From e4a8dff9ba2c4e807bcc374e9f9d77540b2eb10e Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 11:49:43 +0000
Subject: [PATCH 01/13] artdag: Phase 1 DAG model + structural content
 addressing + 20 tests

Content-addressed node = {:op :inputs :params :commutative}; content-id is a
deterministic canonical serialization (sorted param keys; commutative ops sort
inputs). artdag/build validates dangling/cycles, topo-sorts, dedups identical
subgraphs to one id shared across DAGs. conformance.sh + scoreboard (dag 20/20).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/conformance.sh  | 107 ++++++++++++++++++
 lib/artdag/dag.sx          | 226 +++++++++++++++++++++++++++++++++++++
 lib/artdag/scoreboard.json |   8 ++
 lib/artdag/scoreboard.md   |   8 ++
 lib/artdag/tests/dag.sx    | 182 +++++++++++++++++++++++++++++
 plans/artdag-on-sx.md      |  25 ++--
 6 files changed, 549 insertions(+), 7 deletions(-)
 create mode 100755 lib/artdag/conformance.sh
 create mode 100644 lib/artdag/dag.sx
 create mode 100644 lib/artdag/scoreboard.json
 create mode 100644 lib/artdag/scoreboard.md
 create mode 100644 lib/artdag/tests/dag.sx

diff --git a/lib/artdag/conformance.sh b/lib/artdag/conformance.sh
new file mode 100755
index 00000000..5424ae49
--- /dev/null
+++ b/lib/artdag/conformance.sh
@@ -0,0 +1,107 @@
+#!/usr/bin/env bash
+# lib/artdag/conformance.sh — run artdag test suites, emit scoreboard.json + scoreboard.md.
+
+set -uo pipefail
+cd "$(git rev-parse --show-toplevel)"
+
+SX_SERVER="${SX_SERVER:-/root/rose-ash/hosts/ocaml/_build/default/bin/sx_server.exe}"
+if [ ! -x "$SX_SERVER" ]; then
+  SX_SERVER="hosts/ocaml/_build/default/bin/sx_server.exe"
+fi
+if [ ! -x "$SX_SERVER" ]; then
+  echo "ERROR: sx_server.exe not found." >&2
+  exit 1
+fi
+
+SUITES=(dag)
+
+OUT_JSON="lib/artdag/scoreboard.json"
+OUT_MD="lib/artdag/scoreboard.md"
+
+run_suite() {
+  local suite=$1
+  local file="lib/artdag/tests/${suite}.sx"
+  local TMP
+  TMP=$(mktemp)
+  cat > "$TMP" << EPOCHS
+(epoch 1)
+(load "spec/stdlib.sx")
+(load "lib/r7rs.sx")
+(load "lib/artdag/dag.sx")
+(epoch 2)
+(eval "(define artdag-test-pass 0)")
+(eval "(define artdag-test-fail 0)")
+(eval "(define artdag-test (fn (name got expected) (if (= got expected) (set! artdag-test-pass (+ artdag-test-pass 1)) (set! artdag-test-fail (+ artdag-test-fail 1)))))")
+(epoch 3)
+(load "${file}")
+(epoch 4)
+(eval "(list artdag-test-pass artdag-test-fail)")
+EPOCHS
+
+  local OUTPUT
+  OUTPUT=$(timeout 300 "$SX_SERVER" < "$TMP" 2>/dev/null)
+  rm -f "$TMP"
+
+  local LINE
+  LINE=$(echo "$OUTPUT" | awk '/^\(ok-len 4 / {getline; print; exit}')
+  if [ -z "$LINE" ]; then
+    LINE=$(echo "$OUTPUT" | grep -E '^\(ok 4 \([0-9]+ [0-9]+\)\)' | tail -1 \
+            | sed -E 's/^\(ok 4 //; s/\)$//')
+  fi
+
+  local P F
+  P=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\).*/\1/')
+  F=$(echo "$LINE" | sed -E 's/^\(([0-9]+) ([0-9]+)\).*/\2/')
+  P=${P:-0}
+  F=${F:-0}
+  echo "${P} ${F}"
+}
+
+declare -A SUITE_PASS
+declare -A SUITE_FAIL
+TOTAL_PASS=0
+TOTAL_FAIL=0
+
+echo "Running artdag conformance suite..." >&2
+for s in "${SUITES[@]}"; do
+  read -r p f < <(run_suite "$s")
+  SUITE_PASS[$s]=$p
+  SUITE_FAIL[$s]=$f
+  TOTAL_PASS=$((TOTAL_PASS + p))
+  TOTAL_FAIL=$((TOTAL_FAIL + f))
+  printf "  %-12s %d/%d\n" "$s" "$p" "$((p+f))" >&2
+done
+
+{
+  printf '{\n'
+  printf '  "suites": {\n'
+  first=1
+  for s in "${SUITES[@]}"; do
+    if [ $first -eq 0 ]; then printf ',\n'; fi
+    printf '    "%s": {"pass": %d, "fail": %d}' "$s" "${SUITE_PASS[$s]}" "${SUITE_FAIL[$s]}"
+    first=0
+  done
+  printf '\n  },\n'
+  printf '  "total_pass": %d,\n' "$TOTAL_PASS"
+  printf '  "total_fail": %d,\n' "$TOTAL_FAIL"
+  printf '  "total": %d\n' "$((TOTAL_PASS + TOTAL_FAIL))"
+  printf '}\n'
+} > "$OUT_JSON"
+
+{
+  printf '# artdag Conformance Scoreboard\n\n'
+  printf '_Generated by `lib/artdag/conformance.sh`_\n\n'
+  printf '| Suite | Pass | Fail | Total |\n'
+  printf '|-------|-----:|-----:|------:|\n'
+  for s in "${SUITES[@]}"; do
+    p=${SUITE_PASS[$s]}
+    f=${SUITE_FAIL[$s]}
+    printf '| %s | %d | %d | %d |\n' "$s" "$p" "$f" "$((p+f))"
+  done
+  printf '| **Total** | **%d** | **%d** | **%d** |\n' "$TOTAL_PASS" "$TOTAL_FAIL" "$((TOTAL_PASS + TOTAL_FAIL))"
+} > "$OUT_MD"
+
+echo "Wrote $OUT_JSON and $OUT_MD" >&2
+echo "Total: $TOTAL_PASS pass, $TOTAL_FAIL fail" >&2
+
+[ "$TOTAL_FAIL" -eq 0 ]
diff --git a/lib/artdag/dag.sx b/lib/artdag/dag.sx
new file mode 100644
index 00000000..e9e4ba24
--- /dev/null
+++ b/lib/artdag/dag.sx
@@ -0,0 +1,226 @@
+; lib/artdag/dag.sx — DAG model + structural content addressing.
+; A node = {:op :inputs :params :commutative}. inputs are content-ids of upstream
+; nodes. The content-id is a deterministic structural digest so identical
+; subgraphs collapse to one id (and one cache slot). No clock, no randomness.
+
+; ---- string ordering (no host sort/string<?) ----
+
+(define
+  artdag/str<?-at
+  (fn
+    (a b i la lb)
+    (cond
+      ((and (>= i la) (>= i lb)) false)
+      ((>= i la) true)
+      ((>= i lb) false)
+      (else
+        (let
+          ((ca (char-code (substring a i (+ i 1))))
+            (cb (char-code (substring b i (+ i 1)))))
+          (cond
+            ((< ca cb) true)
+            ((> ca cb) false)
+            (else (artdag/str<?-at a b (+ i 1) la lb))))))))
+
+(define
+  artdag/str<?
+  (fn
+    (a b)
+    (artdag/str<?-at a b 0 (string-length a) (string-length b))))
+
+(define
+  artdag/insert-string
+  (fn
+    (sorted x)
+    (cond
+      ((empty? sorted) (list x))
+      ((artdag/str<? x (first sorted)) (cons x sorted))
+      (else (cons (first sorted) (artdag/insert-string (rest sorted) x))))))
+
+(define
+  artdag/sort-strings
+  (fn (xs) (reduce (fn (acc x) (artdag/insert-string acc x)) (list) xs)))
+
+; ---- canonical serialization ----
+
+(define
+  artdag/canon-list
+  (fn
+    (xs)
+    (if
+      (empty? xs)
+      ""
+      (reduce
+        (fn (acc x) (str acc " " (artdag/canon x)))
+        (artdag/canon (first xs))
+        (rest xs)))))
+
+(define
+  artdag/canon-dict
+  (fn
+    (d)
+    (str
+      "{"
+      (reduce
+        (fn (acc k) (str acc " " k "=" (artdag/canon (get d k))))
+        ""
+        (artdag/sort-strings (keys d)))
+      "}")))
+
+(define
+  artdag/canon
+  (fn
+    (v)
+    (let
+      ((t (type-of v)))
+      (cond
+        ((equal? t "nil") "nil")
+        ((equal? t "boolean") (if v "#t" "#f"))
+        ((equal? t "number") (number->string v))
+        ((equal? t "string") (str "\"" v "\""))
+        ((equal? t "keyword") (str ":" (keyword-name v)))
+        ((equal? t "symbol") (str "'" (write-to-string v)))
+        ((equal? t "list") (str "(" (artdag/canon-list v) ")"))
+        ((equal? t "dict") (artdag/canon-dict v))
+        (else (str "<" t ">" (write-to-string v)))))))
+
+; ---- node + content id ----
+
+(define artdag/node (fn (op inputs params) {:inputs inputs :commutative false :op op :params params}))
+
+(define artdag/cnode (fn (op inputs params) {:inputs inputs :commutative true :op op :params params}))
+
+(define artdag/node-op (fn (n) (get n :op)))
+(define artdag/node-inputs (fn (n) (get n :inputs)))
+(define artdag/node-params (fn (n) (get n :params)))
+
+(define
+  artdag/content-id
+  (fn
+    (node)
+    (let
+      ((ins (if (get node :commutative) (artdag/sort-strings (get node :inputs)) (get node :inputs))))
+      (str
+        "node:"
+        (artdag/canon (list (get node :op) ins (get node :params)))))))
+
+(define artdag/id-of artdag/content-id)
+
+; ---- list helpers ----
+
+(define artdag/member? (fn (x xs) (some (fn (y) (equal? y x)) xs)))
+
+(define
+  artdag/all-in?
+  (fn (xs placed) (every? (fn (x) (artdag/member? x placed)) xs)))
+
+; ---- build: entries -> validated, content-addressed dag ----
+; entry = (local-name op (input-local-names...) params [commutative?])
+
+(define artdag/entry-name (fn (e) (nth e 0)))
+(define artdag/entry-op (fn (e) (nth e 1)))
+(define artdag/entry-inputs (fn (e) (nth e 2)))
+(define artdag/entry-params (fn (e) (nth e 3)))
+(define
+  artdag/entry-commutative
+  (fn (e) (if (> (len e) 4) (nth e 4) false)))
+
+(define
+  artdag/entries->map
+  (fn
+    (entries)
+    (reduce
+      (fn (m e) (assoc m (artdag/entry-name e) {:inputs (artdag/entry-inputs e) :commutative (artdag/entry-commutative e) :op (artdag/entry-op e) :params (artdag/entry-params e)}))
+      {}
+      entries)))
+
+(define
+  artdag/dangling
+  (fn
+    (spec-map)
+    (reduce
+      (fn
+        (acc name)
+        (reduce
+          (fn (a in) (if (has-key? spec-map in) a (cons in a)))
+          acc
+          (get (get spec-map name) :inputs)))
+      (list)
+      (keys spec-map))))
+
+(define
+  artdag/ready-names
+  (fn
+    (spec-map placed)
+    (filter
+      (fn
+        (name)
+        (and
+          (not (artdag/member? name placed))
+          (artdag/all-in? (get (get spec-map name) :inputs) placed)))
+      (artdag/sort-strings (keys spec-map)))))
+
+(define
+  artdag/topo-loop
+  (fn
+    (spec-map placed)
+    (if
+      (= (len placed) (len (keys spec-map)))
+      {:order placed :ok true}
+      (let
+        ((ready (artdag/ready-names spec-map placed)))
+        (if
+          (empty? ready)
+          {:error "cycle" :ok false}
+          (artdag/topo-loop spec-map (concat placed ready)))))))
+
+(define artdag/topo (fn (spec-map) (artdag/topo-loop spec-map (list))))
+
+(define
+  artdag/resolve-ids
+  (fn
+    (spec-map order)
+    (reduce
+      (fn
+        (dag name)
+        (let
+          ((spec (get spec-map name)))
+          (let
+            ((resolved (map (fn (in) (get (get dag :names) in)) (get spec :inputs))))
+            (let
+              ((node {:inputs resolved :commutative (get spec :commutative) :op (get spec :op) :params (get spec :params)}))
+              (let ((id (artdag/content-id node))) {:names (assoc (get dag :names) name id) :order (if (artdag/member? id (get dag :order)) (get dag :order) (concat (get dag :order) (list id))) :nodes (assoc (get dag :nodes) id node)})))))
+      {:names {} :order (list) :nodes {}}
+      order)))
+
+(define
+  artdag/build
+  (fn
+    (entries)
+    (let
+      ((spec-map (artdag/entries->map entries)))
+      (let
+        ((dang (artdag/dangling spec-map)))
+        (if
+          (not (empty? dang))
+          {:refs dang :error "dangling" :ok false}
+          (let
+            ((topo (artdag/topo spec-map)))
+            (if
+              (not (get topo :ok))
+              {:error (get topo :error) :ok false}
+              (assoc
+                (artdag/resolve-ids spec-map (get topo :order))
+                :ok true))))))))
+
+; ---- dag accessors ----
+
+(define artdag/dag-nodes (fn (dag) (get dag :nodes)))
+(define artdag/dag-names (fn (dag) (get dag :names)))
+(define artdag/dag-order (fn (dag) (get dag :order)))
+(define artdag/dag-id (fn (dag name) (get (get dag :names) name)))
+(define artdag/dag-get (fn (dag id) (get (get dag :nodes) id)))
+(define
+  artdag/dag-node-by-name
+  (fn (dag name) (artdag/dag-get dag (artdag/dag-id dag name))))
+(define artdag/node-count (fn (dag) (len (keys (get dag :nodes)))))
diff --git a/lib/artdag/scoreboard.json b/lib/artdag/scoreboard.json
new file mode 100644
index 00000000..1ca0b565
--- /dev/null
+++ b/lib/artdag/scoreboard.json
@@ -0,0 +1,8 @@
+{
+  "suites": {
+    "dag": {"pass": 20, "fail": 0}
+  },
+  "total_pass": 20,
+  "total_fail": 0,
+  "total": 20
+}
diff --git a/lib/artdag/scoreboard.md b/lib/artdag/scoreboard.md
new file mode 100644
index 00000000..34e8136d
--- /dev/null
+++ b/lib/artdag/scoreboard.md
@@ -0,0 +1,8 @@
+# artdag Conformance Scoreboard
+
+_Generated by `lib/artdag/conformance.sh`_
+
+| Suite | Pass | Fail | Total |
+|-------|-----:|-----:|------:|
+| dag | 20 | 0 | 20 |
+| **Total** | **20** | **0** | **20** |
diff --git a/lib/artdag/tests/dag.sx b/lib/artdag/tests/dag.sx
new file mode 100644
index 00000000..f92d90ed
--- /dev/null
+++ b/lib/artdag/tests/dag.sx
@@ -0,0 +1,182 @@
+; Phase 1 — dag model + structural content addressing.
+
+; ---- content-id determinism ----
+
+(artdag-test
+  "same spec -> same id"
+  (equal?
+    (artdag/content-id (artdag/node "blur" (list "i1") {:r 3}))
+    (artdag/content-id (artdag/node "blur" (list "i1") {:r 3})))
+  true)
+
+(artdag-test
+  "op affects id"
+  (equal?
+    (artdag/content-id (artdag/node "blur" (list "i1") {}))
+    (artdag/content-id (artdag/node "sharpen" (list "i1") {})))
+  false)
+
+(artdag-test
+  "params affect id"
+  (equal?
+    (artdag/content-id (artdag/node "blur" (list "i1") {:r 3}))
+    (artdag/content-id (artdag/node "blur" (list "i1") {:r 5})))
+  false)
+
+(artdag-test
+  "inputs affect id"
+  (equal?
+    (artdag/content-id (artdag/node "add" (list "i1") {}))
+    (artdag/content-id (artdag/node "add" (list "i2") {})))
+  false)
+
+(artdag-test
+  "param key order does not affect id"
+  (equal?
+    (artdag/content-id (artdag/node "op" (list) {:a 1 :b 2}))
+    (artdag/content-id (artdag/node "op" (list) {:a 1 :b 2})))
+  true)
+
+; ---- commutativity ----
+
+(artdag-test
+  "commutative op: input order ignored"
+  (equal?
+    (artdag/content-id (artdag/cnode "add" (list "i1" "i2") {}))
+    (artdag/content-id (artdag/cnode "add" (list "i2" "i1") {})))
+  true)
+
+(artdag-test
+  "non-commutative op: input order matters"
+  (equal?
+    (artdag/content-id (artdag/node "sub" (list "i1" "i2") {}))
+    (artdag/content-id (artdag/node "sub" (list "i2" "i1") {})))
+  false)
+
+; ---- build: success ----
+
+(artdag-test
+  "build ok for valid dag"
+  (get
+    (artdag/build
+      (list
+        (list "a" "load" (list) {})
+        (list "b" "load" (list) {:s 1})
+        (list "c" "add" (list "a" "b") {})))
+    :ok)
+  true)
+
+(artdag-test
+  "node-count counts distinct nodes"
+  (artdag/node-count
+    (artdag/build
+      (list
+        (list "a" "load" (list) {})
+        (list "b" "load" (list) {:s 1})
+        (list "c" "add" (list "a" "b") {}))))
+  3)
+
+; ---- subgraph sharing ----
+
+(artdag-test
+  "identical leaves dedup to one node"
+  (artdag/node-count
+    (artdag/build
+      (list
+        (list "a" "load" (list) {:s 1})
+        (list "b" "load" (list) {:s 1})
+        (list "c" "add" (list "a" "b") {}))))
+  2)
+
+(artdag-test
+  "duplicate names map to same id"
+  (let
+    ((d (artdag/build (list (list "a" "load" (list) {:s 1}) (list "b" "load" (list) {:s 1})))))
+    (equal? (artdag/dag-id d "a") (artdag/dag-id d "b")))
+  true)
+
+(artdag-test
+  "identical subgraph shares id across dags"
+  (let
+    ((d1 (artdag/build (list (list "x" "load" (list) {:s 7}) (list "y" "neg" (list "x") {}))))
+      (d2
+        (artdag/build
+          (list
+            (list "p" "load" (list) {:s 7})
+            (list "q" "neg" (list "p") {})))))
+    (equal? (artdag/dag-id d1 "y") (artdag/dag-id d2 "q")))
+  true)
+
+; ---- validation ----
+
+(artdag-test
+  "cycle rejected"
+  (get
+    (artdag/build
+      (list
+        (list "a" "f" (list "b") {})
+        (list "b" "g" (list "a") {})))
+    :error)
+  "cycle")
+
+(artdag-test
+  "self-cycle rejected"
+  (get (artdag/build (list (list "a" "f" (list "a") {}))) :error)
+  "cycle")
+
+(artdag-test
+  "dangling input rejected"
+  (get
+    (artdag/build (list (list "a" "f" (list "ghost") {})))
+    :error)
+  "dangling")
+
+(artdag-test
+  "dangling refs reported"
+  (get
+    (artdag/build (list (list "a" "f" (list "ghost") {})))
+    :refs)
+  (list "ghost"))
+
+; ---- topological order ----
+
+(artdag-test
+  "topo order: deps before dependents"
+  (let
+    ((d (artdag/build (list (list "c" "add" (list "a" "b") {}) (list "a" "load" (list) {:s 1}) (list "b" "load" (list) {:s 2})))))
+    (artdag/dag-order d))
+  (let
+    ((d (artdag/build (list (list "c" "add" (list "a" "b") {}) (list "a" "load" (list) {:s 1}) (list "b" "load" (list) {:s 2})))))
+    (list (artdag/dag-id d "a") (artdag/dag-id d "b") (artdag/dag-id d "c"))))
+
+(artdag-test
+  "topo order: deep chain"
+  (let
+    ((d (artdag/build (list (list "d" "f" (list "c") {}) (list "c" "f" (list "b") {}) (list "b" "f" (list "a") {}) (list "a" "load" (list) {})))))
+    (artdag/dag-order d))
+  (let
+    ((d (artdag/build (list (list "d" "f" (list "c") {}) (list "c" "f" (list "b") {}) (list "b" "f" (list "a") {}) (list "a" "load" (list) {})))))
+    (list
+      (artdag/dag-id d "a")
+      (artdag/dag-id d "b")
+      (artdag/dag-id d "c")
+      (artdag/dag-id d "d"))))
+
+; ---- accessors ----
+
+(artdag-test
+  "dag-node-by-name returns node spec"
+  (artdag/node-op
+    (artdag/dag-node-by-name
+      (artdag/build (list (list "a" "load" (list) {})))
+      "a"))
+  "load")
+
+(artdag-test
+  "resolved inputs are content-ids"
+  (let
+    ((d (artdag/build (list (list "a" "load" (list) {}) (list "b" "neg" (list "a") {})))))
+    (artdag/node-inputs (artdag/dag-node-by-name d "b")))
+  (let
+    ((d (artdag/build (list (list "a" "load" (list) {}) (list "b" "neg" (list "a") {})))))
+    (list (artdag/dag-id d "a"))))
diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index 6fe7a2ce..bf5aed91 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -30,7 +30,7 @@ edges.
 
