;; ── retry — re-run on raised exceptions ─────────────────────────
+(flow-ctl-test
+  "retry: succeeds after transient failures"
+  (flow-c
+    "(define ctr 0) (defflow flaky (lambda (x) (set! ctr (+ ctr 1)) (if (< ctr 3) (raise (quote nope)) (* x 10)))) (list (flow/start (retry 5 flaky) 7) ctr)")
+  (list 70 3))
+(flow-ctl-test
+  "retry: exhausted re-raises (caught by try-catch)"
+  (flow-c
+    "(flow/start (try-catch (retry 2 (lambda (x) (raise (quote always)))) (flow-const (quote gaveup))) 0)")
+  "gaveup")
+(flow-ctl-test
+  "retry: n=1 means a single attempt"
+  (flow-c
+    "(define ctr 0) (flow/start (try-catch (retry 1 (lambda (x) (set! ctr (+ ctr 1)) (raise (quote bad)))) (lambda (e) ctr)) 0)")
+  1)
+(flow-ctl-test
+  "retry: success on first attempt does not re-run"
+  (flow-c
+    "(define ctr 0) (flow/start (sequence (retry 5 (lambda (x) (set! ctr (+ ctr 1)) (* x 2))) (lambda (n) ctr)) 21)")
+  1)
+(flow-ctl-test
+  "retry: does not retry explicit failure values"
+  (flow-c
+    "(define ctr 0) (failed? (flow/start (retry 5 (lambda (x) (set! ctr (+ ctr 1)) (fail (quote bad)))) 0))")
+  true)
+(flow-ctl-test
+  "retry: failure-value path runs node exactly once"
+  (flow-c
+    "(define ctr 0) (flow/start (sequence (retry 5 (lambda (x) (set! ctr (+ ctr 1)) (fail (quote bad)))) (lambda (f) ctr)) 0)")
+  1)
+
+;; ── timeout — cooperative step budget ───────────────────────────
+(flow-ctl-test
+  "timeout: work within budget completes"
+  (flow-c
+    "(define (cd n) (if (<= n 0) 99 (begin (tick) (cd (- n 1))))) (flow/start (try-catch (timeout 10 (lambda (x) (cd x))) (flow-const (quote timed-out))) 5)")
+  99)
+(flow-ctl-test
+  "timeout: work exceeding budget raises flow-timeout"
+  (flow-c
+    "(define (cd n) (if (<= n 0) 99 (begin (tick) (cd (- n 1))))) (flow/start (try-catch (timeout 10 (lambda (x) (cd x))) (flow-const (quote timed-out))) 20)")
+  "timed-out")
+(flow-ctl-test
+  "timeout: exact budget boundary completes"
+  (flow-c
+    "(define (cd n) (if (<= n 0) 99 (begin (tick) (cd (- n 1))))) (flow/start (try-catch (timeout 5 (lambda (x) (cd x))) (flow-const (quote timed-out))) 5)")
+  99)
+(flow-ctl-test
+  "timeout: one tick over the budget raises"
+  (flow-c
+    "(define (cd n) (if (<= n 0) 99 (begin (tick) (cd (- n 1))))) (flow/start (try-catch (timeout 5 (lambda (x) (cd x))) (flow-const (quote timed-out))) 6)")
+  "timed-out")
+(flow-ctl-test
+  "timeout: the raised error is identifiable"
+  (flow-c
+    "(define (cd n) (if (<= n 0) 99 (begin (tick) (cd (- n 1))))) (flow/start (try-catch (timeout 2 (lambda (x) (cd x))) (lambda (e) e)) 9)")
+  "flow-timeout")
+(flow-ctl-test
+  "timeout: a node that never ticks is unbounded"
+  (flow-c "(flow/start (timeout 0 (lambda (x) (* x 2))) 5)")
+  10)
+(flow-ctl-test
+  "timeout: budget is restored across sequential timeouts"
+  (flow-c
+    "(define (cd n) (if (<= n 0) 1 (begin (tick) (cd (- n 1))))) (flow/start (sequence (timeout 4 (lambda (x) (cd x))) (timeout 4 (lambda (x) (cd 3))) (lambda (x) (begin (tick) (+ x 100)))) 3)")
+  101)
+
+(define flow-ctl-tests-run! (fn () {:total (+ flow-ctl-pass flow-ctl-fail) :passed flow-ctl-pass :failed flow-ctl-fail :fails flow-ctl-fails}))

lib/flow/tests/distributed.sx

@@ -0,0 +1,120 @@
+;; lib/flow/tests/distributed.sx — Phase 4: distributed nodes via fed-sx (mocked).
+
+(define flow-dist-pass 0)
+(define flow-dist-fail 0)
+(define flow-dist-fails (list))
+
+(define
+  flow-dist-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! flow-dist-pass (+ flow-dist-pass 1))
+      (begin
+        (set! flow-dist-fail (+ flow-dist-fail 1))
+        (append! flow-dist-fails {:name name :expected expected :actual actual})))))
+
+(define flow-d (fn (src) (flow-run src)))
+
+;; ── remote-node ─────────────────────────────────────────────────
+(flow-dist-test
+  "remote: a node executes on a peer"
+  (flow-d
+    "(flow-peer-register! (quote edge) (list (list (quote double) (lambda (x) (* x 2))))) (flow/start (remote-node (quote edge) (quote double)) 21)")
+  42)
+(flow-dist-test
+  "remote: remote nodes compose in a sequence"
+  (flow-d
+    "(flow-peer-register! (quote edge) (list (list (quote inc) (lambda (x) (+ x 1))) (list (quote double) (lambda (x) (* x 2))))) (flow/start (sequence (remote-node (quote edge) (quote inc)) (remote-node (quote edge) (quote double))) 4)")
+  10)
+(flow-dist-test
+  "remote: a remote node mixes with local nodes"
+  (flow-d
+    "(flow-peer-register! (quote edge) (list (list (quote double) (lambda (x) (* x 2))))) (flow/start (sequence (lambda (x) (+ x 5)) (remote-node (quote edge) (quote double)) (lambda (x) (- x 1))) 10)")
+  29)
+(flow-dist-test
+  "remote: unreachable peer raises flow-remote-unreachable"
+  (flow-d
+    "(flow/start (try-catch (remote-node (quote ghost) (quote double)) (lambda (e) e)) 1)")
+  "flow-remote-unreachable")
+(flow-dist-test
+  "remote: unknown function on a peer raises flow-remote-no-fn"
+  (flow-d
+    "(flow-peer-register! (quote edge) (list (list (quote double) (lambda (x) (* x 2))))) (flow/start (try-catch (remote-node (quote edge) (quote missing)) (lambda (e) e)) 1)")
+  "flow-remote-no-fn")
+(flow-dist-test
+  "remote: a remote node can suspend the flow (peer returns control)"
+  (flow-d
+    "(flow-peer-register! (quote edge) (list (list (quote review) (lambda (x) x)))) (flow/start (sequence (remote-node (quote edge) (quote review)) (lambda (x) (suspend (quote human))) (lambda (v) (list (quote published) v))) 7)")
+  (list "flow-suspended" 1 "human"))
+(flow-dist-test
+  "remote: a transient remote failure is recoverable with retry"
+  (flow-d
+    "(define hits 0) (flow-peer-register! (quote edge) (list (list (quote flaky) (lambda (x) (begin (set! hits (+ hits 1)) (if (< hits 2) (raise (quote down)) (* x 3))))))) (list (flow/start (retry 3 (remote-node (quote edge) (quote flaky))) 7) hits)")
+  (list 21 2))
+
+;; ── failover (retry on a different peer, fall through to local) ──
+(flow-dist-test
+  "failover: first reachable peer serves the request"
+  (flow-d
+    "(flow-peer-register! (quote p2) (list (list (quote f) (lambda (x) (+ x 100))))) (flow/start (remote-failover (list (quote p2) (quote down)) (quote f) (flow-const (quote local))) 5)")
+  105)
+(flow-dist-test
+  "failover: skips an unreachable peer to the next one"
+  (flow-d
+    "(flow-peer-register! (quote p2) (list (list (quote f) (lambda (x) (+ x 100))))) (flow/start (remote-failover (list (quote down) (quote p2)) (quote f) (flow-const (quote local))) 5)")
+  105)
+(flow-dist-test
+  "failover: skips a peer whose function raises"
+  (flow-d
+    "(flow-peer-register! (quote bad) (list (list (quote f) (lambda (x) (raise (quote boom)))))) (flow-peer-register! (quote good) (list (list (quote f) (lambda (x) (* x 10))))) (flow/start (remote-failover (list (quote bad) (quote good)) (quote f) (flow-const 0)) 4)")
+  40)
+(flow-dist-test
+  "failover: all peers fail, the local fallback runs"
+  (flow-d
+    "(flow/start (remote-failover (list (quote down1) (quote down2)) (quote f) (lambda (x) (* x -1))) 9)")
+  -9)
+(flow-dist-test
+  "failover: threads the input through to the chosen peer"
+  (flow-d
+    "(flow-peer-register! (quote p) (list (list (quote f) (lambda (x) (list (quote got) x))))) (flow/start (sequence (lambda (x) (+ x 1)) (remote-failover (list (quote p)) (quote f) (flow-const 0))) 41)")
+  (list "got" 42))
+(flow-dist-test
+  "failover: composes inside a larger sequence"
+  (flow-d
+    "(flow-peer-register! (quote p) (list (list (quote f) (lambda (x) (* x 2))))) (flow/start (sequence (remote-failover (list (quote down) (quote p)) (quote f) (flow-const 1)) (lambda (x) (+ x 3))) 5)")
+  13)
+
+;; ── replication + handoff ───────────────────────────────────────
+(flow-dist-test
+  "replicate: a peer holds the exported store"
+  (flow-d
+    "(defflow w (lambda (x) (suspend (quote q)))) (flow/start w 10) (flow-replicate-to (quote peerB)) (if (flow-replica-get (quote peerB)) (quote replicated) (quote missing))")
+  "replicated")
+(flow-dist-test
+  "handoff: a peer resumes a flow after the local instance dies"
+  (flow-d
+    "(defflow w (sequence (lambda (x) (suspend (quote q))) (lambda (v) (list (quote done) v)))) (define id (car (cdr (flow/start w 10)))) (flow-replicate-to (quote peerB)) (set! flow-store (list)) (flow-restore-from (quote peerB)) (flow/resume id 55)")
+  (list "done" 55))
+(flow-dist-test
+  "handoff: restored peer reports the flow as resumable"
+  (flow-d
+    "(defflow w (lambda (x) (suspend (quote q)))) (define id (car (cdr (flow/start w 10)))) (flow-replicate-to (quote peerB)) (set! flow-store (list)) (flow-restore-from (quote peerB)) (flow-resumable-ids)")
+  (list 1))
+(flow-dist-test
+  "handoff: without restore the dead instance has lost the flow"
+  (flow-d
+    "(defflow w (lambda (x) (suspend (quote q)))) (define id (car (cdr (flow/start w 10)))) (flow-replicate-to (quote peerB)) (set! flow-store (list)) (flow/resume id 1)")
+  (list "flow-error" "no-such-flow"))
+(flow-dist-test
+  "restore: from an unknown peer yields false"
+  (flow-d "(flow-restore-from (quote nowhere))")
+  false)
+(flow-dist-test
+  "handoff: replication preserves the replay log across the move"
+  (flow-d
+    "(defflow two (sequence (lambda (x) (suspend (quote a))) (lambda (x) (suspend (quote b))) (lambda (x) (list x)))) (define id (car (cdr (flow/start two 0)))) (flow/resume id 11) (flow-replicate-to (quote peerB)) (set! flow-store (list)) (flow-restore-from (quote peerB)) (flow/resume id 22)")
+  (list 22))
+
+(define flow-dist-tests-run! (fn () {:total (+ flow-dist-pass flow-dist-fail) :passed flow-dist-pass :failed flow-dist-fail :fails flow-dist-fails}))

lib/flow/tests/host.sx

@@ -0,0 +1,106 @@
+;; lib/flow/tests/host.sx — Phase 8: host integration ABI (request/await/host-queue/driver).
+
+(define flow-hst-pass 0)
+(define flow-hst-fail 0)
+(define flow-hst-fails (list))
+
+(define
+  flow-hst-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! flow-hst-pass (+ flow-hst-pass 1))
+      (begin
+        (set! flow-hst-fail (+ flow-hst-fail 1))
+        (append! flow-hst-fails {:name name :expected expected :actual actual})))))
+
+(define flow-hst (fn (src) (flow-run src)))
+
+;; ── request envelope ────────────────────────────────────────────
+(flow-hst-test
+  "request: suspends with a typed envelope"
+  (flow-hst
+    "(car (cdr (cdr (flow/start (lambda (x) (request (quote render) x)) 5))))")
+  (list "flow-request" "render" 5))
+(flow-hst-test
+  "request?: recognizes an envelope"
+  (flow-hst "(request? (list (quote flow-request) (quote human) 1))")
+  true)
+(flow-hst-test
+  "request?: a plain tag is not a request"
+  (flow-hst "(request? (list (quote review) 1))")
+  false)
+(flow-hst-test
+  "request-kind / request-payload: parse the envelope"
+  (flow-hst
+    "(define t (list (quote flow-request) (quote render) (list (quote recipe) 7))) (list (request-kind t) (request-payload t))")
+  (list "render" (list "recipe" 7)))
+
+;; ── named decision points ───────────────────────────────────────
+(flow-hst-test
+  "await-human: is a request of kind human"
+  (flow-hst
+    "(car (cdr (cdr (flow/start (lambda (x) (await-human x)) (quote approve?)))))")
+  (list "flow-request" "human" "approve?"))
+(flow-hst-test
+  "await-render: is a request of kind render"
+  (flow-hst
+    "(car (cdr (cdr (flow/start (lambda (x) (await-render x)) (quote recipe)))))")
+  (list "flow-request" "render" "recipe"))
+(flow-hst-test
+  "request: the host's resume value flows back into the flow"
+  (flow-hst
+    "(defflow f (sequence (lambda (x) (await-render x)) (lambda (art) (list (quote got) art)))) (define id (car (cdr (flow/start f 1)))) (flow/resume id (quote the-artifact))")
+  (list "got" "the-artifact"))
+
+;; ── host work queue ─────────────────────────────────────────────
+(flow-hst-test
+  "flow-host-requests: lists (id kind payload) for pending requests"
+  (flow-hst
+    "(flow/start (lambda (x) (await-render x)) 99) (flow-host-requests)")
+  (list (list 1 "render" 99)))
+(flow-hst-test
+  "flow-host-requests: excludes bare (non-request) suspends"
+  (flow-hst
+    "(defflow a (lambda (x) (await-render x))) (defflow b (lambda (x) (suspend (quote plain)))) (flow/start a 1) (flow/start b 2) (flow-host-requests)")
+  (list (list 1 "render" 1)))
+
+;; ── the art-dag-shaped host driver loop (manual resumes) ────────
+(flow-hst-test
+  "host driver: render then human-review then publish"
+  (flow-hst
+    "(defflow pipeline (sequence (lambda (recipe) (await-render recipe)) (lambda (art) (await-human (list (quote review) art))) (branch (lambda (d) (eq? d (quote approve))) (flow-const (quote published)) (flow-const (fail (quote rejected)))))) (define id (car (cdr (flow/start pipeline 99)))) (define r1 (flow-host-requests)) (flow/resume id (list (quote art) 99)) (define r2 (flow-host-requests)) (flow/resume id (quote approve)) (list r1 r2 (flow/status id) (flow/result id))")
+  (list
+    (list (list 1 "render" 99))
+    (list (list 1 "human" (list "review" (list "art" 99))))
+    "done"
+    "published"))
+(flow-hst-test
+  "host driver: rejection at the human gate yields a failure"
+  (flow-hst
+    "(defflow pipeline (sequence (lambda (recipe) (await-render recipe)) (lambda (art) (await-human (list (quote review) art))) (branch (lambda (d) (eq? d (quote approve))) (flow-const (quote published)) (flow-const (fail (quote rejected)))))) (define id (car (cdr (flow/start pipeline 1)))) (flow/resume id (quote artifact)) (failed? (flow/resume id (quote reject)))")
+  true)
+
+;; ── reference driver: host supplies only a dispatch fn ──────────
+(flow-hst-test
+  "flow-drive-host: one tick services every pending request"
+  (flow-hst
+    "(flow/start (lambda (x) (await-render x)) 5) (define n (flow-drive-host (lambda (k p) (list (quote done) p)))) (list n (flow/status 1) (flow/result 1))")
+  (list 1 "done" (list "done" 5)))
+(flow-hst-test
+  "flow-run-host: drives a render -> human pipeline to completion"
+  (flow-hst
+    "(defflow pipeline (sequence (lambda (recipe) (await-render recipe)) (lambda (art) (await-human (list (quote review) art))) (branch (lambda (d) (eq? d (quote approve))) (flow-const (quote published)) (flow-const (fail (quote rejected)))))) (define id (car (cdr (flow/start pipeline 99)))) (define serviced (flow-run-host (lambda (kind payload) (if (eq? kind (quote render)) (list (quote art) payload) (quote approve))) 10)) (list serviced (flow/status id) (flow/result id))")
+  (list 2 "done" "published"))
+(flow-hst-test
+  "flow-run-host: returns 0 when nothing is pending"
+  (flow-hst "(flow-run-host (lambda (k p) p) 5)")
+  0)
+(flow-hst-test
+  "flow-run-host: respects the maxticks bound"
+  (flow-hst
+    "(defflow pipe2 (sequence (lambda (r) (await-render r)) (lambda (a) (await-human a)) (lambda (d) d))) (define id (car (cdr (flow/start pipe2 1)))) (define serviced (flow-run-host (lambda (k p) p) 1)) (list serviced (flow/status id))")
+  (list 1 "suspended"))
+
+(define flow-hst-tests-run! (fn () {:total (+ flow-hst-pass flow-hst-fail) :passed flow-hst-pass :failed flow-hst-fail :fails flow-hst-fails}))