 ## Status (rolling)
 
-`bash lib/artdag/conformance.sh` → **0/0** (not yet started)
+`bash lib/artdag/conformance.sh` → **20/20** (1 suite: dag)
 
 ## Ground rules
 
@@ -78,13 +78,13 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Phase 1 — DAG model + content addressing
 
-- [ ] `lib/artdag/dag.sx` — node `{:op :inputs :params}`; structural content-id =
+- [x] `lib/artdag/dag.sx` — node `{:op :inputs :params}`; structural content-id =
   digest of `(op, sorted input-ids, params)`; build/validate a DAG (no dangling
   inputs, no accidental cycles); topological order
-- [ ] identical-subgraph sharing: two structurally-equal nodes get the same id
-- [ ] `lib/artdag/tests/dag.sx` — id determinism, subgraph sharing, cycle/dangling
+- [x] identical-subgraph sharing: two structurally-equal nodes get the same id
+- [x] `lib/artdag/tests/dag.sx` — id determinism, subgraph sharing, cycle/dangling
   rejection, topo order
-- [ ] `lib/artdag/conformance.sh` + scoreboard
+- [x] `lib/artdag/conformance.sh` + scoreboard
 
 ## Phase 2 — Analyze (Datalog)
 
@@ -136,8 +136,19 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
-(loop fills this in)
+- **Phase 1 — DAG model + content addressing** (dag suite 20/20). `lib/artdag/dag.sx`:
+  node `{:op :inputs :params :commutative}`; `artdag/content-id` = `"node:"` + a
+  deterministic canonical serialization of `(op, inputs, params)` with dict keys
+  sorted (param order-insensitive) and commutative ops' inputs sorted (input
+  order-insensitive); non-commutative inputs ordered. `artdag/build` takes named
+  entries `(name op (input-names) params [commutative?])`, validates (dangling refs,
+  cycles via fixpoint topo), resolves input-names→content-ids, dedups identical
+  subgraphs to one node + one id (shared across DAGs), returns `{:ok :nodes :names
+  :order}`. No host `sort`/`string<?` — hand-rolled `artdag/str<?` over char-codes.
+  Gotcha logged: SX `equal?` is representation-sensitive (cons-built vs vector lists
+  compare unequal even when identical); `=` is true structural equality — conformance
+  harness compares with `=`. `lib/artdag/conformance.sh` + scoreboard.
 
 ## Blockers
 
-(loop fills this in)
+(none)

From b9afe671ae539e480e2c6b80fb00dfb07e973274 Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 11:53:29 +0000
Subject: [PATCH 02/13] artdag: Phase 2 Analyze on Datalog + 16 tests

analyze.sx projects DAG edges to (edge in out) facts and runs recursive
reachable rules for deps-of/dependents-of/reachable-from/ancestors-of, plus
dirty-closure (dirty(Y):-edge(X,Y),dirty(X)) for incremental recompute. Keystone:
changing a mid node dirties only it + downstream. analyze 16/16, total 36/36.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/analyze.sx       |  88 ++++++++++++++++++++++++++
 lib/artdag/conformance.sh   |  12 +++-
 lib/artdag/scoreboard.json  |   7 ++-
 lib/artdag/scoreboard.md    |   3 +-
 lib/artdag/tests/analyze.sx | 119 ++++++++++++++++++++++++++++++++++++
 plans/artdag-on-sx.md       |  19 ++++--
 6 files changed, 239 insertions(+), 9 deletions(-)
 create mode 100644 lib/artdag/analyze.sx
 create mode 100644 lib/artdag/tests/analyze.sx

diff --git a/lib/artdag/analyze.sx b/lib/artdag/analyze.sx
new file mode 100644
index 00000000..03ac4a12
--- /dev/null
+++ b/lib/artdag/analyze.sx
@@ -0,0 +1,88 @@
+; lib/artdag/analyze.sx — Phase 2: Analyze on Datalog.
+; Project the DAG's edges into a Datalog db and answer dependency questions
+; (deps, dependents, transitive reachability) plus dirty-closure propagation
+; as recursive Datalog — the acl/relations reachability shape. Depends on
+; lib/artdag/dag.sx and the lib/datalog/ public API.
+
+; edge(input-id, node-id): data flows input -> node (input is a dependency).
+(define
+  artdag/edge-facts
+  (fn
+    (dag)
+    (reduce
+      (fn
+        (acc id)
+        (concat
+          acc
+          (map
+            (fn (in) (list (quote edge) in id))
+            (artdag/node-inputs (artdag/dag-get dag id)))))
+      (list)
+      (keys (artdag/dag-nodes dag)))))
+
+; reachable(X,Y): Y is a transitive dependent of X (forward, downstream).
+(define
+  artdag/reach-rules
+  (quote
+    ((reachable X Y <- (edge X Y))
+      (reachable X Z <- (edge X Y) (reachable Y Z)))))
+
+(define
+  artdag/analyze
+  (fn (dag) (dl-program-data (artdag/edge-facts dag) artdag/reach-rules)))
+
+; pull a single variable's bindings out of a subst list, sorted for determinism.
+(define
+  artdag/-bindings
+  (fn
+    (substs var)
+    (artdag/sort-strings (map (fn (s) (get s var)) substs))))
+
+; direct dependencies (inputs) of a node.
+(define
+  artdag/deps-of
+  (fn
+    (db id)
+    (artdag/-bindings (dl-query db (list (quote edge) (quote X) id)) :X)))
+
+; direct dependents of a node.
+(define
+  artdag/dependents-of
+  (fn
+    (db id)
+    (artdag/-bindings (dl-query db (list (quote edge) id (quote Y))) :Y)))
+
+; transitive dependents (everything downstream of a node).
+(define
+  artdag/reachable-from
+  (fn
+    (db id)
+    (artdag/-bindings
+      (dl-query db (list (quote reachable) id (quote Y)))
+      :Y)))
+
+; transitive dependencies (everything upstream of a node).
+(define
+  artdag/ancestors-of
+  (fn
+    (db id)
+    (artdag/-bindings
+      (dl-query db (list (quote reachable) (quote X) id))
+      :X)))
+
+; dirty propagation: dirty(Y) :- edge(X,Y), dirty(X). Seeds are changed nodes.
+(define artdag/dirty-rules (quote ((dirty Y <- (edge X Y) (dirty X)))))
+
+(define
+  artdag/dirty-seeds
+  (fn (changed) (map (fn (c) (list (quote dirty) c)) changed)))
+
+; transitive dirty closure of a set of changed node-ids: the changed nodes plus
+; every transitive dependent that must recompute. Sorted, deduplicated.
+(define
+  artdag/dirty-closure
+  (fn
+    (dag changed)
+    (let
+      ((db (dl-program-data (concat (artdag/edge-facts dag) (artdag/dirty-seeds changed)) artdag/dirty-rules)))
+      (artdag/-bindings (dl-query db (list (quote dirty) (quote X))) :X))))
diff --git a/lib/artdag/conformance.sh b/lib/artdag/conformance.sh
index 5424ae49..63c902ec 100755
--- a/lib/artdag/conformance.sh
+++ b/lib/artdag/conformance.sh
@@ -13,7 +13,7 @@ if [ ! -x "$SX_SERVER" ]; then
   exit 1
 fi
 
-SUITES=(dag)
+SUITES=(dag analyze)
 
 OUT_JSON="lib/artdag/scoreboard.json"
 OUT_MD="lib/artdag/scoreboard.md"
@@ -27,7 +27,17 @@ run_suite() {
 (epoch 1)
 (load "spec/stdlib.sx")
 (load "lib/r7rs.sx")
+(load "lib/datalog/tokenizer.sx")
+(load "lib/datalog/parser.sx")
+(load "lib/datalog/unify.sx")
+(load "lib/datalog/db.sx")
+(load "lib/datalog/builtins.sx")
+(load "lib/datalog/aggregates.sx")
+(load "lib/datalog/strata.sx")
+(load "lib/datalog/eval.sx")
+(load "lib/datalog/api.sx")
 (load "lib/artdag/dag.sx")
+(load "lib/artdag/analyze.sx")
 (epoch 2)
 (eval "(define artdag-test-pass 0)")
 (eval "(define artdag-test-fail 0)")
diff --git a/lib/artdag/scoreboard.json b/lib/artdag/scoreboard.json
index 1ca0b565..46d9d6e8 100644
--- a/lib/artdag/scoreboard.json
+++ b/lib/artdag/scoreboard.json
@@ -1,8 +1,9 @@
 {
   "suites": {
-    "dag": {"pass": 20, "fail": 0}
+    "dag": {"pass": 20, "fail": 0},
+    "analyze": {"pass": 16, "fail": 0}
   },
-  "total_pass": 20,
+  "total_pass": 36,
   "total_fail": 0,
-  "total": 20
+  "total": 36
 }
diff --git a/lib/artdag/scoreboard.md b/lib/artdag/scoreboard.md
index 34e8136d..43f3868d 100644
--- a/lib/artdag/scoreboard.md
+++ b/lib/artdag/scoreboard.md
@@ -5,4 +5,5 @@ _Generated by `lib/artdag/conformance.sh`_
 | Suite | Pass | Fail | Total |
 |-------|-----:|-----:|------:|
 | dag | 20 | 0 | 20 |
-| **Total** | **20** | **0** | **20** |
+| analyze | 16 | 0 | 16 |
+| **Total** | **36** | **0** | **36** |
diff --git a/lib/artdag/tests/analyze.sx b/lib/artdag/tests/analyze.sx
new file mode 100644
index 00000000..fc84f045
--- /dev/null
+++ b/lib/artdag/tests/analyze.sx
@@ -0,0 +1,119 @@
+; Phase 2 — Analyze on Datalog: deps/dependents/reachability + dirty closure.
+
+; diamond:  a -> b, a -> c, (b,c) -> d
+(define
+  an-D
+  (artdag/build
+    (list
+      (list "a" "load" (list) {})
+      (list "b" "f" (list "a") {})
+      (list "c" "g" (list "a") {})
+      (list "d" "add" (list "b" "c") {} true))))
+(define an-db (artdag/analyze an-D))
+(define an-a (artdag/dag-id an-D "a"))
+(define an-b (artdag/dag-id an-D "b"))
+(define an-c (artdag/dag-id an-D "c"))
+(define an-d (artdag/dag-id an-D "d"))
+
+; ---- direct deps / dependents ----
+
+(artdag-test
+  "deps-of: direct inputs"
+  (artdag/deps-of an-db an-d)
+  (artdag/sort-strings (list an-b an-c)))
+
+(artdag-test "deps-of: leaf has none" (artdag/deps-of an-db an-a) (list))
+
+(artdag-test
+  "dependents-of: direct consumers"
+  (artdag/dependents-of an-db an-a)
+  (artdag/sort-strings (list an-b an-c)))
+
+(artdag-test
+  "dependents-of: output has none"
+  (artdag/dependents-of an-db an-d)
+  (list))
+
+; ---- transitive reachability ----
+
+(artdag-test
+  "reachable-from: all downstream"
+  (artdag/reachable-from an-db an-a)
+  (artdag/sort-strings (list an-b an-c an-d)))
+
+(artdag-test
+  "reachable-from: mid node reaches output"
+  (artdag/reachable-from an-db an-b)
+  (list an-d))
+
+(artdag-test
+  "ancestors-of: all upstream"
+  (artdag/ancestors-of an-db an-d)
+  (artdag/sort-strings (list an-a an-b an-c)))
+
+(artdag-test
+  "ancestors-of: leaf has none"
+  (artdag/ancestors-of an-db an-a)
+  (list))
+
+; ---- deep chain ----
+
+(define
+  ch-D
+  (artdag/build
+    (list
+      (list "a" "load" (list) {})
+      (list "b" "f" (list "a") {})
+      (list "c" "f" (list "b") {})
+      (list "d" "f" (list "c") {}))))
+(define ch-db (artdag/analyze ch-D))
+
+(artdag-test
+  "deep chain: reachable-from leaf"
+  (artdag/reachable-from ch-db (artdag/dag-id ch-D "a"))
+  (artdag/sort-strings
+    (list
+      (artdag/dag-id ch-D "b")
+      (artdag/dag-id ch-D "c")
+      (artdag/dag-id ch-D "d"))))
+
+(artdag-test
+  "deep chain: ancestors of tip"
+  (artdag/ancestors-of ch-db (artdag/dag-id ch-D "d"))
+  (artdag/sort-strings
+    (list
+      (artdag/dag-id ch-D "a")
+      (artdag/dag-id ch-D "b")
+      (artdag/dag-id ch-D "c"))))
+
+; ---- dirty closure ----
+
+(artdag-test
+  "dirty closure: change leaf dirties all"
+  (artdag/dirty-closure an-D (list an-a))
+  (artdag/sort-strings (list an-a an-b an-c an-d)))
+
+(artdag-test
+  "dirty closure: change mid touches only downstream"
+  (artdag/dirty-closure an-D (list an-b))
+  (artdag/sort-strings (list an-b an-d)))
+
+(artdag-test
+  "dirty closure: unaffected stay clean (count)"
+  (len (artdag/dirty-closure an-D (list an-b)))
+  2)
+
+(artdag-test
+  "dirty closure: change output dirties only itself"
+  (artdag/dirty-closure an-D (list an-d))
+  (list an-d))
+
+(artdag-test
+  "dirty closure: multiple seeds union"
+  (artdag/dirty-closure an-D (list an-b an-c))
+  (artdag/sort-strings (list an-b an-c an-d)))
+
+(artdag-test
+  "dirty closure: empty seed set"
+  (artdag/dirty-closure an-D (list))
+  (list))
diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index bf5aed91..0ce869c1 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -30,7 +30,7 @@ edges.
 