lib/flow/tests/hygiene.sx

@@ -0,0 +1,67 @@
+;; lib/flow/tests/hygiene.sx — Phase 5: store hygiene (flow/gc, flow/forget).
+
+(define flow-hyg-pass 0)
+(define flow-hyg-fail 0)
+(define flow-hyg-fails (list))
+
+(define
+  flow-hyg-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! flow-hyg-pass (+ flow-hyg-pass 1))
+      (begin
+        (set! flow-hyg-fail (+ flow-hyg-fail 1))
+        (append! flow-hyg-fails {:name name :expected expected :actual actual})))))
+
+(define flow-h (fn (src) (flow-run src)))
+
+;; ── flow/gc ─────────────────────────────────────────────────────
+(flow-hyg-test
+  "gc: empty store removes nothing"
+  (flow-h "(flow/gc)")
+  0)
+(flow-hyg-test
+  "gc: removes a done flow, keeps a suspended one"
+  (flow-h
+    "(defflow w (lambda (x) (suspend (quote q)))) (flow/start w 0) (flow/start (lambda (x) x) 5) (define removed (flow/gc)) (list removed (flow/list))")
+  (list 1 (list (list 1 "suspended"))))
+(flow-hyg-test
+  "gc: removes a cancelled flow"
+  (flow-h
+    "(defflow w (lambda (x) (suspend (quote q)))) (define id (car (cdr (flow/start w 0)))) (flow/cancel id) (flow/gc)")
+  1)
+(flow-hyg-test
+  "gc: a kept suspended flow is still resumable"
+  (flow-h
+    "(defflow w (sequence (lambda (x) (suspend (quote q))) (lambda (v) (* v 2)))) (define id (car (cdr (flow/start w 0)))) (flow/start (lambda (x) x) 1) (flow/gc) (flow/resume id 21)")
+  42)
+(flow-hyg-test
+  "gc: counts every terminal flow it drops"
+  (flow-h
+    "(flow/start (lambda (x) x) 1) (flow/start (lambda (x) x) 2) (defflow w (lambda (x) (suspend (quote q)))) (flow/start w 0) (flow/gc)")
+  2)
+
+;; ── flow/forget ─────────────────────────────────────────────────
+(flow-hyg-test
+  "forget: drops a completed flow"
+  (flow-h
+    "(defflow w (sequence (lambda (x) (suspend (quote q))) (lambda (v) v))) (define id (car (cdr (flow/start w 0)))) (flow/resume id 7) (list (flow/forget id) (flow/status id))")
+  (list true "unknown"))
+(flow-hyg-test
+  "forget: refuses to drop a live (suspended) flow"
+  (flow-h
+    "(defflow w (lambda (x) (suspend (quote q)))) (define id (car (cdr (flow/start w 0)))) (list (flow/forget id) (flow/status id))")
+  (list false "suspended"))
+(flow-hyg-test
+  "forget: drops a cancelled flow"
+  (flow-h
+    "(defflow w (lambda (x) (suspend (quote q)))) (define id (car (cdr (flow/start w 0)))) (flow/cancel id) (list (flow/forget id) (flow/status id))")
+  (list true "unknown"))
+(flow-hyg-test
+  "forget: unknown id yields false"
+  (flow-h "(flow/forget 999)")
+  false)
+
+(define flow-hyg-tests-run! (fn () {:total (+ flow-hyg-pass flow-hyg-fail) :passed flow-hyg-pass :failed flow-hyg-fail :fails flow-hyg-fails}))

lib/flow/tests/integration.sx

@@ -0,0 +1,115 @@
+;; lib/flow/tests/integration.sx — Phase 7: end-to-end flows composing every phase.
+
+(define flow-int-pass 0)
+(define flow-int-fail 0)
+(define flow-int-fails (list))
+
+(define
+  flow-int-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! flow-int-pass (+ flow-int-pass 1))
+      (begin
+        (set! flow-int-fail (+ flow-int-fail 1))
+        (append! flow-int-fails {:name name :expected expected :actual actual})))))
+
+(define flow-i (fn (src) (flow-run src)))
+
+;; The order-processing flow, defined once per program via this prelude string:
+;;   validate amount (attempt: fail if <= 0)
+;;   -> suspend for payment confirmation (resume value = confirmed amount)
+;;   -> branch: confirmed>0 ? record on the ledger peer : declined failure
+(define
+  order-prelude
+  "(flow-peer-register! (quote ledger) (list (list (quote record) (lambda (amt) (list (quote recorded) amt)))))\n   (defflow order\n     (attempt\n       (lambda (amt) (if (> amt 0) amt (fail (quote invalid-amount))))\n       (lambda (amt) (suspend (quote await-payment)))\n       (branch (lambda (amt) (> amt 0))\n               (remote-node (quote ledger) (quote record))\n               (flow-const (fail (quote declined))))))")
+
+;; ── happy path through every phase ──────────────────────────────
+(flow-int-test
+  "order: validate -> suspend -> resume -> branch -> federate"
+  (flow-i
+    (str
+      order-prelude
+      "(define id (car (cdr (flow/start order 100)))) (flow/resume id 250)"))
+  (list "recorded" 250))
+(flow-int-test
+  "order: starting suspends awaiting payment"
+  (flow-i
+    (str
+      order-prelude
+      "(define s (flow/start order 100)) (list (car s) (car (cdr (cdr s))))"))
+  (list "flow-suspended" "await-payment"))
+(flow-int-test
+  "order: invalid amount fails up front and never suspends"
+  (flow-i
+    (str
+      order-prelude
+      "(define r (flow/start order -5)) (list (failed? r) (fail-reason r))"))
+  (list true "invalid-amount"))
+(flow-int-test
+  "order: a declined payment yields a failure value"
+  (flow-i
+    (str
+      order-prelude
+      "(define id (car (cdr (flow/start order 100)))) (failed? (flow/resume id 0))"))
+  true)
+
+;; ── crash recovery mid-flow ─────────────────────────────────────
+(flow-int-test
+  "order: survives a simulated crash between suspend and resume"
+  (flow-i
+    (str
+      order-prelude
+      "(define id (car (cdr (flow/start order 100)))) (define saved (flow-store-export)) (set! flow-store (list)) (flow-store-import! saved) (flow/resume id 250)"))
+  (list "recorded" 250))
+
+;; ── handoff to a peer mid-flow ──────────────────────────────────
+(flow-int-test
+  "order: hands off to a peer that resumes and completes"
+  (flow-i
+    (str
+      order-prelude
+      "(define id (car (cdr (flow/start order 100)))) (flow-replicate-to (quote nodeB)) (set! flow-store (list)) (flow-restore-from (quote nodeB)) (flow/resume id 250)"))
+  (list "recorded" 250))
+
+;; ── introspection during the flow's life ────────────────────────
+(flow-int-test
+  "order: pending shows what the flow awaits, then result after resume"
+  (flow-i
+    (str
+      order-prelude
+      "(define id (car (cdr (flow/start order 100)))) (define p (flow/pending)) (flow/resume id 250) (list p (flow/status id) (flow/result id))"))
+  (list
+    (list (list 1 "await-payment"))
+    "done"
+    (list "recorded" 250)))
+
+;; ── onboarding: two human steps + cancellation ──────────────────
+(define
+  onboard-prelude
+  "(defflow onboard\n     (sequence\n       (lambda (user) (+ user 1))\n       (lambda (x) (suspend (quote confirm-email)))\n       (lambda (x) (suspend (quote complete-profile)))\n       (lambda (x) (list (quote onboarded) x))))")
+
+(flow-int-test
+  "onboard: two suspends resume in order to completion"
+  (flow-i
+    (str
+      onboard-prelude
+      "(define id (car (cdr (flow/start onboard 0)))) (flow/resume id 7) (flow/resume id 9)"))
+  (list "onboarded" 9))
+(flow-int-test
+  "onboard: the second pending tag appears after the first resume"
+  (flow-i
+    (str
+      onboard-prelude
+      "(define id (car (cdr (flow/start onboard 0)))) (flow/resume id 7) (car (cdr (car (flow/pending))))"))
+  "complete-profile")
+(flow-int-test
+  "onboard: cancelling abandons the flow"
+  (flow-i
+    (str
+      onboard-prelude
+      "(define id (car (cdr (flow/start onboard 0)))) (flow/cancel id) (list (flow/status id) (car (flow/resume id 7)))"))
+  (list "cancelled" "flow-error"))
+
+(define flow-int-tests-run! (fn () {:total (+ flow-int-pass flow-int-fail) :passed flow-int-pass :failed flow-int-fail :fails flow-int-fails}))

lib/flow/tests/railway.sx

@@ -0,0 +1,73 @@
+;; lib/flow/tests/railway.sx — Phase 6: railway-oriented composition (attempt).
+
+(define flow-rail-pass 0)
+(define flow-rail-fail 0)
+(define flow-rail-fails (list))
+
+(define
+  flow-rail-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! flow-rail-pass (+ flow-rail-pass 1))
+      (begin
+        (set! flow-rail-fail (+ flow-rail-fail 1))
+        (append! flow-rail-fails {:name name :expected expected :actual actual})))))
+
+(define flow-r (fn (src) (flow-run src)))
+
+;; ── attempt — short-circuit on the first (fail ...) ─────────────
+(flow-rail-test
+  "attempt: threads like sequence when nothing fails"
+  (flow-r
+    "(flow/start (attempt (lambda (x) (+ x 1)) (lambda (x) (* x 10))) 4)")
+  50)
+(flow-rail-test
+  "attempt: empty is identity"
+  (flow-r "(flow/start (attempt) 7)")
+  7)
+(flow-rail-test
+  "attempt: returns the first failure"
+  (flow-r
+    "(failed? (flow/start (attempt (lambda (x) (fail (quote bad))) (lambda (x) (* x 10))) 4))")
+  true)
+(flow-rail-test
+  "attempt: the failure carries its reason"
+  (flow-r
+    "(fail-reason (flow/start (attempt (lambda (x) x) (lambda (x) (fail (quote rejected)))) 4))")
+  "rejected")
+(flow-rail-test
+  "attempt: nodes after a failure do not run"
+  (flow-r
+    "(define ran 0) (flow/start (attempt (lambda (x) (fail (quote stop))) (lambda (x) (begin (set! ran (+ ran 1)) x))) 0) ran")
+  0)
+(flow-rail-test
+  "attempt: a failed input short-circuits immediately"
+  (flow-r
+    "(define ran 0) (fail-reason (flow/start (attempt (lambda (x) (begin (set! ran (+ ran 1)) x))) (fail (quote pre))))")
+  "pre")
+(flow-rail-test
+  "attempt: middle failure halts the chain"
+  (flow-r
+    "(define ran 0) (flow/start (attempt (lambda (x) (+ x 1)) (lambda (x) (fail (quote mid))) (lambda (x) (begin (set! ran (+ ran 1)) x))) 5) ran")
+  0)
+
+;; ── attempt + recover (rejoin the happy track) ──────────────────
+(flow-rail-test
+  "attempt + recover: recover turns a failure into a value"
+  (flow-r
+    "(flow/start (recover (attempt (lambda (x) (if (> x 0) x (fail (quote non-positive)))) (lambda (x) (* x 2))) (flow-const 0)) -5)")
+  0)
+(flow-rail-test
+  "attempt + recover: happy path passes recover through"
+  (flow-r
+    "(flow/start (recover (attempt (lambda (x) (if (> x 0) x (fail (quote non-positive)))) (lambda (x) (* x 2))) (flow-const 0)) 5)")
+  10)
+(flow-rail-test
+  "attempt: validation pipeline reports the failing stage"
+  (flow-r
+    "(defflow validate (attempt (lambda (s) (if (>= (string-length s) 3) s (fail (quote too-short)))) (lambda (s) (if (<= (string-length s) 8) s (fail (quote too-long)))) (lambda (s) (list (quote ok) (string-length s))))) (list (fail-reason (flow/start validate \"hi\")) (flow/start validate \"hello\"))")
+  (list "too-short" (list "ok" 5)))
+
+(define flow-rail-tests-run! (fn () {:total (+ flow-rail-pass flow-rail-fail) :passed flow-rail-pass :failed flow-rail-fail :fails flow-rail-fails}))

lib/flow/tests/recovery.sx

@@ -0,0 +1,71 @@
+;; lib/flow/tests/recovery.sx — Phase 3: crash recovery (store export/import + restart).
+;;
+;; "restart" is simulated within one program: (set! flow-store (list)) wipes the
+;; in-memory store (process death), while flow-registry persists as it would after
+;; reloading flow definitions. Recovery = import the exported (plain-data) store and
+;; resume; the flow proc is re-resolved by name.
+
+(define flow-rec-pass 0)
+(define flow-rec-fail 0)
+(define flow-rec-fails (list))
+
+(define
+  flow-rec-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! flow-rec-pass (+ flow-rec-pass 1))
+      (begin
+        (set! flow-rec-fail (+ flow-rec-fail 1))
+        (append! flow-rec-fails {:name name :expected expected :actual actual})))))
+
+(define flow-r (fn (src) (flow-run src)))
+
+;; ── export / wipe / import ──────────────────────────────────────
+(flow-rec-test
+  "export nulls the live procedure"
+  (flow-r
+    "(defflow w (lambda (x) (suspend (quote await)))) (flow/start w 10) (car (cdr (car (cdr (car (flow-store-export))))))")
+  false)
+(flow-rec-test
+  "a wiped store loses the flow (process death)"
+  (flow-r
+    "(defflow w (lambda (x) (suspend (quote await)))) (define id (car (cdr (flow/start w 10)))) (set! flow-store (list)) (flow/resume id 1)")
+  (list "flow-error" "no-such-flow"))
+(flow-rec-test
+  "import restores a wiped store and resume completes"
+  (flow-r
+    "(defflow w (sequence (lambda (x) (suspend (quote await))) (lambda (c) (list (quote done) c)))) (define id (car (cdr (flow/start w 10)))) (define saved (flow-store-export)) (set! flow-store (list)) (flow-store-import! saved) (flow/resume id 777)")
+  (list "done" 777))
+
+;; ── resumable scan ──────────────────────────────────────────────
+(flow-rec-test
+  "resumable-ids lists the suspended flow after import"
+  (flow-r
+    "(defflow w (lambda (x) (suspend (quote await)))) (define id (car (cdr (flow/start w 10)))) (define saved (flow-store-export)) (set! flow-store (list)) (flow-store-import! saved) (flow-resumable-ids)")
+  (list 1))
+(flow-rec-test
+  "resumable-ids excludes completed flows"
+  (flow-r
+    "(defflow w (sequence (lambda (x) (suspend (quote await))) (lambda (c) c))) (define id (car (cdr (flow/start w 10)))) (flow/resume id 5) (flow-resumable-ids)")
+  (list))
+(flow-rec-test
+  "resumable-ids excludes cancelled flows after import"
+  (flow-r
+    "(defflow w (lambda (x) (suspend (quote await)))) (define id (car (cdr (flow/start w 10)))) (flow/cancel id) (define saved (flow-store-export)) (set! flow-store (list)) (flow-store-import! saved) (flow-resumable-ids)")
+  (list))
+
+;; ── restart at every step ───────────────────────────────────────
+(flow-rec-test
+  "two suspends survive a restart between each step"
+  (flow-r
+    "(defflow two (sequence (lambda (x) (suspend (quote a))) (lambda (x) (suspend (quote b))) (lambda (x) (list (quote end) x)))) (define id (car (cdr (flow/start two 0)))) (define s1 (flow-store-export)) (set! flow-store (list)) (flow-store-import! s1) (flow/resume id 100) (define s2 (flow-store-export)) (set! flow-store (list)) (flow-store-import! s2) (flow/resume id 200)")
+  (list "end" 200))
+(flow-rec-test
+  "import preserves the replay log (earlier value survives restart)"
+  (flow-r
+    "(defflow two (sequence (lambda (x) (suspend (quote a))) (lambda (x) (suspend (quote b))) (lambda (x) (list x)))) (define id (car (cdr (flow/start two 0)))) (flow/resume id 11) (define saved (flow-store-export)) (set! flow-store (list)) (flow-store-import! saved) (flow/resume id 22)")
+  (list 22))
+
+(define flow-rec-tests-run! (fn () {:total (+ flow-rec-pass flow-rec-fail) :passed flow-rec-pass :failed flow-rec-fail :fails flow-rec-fails}))