 ## Status (rolling)
 
-`bash lib/artdag/conformance.sh` → **20/20** (1 suite: dag)
+`bash lib/artdag/conformance.sh` → **36/36** (2 suites: dag, analyze)
 
 ## Ground rules
 
@@ -88,11 +88,11 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Phase 2 — Analyze (Datalog)
 
-- [ ] `lib/artdag/analyze.sx` — project edges to Datalog; `deps-of`, `dependents-of`,
+- [x] `lib/artdag/analyze.sx` — project edges to Datalog; `deps-of`, `dependents-of`,
   transitive `reachable` (the recursive-reachability shape)
-- [ ] **dirty propagation:** given a set of changed nodes, compute the transitive
+- [x] **dirty propagation:** given a set of changed nodes, compute the transitive
   set of dependents that must recompute (`dirty-closure`)
-- [ ] `lib/artdag/tests/analyze.sx` — deep chains, diamonds, dirty closure
+- [x] `lib/artdag/tests/analyze.sx` — deep chains, diamonds, dirty closure
   correctness, unaffected nodes stay clean
 
 ## Phase 3 — Plan
@@ -136,6 +136,17 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
+- **Phase 2 — Analyze on Datalog** (analyze suite 16/16, total 36/36).
+  `lib/artdag/analyze.sx`: `artdag/edge-facts` projects each `(input-id, node-id)`
+  pair to an `(edge ...)` fact; `artdag/analyze` builds a `dl-program-data` db with
+  recursive `reachable(X,Y) :- edge(X,Y); edge(X,Y),reachable(Y,Z)` (the acl/relations
+  reachability shape). Query helpers `deps-of`/`dependents-of` (direct),
+  `reachable-from` (transitive downstream), `ancestors-of` (transitive upstream), all
+  returning sorted id lists. `dirty-closure` builds a db with `dirty(Y) :- edge(X,Y),
+  dirty(X)` seeded by changed-node facts and returns the transitive forward closure —
+  keystone test confirms changing a mid node dirties only it + downstream, leaving
+  siblings/upstream clean. Content-ids work as opaque Datalog string constants.
+
 - **Phase 1 — DAG model + content addressing** (dag suite 20/20). `lib/artdag/dag.sx`:
   node `{:op :inputs :params :commutative}`; `artdag/content-id` = `"node:"` + a
   deterministic canonical serialization of `(op, inputs, params)` with dict keys

From 9a0f3d872cac33aed62fcc1541a6ad8210f312cb Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 11:56:13 +0000
Subject: [PATCH 03/13] =?UTF-8?q?artdag:=20Phase=203=20Plan=20=E2=80=94=20?=
 =?UTF-8?q?topological=20batches=20+=20parallelism=20cap=20+=20dirty=20pla?=
 =?UTF-8?q?n=20+=2018=20tests?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

plan.sx schedules a dag into Kahn-wave batches (parallel-safe), splits waves
wider than a cap into sub-batches, and plans incrementally over the dirty
closure only (out-of-set deps treated as satisfied cache hits). plan 18/18,
total 54/54.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/conformance.sh  |   3 +-
 lib/artdag/plan.sx         | 100 ++++++++++++++++++++++++++++++
 lib/artdag/scoreboard.json |   7 ++-
 lib/artdag/scoreboard.md   |   3 +-
 lib/artdag/tests/plan.sx   | 122 +++++++++++++++++++++++++++++++++++++
 plans/artdag-on-sx.md      |  17 ++++--
 6 files changed, 243 insertions(+), 9 deletions(-)
 create mode 100644 lib/artdag/plan.sx
 create mode 100644 lib/artdag/tests/plan.sx

diff --git a/lib/artdag/conformance.sh b/lib/artdag/conformance.sh
index 63c902ec..cb59c336 100755
--- a/lib/artdag/conformance.sh
+++ b/lib/artdag/conformance.sh
@@ -13,7 +13,7 @@ if [ ! -x "$SX_SERVER" ]; then
   exit 1
 fi
 
-SUITES=(dag analyze)
+SUITES=(dag analyze plan)
 
 OUT_JSON="lib/artdag/scoreboard.json"
 OUT_MD="lib/artdag/scoreboard.md"
@@ -38,6 +38,7 @@ run_suite() {
 (load "lib/datalog/api.sx")
 (load "lib/artdag/dag.sx")
 (load "lib/artdag/analyze.sx")
+(load "lib/artdag/plan.sx")
 (epoch 2)
 (eval "(define artdag-test-pass 0)")
 (eval "(define artdag-test-fail 0)")
diff --git a/lib/artdag/plan.sx b/lib/artdag/plan.sx
new file mode 100644
index 00000000..c0dde7a8
--- /dev/null
+++ b/lib/artdag/plan.sx
@@ -0,0 +1,100 @@
+; lib/artdag/plan.sx — Phase 3: schedule a DAG (or its dirty subset) into
+; topological batches under a max-parallelism cap. A batch is a set of nodes
+; whose deps are all satisfied by earlier batches, so they run in parallel.
+; cap <= 0 means unlimited width. Depends on dag.sx and analyze.sx.
+
+; inputs of id that also lie inside the scheduled set (out-of-set deps are
+; treated as already satisfied — e.g. clean cache hits in an incremental plan).
+(define
+  artdag/-deps-in
+  (fn
+    (dag id sset)
+    (filter
+      (fn (in) (artdag/member? in sset))
+      (artdag/node-inputs (artdag/dag-get dag id)))))
+
+(define
+  artdag/-ready-in
+  (fn
+    (dag sset placed)
+    (filter
+      (fn
+        (id)
+        (and
+          (not (artdag/member? id placed))
+          (artdag/all-in? (artdag/-deps-in dag id sset) placed)))
+      (artdag/sort-strings sset))))
+
+(define
+  artdag/-batch-loop
+  (fn
+    (dag sset placed batches)
+    (if
+      (= (len placed) (len sset))
+      batches
+      (let
+        ((wave (artdag/-ready-in dag sset placed)))
+        (artdag/-batch-loop
+          dag
+          sset
+          (concat placed wave)
+          (concat batches (list wave)))))))
+
+; split a wave into consecutive chunks of at most n (sorted order preserved).
+(define
+  artdag/-chunk
+  (fn
+    (xs n)
+    (if
+      (<= (len xs) n)
+      (list xs)
+      (cons
+        (slice xs 0 n)
+        (artdag/-chunk (slice xs n (len xs)) n)))))
+
+(define
+  artdag/-cap-split
+  (fn
+    (batches cap)
+    (if
+      (<= cap 0)
+      batches
+      (reduce
+        (fn (acc b) (concat acc (artdag/-chunk b cap)))
+        (list)
+        batches))))
+
+; schedule an explicit set of node-ids into capped topological batches.
+(define
+  artdag/plan-subset
+  (fn
+    (dag node-ids cap)
+    (artdag/-cap-split (artdag/-batch-loop dag node-ids (list) (list)) cap)))
+
+; full plan over every node in the dag.
+(define
+  artdag/plan
+  (fn (dag cap) (artdag/plan-subset dag (keys (artdag/dag-nodes dag)) cap)))
+
+; incremental plan: schedule only the dirty closure of the changed nodes.
+(define
+  artdag/plan-dirty
+  (fn
+    (dag changed cap)
+    (artdag/plan-subset dag (artdag/dirty-closure dag changed) cap)))
+
+; ---- plan inspection ----
+
+(define artdag/plan-batches (fn (plan) (len plan)))
+
+(define
+  artdag/plan-width
+  (fn
+    (plan)
+    (reduce (fn (m b) (if (> (len b) m) (len b) m)) 0 plan)))
+
+(define
+  artdag/plan-flatten
+  (fn (plan) (reduce (fn (acc b) (concat acc b)) (list) plan)))
+
+(define artdag/plan-size (fn (plan) (len (artdag/plan-flatten plan))))
diff --git a/lib/artdag/scoreboard.json b/lib/artdag/scoreboard.json
index 46d9d6e8..cb0b8677 100644
--- a/lib/artdag/scoreboard.json
+++ b/lib/artdag/scoreboard.json
@@ -1,9 +1,10 @@
 {
   "suites": {
     "dag": {"pass": 20, "fail": 0},
-    "analyze": {"pass": 16, "fail": 0}
+    "analyze": {"pass": 16, "fail": 0},
+    "plan": {"pass": 18, "fail": 0}
   },
-  "total_pass": 36,
+  "total_pass": 54,
   "total_fail": 0,
-  "total": 36
+  "total": 54
 }
diff --git a/lib/artdag/scoreboard.md b/lib/artdag/scoreboard.md
index 43f3868d..30ab2fc4 100644
--- a/lib/artdag/scoreboard.md
+++ b/lib/artdag/scoreboard.md
@@ -6,4 +6,5 @@ _Generated by `lib/artdag/conformance.sh`_
 |-------|-----:|-----:|------:|
 | dag | 20 | 0 | 20 |
 | analyze | 16 | 0 | 16 |
-| **Total** | **36** | **0** | **36** |
+| plan | 18 | 0 | 18 |
+| **Total** | **54** | **0** | **54** |
diff --git a/lib/artdag/tests/plan.sx b/lib/artdag/tests/plan.sx
new file mode 100644
index 00000000..100155c6
--- /dev/null
+++ b/lib/artdag/tests/plan.sx
@@ -0,0 +1,122 @@
+; Phase 3 — Plan: topological batches under a parallelism cap, incremental plan.
+
+; diamond:  a -> b, a -> c, (b,c) -> d
+(define
+  pl-D
+  (artdag/build
+    (list
+      (list "a" "load" (list) {})
+      (list "b" "f" (list "a") {})
+      (list "c" "g" (list "a") {})
+      (list "d" "add" (list "b" "c") {} true))))
+(define pl-a (artdag/dag-id pl-D "a"))
+(define pl-b (artdag/dag-id pl-D "b"))
+(define pl-c (artdag/dag-id pl-D "c"))
+(define pl-d (artdag/dag-id pl-D "d"))
+
+; wide:  a -> b, c, e, f  (four independent dependents)
+(define
+  pl-W
+  (artdag/build
+    (list
+      (list "a" "load" (list) {})
+      (list "b" "f" (list "a") {})
+      (list "c" "g" (list "a") {})
+      (list "e" "h" (list "a") {})
+      (list "f" "k" (list "a") {}))))
+
+; ---- full plan, unlimited width ----
+
+(artdag-test
+  "full plan: batch count"
+  (artdag/plan-batches (artdag/plan pl-D 0))
+  3)
+
+(artdag-test
+  "full plan: schedules every node"
+  (artdag/plan-size (artdag/plan pl-D 0))
+  4)
+
+(artdag-test
+  "full plan: first batch is the leaf"
+  (first (artdag/plan pl-D 0))
+  (list pl-a))
+
+(artdag-test
+  "full plan: middle batch runs b,c in parallel"
+  (first (rest (artdag/plan pl-D 0)))
+  (artdag/sort-strings (list pl-b pl-c)))
+
+(artdag-test
+  "full plan: last batch is the sink"
+  (first (rest (rest (artdag/plan pl-D 0))))
+  (list pl-d))
+
+(artdag-test
+  "full plan: max width is 2"
+  (artdag/plan-width (artdag/plan pl-D 0))
+  2)
+
+; ---- parallelism cap ----
+
+(artdag-test
+  "cap 1: width never exceeds 1"
+  (artdag/plan-width (artdag/plan pl-D 1))
+  1)
+
+(artdag-test
+  "cap 1: serializes into one node per batch"
+  (artdag/plan-batches (artdag/plan pl-D 1))
+  4)
+
+(artdag-test
+  "cap larger than widest wave is a no-op"
+  (artdag/plan pl-D 10)
+  (artdag/plan pl-D 0))
+
+(artdag-test
+  "wide cap 2: width capped at 2"
+  (artdag/plan-width (artdag/plan pl-W 2))
+  2)
+
+(artdag-test
+  "wide cap 2: leaf wave then two capped sub-batches"
+  (artdag/plan-batches (artdag/plan pl-W 2))
+  3)
+
+(artdag-test
+  "wide cap 2: still schedules all five nodes"
+  (artdag/plan-size (artdag/plan pl-W 2))
+  5)
+
+(artdag-test
+  "wide unlimited: single wave of four after leaf"
+  (artdag/plan-width (artdag/plan pl-W 0))
+  4)
+
+; ---- incremental (dirty-only) plan ----
+
+(artdag-test
+  "dirty plan: schedules only the dirty closure"
+  (artdag/plan-size (artdag/plan-dirty pl-D (list pl-b) 0))
+  2)
+
+(artdag-test
+  "dirty plan: b then d"
+  (artdag/plan-dirty pl-D (list pl-b) 0)
+  (list (list pl-b) (list pl-d)))
+
+(artdag-test
+  "dirty plan: clean deps treated as satisfied"
+  (first (artdag/plan-dirty pl-D (list pl-b) 0))
+  (list pl-b))
+
+(artdag-test
+  "dirty plan: leaf change replans whole graph"
+  (artdag/plan-size (artdag/plan-dirty pl-D (list pl-a) 0))
+  4)
+
+(artdag-test
+  "dirty plan: sink change is a single batch"
+  (artdag/plan-dirty pl-D (list pl-d) 0)
+  (list (list pl-d)))
diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index 0ce869c1..4d8ab8e7 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -30,7 +30,7 @@ edges.
 