lib/flow/tests/suspend.sx

@@ -0,0 +1,114 @@
+;; lib/flow/tests/suspend.sx — Phase 3: suspend / resume / cancel (deterministic replay).
+
+(define flow-sus-pass 0)
+(define flow-sus-fail 0)
+(define flow-sus-fails (list))
+
+(define
+  flow-sus-test
+  (fn
+    (name actual expected)
+    (if
+      (= actual expected)
+      (set! flow-sus-pass (+ flow-sus-pass 1))
+      (begin
+        (set! flow-sus-fail (+ flow-sus-fail 1))
+        (append! flow-sus-fails {:name name :expected expected :actual actual})))))
+
+(define flow-s (fn (src) (flow-run src)))
+
+;; ── flow/start ──────────────────────────────────────────────────
+(flow-sus-test
+  "start: non-suspending flow returns the raw result"
+  (flow-s "(flow/start (lambda (x) (* x 2)) 5)")
+  10)
+(flow-sus-test
+  "start: a suspending flow returns a flow-suspended state"
+  (flow-s
+    "(defflow w (sequence (lambda (x) (+ x 1)) (lambda (g) (suspend (quote await))) (lambda (c) c))) (car (flow/start w 10))")
+  "flow-suspended")
+(flow-sus-test
+  "start: suspended state carries a numeric id"
+  (flow-s
+    "(defflow w (lambda (x) (suspend (quote await)))) (car (cdr (flow/start w 10)))")
+  1)
+(flow-sus-test
+  "start: suspended state carries the suspend tag"
+  (flow-s
+    "(defflow w (lambda (x) (suspend (quote await)))) (car (cdr (cdr (flow/start w 10))))")
+  "await")
+
+;; ── flow/resume ─────────────────────────────────────────────────
+(flow-sus-test
+  "resume: injects the value and completes"
+  (flow-s
+    "(defflow w (sequence (lambda (x) (+ x 1)) (lambda (g) (suspend (quote await))) (lambda (c) (list (quote done) c)))) (define s (flow/start w 10)) (flow/resume (car (cdr s)) 777)")
+  (list "done" 777))
+(flow-sus-test
+  "resume: injected value threads into the next node"
+  (flow-s
+    "(defflow w (sequence (lambda (x) (suspend (quote v))) (lambda (n) (* n 3)))) (define s (flow/start w 0)) (flow/resume (car (cdr s)) 14)")
+  42)
+(flow-sus-test
+  "resume: replays earlier suspends (recompute is deterministic)"
+  (flow-s
+    "(define runs 0) (defflow w (sequence (lambda (x) (begin (set! runs (+ runs 1)) (+ x 1))) (lambda (g) (suspend (quote await))) (lambda (c) c))) (define s (flow/start w 10)) (flow/resume (car (cdr s)) 99) runs")
+  2)
+
+;; ── multi-step suspension ───────────────────────────────────────
+(flow-sus-test
+  "multi: first resume suspends at the next tag"
+  (flow-s
+    "(defflow two (sequence (lambda (x) (suspend (quote a))) (lambda (x) (suspend (quote b))) (lambda (x) (list (quote end) x)))) (define s (flow/start two 0)) (define s2 (flow/resume (car (cdr s)) 100)) (car (cdr (cdr s2)))")
+  "b")
+(flow-sus-test
+  "multi: second resume completes with the latest value"
+  (flow-s
+    "(defflow two (sequence (lambda (x) (suspend (quote a))) (lambda (x) (suspend (quote b))) (lambda (x) (list (quote end) x)))) (define id (car (cdr (flow/start two 0)))) (flow/resume id 100) (flow/resume id 200)")
+  (list "end" 200))
+
+;; ── error / lifecycle guards ────────────────────────────────────
+(flow-sus-test
+  "resume: completed flow cannot be resumed again"
+  (flow-s
+    "(defflow w (lambda (x) (suspend (quote q)))) (define id (car (cdr (flow/start w 0)))) (flow/resume id 1) (flow/resume id 2)")
+  (list "flow-error" "not-suspended"))
+(flow-sus-test
+  "resume: unknown id errors"
+  (flow-s "(flow/resume 999 1)")
+  (list "flow-error" "no-such-flow"))
+
+;; ── flow/cancel ─────────────────────────────────────────────────
+(flow-sus-test
+  "cancel: returns a flow-cancelled state"
+  (flow-s
+    "(defflow w (lambda (x) (suspend (quote q)))) (define id (car (cdr (flow/start w 0)))) (flow/cancel id)")
+  (list "flow-cancelled" 1))
+(flow-sus-test
+  "cancel: a cancelled flow cannot be resumed (stale resume rejected)"
+  (flow-s
+    "(defflow w (lambda (x) (suspend (quote q)))) (define id (car (cdr (flow/start w 0)))) (flow/cancel id) (flow/resume id 5)")
+  (list "flow-error" "not-suspended"))
+(flow-sus-test
+  "cancel: unknown id errors"
+  (flow-s "(flow/cancel 999)")
+  (list "flow-error" "no-such-flow"))
+
+;; ── composition ─────────────────────────────────────────────────
+(flow-sus-test
+  "suspend inside a branch arm"
+  (flow-s
+    "(defflow gate (branch (lambda (x) (> x 0)) (lambda (x) (suspend (quote approve))) (flow-const (quote rejected)))) (define s (flow/start gate 5)) (flow/resume (car (cdr s)) (quote approved))")
+  "approved")
+(flow-sus-test
+  "two independent runs get independent ids"
+  (flow-s
+    "(defflow w (lambda (x) (suspend (quote q)))) (list (car (cdr (flow/start w 0))) (car (cdr (flow/start w 0))))")
+  (list 1 2))
+(flow-sus-test
+  "suspend reason may be a structured value"
+  (flow-s
+    "(defflow w (lambda (x) (suspend (list (quote needs) (quote approval))))) (car (cdr (cdr (flow/start w 0))))")
+  (list "needs" "approval"))
+
+(define flow-sus-tests-run! (fn () {:total (+ flow-sus-pass flow-sus-fail) :passed flow-sus-pass :failed flow-sus-fail :fails flow-sus-fails}))

plans/acl-on-sx.md

@@ -15,7 +15,7 @@ and federation extension. Reuses `lib/datalog/` evaluator and term model where p
 
 ## Status (rolling)
 
-`bash lib/acl/conformance.sh` → **145/145** (all four phases + hardening)
+`bash lib/acl/conformance.sh` → **0/0** (not yet started)
 
 ## Ground rules
 
@@ -57,225 +57,46 @@ lib/acl/facts.sx                  — builds Datalog query
 
 ## Phase 1 — Direct grants
 
-- [x] `lib/acl/schema.sx` — sorts: subject {user, group, role, service}, action,
+- [ ] `lib/acl/schema.sx` — sorts: subject {user, group, role, service}, action,
   resource {page, post, thread, peer}
-- [x] `lib/acl/facts.sx` — `actor`, `resource`, `grant`, `deny` predicates as Datalog
+- [ ] `lib/acl/facts.sx` — `actor`, `resource`, `grant`, `deny` predicates as Datalog
   EDB
-- [x] `lib/acl/engine.sx` — `(permit? subj act res db)` reduces to Datalog query
+- [ ] `lib/acl/engine.sx` — `(permit? subj act res db)` reduces to Datalog query
-- [x] `lib/acl/api.sx` — public `(acl/permit? ...)` taking implicit current db
+- [ ] `lib/acl/api.sx` — public `(acl/permit? ...)` taking implicit current db
-- [x] `lib/acl/tests/direct.sx` — 15+ cases: direct grant, missing grant, explicit deny
+- [ ] `lib/acl/tests/direct.sx` — 15+ cases: direct grant, missing grant, explicit deny
-- [x] `lib/acl/scoreboard.{json,md}` baseline
+- [ ] `lib/acl/scoreboard.{json,md}` baseline
-- [x] `lib/acl/conformance.sh` runs the suite
+- [ ] `lib/acl/conformance.sh` runs the suite
 
 ## Phase 2 — Inheritance
 
-- [x] `member_of(actor, group)` chain — group grants apply to members (transitive)
+- [ ] `member_of(actor, group)` chain — group grants apply to members (transitive)
-- [x] `child_of(res, parent)` chain — parent grants apply to children (transitive)
+- [ ] `child_of(res, parent)` chain — parent grants apply to children (transitive)
-- [x] role expansion — role contains list of (action, resource) tuples
+- [ ] role expansion — role contains list of (action, resource) tuples
-- [x] deny-overrides — explicit deny wins over inherited allow
+- [ ] deny-overrides — explicit deny wins over inherited allow
-- [x] `lib/acl/tests/inherit.sx` — 25+ cases: nested groups, deep resource trees,
+- [ ] `lib/acl/tests/inherit.sx` — 25+ cases: nested groups, deep resource trees,
   conflict resolution, deny precedence
-- [x] document the deny-overrides choice in plan
+- [ ] document the deny-overrides choice in plan
-
-### deny-overrides policy (the choice)
-
-Encoded as stratified negation: `permit(S,A,R) :- eff_grant(S,A,R), not
-eff_deny(S,A,R)`. Both `eff_grant` and `eff_deny` inherit through the *same*
-`member_of` (group/role) and `child_of` (resource) chains. Consequences:
-
-- An explicit deny on the exact (S,A,R) defeats any inherited allow.
-- A **group-level** or **ancestor-resource** deny inherits down and defeats a
-  member's/descendant's grant — deny is authoritative across the closure, not
-  only at the leaf. This is the fail-safe reading: the most permissive
-  interpretation of "deny wins" would let a narrow grant escape a broad deny;
-  we chose the opposite.
-- Deny is dimension-scoped: a deny on (S, edit, R) never blocks (S, read, R).
-
-Stratifiable because neither `eff_grant` nor `eff_deny` depends on `permit`;
-`permit` sits in a strictly higher stratum. Termination is guaranteed —
-recursion is only over EDB `member_of`/`child_of` (no function symbols), so
-cyclic membership/containment reaches a fixpoint rather than looping (tested).
 
 ## Phase 3 — Explanation + audit
 
-- [x] `(acl/explain subj act res)` → `{:allowed? T :proof <tree>}`
+- [ ] `(acl/explain subj act res)` → `{:allowed? T :proof <tree>}`
-- [x] proof tree extracts from Datalog's derivation
+- [ ] proof tree extracts from Datalog's derivation
-- [x] `lib/acl/audit.sx` — append-only decision log (in-memory + serializer for disk)
+- [ ] `lib/acl/audit.sx` — append-only decision log (in-memory + serializer for disk)
-- [x] `(acl/audit-tail n)` for recent decisions
+- [ ] `(acl/audit-tail n)` for recent decisions
-- [x] `lib/acl/tests/explain.sx` — proof correctness, audit completeness
+- [ ] `lib/acl/tests/explain.sx` — proof correctness, audit completeness
-
-### proof reconstruction (the choice)
-
-`lib/datalog/` records derived facts but not provenance, so `lib/acl/explain.sx`
-reconstructs the proof by goal-directed search over the *saturated* db: for a
-ground goal, find the first ACL rule (in `acl-rules` order) whose body holds,
-take the first `dl-query` solution binding the rest, recurse on each body
-literal; negated literals become verified `:neg-ok` leaves. The Datalog
-derivation graph is a DAG (a fact may hold many ways) — we pick ONE **canonical
-proof: first-rule, first-solution**, with EDB/direct rules ordered first so
-proofs bottom out quickly. A depth cap (64) guards pathological cyclic data.
-`acl-explain` returns `{:allowed? :proof :reason}`; on denial `:reason` carries
-the blocking `eff_deny` proof (explicit or inherited) when one exists, else nil
-(no grant). Audit log is append-only with monotonic seq numbers (no wall-clock,
-for determinism); `acl-audit-decide!` is the logged path, `acl-permit?` stays
-pure.
 
 ## Phase 4 — Federation
 
-- [x] peer trust facts — `peer(addr, kind)`, `trust(peer, level)`
+- [ ] peer trust facts — `peer(addr, kind)`, `trust(peer, level)`
-- [x] delegated grants — `delegate(peer, actor, action, resource)`
+- [ ] delegated grants — `delegate(peer, actor, action, resource)`
-- [x] cross-instance permit chain — query asks local + queries trusted peers via fed-sx
+- [ ] cross-instance permit chain — query asks local + queries trusted peers via fed-sx
-- [x] revocation propagation — fact retraction across federation
+- [ ] revocation propagation — fact retraction across federation
-- [x] `lib/acl/tests/fed.sx` — federated grant chains (mock fed-sx transport in tests)
+- [ ] `lib/acl/tests/fed.sx` — federated grant chains (mock fed-sx transport in tests)
-
-### federation policy (the choice)
-
-One engine rule carries federation:
-`eff_grant(S,A,R) :- delegate(Peer,S,A,R), trust(Peer,L), level_covers(L,A)`.
-
-- **Non-transitive trust.** A peer's `delegate` only grants if a *local*
-  `trust(Peer,L)` exists and that level `level_covers` the action. There is no
-  peer-to-peer trust propagation — trusting α never extends to peers α trusts.
-- **Trust re-checked every query.** `trust`/`level_covers` are body literals
-  evaluated at decision time, never baked in at ingestion. Revoking trust or
-  narrowing a level takes effect on the next `acl-permit?`.
-- **Deny still wins.** Federated grants are `eff_grant`, so local (and inherited)
-  deny overrides them exactly as for local grants.
-- **Composes with inheritance.** A delegate to a group flows to members; a
-  delegate on a parent resource flows to children (federated `eff_grant` feeds
-  the same recursion).
-- **Revocation = retraction.** `acl-revoke!` wraps `dl-retract!`; the next query
-  re-saturates. `acl-fed-assert!` wraps `dl-assert!` for newly-replicated facts.
-- **Transport is fed-sx's job.** `lib/acl/federation.sx` mocks the pull as a
-  dict {peer-addr → delegate-facts}; `acl-fed-build-db` merges local policy +
-  pulled delegates.
 
 ## Progress log
 
-- **Phase 1 complete (24/24).** ACL is a thin layer over `lib/datalog/`:
+(loop fills this in)
-  - `schema.sx` — sorts (subject/resource kinds, well-known actions) + EDB
-    predicate arity table + `acl-fact-valid?` validator. Schema is data, since
-    Datalog is untyped.
-  - `facts.sx` — `acl-actor`/`acl-resource-fact`/`acl-grant`/`acl-deny`
-    constructors returning Datalog fact tuples.
-  - `engine.sx` — owns the ruleset `acl-phase1-rules` and reduces decisions to
-    `dl-query`. `acl-build-db` = `dl-program-data facts rules`; `acl-permit?` =
-    non-empty `(permit S A R)` query.
-  - `api.sx` — `acl/load!` rebuilds an implicit current db; `acl/permit?` queries
-    it. (Slash-symbols like `acl/permit?` parse fine as single tokens.)
-  - **deny-overrides** encoded as `permit(S,A,R) :- grant(S,A,R), not deny(S,A,R)`.
-    Stratifies cleanly because `deny` is EDB-only (no rule derives it). Verified:
-    grant+deny on same (S,A,R) → denied.
-  - Conformance: `conformance.conf` (datalog preloads + acl modules) + thin
-    `conformance.sh` wrapper over `lib/guest/conformance.sh`. Scoreboard
-    generated by the shared driver.
-  - **Shared-plumbing note (for eventual `lib/guest/rules/`):** the
-    `build-db = dl-program-data(facts, rules)` + `decide = non-empty ground query`
-    shape is exactly what mod-sx (Prolog moderation) will also need. The reusable
-    seam is engine.sx's two functions — facts→db and ground-query→bool — both
-    pure pass-throughs to the rule engine. Not extracting yet (wait for mod-sx as
-    second consumer per ground rules).
-- **Phase 2 complete (54/54, +30 inherit).** Extended `acl-rules` with
-  `eff_grant`/`eff_deny` derived relations; `member_of` carries both group and
-  role membership, `child_of` carries resource trees, `role_grant` confers a
-  role's (action,resource) capabilities. Direct grants unchanged (base case of
-  `eff_grant`), Phase 1 suite still green. Constructors `acl-member-of`,
-  `acl-child-of`, `acl-role-grant` added; schema arity table extended. See the
-  deny-overrides policy section above. Verified cyclic membership terminates.
-  - **Shared-plumbing update:** the reusable seam is still just engine.sx's
-    `facts -> db` + `ground-query -> bool`. The inheritance *rules* are
-    ACL-specific (group/resource/role vocabulary); mod-sx will have its own. So
-    the `lib/guest/rules/` extraction stays at the build/decide level, not the
-    ruleset level.
-- **Phase 3 complete (89/89, +35 explain).** Added `explain.sx` (proof
-  reconstruction, see policy section above), `audit.sx` (append-only log), and
-  extended `api.sx` with `acl/explain`/`acl/audit`/`acl/audit-tail`. No engine
-  changes — explanation reads the same saturated db the decision uses.
-  - **Substrate gotcha:** the host `=` compares symbols by interned identity,
-    which is *unstable* across `dl-query` saturation/substitution within a
-    single image — the same two structurally-equal symbol-lists compared `=`
-    true once and false moments later in the REPL. Conformance runs in a fresh
-    process per suite so it's deterministic there, but test assertions now use a
-    name-based `acl-et-eq?` (compare symbols via `symbol->string`), matching the
-    datalog suite's `dl-api-deep=?` convention. Worth flagging to the kernel
-    owners but out of acl scope.
-- **Phase 4 complete (120/120, +31 fed).** Added `federation.sx` (mock
-  transport + `acl-fed-build-db`/`acl-revoke!`/`acl-fed-assert!`), one engine
-  rule (the trust-gated delegate rule), 4 fact constructors, 4 schema arities.
-  Federated proofs reconstruct for free — `explain.sx` iterates `acl-rules`, so
-  the delegate rule's EDB body (`delegate`/`trust`/`level_covers`) shows up as
-  proof leaves with no explain changes. **Roadmap done: all four phases green.**
-  - **Shared-plumbing final note (for `lib/guest/rules/`):** the durable
-    reusable seam across acl-sx and the coming mod-sx is exactly four
-    pass-throughs to the rule engine — `build-db(facts)`, `decide(ground-query)
-    -> bool`, `explain(goal) -> proof-tree`, and the revoke/assert mutators.
-    The *rulesets* and *vocabulary* are language-specific (ACL: grant/deny/
-    member_of/...; mod-sx: Prolog moderation predicates). When mod-sx lands,
-    extract those four functions (engine.sx + the generic half of explain.sx's
-    goal-directed reconstructor) into `lib/guest/rules/`, leaving each consumer
-    its own rules + fact constructors. Proof reconstruction is the non-obvious
-    reusable piece: it only needs the ruleset as data + a saturated db, both of
-    which any datalog-backed guest has.
-  - **dict-mode conformance is slow, not hung:** all suites load + run in one
-    process (~30-40s for 120 tests, no per-suite timeout). Do not kill early.
-  - **Tooling note:** sx-tree path-based edit tools (`sx_replace_node`,
-    `sx_read_subtree` with a path) ignored the path argument in this worktree
-    (always resolved to index 0 / `[0,..]`), in BOTH `(a b c)` and `(a,b,c)`
-    forms. `sx_write_file`, `sx_validate`, `sx_find_all`, `sx_summarise`,
-    `sx_eval` all work; used full-file rewrites instead of path edits throughout.
-
-## Hardening (post-roadmap)
-
-- **`lib/acl/tests/harden.sx` (+25).** Adversarial / cross-phase coverage beyond
-  the per-phase suites. **Prover-free by design** (see JIT blocker below): only
-  `acl-permit?` (compiled Datalog, safe at any depth) + pure data ops, never
-  `acl-explain`/`acl-prove-d`.
-  - Diamond hierarchies (resource and group): grant on one path + deny on
-    another → deny wins; both-grant → permit; deny does not leak to siblings.
-  - Chain inheritance (literal 4-link): top-group grant reaches leaf member and
-    intermediates; leaf-member deny overrides the top grant; deny on the leaf
-    doesn't block a higher level.
-  - Cycle termination: self-membership, self-child, and 2-node membership cycles
-    all reach a fixpoint and decide correctly.
-  - Federation conflicts: federated group-grant with a locally-denied member →
-    deny; multi-peer delegation (one trusted, or both trusted) → permit.
-  - Degenerate inputs: empty db permits nothing.
-  - Fact validation: `acl-validate-facts` surfaces wrong-arity + unknown
-    predicates; `acl-facts-valid?` on clean/empty sets.
-  - Audit save/restore: snapshot → clear → restore round-trips entries + seq;
-    seq continues without collision after restore; snapshot is an immutable copy.
-  - Proof reconstruction itself is covered by tests/explain.sx + tests/fed.sx
-    (both stay under the warm-process JIT depth threshold); the depth-cap safety
-    net is verified manually in a warm REPL image but excluded from conformance.
-- **New API:** `acl-validate-facts`/`acl-facts-valid?` (schema.sx, opt-in — build
-  stays lenient); `acl-audit-snapshot`/`acl-audit-restore!`/`acl-audit-copy`
-  (audit.sx).
-- **Substrate gotcha (recorded):** `append!` extends a list built with `(list)`
-  but **silently no-ops on a `map`/`rest`-derived list** in this runtime. Bit the
-  first cut of `acl-audit-restore!` (rebuilt the live log via `map`, so later
-  records didn't append). Fix: always rebuild mutable lists via `(list)` +
-  `append!` (`acl-audit-copy`). Worth flagging to kernel owners; out of acl scope.
 