 ## Status (rolling)
 
-`bash lib/artdag/conformance.sh` → **36/36** (2 suites: dag, analyze)
+`bash lib/artdag/conformance.sh` → **54/54** (3 suites: dag, analyze, plan)
 
 ## Ground rules
 
@@ -97,10 +97,10 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Phase 3 — Plan
 
-- [ ] `lib/artdag/plan.sx` — schedule into topological **batches** (each batch's
+- [x] `lib/artdag/plan.sx` — schedule into topological **batches** (each batch's
   nodes have all deps satisfied → run in parallel); respect a max-parallelism limit
-- [ ] plan over the *dirty* subset only (incremental plan)
-- [ ] `lib/artdag/tests/plan.sx` — batch correctness, parallelism cap, dirty-only plan
+- [x] plan over the *dirty* subset only (incremental plan)
+- [x] `lib/artdag/tests/plan.sx` — batch correctness, parallelism cap, dirty-only plan
 - [ ] (optional/later) miniKanren constraint scheduling — flag, don't block on it
 
 ## Phase 4 — Execute (incremental + memoized)
@@ -136,6 +136,15 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
+- **Phase 3 — Plan** (plan suite 18/18, total 54/54). `lib/artdag/plan.sx`:
+  `artdag/plan` schedules a dag into Kahn-wave topological batches — each batch's
+  nodes have all in-scope deps satisfied by earlier batches, so they run in parallel.
+  A `cap` (>0) splits any wave wider than the cap into consecutive sub-batches;
+  `cap<=0` is unlimited. `artdag/plan-dirty` schedules only the dirty closure: deps
+  outside the scheduled set (clean cache hits) count as already satisfied, so a
+  mid-node change yields just `[[changed]…[downstream]]`. Inspection helpers
+  `plan-batches`/`plan-width`/`plan-size`/`plan-flatten`.
+
 - **Phase 2 — Analyze on Datalog** (analyze suite 16/16, total 36/36).
   `lib/artdag/analyze.sx`: `artdag/edge-facts` projects each `(input-id, node-id)`
   pair to an `(edge ...)` fact; `artdag/analyze` builds a `dl-program-data` db with

From a2f4fb5e894da8b0dcd9d385294d49c1edd3b809 Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 12:00:50 +0000
Subject: [PATCH 04/13] =?UTF-8?q?artdag:=20Phase=204=20Execute=20=E2=80=94?=
 =?UTF-8?q?=20content-addressed=20memo=20+=20incremental=20recompute=20+?=
 =?UTF-8?q?=2015=20tests?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

execute.sx folds a plan, runs each node via an injected runner (perform in
prod, op-table in tests), and memoizes results in a lib/persist kv backend
keyed by content-id. Incremental recompute falls out of content addressing:
a leaf change reassigns ids across its dirty closure, so re-running hits the
unchanged nodes and recomputes only the closure (cold 5 -> rerun 0 -> change 3).
Cross-dag subgraph sharing verified. execute 15/15, total 69/69.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/conformance.sh   |   8 +-
 lib/artdag/execute.sx       |  82 ++++++++++++++++
 lib/artdag/scoreboard.json  |   7 +-
 lib/artdag/scoreboard.md    |   3 +-
 lib/artdag/tests/execute.sx | 188 ++++++++++++++++++++++++++++++++++++
 plans/artdag-on-sx.md       |  22 ++++-
 6 files changed, 300 insertions(+), 10 deletions(-)
 create mode 100644 lib/artdag/execute.sx
 create mode 100644 lib/artdag/tests/execute.sx

diff --git a/lib/artdag/conformance.sh b/lib/artdag/conformance.sh
index cb59c336..0d439b5a 100755
--- a/lib/artdag/conformance.sh
+++ b/lib/artdag/conformance.sh
@@ -13,7 +13,7 @@ if [ ! -x "$SX_SERVER" ]; then
   exit 1
 fi
 
-SUITES=(dag analyze plan)
+SUITES=(dag analyze plan execute)
 
 OUT_JSON="lib/artdag/scoreboard.json"
 OUT_MD="lib/artdag/scoreboard.md"
@@ -36,9 +36,15 @@ run_suite() {
 (load "lib/datalog/strata.sx")
 (load "lib/datalog/eval.sx")
 (load "lib/datalog/api.sx")
+(load "lib/persist/event.sx")
+(load "lib/persist/backend.sx")
+(load "lib/persist/log.sx")
+(load "lib/persist/kv.sx")
+(load "lib/persist/api.sx")
 (load "lib/artdag/dag.sx")
 (load "lib/artdag/analyze.sx")
 (load "lib/artdag/plan.sx")
+(load "lib/artdag/execute.sx")
 (epoch 2)
 (eval "(define artdag-test-pass 0)")
 (eval "(define artdag-test-fail 0)")
diff --git a/lib/artdag/execute.sx b/lib/artdag/execute.sx
new file mode 100644
index 00000000..d0bc1d18
--- /dev/null
+++ b/lib/artdag/execute.sx
@@ -0,0 +1,82 @@
+; lib/artdag/execute.sx — Phase 4: interpret a plan with a content-addressed
+; memo cache. A node's result is keyed by its content-id, so a node whose id is
+; already in the cache is skipped (cache hit). Because changing a leaf changes
+; the content-ids of its whole dirty closure, re-running recomputes exactly those
+; nodes and cache-hits the rest — incremental recompute falls out of content
+; addressing. Depends on dag.sx and plan.sx; the cache is a lib/persist/ backend.
+
+; runner: (fn (op params input-results) -> result). The injected effect interface.
+; In production this performs the op (perform -> JAX/IPFS adapter); in tests it
+; dispatches a pure SX op over its already-computed input results.
+
+; build a runner from a dict of op-name -> (fn (params inputs) -> result).
+(define
+  artdag/op-table-runner
+  (fn (table) (fn (op params inputs) ((get table op) params inputs))))
+
+; resolve an input id's result: this run's results first, then the warm cache.
+(define
+  artdag/-input-result
+  (fn
+    (results cache in)
+    (if (has-key? results in) (get results in) (persist/kv-get cache in))))
+
+(define
+  artdag/-exec-node
+  (fn
+    (dag runner cache acc id)
+    (let
+      ((node (artdag/dag-get dag id)))
+      (if
+        (persist/kv-has? cache id)
+        (assoc
+          acc
+          :results (assoc (get acc :results) id (persist/kv-get cache id))
+          :hits (concat (get acc :hits) (list id)))
+        (let
+          ((inputs (map (fn (in) (artdag/-input-result (get acc :results) cache in)) (artdag/node-inputs node))))
+          (let
+            ((result (runner (artdag/node-op node) (artdag/node-params node) inputs)))
+            (begin
+              (persist/kv-put cache id result)
+              (assoc
+                acc
+                :results (assoc (get acc :results) id result)
+                :recomputed (concat (get acc :recomputed) (list id))))))))))
+
+; execute a plan against a memo cache, returning {:results :recomputed :hits}.
+(define
+  artdag/execute
+  (fn
+    (dag plan runner cache)
+    (reduce
+      (fn (acc id) (artdag/-exec-node dag runner cache acc id))
+      {:recomputed (list) :results {} :hits (list)}
+      (artdag/plan-flatten plan))))
+
+; full run over every node, unlimited width.
+(define
+  artdag/run
+  (fn
+    (dag runner cache)
+    (artdag/execute dag (artdag/plan dag 0) runner cache)))
+
+; incremental run: schedule only the dirty closure of the changed nodes.
+(define
+  artdag/run-dirty
+  (fn
+    (dag changed runner cache)
+    (artdag/execute
+      dag
+      (artdag/plan-dirty dag changed 0)
+      runner
+      cache)))
+
+; ---- result inspection ----
+
+(define artdag/result-of (fn (exec id) (get (get exec :results) id)))
+(define
+  artdag/recomputed
+  (fn (exec) (artdag/sort-strings (get exec :recomputed))))
+(define artdag/recompute-count (fn (exec) (len (get exec :recomputed))))
+(define artdag/hit-count (fn (exec) (len (get exec :hits))))
diff --git a/lib/artdag/scoreboard.json b/lib/artdag/scoreboard.json
index cb0b8677..d6412a3e 100644
--- a/lib/artdag/scoreboard.json
+++ b/lib/artdag/scoreboard.json
@@ -2,9 +2,10 @@
   "suites": {
     "dag": {"pass": 20, "fail": 0},
     "analyze": {"pass": 16, "fail": 0},
-    "plan": {"pass": 18, "fail": 0}
+    "plan": {"pass": 18, "fail": 0},
+    "execute": {"pass": 15, "fail": 0}
   },
-  "total_pass": 54,
+  "total_pass": 69,
   "total_fail": 0,
-  "total": 54
+  "total": 69
 }
diff --git a/lib/artdag/scoreboard.md b/lib/artdag/scoreboard.md
index 30ab2fc4..4a901cc4 100644
--- a/lib/artdag/scoreboard.md
+++ b/lib/artdag/scoreboard.md
@@ -7,4 +7,5 @@ _Generated by `lib/artdag/conformance.sh`_
 | dag | 20 | 0 | 20 |
 | analyze | 16 | 0 | 16 |
 | plan | 18 | 0 | 18 |
-| **Total** | **54** | **0** | **54** |
+| execute | 15 | 0 | 15 |
+| **Total** | **69** | **0** | **69** |
diff --git a/lib/artdag/tests/execute.sx b/lib/artdag/tests/execute.sx
new file mode 100644
index 00000000..bc36b8d1
--- /dev/null
+++ b/lib/artdag/tests/execute.sx
@@ -0,0 +1,188 @@
+; Phase 4 — Execute: effect interpreter + content-addressed memo + incremental.
+
+(define ex-RT (artdag/op-table-runner {:in (fn (params inputs) (get params :v)) :add (fn (params inputs) (+ (nth inputs 0) (nth inputs 1))) :inc (fn (params inputs) (+ 1 (first inputs)))}))
+
+; two-leaf diamond: p,q leaves; b=inc(p); c=inc(q); d=add(b,c)
+(define
+  ex-D1
+  (artdag/build
+    (list
+      (list "p" "in" (list) {:v 10})
+      (list "q" "in" (list) {:v 20})
+      (list "b" "inc" (list "p") {})
+      (list "c" "inc" (list "q") {})
+      (list "d" "add" (list "b" "c") {} true))))
+
+; same shape, leaf q changed (20 -> 21)
+(define
+  ex-D2
+  (artdag/build
+    (list
+      (list "p" "in" (list) {:v 10})
+      (list "q" "in" (list) {:v 21})
+      (list "b" "inc" (list "p") {})
+      (list "c" "inc" (list "q") {})
+      (list "d" "add" (list "b" "c") {} true))))
+
+; a different dag that shares the p->b subgraph with ex-D1, plus z=inc(b)
+(define
+  ex-D3
+  (artdag/build
+    (list
+      (list "p" "in" (list) {:v 10})
+      (list "b" "inc" (list "p") {})
+      (list "z" "inc" (list "b") {}))))
+
+; ---- full execution ----
+
+(artdag-test
+  "full run: result is correct"
+  (let
+    ((cache (persist/open)))
+    (artdag/result-of
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/dag-id ex-D1 "d")))
+  32)
+
+(artdag-test
+  "full run: cold cache recomputes every node"
+  (let
+    ((cache (persist/open)))
+    (artdag/recompute-count (artdag/run ex-D1 ex-RT cache)))
+  5)
+
+(artdag-test
+  "full run: cold cache has no hits"
+  (let
+    ((cache (persist/open)))
+    (artdag/hit-count (artdag/run ex-D1 ex-RT cache)))
+  0)
+
+; ---- memoization ----
+
+(artdag-test
+  "re-run unchanged: zero recomputes"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/recompute-count (artdag/run ex-D1 ex-RT cache))))
+  0)
+
+(artdag-test
+  "re-run unchanged: all cache hits"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/hit-count (artdag/run ex-D1 ex-RT cache))))
+  5)
+
+(artdag-test
+  "re-run unchanged: result preserved"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/result-of
+        (artdag/run ex-D1 ex-RT cache)
+        (artdag/dag-id ex-D1 "d"))))
+  32)
+
+; ---- incremental recompute (the keystone) ----
+
+(artdag-test
+  "leaf change recomputes only the dirty closure (count)"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/recompute-count (artdag/run ex-D2 ex-RT cache))))
+  3)
+
+(artdag-test
+  "leaf change: unchanged nodes are cache hits"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/hit-count (artdag/run ex-D2 ex-RT cache))))
+  2)
+
+(artdag-test
+  "leaf change: recomputed set is exactly q,c,d"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/recomputed (artdag/run ex-D2 ex-RT cache))))
+  (artdag/sort-strings
+    (list
+      (artdag/dag-id ex-D2 "q")
+      (artdag/dag-id ex-D2 "c")
+      (artdag/dag-id ex-D2 "d"))))
+
+(artdag-test
+  "leaf change: untouched sibling p is reused"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/member?
+        (artdag/dag-id ex-D2 "p")
+        (get (artdag/run ex-D2 ex-RT cache) :hits))))
+  true)
+
+(artdag-test
+  "leaf change: new result is correct"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/result-of
+        (artdag/run ex-D2 ex-RT cache)
+        (artdag/dag-id ex-D2 "d"))))
+  33)
+
+; ---- explicit dirty-only execution ----
+
+(artdag-test
+  "run-dirty: schedules only the changed closure"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/recompute-count
+        (artdag/run-dirty ex-D2 (list (artdag/dag-id ex-D2 "q")) ex-RT cache))))
+  3)
+
+; ---- cross-dag cache sharing (content addressing) ----
+
+(artdag-test
+  "shared subgraph hits cache across different dags"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/recompute-count (artdag/run ex-D3 ex-RT cache))))
+  1)
+
+(artdag-test
+  "shared subgraph: p and b reused across dags"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/hit-count (artdag/run ex-D3 ex-RT cache))))
+  2)
+
+(artdag-test
+  "shared subgraph: z still computes correctly"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run ex-D1 ex-RT cache)
+      (artdag/result-of
+        (artdag/run ex-D3 ex-RT cache)
+        (artdag/dag-id ex-D3 "z"))))
+  12)
diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index 4d8ab8e7..7421af6a 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -30,7 +30,7 @@ edges.
 
 ## Status (rolling)
 
-`bash lib/artdag/conformance.sh` → **54/54** (3 suites: dag, analyze, plan)
+`bash lib/artdag/conformance.sh` → **69/69** (4 suites: dag, analyze, plan, execute)
 
 ## Ground rules
 
@@ -105,13 +105,13 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Phase 4 — Execute (incremental + memoized)
 
-- [ ] `lib/artdag/execute.sx` — interpret a plan: each node op runs via `perform`
+- [x] `lib/artdag/execute.sx` — interpret a plan: each node op runs via `perform`
   (mocked op in tests); results keyed by content-id
-- [ ] **content-addressed memo cache** backed by `lib/persist/`: a node whose
+- [x] **content-addressed memo cache** backed by `lib/persist/`: a node whose
   content-id already has a stored result is skipped (cache hit)
-- [ ] **incremental execute:** re-running after a leaf change recomputes only the
+- [x] **incremental execute:** re-running after a leaf change recomputes only the
   dirty closure; everything else is a cache hit
-- [ ] `lib/artdag/tests/execute.sx` — full run, cache-hit on re-run, incremental
+- [x] `lib/artdag/tests/execute.sx` — full run, cache-hit on re-run, incremental
   recompute touches only dirty nodes (assert recompute count)
 
 ## Phase 5 — Effect-pipeline optimization
@@ -136,6 +136,18 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
+- **Phase 4 — Execute (incremental + memoized)** (execute suite 15/15, total 69/69).
+  `lib/artdag/execute.sx`: `artdag/execute` folds a plan, computing each node via an
+  injected `runner (op params input-results)` (production = `perform` to JAX/IPFS
+  adapter; tests = a pure op-table) and memoizing the result in a `lib/persist/` kv
+  backend keyed by **content-id**. A node whose content-id is already cached is a hit
+  (skipped). The keystone falls out of content addressing: changing a leaf changes the
+  ids of its whole dirty closure, so re-running the full plan against a warm cache
+  recomputes exactly those nodes and hits the rest — verified by recompute/hit counts
+  (5 cold → 0 on rerun → 3 after one leaf change, sibling reused). Cross-DAG sharing
+  verified: a different DAG containing a shared subgraph cache-hits it. `run`/`run-dirty`
+  helpers; `result-of`/`recompute-count`/`hit-count`/`recomputed` inspection.
+
 - **Phase 3 — Plan** (plan suite 18/18, total 54/54). `lib/artdag/plan.sx`:
   `artdag/plan` schedules a dag into Kahn-wave topological batches — each batch's
   nodes have all in-scope deps satisfied by earlier batches, so they run in parallel.