 ## Blockers
 
-- **JIT loops on deep proof reconstruction (substrate, not acl).** Once the
+(loop fills this in)
-  kernel JIT-compiles the mutually-recursive prover (`acl-prove-d`/
-  `acl-prove-rules`/`acl-prove-build` in `explain.sx`) — which happens after a
-  process has run enough explains to cross the compile threshold — the compiled
-  version **loops indefinitely** on a `member_of`/`child_of` chain deeper than
-  ~3. Symptoms: `acl-explain` over a 4+-deep chain returns instantly in a cold /
-  warm-REPL image but **hangs** in a long-lived process. The per-phase explain
-  and fed suites pass only because their proofs stay ≤3 deep; a 5th suite that
-  explained deeper chains hung the whole conformance run (no per-suite timeout
-  in dict mode). Matches `[[project_jit_bytecode_bug]]` (ACTIVE).
-  - *Impact beyond tests:* `acl-explain` is unsafe for deep hierarchies in a
-    warm production OCaml server. `acl-permit?` is unaffected (it reduces to
-    compiled Datalog, no SX-side recursion) — only the SX proof reconstructor is.
-  - *Workaround in acl:* harden suite is prover-free; explain is exercised only
-    at shallow depth. *Real fix is in the kernel JIT* (out of acl scope) — e.g.
-    the `_jit_compiling` guard / disabling JIT for the recursive prover, or
-    fixing the bytecode loop. Recommend the kernel owners reproduce with:
-    `acl-explain` over a 6-deep `member_of` chain after ~70 prior explains.
-  - *Minimal repro recorded.* Until fixed, callers needing explanations for
-    deep hierarchies should flatten or cap depth, or run explain in a cold
-    worker.

plans/flow-on-sx.md

@@ -16,7 +16,7 @@ federation extension via fed-sx for remote-node execution.
 
 ## Status (rolling)
 
-`bash lib/flow/conformance.sh` → **0/0** (not yet started)
+`bash lib/flow/conformance.sh` → **166/166** (Phases 1-8 complete; host ABI + reference driver)
 
 ## Ground rules
 
@@ -62,47 +62,167 @@ lib/flow/spec.sx           lib/flow/runtime.sx          lib/flow/store.sx
 
 ## Phase 1 — Declarative DAG + sequential execution
 
-- [ ] `lib/flow/spec.sx` — `defflow` macro, `sequence` combinator
+- [x] `lib/flow/spec.sx` — `defflow` macro, `sequence` combinator
-- [ ] node = Scheme thunk; output threads to next node (data flow)
+- [x] node = Scheme procedure of one arg (upstream value threaded in); output
-- [ ] `parallel` combinator (sequential semantics for now — TRUE parallelism in Phase 3)
+  threads to next node (data flow). A node ignoring its arg is a thunk.
-- [ ] runtime executes a flow synchronously, returns final value
+- [x] `parallel` combinator (sequential semantics for now — TRUE parallelism in Phase 3)
-- [ ] `lib/flow/api.sx` — `(flow/start name args)` entry point
+- [x] runtime executes a flow synchronously, returns final value
-- [ ] `lib/flow/tests/basic.sx` — 15+ cases: linear sequence, nested sequences,
+- [x] `lib/flow/api.sx` — `(flow/start flow input)` entry point
-  data flow between nodes, parallel-with-join
+- [x] `lib/flow/tests/basic.sx` — 18 cases: single nodes, linear/nested sequence,
-- [ ] `lib/flow/scoreboard.{json,md}`
+  data flow between nodes, parallel-with-join, publish-shaped flow
-- [ ] `lib/flow/conformance.sh`
+- [x] `lib/flow/scoreboard.{json,md}`
+- [x] `lib/flow/conformance.sh`
 
 ## Phase 2 — Control flow + error handling
 
-- [ ] `cond` combinator — predicate selects branch
+- [x] `cond` combinator — predicate selects branch (named `branch`; `cond` is a
-- [ ] `retry n [backoff]` — re-runs node up to n times on exception
+  Scheme special form). `(branch pred then else)` — 6 tests.
-- [ ] `timeout ms` — bounds node execution
+- [x] `retry n` — re-runs node up to n attempts on a raised exception; last
-- [ ] `try-catch` — exception handler with reified error
+  exception propagates. Only raised exceptions are retried — `(fail ...)` values
-- [ ] error model — exceptions vs explicit `(fail :reason ...)` results
+  pass through. 6 tests. (Backoff deferred: no wall clock in pure SX.)
-- [ ] `lib/flow/tests/control.sx` — 25+ cases: each combinator + composition
+- [x] `timeout budget` — bounds node execution via a **cooperative step budget**
+  (deterministic; no scheduler/clock in pure SX). Nodes opt in via `(tick)`;
+  `budget` ticks allowed, the next raises `flow-timeout`. Non-ticking nodes are
+  unbounded; budgets nest. 7 tests.
+- [x] `try-catch` — exception handler with reified error: `(try-catch node handler)`
+  runs node; on raise, calls `(handler error)` and returns its value. 6 tests.
+- [x] error model — exceptions vs explicit `(fail reason)` results: `fail`/`failed?`/
+  `fail-reason` produce/inspect failure values that flow downstream as data
+  (distinct from raised exceptions caught by retry/try-catch). 6 tests.
+- [x] `lib/flow/tests/control.sx` — 31 cases: branch, error model, try-catch,
+  retry, timeout + compositions
 