From 228861215de019bccde8a15c52e88710c687d1a7 Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 12:08:12 +0000
Subject: [PATCH 05/13] =?UTF-8?q?artdag:=20Phase=205=20optimization=20?=
 =?UTF-8?q?=E2=80=94=20DCE=20+=20CSE=20+=20adjacent-op=20fusion=20+=2018?=
 =?UTF-8?q?=20tests?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

optimize.sx adds three result-preserving passes: dce (keep outputs + ancestors,
preserve ids), cse (==build; structural sharing is free from content addressing),
and fuse (collapse 1-to-1 fusible unary chains into an artdag/pipeline node fed by
the chain head's input; leaves/fan-out/non-fusible ops never fuse). fusing-runner
replays pipeline stages, output-equivalent to the unfused dag. optimize 18/18,
total 87/87.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/conformance.sh    |   3 +-
 lib/artdag/optimize.sx       | 190 +++++++++++++++++++++++++++++++++++
 lib/artdag/scoreboard.json   |   7 +-
 lib/artdag/scoreboard.md     |   3 +-
 lib/artdag/tests/optimize.sx | 176 ++++++++++++++++++++++++++++++++
 plans/artdag-on-sx.md        |  21 +++-
 6 files changed, 391 insertions(+), 9 deletions(-)
 create mode 100644 lib/artdag/optimize.sx
 create mode 100644 lib/artdag/tests/optimize.sx

diff --git a/lib/artdag/conformance.sh b/lib/artdag/conformance.sh
index 0d439b5a..dcccfa4a 100755
--- a/lib/artdag/conformance.sh
+++ b/lib/artdag/conformance.sh
@@ -13,7 +13,7 @@ if [ ! -x "$SX_SERVER" ]; then
   exit 1
 fi
 
-SUITES=(dag analyze plan execute)
+SUITES=(dag analyze plan execute optimize)
 
 OUT_JSON="lib/artdag/scoreboard.json"
 OUT_MD="lib/artdag/scoreboard.md"
@@ -45,6 +45,7 @@ run_suite() {
 (load "lib/artdag/analyze.sx")
 (load "lib/artdag/plan.sx")
 (load "lib/artdag/execute.sx")
+(load "lib/artdag/optimize.sx")
 (epoch 2)
 (eval "(define artdag-test-pass 0)")
 (eval "(define artdag-test-fail 0)")
diff --git a/lib/artdag/optimize.sx b/lib/artdag/optimize.sx
new file mode 100644
index 00000000..022c4825
--- /dev/null
+++ b/lib/artdag/optimize.sx
@@ -0,0 +1,190 @@
+; lib/artdag/optimize.sx — Phase 5: result-preserving DAG rewrites.
+;   DCE    — drop nodes not reachable upstream from the requested outputs.
+;   CSE    — free from content addressing: structurally identical subexpressions
+;            already collapse to one node at build time (artdag/cse == build).
+;   Fusion — collapse a maximal 1-to-1 chain of fusible unary ops into a single
+;            "artdag/pipeline" node that replays the stages; output-equivalent.
+; Depends on dag.sx and analyze.sx.
+
+; ---- dict helper ----
+
+(define
+  artdag/-dict-filter
+  (fn
+    (d keep?)
+    (reduce
+      (fn (acc k) (if (keep? k (get d k)) (assoc acc k (get d k)) acc))
+      {}
+      (keys d))))
+
+(define
+  artdag/-union
+  (fn
+    (a b)
+    (reduce (fn (acc x) (if (artdag/member? x acc) acc (cons x acc))) a b)))
+
+; ---- dead-node elimination ----
+; keep only the outputs and their transitive dependencies; ids are preserved.
+(define
+  artdag/dce
+  (fn
+    (dag outputs)
+    (let
+      ((db (artdag/analyze dag)))
+      (let
+        ((live (reduce (fn (acc out) (artdag/-union (artdag/-union acc (list out)) (artdag/ancestors-of db out))) (list) outputs)))
+        {:names (artdag/-dict-filter (artdag/dag-names dag) (fn (k v) (artdag/member? v live))) :order (filter (fn (id) (artdag/member? id live)) (artdag/dag-order dag)) :ok true :nodes (artdag/-dict-filter (artdag/dag-nodes dag) (fn (k v) (artdag/member? k live)))}))))
+
+; ---- common-subexpression elimination ----
+; structural sharing is inherent to content addressing: build already maps
+; structurally identical specs to a single node/id.
+(define artdag/cse artdag/build)
+
+; ---- adjacent-op fusion (entry-level rewrite) ----
+
+(define artdag/pipeline-op "artdag/pipeline")
+
+(define
+  artdag/-name->entry
+  (fn
+    (entries)
+    (reduce
+      (fn (m e) (assoc m (artdag/entry-name e) e))
+      {}
+      entries)))
+
+; name -> list of dependent names
+(define
+  artdag/-deps-map
+  (fn
+    (entries)
+    (reduce
+      (fn
+        (m e)
+        (reduce
+          (fn
+            (mm i)
+            (assoc
+              mm
+              i
+              (cons
+                (artdag/entry-name e)
+                (if (has-key? mm i) (get mm i) (list)))))
+          m
+          (artdag/entry-inputs e)))
+      {}
+      entries)))
+
+(define artdag/-stage (fn (e) {:op (artdag/entry-op e) :params (artdag/entry-params e)}))
+
+; the single predecessor that `name` may absorb, or nil. Requires: name is a
+; fusible unary op; its one input is a locally-defined fusible node whose ONLY
+; dependent is name (so fusing cannot break sharing).
+(define
+  artdag/-absorbs
+  (fn
+    (n->e deps fusible? name)
+    (let
+      ((e (get n->e name)))
+      (let
+        ((ins (artdag/entry-inputs e)))
+        (if
+          (= (len ins) 1)
+          (let
+            ((x (first ins)))
+            (if
+              (and
+                (has-key? n->e x)
+                (fusible? (artdag/entry-op e))
+                (fusible? (artdag/entry-op (get n->e x)))
+                (= (get deps x) (list name)))
+              x
+              nil))
+          nil)))))
+
+(define
+  artdag/-absorbed-set
+  (fn
+    (n->e deps fusible? names)
+    (reduce
+      (fn
+        (acc y)
+        (let
+          ((p (artdag/-absorbs n->e deps fusible? y)))
+          (if (nil? p) acc (cons p acc))))
+      (list)
+      names)))
+
+; walk predecessors from a tail, building stages head->tail.
+(define
+  artdag/-fuse-chain
+  (fn
+    (n->e deps fusible? cur stages)
+    (let
+      ((p (artdag/-absorbs n->e deps fusible? cur)))
+      (if
+        (nil? p)
+        {:stages (cons (artdag/-stage (get n->e cur)) stages) :head cur}
+        (artdag/-fuse-chain
+          n->e
+          deps
+          fusible?
+          p
+          (cons (artdag/-stage (get n->e cur)) stages))))))
+
+(define
+  artdag/fuse-entries
+  (fn
+    (entries fusible?)
+    (let
+      ((n->e (artdag/-name->entry entries))
+        (deps (artdag/-deps-map entries))
+        (names (map artdag/entry-name entries)))
+      (let
+        ((absorbed (artdag/-absorbed-set n->e deps fusible? names)))
+        (map
+          (fn
+            (name)
+            (let
+              ((c (artdag/-fuse-chain n->e deps fusible? name (list))))
+              (if
+                (> (len (get c :stages)) 1)
+                (list
+                  name
+                  artdag/pipeline-op
+                  (artdag/entry-inputs (get n->e (get c :head)))
+                  {:stages (get c :stages)})
+                (get n->e name))))
+          (filter (fn (name) (not (artdag/member? name absorbed))) names))))))
+
+(define
+  artdag/fuse
+  (fn
+    (entries fusible?)
+    (artdag/build (artdag/fuse-entries entries fusible?))))
+
+; runner that replays a fused pipeline over its single input, delegating each
+; stage to a base runner; non-pipeline ops fall through unchanged.
+(define
+  artdag/pipeline-run
+  (fn
+    (base-runner)
+    (fn
+      (params inputs)
+      (reduce
+        (fn
+          (val stage)
+          (base-runner (get stage :op) (get stage :params) (list val)))
+        (first inputs)
+        (get params :stages)))))
+
+(define
+  artdag/fusing-runner
+  (fn
+    (base-runner)
+    (fn
+      (op params inputs)
+      (if
+        (= op artdag/pipeline-op)
+        ((artdag/pipeline-run base-runner) params inputs)
+        (base-runner op params inputs)))))
diff --git a/lib/artdag/scoreboard.json b/lib/artdag/scoreboard.json
index d6412a3e..7be1073f 100644
--- a/lib/artdag/scoreboard.json
+++ b/lib/artdag/scoreboard.json
@@ -3,9 +3,10 @@
     "dag": {"pass": 20, "fail": 0},
     "analyze": {"pass": 16, "fail": 0},
     "plan": {"pass": 18, "fail": 0},
-    "execute": {"pass": 15, "fail": 0}
+    "execute": {"pass": 15, "fail": 0},
+    "optimize": {"pass": 18, "fail": 0}
   },
-  "total_pass": 69,
+  "total_pass": 87,
   "total_fail": 0,
-  "total": 69
+  "total": 87
 }
diff --git a/lib/artdag/scoreboard.md b/lib/artdag/scoreboard.md
index 4a901cc4..14f8c5c8 100644
--- a/lib/artdag/scoreboard.md
+++ b/lib/artdag/scoreboard.md
@@ -8,4 +8,5 @@ _Generated by `lib/artdag/conformance.sh`_
 | analyze | 16 | 0 | 16 |
 | plan | 18 | 0 | 18 |
 | execute | 15 | 0 | 15 |
-| **Total** | **69** | **0** | **69** |
+| optimize | 18 | 0 | 18 |
+| **Total** | **87** | **0** | **87** |
diff --git a/lib/artdag/tests/optimize.sx b/lib/artdag/tests/optimize.sx
new file mode 100644
index 00000000..6e275ad0
--- /dev/null
+++ b/lib/artdag/tests/optimize.sx
@@ -0,0 +1,176 @@
+; Phase 5 — optimization: DCE, CSE (content-id sharing), adjacent-op fusion.
+
+(define opt-BASE (artdag/op-table-runner {:in (fn (params inputs) (get params :v)) :sq (fn (params inputs) (* (first inputs) (first inputs))) :add (fn (params inputs) (+ (nth inputs 0) (nth inputs 1))) :inc (fn (params inputs) (+ 1 (first inputs)))}))
+(define opt-RUN (artdag/fusing-runner opt-BASE))
+(define opt-inc? (fn (op) (= op "inc")))
+(define opt-incsq? (fn (op) (or (= op "inc") (= op "sq"))))
+
+; linear chain a(in) -> b -> c -> d, all inc
+(define
+  opt-chain
+  (list
+    (list "a" "in" (list) {:v 5})
+    (list "b" "inc" (list "a") {})
+    (list "c" "inc" (list "b") {})
+    (list "d" "inc" (list "c") {})))
+
+; ---- DCE ----
+
+(define
+  dce-entries
+  (list
+    (list "a" "in" (list) {:v 5})
+    (list "b" "inc" (list "a") {})
+    (list "c" "inc" (list "b") {})
+    (list "x" "sq" (list "a") {})))
+(define dce-G (artdag/build dce-entries))
+
+(artdag-test
+  "dce: removes dead node"
+  (artdag/node-count (artdag/dce dce-G (list (artdag/dag-id dce-G "c"))))
+  3)
+
+(artdag-test
+  "dce: keeps live closure intact"
+  (artdag/node-count (artdag/dce dce-G (list (artdag/dag-id dce-G "x"))))
+  2)
+
+(artdag-test
+  "dce: preserves surviving node ids"
+  (artdag/member?
+    (artdag/dag-id dce-G "c")
+    (keys
+      (artdag/dag-nodes (artdag/dce dce-G (list (artdag/dag-id dce-G "c"))))))
+  true)
+
+(artdag-test
+  "dce: output result unchanged after elimination"
+  (let
+    ((cache (persist/open)))
+    (artdag/result-of
+      (artdag/run
+        (artdag/dce dce-G (list (artdag/dag-id dce-G "c")))
+        opt-RUN
+        cache)
+      (artdag/dag-id dce-G "c")))
+  7)
+
+(artdag-test
+  "dce: nothing dead is a no-op on count"
+  (artdag/node-count
+    (artdag/dce
+      dce-G
+      (list (artdag/dag-id dce-G "c") (artdag/dag-id dce-G "x"))))
+  4)
+
+; ---- CSE (free from content addressing) ----
+
+(define
+  cse-entries
+  (list
+    (list "a" "in" (list) {:v 3})
+    (list "s1" "sq" (list "a") {})
+    (list "s2" "sq" (list "a") {})
+    (list "d" "add" (list "s1" "s2") {} true)))
+(define cse-C (artdag/cse cse-entries))
+
+(artdag-test
+  "cse: identical subexpressions collapse to one node"
+  (artdag/node-count cse-C)
+  3)
+
+(artdag-test
+  "cse: shared node computes once"
+  (let
+    ((cache (persist/open)))
+    (artdag/recompute-count (artdag/run cse-C opt-RUN cache)))
+  3)
+
+(artdag-test
+  "cse: s1 and s2 are the same id"
+  (equal? (artdag/dag-id cse-C "s1") (artdag/dag-id cse-C "s2"))
+  true)
+
+(artdag-test
+  "cse: result is correct"
+  (let
+    ((cache (persist/open)))
+    (artdag/result-of
+      (artdag/run cse-C opt-RUN cache)
+      (artdag/dag-id cse-C "d")))
+  18)
+
+; ---- fusion ----
+
+(artdag-test
+  "fusion: collapses a unary chain"
+  (artdag/node-count (artdag/fuse opt-chain opt-inc?))
+  2)
+
+(artdag-test
+  "fusion: unfused has all nodes"
+  (artdag/node-count (artdag/build opt-chain))
+  4)
+
+(artdag-test
+  "fusion: output-equivalent to unfused"
+  (let
+    ((c1 (persist/open)) (c2 (persist/open)))
+    (=
+      (artdag/result-of
+        (artdag/run (artdag/build opt-chain) opt-RUN c1)
+        (artdag/dag-id (artdag/build opt-chain) "d"))
+      (artdag/result-of
+        (artdag/run (artdag/fuse opt-chain opt-inc?) opt-RUN c2)
+        (artdag/dag-id (artdag/fuse opt-chain opt-inc?) "d"))))
+  true)
+
+(artdag-test
+  "fusion: leaf is never fused"
+  (artdag/node-op
+    (artdag/dag-node-by-name (artdag/fuse opt-chain opt-inc?) "a"))
+  "in")
+
+(artdag-test
+  "fusion: tail becomes a pipeline node"
+  (artdag/node-op
+    (artdag/dag-node-by-name (artdag/fuse opt-chain opt-inc?) "d"))
+  "artdag/pipeline")
+
+(artdag-test
+  "fusion: mixed fusible set fuses across op kinds"
+  (artdag/node-count
+    (artdag/fuse
+      (list
+        (list "a" "in" (list) {:v 2})
+        (list "b" "inc" (list "a") {})
+        (list "c" "sq" (list "b") {})
+        (list "d" "inc" (list "c") {}))
+      opt-incsq?))
+  2)
+
+(artdag-test
+  "fusion: mixed chain replays correctly"
+  (let
+    ((cache (persist/open)))
+    (let
+      ((f (artdag/fuse (list (list "a" "in" (list) {:v 2}) (list "b" "inc" (list "a") {}) (list "c" "sq" (list "b") {}) (list "d" "inc" (list "c") {})) opt-incsq?)))
+      (artdag/result-of (artdag/run f opt-RUN cache) (artdag/dag-id f "d"))))
+  10)
+
+(artdag-test
+  "fusion: fanout node is not fused"
+  (artdag/node-count
+    (artdag/fuse
+      (list
+        (list "a" "in" (list) {:v 1})
+        (list "b" "inc" (list "a") {})
+        (list "c" "inc" (list "b") {})
+        (list "e" "sq" (list "b") {}))
+      opt-inc?))
+  4)
+
+(artdag-test
+  "fusion: empty fusible set leaves dag unchanged"
+  (artdag/node-count (artdag/fuse opt-chain (fn (op) false)))
+  4)
diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index 7421af6a..0ebb38b4 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -30,7 +30,7 @@ edges.
 