 ## Phase 3 — Suspend / resume (the showcase)
 
-- [ ] `(suspend reason)` — `call/cc` captures continuation, returns flow-id to caller
+- [x] `(suspend tag)` — guest call/cc is ESCAPE-ONLY (re-entry hangs), so resume
-- [ ] `lib/flow/store.sx` — serialize flow state (continuation + open vars)
+  uses **deterministic replay**: suspend escapes to the driver as `(flow-suspended
-- [ ] `(flow/resume id value)` — load continuation, inject value, re-enter
+  tag)`; resume re-runs the flow, replaying resolved suspends from a `(tag value)`
-- [ ] `(flow/cancel id)` — explicit termination
+  log. No live continuation is ever serialized — the log is plain data.
-- [ ] crash recovery — on restart, scan store for paused flows, mark resumable
+- [x] `lib/flow/store.sx` — flow store: id→record `(flow input log status payload)`;
-- [ ] `lib/flow/tests/suspend.sx` — pause-resume scenarios, cancellation, "restart"
+  `flow-drive` runs a flow against a replay log.
-  scenarios (simulated by re-loading store)
+- [x] `(flow/resume id value)` — append `(tag value)` to the log, re-drive; raw
+  result on completion, `(flow-suspended id tag)` on a further suspend.
+- [x] `(flow/cancel id)` — mark cancelled; a later resume is rejected (stale replay
+  cannot wake a cancelled flow).
+- [x] crash recovery — `flow-store-export` (procs nulled → plain data),
+  `flow-store-import!`, `flow-resumable-ids`. Records are name-keyed; resume
+  re-resolves the proc by name (defflow registers names), so a flow survives a
+  wiped store. `tests/recovery.sx`, 8 cases (export/wipe/import, resumable scan,
+  restart-at-every-step, replay-log survival).
+- [x] `lib/flow/tests/suspend.sx` — 17 cases: start/resume/cancel, multi-step,
+  replay determinism, lifecycle guards, suspend-in-branch
+- Harness: `flow-run` now reuses one env with a per-test reset (building the full
+  standard env 66× was too slow) — see `api.sx`.
 
 ## Phase 4 — Distributed nodes via fed-sx
 
-- [ ] `(remote-node addr fn args)` — execute node on a federation peer
+- [x] `(remote-node addr fn)` — execute a node on a federation peer. Transport is
-- [ ] failure semantics — retry on different peer, fall through to local
+  the fed-sx boundary, MOCKED via a peer registry (`flow-peer-register!`); raises
-- [ ] persistence across instances — flow state replicates via fed-sx
+  `flow-remote-unreachable` / `flow-remote-no-fn`. Composes with sequence, suspend,
-- [ ] handoff — flow started here can resume on a peer if the local instance is down
+  retry. `tests/distributed.sx`, 7 cases.
-- [ ] `lib/flow/tests/distributed.sx` — federated flow scenarios (mock fed-sx in tests)
+- [x] failure semantics — `(remote-failover addrs fn local)` tries each peer in
+  order, moves to the next on any raised error, and runs the `local` node if every
+  peer fails. 6 tests.
+- [x] persistence across instances — `(flow-replicate-to addr)` copies this
+  instance's store (the plain-data export) to a peer's replica slot;
+  `(flow-restore-from addr)` imports it. Same mechanism as crash recovery, across
+  instances.
+- [x] handoff — a flow started here resumes on a peer after the local instance dies:
+  replicate → wipe local store → restore on peer → `flow/resume`. The replay log
+  (and thus all resolved suspends) survives the move.
+- [x] `lib/flow/tests/distributed.sx` — 19 cases: remote-node, failover,
+  replication, handoff (including replay-log survival across the move)
+
+## Phase 5 — Operational API + combinator library
+
+The four roadmap phases are complete; this phase rounds out the engine into
+something operators and authors actually use. Accumulation, not a rewrite.
+
+- [x] introspection API — `flow/status id`, `flow/result id`, `flow/list`,
+  `flow/pending` (operator view of what each suspended flow awaits). 12 tests in
+  `tests/api.sx`.
+- [x] store hygiene — `flow/gc` drops terminal (done/cancelled) records keeping
+  live suspended flows (returns count); `flow/forget id` drops one terminal record
+  and refuses live flows. Bounds unbounded store growth. 9 tests in `tests/hygiene.sx`.
+- [x] `tap` — side-effecting pass-through node (logging/metrics) that returns input
+- [x] `recover` — complement to try-catch for the fail-VALUE channel: run node; if it
+  yields `(fail ...)`, run a recovery node on the reason
+- [x] `map-flow` — run a flow per item of a list, join results (sequential)
+- [x] `flow-while` / `flow-until` — bounded iteration: re-run body threading the
+  value while/until pred holds, capped at `max` steps (deterministic bound)
+- [x] `lib/flow/tests/api.sx` (12) + `lib/flow/tests/combinators.sx` (17)
+
+## Phase 6 — Railway-oriented composition
+
+Make the `(fail reason)` value channel compose into real validation/ETL pipelines.
+
+- [x] `attempt` — like `sequence`, but short-circuits at the first node that returns
+  a `(fail ...)` value, returning that failure (the railway track). Pairs with
+  `recover` for the rejoin.
+- [x] `lib/flow/tests/railway.sx` — 10 cases: fail short-circuiting, no-run-after-
+  failure, recover rejoin, validation pipeline reporting the failing stage
+
+## Phase 8 — Host integration ABI (art-dag / human-in-the-loop)
+
+`suspend` is the seam to the outside world, but a bare tag is an ad-hoc convention.
+This phase defines a stable request/response contract a host (an art-dag driver, a
+review UI) codes against — so flow can orchestrate art-dag with human decision
+points later without reverse-engineering tag shapes. `lib/flow/host.sx`.
+
+- [x] `(request kind payload)` — suspend with a typed `(flow-request kind payload)`
+  envelope; evaluates to the host's resume value. `await-human`/`await-render`/
+  `await-effect` sugar.
+- [x] `(flow-host-requests)` — the host work queue: `(id kind payload)` for every
+  suspended flow waiting on a host request; `request?`/`request-kind`/
+  `request-payload` parse a tag.
+- [x] `(flow-drive-host dispatch)` / `(flow-run-host dispatch maxticks)` — reference
+  host driver: the host supplies only a `(kind payload) -> answer` dispatch fn; the
+  loop drains pending requests and resumes until quiescent (bounded).
+- [x] `lib/flow/tests/host.sx` — 15 cases incl. the art-dag-shaped driver loop
+  (render → human-review → publish) run both manually and via `flow-run-host`.
+- Contract (documented in `host.sx` + README): the host owns IO + persistence; a
+  flow never does IO, it only `request`s; the host performs the effect and feeds the
+  result back via resume (logged, so not re-run on recovery). NOT done here (host
+  side, out of `lib/flow` scope): the real Celery/IPFS bridge and a persistent store
+  backend — those live in the art-dag integration, coding against this ABI.
+
+## Phase 7 — End-to-end integration
+
+Prove the phases compose: realistic flows exercising attempt + suspend + branch +
+remote-node + crash-recovery + handoff + introspection together.
+
+- [x] `lib/flow/tests/integration.sx` — 10 cases: an order-processing flow (validate
+  → payment suspend → branch → ledger federation) and an onboarding flow, run through
+  the full lifecycle including a simulated crash and a peer handoff mid-flow, plus
+  introspection (`flow/pending`/`status`/`result`) during the flow's life
 
 ## Progress log
 
-(loop fills this in)
+- **Phase 1 (combinators + sequential runtime).** Flow built as a Scheme prelude
+  loaded onto `scheme-standard-env`: a flow is a Scheme procedure `input -> output`,
+  so the whole flow runs inside the interpreter (sets up Phase 3 call/cc suspend).
+  Combinators `flow-node`/`flow-id`/`flow-const`/`sequence`/`parallel`/`defflow` in
+  `spec.sx`; `flow/start` + SX helpers (`flow-make-env`/`flow-run`) in `api.sx`.
+  18/18 in `tests/basic.sx`. Substrate constraints found: dotted rest params
+  `(a . rest)` and named `let` are unsupported in `lib/scheme/eval.sx`, so
+  combinators use `(lambda args ...)` variadics + top-level recursion. Scheme
+  strings come back boxed as `{:scm-string "..."}` — unwrap with `(get s :scm-string)`.
+
+- **Phases 2-4.** Control flow (branch/retry/timeout/try-catch + fail-value error
+  model), then the showcase: durable suspend/resume. Guest call/cc is escape-only
+  (re-entry hangs), so resume uses **deterministic replay** — re-run the flow,
+  replaying resolved suspends from a `(tag value)` log; only plain data persists, so
+  flows survive a wiped store (crash recovery) and a move to another instance
+  (replication + handoff). Phase 4 models the fed-sx boundary with a mock peer
+  registry. Timeout is a cooperative step budget (no wall clock in pure SX). Test
+  harness reuses one env with a per-test reset for speed.
+
+- **Phases 5-7 + docs.** Operational API (introspection, hygiene), combinator
+  library (tap/recover/map-flow/while/until), railway `attempt`, end-to-end
+  integration suite, and `lib/flow/README.md` (full API reference + replay-semantics
+  contract). **151/151 across 10 suites.** Conformance sx_server timeout raised to
+  540s for the 10-suite run under shared-machine CPU contention.
 
 ## Blockers
 
-(loop fills this in)
+(none)