 ## Status (rolling)
 
-`bash lib/artdag/conformance.sh` → **69/69** (4 suites: dag, analyze, plan, execute)
+`bash lib/artdag/conformance.sh` → **87/87** (5 suites: dag, analyze, plan, execute, optimize)
 
 ## Ground rules
 
@@ -116,12 +116,12 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Phase 5 — Effect-pipeline optimization
 
-- [ ] `lib/artdag/optimize.sx` — rewrite the DAG before execution: dead-node
+- [x] `lib/artdag/optimize.sx` — rewrite the DAG before execution: dead-node
   elimination (unreachable from outputs), common-subexpression sharing (free from
   content ids), adjacent-op fusion
-- [ ] optimizations are content-id-preserving where semantically identical; assert
+- [x] optimizations are content-id-preserving where semantically identical; assert
   the optimized DAG produces identical results
-- [ ] `lib/artdag/tests/optimize.sx` — DCE, CSE dedup, fusion equivalence
+- [x] `lib/artdag/tests/optimize.sx` — DCE, CSE dedup, fusion equivalence
 - [ ] (optional/later) rule-based optimization via `maude-on-sx`'s rewriting engine —
   flag the integration point, don't block on it
 
@@ -136,6 +136,19 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
+- **Phase 5 — Effect-pipeline optimization** (optimize suite 18/18, total 87/87).
+  `lib/artdag/optimize.sx`: `artdag/dce dag outputs` keeps only the outputs plus
+  their transitive ancestors (via analyze), preserving surviving content-ids.
+  `artdag/cse` == build — structural sharing is inherent to content addressing, so
+  identical subexpressions collapse to one node/id and execute once (verified).
+  `artdag/fuse entries fusible?` rewrites entries: a maximal 1-to-1 chain of fusible
+  unary ops (predecessor used only by its single consumer, both fusible) collapses
+  into one `artdag/pipeline` node carrying ordered `{:op :params}` stages, fed by the
+  chain head's external input; leaves, fan-out nodes, and non-fusible ops never fuse.
+  `artdag/fusing-runner` wraps a base runner to replay pipeline stages — output
+  equivalent to the unfused DAG (asserted). Note: CSE auto-dedup means test fixtures
+  intended as distinct nodes must use distinct op/params.
+
 - **Phase 4 — Execute (incremental + memoized)** (execute suite 15/15, total 69/69).
   `lib/artdag/execute.sx`: `artdag/execute` folds a plan, computing each node via an
   injected `runner (op params input-results)` (production = `perform` to JAX/IPFS

From 985dbb4c8fbd9c9c929f0ae92a8bde7dfdbc219e Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 12:11:11 +0000
Subject: [PATCH 06/13] =?UTF-8?q?artdag:=20Phase=206=20federation=20?=
 =?UTF-8?q?=E2=80=94=20shared=20content-addressed=20cache=20+=20trust=20+?=
 =?UTF-8?q?=20invalidation=20+=2015=20tests?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

federation.sx: instance = {cache, prov cid->peer}. fed-export/import share results
by global content-id (trusted import -> pure cache hit, the L2-registry analog);
trust gating rejects untrusted peers; fed-pull uses an injected fetch transport;
fed-invalidate drops a peer's provenanced results (peer-scoped, leaves local
results). fed 15/15, total 102/102. All 6 phases complete.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/conformance.sh  |   3 +-
 lib/artdag/federation.sx   |  75 ++++++++++++++++++
 lib/artdag/scoreboard.json |   7 +-
 lib/artdag/scoreboard.md   |   3 +-
 lib/artdag/tests/fed.sx    | 157 +++++++++++++++++++++++++++++++++++++
 plans/artdag-on-sx.md      |  22 ++++--
 6 files changed, 257 insertions(+), 10 deletions(-)
 create mode 100644 lib/artdag/federation.sx
 create mode 100644 lib/artdag/tests/fed.sx

diff --git a/lib/artdag/conformance.sh b/lib/artdag/conformance.sh
index dcccfa4a..0551abb3 100755
--- a/lib/artdag/conformance.sh
+++ b/lib/artdag/conformance.sh
@@ -13,7 +13,7 @@ if [ ! -x "$SX_SERVER" ]; then
   exit 1
 fi
 
-SUITES=(dag analyze plan execute optimize)
+SUITES=(dag analyze plan execute optimize fed)
 
 OUT_JSON="lib/artdag/scoreboard.json"
 OUT_MD="lib/artdag/scoreboard.md"
@@ -46,6 +46,7 @@ run_suite() {
 (load "lib/artdag/plan.sx")
 (load "lib/artdag/execute.sx")
 (load "lib/artdag/optimize.sx")
+(load "lib/artdag/federation.sx")
 (epoch 2)
 (eval "(define artdag-test-pass 0)")
 (eval "(define artdag-test-fail 0)")
diff --git a/lib/artdag/federation.sx b/lib/artdag/federation.sx
new file mode 100644
index 00000000..15780b46
--- /dev/null
+++ b/lib/artdag/federation.sx
@@ -0,0 +1,75 @@
+; lib/artdag/federation.sx — Phase 6: shared content-addressed cache across
+; instances (the L2-registry analog). Because content-ids are global, a result
+; computed on one instance is reusable on another by id. Imports are trust-gated
+; and carry provenance so a peer's results can be invalidated when trust is
+; withdrawn. Transport is injected (mock in tests). Depends on dag.sx, execute.sx
+; (the cache is a lib/persist/ kv backend) — federation tracks provenance beside it.
+
+; an instance: a persist kv cache + a provenance map {cid -> origin-peer}.
+(define artdag/fed-open (fn () {:cache (persist/open) :prov {}}))
+(define artdag/fed-cache (fn (fed) (get fed :cache)))
+(define artdag/fed-prov (fn (fed) (get fed :prov)))
+
+(define
+  artdag/-dict-remove
+  (fn
+    (d key)
+    (reduce
+      (fn (acc k) (if (= k key) acc (assoc acc k (get d k))))
+      {}
+      (keys d))))
+
+; export every cached result as a bundle of {:cid :result :peer}, tagged with
+; the exporting instance's peer id (the result's origin/provenance).
+(define
+  artdag/fed-export
+  (fn
+    (fed peer-id)
+    (map (fn (cid) {:peer peer-id :cid cid :result (persist/kv-get (get fed :cache) cid)}) (persist/kv-keys (get fed :cache)))))
+
+; import a bundle, accepting only records from trusted peers (trust gating) and
+; recording each accepted result's provenance. Returns the updated instance.
+(define
+  artdag/fed-import
+  (fn
+    (fed bundle trusted?)
+    (reduce
+      (fn
+        (f rec)
+        (if
+          (trusted? (get rec :peer))
+          (begin
+            (persist/kv-put (get f :cache) (get rec :cid) (get rec :result))
+            {:cache (get f :cache) :prov (assoc (get f :prov) (get rec :cid) (get rec :peer))})
+          f))
+      fed
+      bundle)))
+
+; pull from a peer through an injected transport (fetch-fn peer-id -> bundle).
+(define
+  artdag/fed-pull
+  (fn
+    (fed fetch-fn peer-id trusted?)
+    (artdag/fed-import fed (fetch-fn peer-id) trusted?)))
+
+; invalidate: drop every cached result provenanced to a peer (trust withdrawn),
+; from both the cache and the provenance map. Locally-computed results (no
+; provenance) are untouched. Returns the updated instance.
+(define
+  artdag/fed-invalidate
+  (fn
+    (fed peer-id)
+    (reduce
+      (fn
+        (f cid)
+        (if
+          (= (get (get f :prov) cid) peer-id)
+          (begin (persist/kv-delete (get f :cache) cid) {:cache (get f :cache) :prov (artdag/-dict-remove (get f :prov) cid)})
+          f))
+      fed
+      (keys (get fed :prov)))))
+
+; convenience: run a dag against an instance's cache.
+(define
+  artdag/fed-run
+  (fn (fed dag runner) (artdag/run dag runner (artdag/fed-cache fed))))
diff --git a/lib/artdag/scoreboard.json b/lib/artdag/scoreboard.json
index 7be1073f..1c4bedd3 100644
--- a/lib/artdag/scoreboard.json
+++ b/lib/artdag/scoreboard.json
@@ -4,9 +4,10 @@
     "analyze": {"pass": 16, "fail": 0},
     "plan": {"pass": 18, "fail": 0},
     "execute": {"pass": 15, "fail": 0},
-    "optimize": {"pass": 18, "fail": 0}
+    "optimize": {"pass": 18, "fail": 0},
+    "fed": {"pass": 15, "fail": 0}
   },
-  "total_pass": 87,
+  "total_pass": 102,
   "total_fail": 0,
-  "total": 87
+  "total": 102
 }
diff --git a/lib/artdag/scoreboard.md b/lib/artdag/scoreboard.md
index 14f8c5c8..e5d97fb9 100644
--- a/lib/artdag/scoreboard.md
+++ b/lib/artdag/scoreboard.md
@@ -9,4 +9,5 @@ _Generated by `lib/artdag/conformance.sh`_
 | plan | 18 | 0 | 18 |
 | execute | 15 | 0 | 15 |
 | optimize | 18 | 0 | 18 |
-| **Total** | **87** | **0** | **87** |
+| fed | 15 | 0 | 15 |
+| **Total** | **102** | **0** | **102** |
diff --git a/lib/artdag/tests/fed.sx b/lib/artdag/tests/fed.sx
new file mode 100644
index 00000000..981bcfcd
--- /dev/null
+++ b/lib/artdag/tests/fed.sx
@@ -0,0 +1,157 @@
+; Phase 6 — federation: shared content-addressed cache, trust gating, invalidation.
+
+(define fed-BASE (artdag/op-table-runner {:in (fn (params inputs) (get params :v)) :add (fn (params inputs) (+ (nth inputs 0) (nth inputs 1))) :inc (fn (params inputs) (+ 1 (first inputs)))}))
+
+(define
+  fed-D
+  (artdag/build
+    (list
+      (list "p" "in" (list) {:v 10})
+      (list "q" "in" (list) {:v 20})
+      (list "b" "inc" (list "p") {})
+      (list "c" "inc" (list "q") {})
+      (list "d" "add" (list "b" "c") {} true))))
+
+(define fed-trust-A (fn (p) (= p "A")))
+(define fed-trust-none (fn (p) false))
+
+; a warmed instance A and its export bundle (origin peer "A").
+(define fed-A (artdag/fed-open))
+(define fed-warm (artdag/fed-run fed-A fed-D fed-BASE))
+(define fed-bundle (artdag/fed-export fed-A "A"))
+
+; ---- export ----
+
+(artdag-test
+  "export: bundle covers every cached node"
+  (len fed-bundle)
+  5)
+
+; ---- remote cache hit ----
+
+(artdag-test
+  "trusted import enables remote cache hit (no recompute)"
+  (artdag/recompute-count
+    (artdag/fed-run
+      (artdag/fed-import (artdag/fed-open) fed-bundle fed-trust-A)
+      fed-D
+      fed-BASE))
+  0)
+
+(artdag-test
+  "trusted import: every node is a hit"
+  (artdag/hit-count
+    (artdag/fed-run
+      (artdag/fed-import (artdag/fed-open) fed-bundle fed-trust-A)
+      fed-D
+      fed-BASE))
+  5)
+
+(artdag-test
+  "remote hit yields correct result"
+  (artdag/result-of
+    (artdag/fed-run
+      (artdag/fed-import (artdag/fed-open) fed-bundle fed-trust-A)
+      fed-D
+      fed-BASE)
+    (artdag/dag-id fed-D "d"))
+  32)
+
+; ---- trust gating ----
+
+(artdag-test
+  "untrusted peer is rejected (recompute everything)"
+  (artdag/recompute-count
+    (artdag/fed-run
+      (artdag/fed-import (artdag/fed-open) fed-bundle fed-trust-none)
+      fed-D
+      fed-BASE))
+  5)
+
+(artdag-test
+  "trust gating: untrusted records never enter the cache"
+  (let
+    ((B (artdag/fed-import (artdag/fed-open) (cons {:peer "C" :cid "node:foreign" :result 99} fed-bundle) fed-trust-A)))
+    (persist/kv-has? (artdag/fed-cache B) "node:foreign"))
+  false)
+
+(artdag-test
+  "trust gating: trusted records still admitted alongside rejected"
+  (let
+    ((B (artdag/fed-import (artdag/fed-open) (cons {:peer "C" :cid "node:foreign" :result 99} fed-bundle) fed-trust-A)))
+    (persist/kv-has? (artdag/fed-cache B) (artdag/dag-id fed-D "d")))
+  true)
+
+; ---- provenance ----
+
+(artdag-test
+  "provenance is recorded for imported results"
+  (get
+    (artdag/fed-prov
+      (artdag/fed-import (artdag/fed-open) fed-bundle fed-trust-A))
+    (artdag/dag-id fed-D "d"))
+  "A")
+
+(artdag-test
+  "locally computed results carry no provenance"
+  (len (keys (artdag/fed-prov fed-A)))
+  0)
+
+; ---- injected transport ----
+
+(artdag-test
+  "fed-pull imports via an injected fetch transport"
+  (artdag/recompute-count
+    (artdag/fed-run
+      (artdag/fed-pull
+        (artdag/fed-open)
+        (fn (peer) fed-bundle)
+        "A"
+        fed-trust-A)
+      fed-D
+      fed-BASE))
+  0)
+
+; ---- invalidation ----
+
+(artdag-test
+  "invalidation drops a peer's results (recompute again)"
+  (let
+    ((B (artdag/fed-import (artdag/fed-open) fed-bundle fed-trust-A)))
+    (artdag/recompute-count
+      (artdag/fed-run (artdag/fed-invalidate B "A") fed-D fed-BASE)))
+  5)
+
+(artdag-test
+  "invalidation: recomputed result still correct"
+  (let
+    ((B (artdag/fed-import (artdag/fed-open) fed-bundle fed-trust-A)))
+    (artdag/result-of
+      (artdag/fed-run (artdag/fed-invalidate B "A") fed-D fed-BASE)
+      (artdag/dag-id fed-D "d")))
+  32)
+
+(artdag-test
+  "invalidation: provenance map is cleared for that peer"
+  (let
+    ((B (artdag/fed-import (artdag/fed-open) fed-bundle fed-trust-A)))
+    (len (keys (artdag/fed-prov (artdag/fed-invalidate B "A")))))
+  0)
+
+(artdag-test
+  "invalidation is peer-scoped: other peers' results survive"
+  (let
+    ((B (artdag/fed-import (artdag/fed-open) (cons {:peer "C" :cid "node:fromC" :result 7} fed-bundle) (fn (p) true))))
+    (persist/kv-has?
+      (artdag/fed-cache (artdag/fed-invalidate B "A"))
+      "node:fromC"))
+  true)
+
+(artdag-test
+  "invalidation is peer-scoped: target peer's results removed"
+  (let
+    ((B (artdag/fed-import (artdag/fed-open) (cons {:peer "C" :cid "node:fromC" :result 7} fed-bundle) (fn (p) true))))
+    (persist/kv-has?
+      (artdag/fed-cache (artdag/fed-invalidate B "A"))
+      (artdag/dag-id fed-D "d")))
+  false)
diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index 0ebb38b4..95e168b0 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -30,7 +30,7 @@ edges.
 
 ## Status (rolling)
 
-`bash lib/artdag/conformance.sh` → **87/87** (5 suites: dag, analyze, plan, execute, optimize)
+`bash lib/artdag/conformance.sh` → **102/102** (6 suites: dag, analyze, plan, execute, optimize, fed)
 
 ## Ground rules
 
@@ -127,15 +127,27 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Phase 6 — Federation (shared content-addressed cache)
 
-- [ ] a result computed on one instance is reusable on another by content-id (the
+- [x] a result computed on one instance is reusable on another by content-id (the
   L2-registry analog): export/import `{content-id → result}` with provenance
-- [ ] trust gating — accept a remote result only from a trusted peer (mirror the
+- [x] trust gating — accept a remote result only from a trusted peer (mirror the
   fed trust shape; mock the transport in tests)
-- [ ] revocation/invalidation — drop a remote result if its provenance is withdrawn
-- [ ] `lib/artdag/tests/fed.sx` — remote cache hit, trust gating, invalidation
+- [x] revocation/invalidation — drop a remote result if its provenance is withdrawn
+- [x] `lib/artdag/tests/fed.sx` — remote cache hit, trust gating, invalidation
 
 ## Progress log
 
+- **Phase 6 — Federation (shared content-addressed cache)** (fed suite 15/15, total
+  102/102). `lib/artdag/federation.sx`: an instance = `{:cache <persist kv> :prov
+  {cid->origin-peer}}`. `fed-export` dumps the whole cache as `{:cid :result :peer}`
+  records tagged with the exporter's id; `fed-import` accepts only records from
+  trusted peers (trust gating) and records provenance; `fed-pull` imports via an
+  injected `fetch-fn(peer-id)` transport (mocked in tests). Because content-ids are
+  global, a trusted import makes the importer's run a pure cache hit (recompute 0) —
+  the L2-registry analog. `fed-invalidate peer` drops every result provenanced to a
+  peer from cache + prov (trust withdrawn → recompute), peer-scoped (other peers'
+  results survive) and leaving locally-computed (un-provenanced) results untouched.
+  ALL 6 PHASES COMPLETE.
+
 - **Phase 5 — Effect-pipeline optimization** (optimize suite 18/18, total 87/87).
   `lib/artdag/optimize.sx`: `artdag/dce dag outputs` keeps only the outputs plus
   their transitive ancestors (via analyze), preserving surviving content-ids.

From afe69cbdc6fc1de7c6e901fcedb4f5b655938804 Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 12:15:51 +0000
Subject: [PATCH 07/13] =?UTF-8?q?artdag:=20cost-based=20scheduling=20?=
 =?UTF-8?q?=E2=80=94=20critical=20path=20+=20makespan=20+=20speedup=20+=20?=
 =?UTF-8?q?13=20tests?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

cost.sx: injected cost-fn keeps media costs opaque. critical-path = longest
weighted path (= unlimited-worker makespan); makespan sums each batch's slowest
node (full plan == critical path, serial == total-work); speedup = work/makespan.
cost 13/13, total 115/115.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/conformance.sh  |   3 +-
 lib/artdag/cost.sx         |  66 +++++++++++++++++++++
 lib/artdag/scoreboard.json |   7 ++-
 lib/artdag/scoreboard.md   |   3 +-
 lib/artdag/tests/cost.sx   | 117 +++++++++++++++++++++++++++++++++++++
 plans/artdag-on-sx.md      |  13 ++++-
 6 files changed, 203 insertions(+), 6 deletions(-)
 create mode 100644 lib/artdag/cost.sx
 create mode 100644 lib/artdag/tests/cost.sx

diff --git a/lib/artdag/conformance.sh b/lib/artdag/conformance.sh
index 0551abb3..ff32eaf2 100755
--- a/lib/artdag/conformance.sh
+++ b/lib/artdag/conformance.sh
@@ -13,7 +13,7 @@ if [ ! -x "$SX_SERVER" ]; then
   exit 1
 fi
 
-SUITES=(dag analyze plan execute optimize fed)
+SUITES=(dag analyze plan execute optimize fed cost)
 
 OUT_JSON="lib/artdag/scoreboard.json"
 OUT_MD="lib/artdag/scoreboard.md"
@@ -47,6 +47,7 @@ run_suite() {
 (load "lib/artdag/execute.sx")
 (load "lib/artdag/optimize.sx")
 (load "lib/artdag/federation.sx")
+(load "lib/artdag/cost.sx")
 (epoch 2)
 (eval "(define artdag-test-pass 0)")
 (eval "(define artdag-test-fail 0)")
diff --git a/lib/artdag/cost.sx b/lib/artdag/cost.sx
new file mode 100644
index 00000000..6cbf9547
--- /dev/null
+++ b/lib/artdag/cost.sx
@@ -0,0 +1,66 @@
+; lib/artdag/cost.sx — cost model for the scheduler: per-node weights, critical
+; path (min makespan with unlimited parallelism), plan makespan under batching/cap,
+; total serial work, and the resulting speedup. Costs come from an injected
+; cost-fn (op params) -> number so media-op costs stay opaque. Depends on dag.sx.
+
+(define artdag/const-cost (fn (op params) 1))
+
+(define
+  artdag/op-cost
+  (fn
+    (table)
+    (fn (op params) (if (has-key? table op) (get table op) 1))))
+
+(define
+  artdag/-node-cost
+  (fn
+    (dag cost-fn id)
+    (let
+      ((n (artdag/dag-get dag id)))
+      (cost-fn (artdag/node-op n) (artdag/node-params n)))))
+
+(define
+  artdag/-max
+  (fn (xs) (reduce (fn (mx x) (if (> x mx) x mx)) 0 xs)))
+
+; longest weighted path through the dag = makespan with unlimited workers.
+(define
+  artdag/critical-path
+  (fn
+    (dag cost-fn)
+    (let
+      ((ft (reduce (fn (m id) (let ((maxdep (artdag/-max (map (fn (d) (get m d)) (artdag/node-inputs (artdag/dag-get dag id)))))) (assoc m id (+ (artdag/-node-cost dag cost-fn id) maxdep)))) {} (artdag/dag-order dag))))
+      (artdag/-max (map (fn (id) (get ft id)) (keys ft))))))
+
+; estimated wall-clock for a plan: each batch runs in parallel (costs its
+; slowest node), batches run in sequence.
+(define
+  artdag/makespan
+  (fn
+    (dag plan cost-fn)
+    (reduce
+      (fn
+        (total batch)
+        (+
+          total
+          (artdag/-max
+            (map (fn (id) (artdag/-node-cost dag cost-fn id)) batch))))
+      0
+      plan)))
+
+; total serial work = sum of all node costs.
+(define
+  artdag/total-work
+  (fn
+    (dag cost-fn)
+    (reduce
+      (fn (s id) (+ s (artdag/-node-cost dag cost-fn id)))
+      0
+      (keys (artdag/dag-nodes dag)))))
+
+; speedup of a plan vs running everything serially.
+(define
+  artdag/speedup
+  (fn
+    (dag plan cost-fn)
+    (/ (artdag/total-work dag cost-fn) (artdag/makespan dag plan cost-fn))))
diff --git a/lib/artdag/scoreboard.json b/lib/artdag/scoreboard.json
index 1c4bedd3..e707a6d3 100644
--- a/lib/artdag/scoreboard.json
+++ b/lib/artdag/scoreboard.json
@@ -5,9 +5,10 @@
     "plan": {"pass": 18, "fail": 0},
     "execute": {"pass": 15, "fail": 0},
     "optimize": {"pass": 18, "fail": 0},
-    "fed": {"pass": 15, "fail": 0}
+    "fed": {"pass": 15, "fail": 0},
+    "cost": {"pass": 13, "fail": 0}
   },
-  "total_pass": 102,
+  "total_pass": 115,
   "total_fail": 0,
-  "total": 102
+  "total": 115
 }
diff --git a/lib/artdag/scoreboard.md b/lib/artdag/scoreboard.md
index e5d97fb9..6440f9d5 100644
--- a/lib/artdag/scoreboard.md
+++ b/lib/artdag/scoreboard.md
@@ -10,4 +10,5 @@ _Generated by `lib/artdag/conformance.sh`_
 | execute | 15 | 0 | 15 |
 | optimize | 18 | 0 | 18 |
 | fed | 15 | 0 | 15 |
-| **Total** | **102** | **0** | **102** |
+| cost | 13 | 0 | 13 |
+| **Total** | **115** | **0** | **115** |
diff --git a/lib/artdag/tests/cost.sx b/lib/artdag/tests/cost.sx
new file mode 100644
index 00000000..fbc71da5
--- /dev/null
+++ b/lib/artdag/tests/cost.sx
@@ -0,0 +1,117 @@
+; cost model: critical path, makespan under cap, total work, speedup.
+
+(define
+  cost-CHAIN
+  (artdag/build
+    (list
+      (list "a" "in" (list) {})
+      (list "b" "f" (list "a") {})
+      (list "c" "f" (list "b") {})
+      (list "d" "f" (list "c") {}))))
+
+(define
+  cost-DIA
+  (artdag/build
+    (list
+      (list "a" "in" (list) {})
+      (list "b" "f" (list "a") {})
+      (list "c" "g" (list "a") {})
+      (list "d" "add" (list "b" "c") {} true))))
+
+(define cost-W (artdag/op-cost {:f 2 :add 5}))
+
+; ---- unit cost ----
+
+(artdag-test
+  "critical path: chain is its length"
+  (artdag/critical-path cost-CHAIN artdag/const-cost)
+  4)
+
+(artdag-test
+  "critical path: diamond longest path"
+  (artdag/critical-path cost-DIA artdag/const-cost)
+  3)
+
+(artdag-test
+  "total work: unit cost equals node count"
+  (artdag/total-work cost-DIA artdag/const-cost)
+  4)
+
+(artdag-test
+  "single node critical path is its cost"
+  (artdag/critical-path
+    (artdag/build (list (list "a" "in" (list) {})))
+    artdag/const-cost)
+  1)
+
+; ---- makespan vs cap ----
+
+(artdag-test
+  "full plan makespan equals critical path"
+  (artdag/makespan
+    cost-DIA
+    (artdag/plan cost-DIA 0)
+    artdag/const-cost)
+  (artdag/critical-path cost-DIA artdag/const-cost))
+
+(artdag-test
+  "serial plan makespan equals total work"
+  (artdag/makespan
+    cost-DIA
+    (artdag/plan cost-DIA 1)
+    artdag/const-cost)
+  (artdag/total-work cost-DIA artdag/const-cost))
+
+(artdag-test
+  "capped makespan is never below the critical path"
+  (>=
+    (artdag/makespan
+      cost-DIA
+      (artdag/plan cost-DIA 1)
+      artdag/const-cost)
+    (artdag/critical-path cost-DIA artdag/const-cost))
+  true)
+
+; ---- weighted costs ----
+
+(artdag-test
+  "weighted critical path follows heavy ops"
+  (artdag/critical-path cost-DIA cost-W)
+  8)
+
+(artdag-test
+  "weighted total work sums all node costs"
+  (artdag/total-work cost-DIA cost-W)
+  9)
+
+(artdag-test
+  "op-cost defaults unknown ops to 1"
+  (artdag/total-work
+    (artdag/build (list (list "a" "in" (list) {})))
+    cost-W)
+  1)
+
+(artdag-test
+  "weighted full-plan makespan equals critical path"
+  (artdag/makespan cost-DIA (artdag/plan cost-DIA 0) cost-W)
+  (artdag/critical-path cost-DIA cost-W))
+
+; ---- speedup ----
+
+(artdag-test
+  "serial plan has no speedup"
+  (artdag/speedup
+    cost-DIA
+    (artdag/plan cost-DIA 1)
+    artdag/const-cost)
+  1)
+
+(artdag-test
+  "parallel plan beats serial"
+  (>
+    (artdag/speedup
+      cost-DIA
+      (artdag/plan cost-DIA 0)
+      artdag/const-cost)
+    1)
+  true)
diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index 95e168b0..af9ee3a7 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -30,7 +30,9 @@ edges.
 
 ## Status (rolling)
 
-`bash lib/artdag/conformance.sh` → **102/102** (6 suites: dag, analyze, plan, execute, optimize, fed)
+`bash lib/artdag/conformance.sh` → **115/115** (7 suites: dag, analyze, plan, execute, optimize, fed, cost)
+
+Base roadmap (Phases 1–6) COMPLETE. Now extending.
 
 ## Ground rules
 
@@ -136,6 +138,15 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
+- **Ext: cost-based scheduling** (cost suite 13/13, total 115/115).
+  `lib/artdag/cost.sx`: an injected `cost-fn (op params)` keeps media-op costs opaque
+  (`const-cost`, `op-cost table`). `critical-path` = longest weighted path (finish-time
+  fold over topo order) = min makespan with unlimited workers. `makespan dag plan
+  cost-fn` sums each batch's slowest node — full plan (cap 0) makespan == critical
+  path, serial (cap 1) == `total-work`. `speedup` = total-work / makespan. Verified
+  weighted paths follow heavy ops and capped makespan never dips below the critical
+  path.
+
 - **Phase 6 — Federation (shared content-addressed cache)** (fed suite 15/15, total
   102/102). `lib/artdag/federation.sx`: an instance = `{:cache <persist kv> :prov
   {cid->origin-peer}}`. `fed-export` dumps the whole cache as `{:cid :result :peer}`

From 4947d1f5aa808549b7705ddf842b484544a9c1a2 Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 12:22:17 +0000
Subject: [PATCH 08/13] =?UTF-8?q?artdag:=20DAG=20wire=20serialization=20?=
 =?UTF-8?q?=E2=80=94=20portable=20record=20form=20+=20integrity=20+=2013?=
 =?UTF-8?q?=20tests?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

serialize.sx emits a topo-ordered (id op inputs params commutative) record list
that survives write/read (string-keyed node dicts do not; empty inputs read back
as nil and are normalized). wire->dag reconstructs a runnable dag by content-id;
wire-verify recomputes ids to reject tampering. dag->string/string->dag for text
transport. serialize 13/13, total 128/128.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/conformance.sh     |   3 +-
 lib/artdag/scoreboard.json    |   7 ++-
 lib/artdag/scoreboard.md      |   3 +-
 lib/artdag/serialize.sx       |  62 ++++++++++++++++++
 lib/artdag/tests/serialize.sx | 115 ++++++++++++++++++++++++++++++++++
 plans/artdag-on-sx.md         |  13 +++-
 6 files changed, 197 insertions(+), 6 deletions(-)
 create mode 100644 lib/artdag/serialize.sx
 create mode 100644 lib/artdag/tests/serialize.sx

diff --git a/lib/artdag/conformance.sh b/lib/artdag/conformance.sh
index ff32eaf2..050b6687 100755
--- a/lib/artdag/conformance.sh
+++ b/lib/artdag/conformance.sh
@@ -13,7 +13,7 @@ if [ ! -x "$SX_SERVER" ]; then
   exit 1
 fi
 
-SUITES=(dag analyze plan execute optimize fed cost)
+SUITES=(dag analyze plan execute optimize fed cost serialize)
 
 OUT_JSON="lib/artdag/scoreboard.json"
 OUT_MD="lib/artdag/scoreboard.md"
@@ -48,6 +48,7 @@ run_suite() {
 (load "lib/artdag/optimize.sx")
 (load "lib/artdag/federation.sx")
 (load "lib/artdag/cost.sx")
+(load "lib/artdag/serialize.sx")
 (epoch 2)
 (eval "(define artdag-test-pass 0)")
 (eval "(define artdag-test-fail 0)")
diff --git a/lib/artdag/scoreboard.json b/lib/artdag/scoreboard.json
index e707a6d3..619b39e7 100644
--- a/lib/artdag/scoreboard.json
+++ b/lib/artdag/scoreboard.json
@@ -6,9 +6,10 @@
     "execute": {"pass": 15, "fail": 0},
     "optimize": {"pass": 18, "fail": 0},
     "fed": {"pass": 15, "fail": 0},
-    "cost": {"pass": 13, "fail": 0}
+    "cost": {"pass": 13, "fail": 0},
+    "serialize": {"pass": 13, "fail": 0}
   },
-  "total_pass": 115,
+  "total_pass": 128,
   "total_fail": 0,
-  "total": 115
+  "total": 128
 }
diff --git a/lib/artdag/scoreboard.md b/lib/artdag/scoreboard.md
index 6440f9d5..781cfcd3 100644
--- a/lib/artdag/scoreboard.md
+++ b/lib/artdag/scoreboard.md
@@ -11,4 +11,5 @@ _Generated by `lib/artdag/conformance.sh`_
 | optimize | 18 | 0 | 18 |
 | fed | 15 | 0 | 15 |
 | cost | 13 | 0 | 13 |
-| **Total** | **115** | **0** | **115** |
+| serialize | 13 | 0 | 13 |
+| **Total** | **128** | **0** | **128** |
diff --git a/lib/artdag/serialize.sx b/lib/artdag/serialize.sx
new file mode 100644
index 00000000..f8f337e9
--- /dev/null
+++ b/lib/artdag/serialize.sx
@@ -0,0 +1,62 @@
+; lib/artdag/serialize.sx — portable wire form for whole DAGs, so a peer can
+; receive and run a graph it did not author. The form is a topo-ordered list of
+; node records (id op inputs params commutative) — plain lists with keyword-keyed
+; param dicts, which survive write/read (unlike string-keyed node dicts). The id
+; is the content-id, so the form is self-verifying. Depends on dag.sx.
+
+(define
+  artdag/node->record
+  (fn
+    (dag id)
+    (let
+      ((n (artdag/dag-get dag id)))
+      (list
+        id
+        (artdag/node-op n)
+        (artdag/node-inputs n)
+        (artdag/node-params n)
+        (get n :commutative)))))
+
+; dag -> list of records, in topological order.
+(define
+  artdag/dag->wire
+  (fn
+    (dag)
+    (map (fn (id) (artdag/node->record dag id)) (artdag/dag-order dag))))
+
+; an empty input list reads back as nil; normalize it.
+(define
+  artdag/-rec-inputs
+  (fn (rec) (let ((i (nth rec 2))) (if (nil? i) (list) i))))
+
+(define artdag/-rec->node (fn (rec) {:inputs (artdag/-rec-inputs rec) :commutative (nth rec 4) :op (nth rec 1) :params (nth rec 3)}))
+
+; records -> dag. Local author names are not part of the wire form; the receiver
+; works by content-id. :names is left empty.
+(define
+  artdag/wire->dag
+  (fn
+    (records)
+    (reduce
+      (fn (dag rec) (let ((id (nth rec 0))) {:names (get dag :names) :order (concat (get dag :order) (list id)) :ok true :nodes (assoc (get dag :nodes) id (artdag/-rec->node rec))}))
+      {:names {} :order (list) :ok true :nodes {}}
+      records)))
+
+; integrity: each record's id must equal the content-id recomputed from its spec.
+(define
+  artdag/wire-verify
+  (fn
+    (records)
+    (every?
+      (fn
+        (rec)
+        (= (nth rec 0) (artdag/content-id (artdag/-rec->node rec))))
+      records)))
+
+; string transport.
+(define
+  artdag/dag->string
+  (fn (dag) (write-to-string (artdag/dag->wire dag))))
+(define
+  artdag/string->dag
+  (fn (s) (artdag/wire->dag (read (open-input-string s)))))
diff --git a/lib/artdag/tests/serialize.sx b/lib/artdag/tests/serialize.sx
new file mode 100644
index 00000000..f788c329
--- /dev/null
+++ b/lib/artdag/tests/serialize.sx
@@ -0,0 +1,115 @@
+; portable wire form: dag <-> records <-> string, with content-id integrity.
+
+(define ser-RT (artdag/op-table-runner {:in (fn (p i) (get p :v)) :add (fn (p i) (+ (nth i 0) (nth i 1))) :inc (fn (p i) (+ 1 (first i)))}))
+
+(define
+  ser-D
+  (artdag/build
+    (list
+      (list "a" "in" (list) {:v 10})
+      (list "b" "inc" (list "a") {})
+      (list "c" "add" (list "a" "b") {} true))))
+
+(define ser-cid (artdag/dag-id ser-D "c"))
+
+; ---- wire form ----
+
+(artdag-test
+  "wire has one record per node"
+  (len (artdag/dag->wire ser-D))
+  3)
+
+(artdag-test
+  "wire records follow topological order"
+  (map (fn (rec) (nth rec 0)) (artdag/dag->wire ser-D))
+  (artdag/dag-order ser-D))
+
+(artdag-test
+  "wire record carries the content-id"
+  (nth (nth (artdag/dag->wire ser-D) 0) 0)
+  (artdag/dag-id ser-D "a"))
+
+; ---- reconstruction ----
+
+(artdag-test
+  "wire->dag restores node count"
+  (artdag/node-count (artdag/wire->dag (artdag/dag->wire ser-D)))
+  3)
+
+(artdag-test
+  "wire->dag restores order"
+  (artdag/dag-order (artdag/wire->dag (artdag/dag->wire ser-D)))
+  (artdag/dag-order ser-D))
+
+(artdag-test
+  "reconstructed leaf inputs normalize to empty list"
+  (artdag/node-inputs
+    (artdag/dag-get
+      (artdag/wire->dag (artdag/dag->wire ser-D))
+      (artdag/dag-id ser-D "a")))
+  (list))
+
+(artdag-test
+  "reconstructed node preserves inputs"
+  (artdag/node-inputs
+    (artdag/dag-get (artdag/wire->dag (artdag/dag->wire ser-D)) ser-cid))
+  (artdag/node-inputs (artdag/dag-get ser-D ser-cid)))
+
+(artdag-test
+  "reconstructed node id matches recomputed content-id"
+  (artdag/content-id
+    (artdag/dag-get (artdag/wire->dag (artdag/dag->wire ser-D)) ser-cid))
+  ser-cid)
+
+; ---- execution equivalence ----
+
+(artdag-test
+  "reconstructed dag executes to same result"
+  (let
+    ((c1 (persist/open)) (c2 (persist/open)))
+    (=
+      (artdag/result-of (artdag/run ser-D ser-RT c1) ser-cid)
+      (artdag/result-of
+        (artdag/run (artdag/wire->dag (artdag/dag->wire ser-D)) ser-RT c2)
+        ser-cid)))
+  true)
+
+(artdag-test
+  "string round-trip executes to same result"
+  (let
+    ((cache (persist/open)))
+    (artdag/result-of
+      (artdag/run
+        (artdag/string->dag (artdag/dag->string ser-D))
+        ser-RT
+        cache)
+      ser-cid))
+  21)
+
+; ---- integrity ----
+
+(artdag-test
+  "wire-verify accepts a genuine wire form"
+  (artdag/wire-verify (artdag/dag->wire ser-D))
+  true)
+
+(artdag-test
+  "wire-verify rejects a tampered id"
+  (artdag/wire-verify
+    (list (list "node:bogus" "in" (list) {:v 1} false)))
+  false)
+
+(artdag-test
+  "wire-verify rejects mutated params under a stale id"
+  (artdag/wire-verify
+    (map
+      (fn
+        (rec)
+        (list
+          (nth rec 0)
+          (nth rec 1)
+          (nth rec 2)
+          {:v 999}
+          (nth rec 4)))
+      (artdag/dag->wire ser-D)))
+  false)
diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index af9ee3a7..fcfade9a 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -30,7 +30,7 @@ edges.
 
 ## Status (rolling)
 
-`bash lib/artdag/conformance.sh` → **115/115** (7 suites: dag, analyze, plan, execute, optimize, fed, cost)
+`bash lib/artdag/conformance.sh` → **128/128** (8 suites: dag, analyze, plan, execute, optimize, fed, cost, serialize)
 
 Base roadmap (Phases 1–6) COMPLETE. Now extending.
 
@@ -138,6 +138,17 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
+- **Ext: DAG wire serialization** (serialize suite 13/13, total 128/128).
+  `lib/artdag/serialize.sx`: `dag->wire` emits a topo-ordered list of
+  `(id op inputs params commutative)` records — plain lists with keyword-keyed param
+  dicts, which survive `write-to-string`/`read` (string-keyed node dicts do NOT; and
+  `()` reads back as nil, so `wire->dag` normalizes empty inputs). `wire->dag`
+  reconstructs a runnable dag by content-id (author names dropped); executes
+  identically to the original. `wire-verify` recomputes each record's content-id and
+  rejects tampered ids or mutated params under a stale id (self-verifying transport).
+  `dag->string`/`string->dag` for text transport. Gotcha logged: `sx-parse` primitive
+  is unbound in the server env — use `(read (open-input-string s))`.
+
 - **Ext: cost-based scheduling** (cost suite 13/13, total 115/115).
   `lib/artdag/cost.sx`: an injected `cost-fn (op params)` keeps media-op costs opaque
   (`const-cost`, `op-cost table`). `critical-path` = longest weighted path (finish-time

From 64ddd291760c3a0ce35fa1e091c933d42c98765c Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 12:25:41 +0000
Subject: [PATCH 09/13] artdag: optimize composition pass (fuse + dce) + 4
 tests
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

artdag/optimize entries outputs fusible? fuses the entry list then DCEs against
the output names — sinks survive fusion (never absorbed), so output-equivalent
with fewer nodes. optimize 22/22, total 132/132.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/optimize.sx       | 12 +++++++++++
 lib/artdag/scoreboard.json   |  6 +++---
 lib/artdag/scoreboard.md     |  4 ++--
 lib/artdag/tests/optimize.sx | 39 ++++++++++++++++++++++++++++++++++++
 plans/artdag-on-sx.md        |  8 +++++++-
 5 files changed, 63 insertions(+), 6 deletions(-)

diff --git a/lib/artdag/optimize.sx b/lib/artdag/optimize.sx
index 022c4825..c435313a 100644
--- a/lib/artdag/optimize.sx
+++ b/lib/artdag/optimize.sx
@@ -4,6 +4,7 @@
 ;            already collapse to one node at build time (artdag/cse == build).
 ;   Fusion — collapse a maximal 1-to-1 chain of fusible unary ops into a single
 ;            "artdag/pipeline" node that replays the stages; output-equivalent.
+;   optimize — fuse then DCE in one pass.
 ; Depends on dag.sx and analyze.sx.
 
 ; ---- dict helper ----
@@ -188,3 +189,14 @@
         (= op artdag/pipeline-op)
         ((artdag/pipeline-run base-runner) params inputs)
         (base-runner op params inputs)))))
+
+; ---- full optimization pass ----
+; fuse the entry list, then drop everything not feeding the requested output
+; names. Output names survive fusion (sinks are never absorbed).
+(define
+  artdag/optimize
+  (fn
+    (entries outputs fusible?)
+    (let
+      ((fused (artdag/fuse entries fusible?)))
+      (artdag/dce fused (map (fn (nm) (artdag/dag-id fused nm)) outputs)))))
diff --git a/lib/artdag/scoreboard.json b/lib/artdag/scoreboard.json
index 619b39e7..f46251b7 100644
--- a/lib/artdag/scoreboard.json
+++ b/lib/artdag/scoreboard.json
@@ -4,12 +4,12 @@
     "analyze": {"pass": 16, "fail": 0},
     "plan": {"pass": 18, "fail": 0},
     "execute": {"pass": 15, "fail": 0},
-    "optimize": {"pass": 18, "fail": 0},
+    "optimize": {"pass": 22, "fail": 0},
     "fed": {"pass": 15, "fail": 0},
     "cost": {"pass": 13, "fail": 0},
     "serialize": {"pass": 13, "fail": 0}
   },
-  "total_pass": 128,
+  "total_pass": 132,
   "total_fail": 0,
-  "total": 128
+  "total": 132
 }
diff --git a/lib/artdag/scoreboard.md b/lib/artdag/scoreboard.md
index 781cfcd3..5d1a483c 100644
--- a/lib/artdag/scoreboard.md
+++ b/lib/artdag/scoreboard.md
@@ -8,8 +8,8 @@ _Generated by `lib/artdag/conformance.sh`_
 | analyze | 16 | 0 | 16 |
 | plan | 18 | 0 | 18 |
 | execute | 15 | 0 | 15 |
-| optimize | 18 | 0 | 18 |
+| optimize | 22 | 0 | 22 |
 | fed | 15 | 0 | 15 |
 | cost | 13 | 0 | 13 |
 | serialize | 13 | 0 | 13 |
-| **Total** | **128** | **0** | **128** |
+| **Total** | **132** | **0** | **132** |
diff --git a/lib/artdag/tests/optimize.sx b/lib/artdag/tests/optimize.sx
index 6e275ad0..88cf4fdd 100644
--- a/lib/artdag/tests/optimize.sx
+++ b/lib/artdag/tests/optimize.sx
@@ -174,3 +174,42 @@
   "fusion: empty fusible set leaves dag unchanged"
   (artdag/node-count (artdag/fuse opt-chain (fn (op) false)))
   4)
+
+; ---- full optimization pass (fuse + dce) ----
+
+(define
+  optp-entries
+  (list
+    (list "a" "in" (list) {:v 5})
+    (list "b" "inc" (list "a") {})
+    (list "c" "inc" (list "b") {})
+    (list "x" "sq" (list "a") {})))
+
+(artdag-test
+  "optimize: fuses chain and drops dead node"
+  (artdag/node-count (artdag/optimize optp-entries (list "c") opt-inc?))
+  2)
+
+(artdag-test
+  "optimize: leaves dead node when it is an output"
+  (artdag/node-count (artdag/optimize optp-entries (list "c" "x") opt-inc?))
+  3)
+
+(artdag-test
+  "optimize: result equals the unoptimized dag"
+  (let
+    ((c1 (persist/open)) (c2 (persist/open)))
+    (let
+      ((o (artdag/optimize optp-entries (list "c") opt-inc?)))
+      (=
+        (artdag/result-of (artdag/run o opt-RUN c1) (artdag/dag-id o "c"))
+        (artdag/result-of
+          (artdag/run (artdag/build optp-entries) opt-RUN c2)
+          (artdag/dag-id (artdag/build optp-entries) "c")))))
+  true)
+
+(artdag-test
+  "optimize: no fusible ops still drops dead nodes"
+  (artdag/node-count
+    (artdag/optimize optp-entries (list "c") (fn (op) false)))
+  3)
diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index fcfade9a..b8019bee 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -30,7 +30,7 @@ edges.
 
 ## Status (rolling)
 
-`bash lib/artdag/conformance.sh` → **128/128** (8 suites: dag, analyze, plan, execute, optimize, fed, cost, serialize)
+`bash lib/artdag/conformance.sh` → **132/132** (8 suites: dag, analyze, plan, execute, optimize, fed, cost, serialize)
 
 Base roadmap (Phases 1–6) COMPLETE. Now extending.
 
@@ -138,6 +138,12 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
+- **Ext: optimize composition pass** (optimize suite 22/22, total 132/132).
+  `artdag/optimize entries outputs fusible?` fuses the entry list then DCEs against
+  the output names (sinks survive fusion since they're never absorbed) — fewer nodes,
+  identical results. Verified: dead branch dropped + chain fused (4→2), an output that
+  is itself "dead" is retained, no-fusible-set still DCEs.
+
 - **Ext: DAG wire serialization** (serialize suite 13/13, total 128/128).
   `lib/artdag/serialize.sx`: `dag->wire` emits a topo-ordered list of
   `(id op inputs params commutative)` records — plain lists with keyword-keyed param

From f29d8c047b881f5dd64dd7ad0e4c377c650127a6 Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 12:28:06 +0000
Subject: [PATCH 10/13] artdag: execution stats / cache analytics + 12 tests

stats.sx reports hit-ratio, cost-weighted work-recomputed/work-saved,
savings-ratio, and exec-summary over an execution record. Verifies cold (0
saved), warm (all saved), and incremental (saved = unchanged, ran = dirty
closure). stats 12/12, total 144/144.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/conformance.sh  |   3 +-
 lib/artdag/scoreboard.json |   7 +-
 lib/artdag/scoreboard.md   |   3 +-
 lib/artdag/stats.sx        |  51 +++++++++++++
 lib/artdag/tests/stats.sx  | 150 +++++++++++++++++++++++++++++++++++++
 plans/artdag-on-sx.md      |   8 +-
 6 files changed, 216 insertions(+), 6 deletions(-)
 create mode 100644 lib/artdag/stats.sx
 create mode 100644 lib/artdag/tests/stats.sx

diff --git a/lib/artdag/conformance.sh b/lib/artdag/conformance.sh
index 050b6687..c2d19bba 100755
--- a/lib/artdag/conformance.sh
+++ b/lib/artdag/conformance.sh
@@ -13,7 +13,7 @@ if [ ! -x "$SX_SERVER" ]; then
   exit 1
 fi
 
-SUITES=(dag analyze plan execute optimize fed cost serialize)
+SUITES=(dag analyze plan execute optimize fed cost serialize stats)
 
 OUT_JSON="lib/artdag/scoreboard.json"
 OUT_MD="lib/artdag/scoreboard.md"
@@ -49,6 +49,7 @@ run_suite() {
 (load "lib/artdag/federation.sx")
 (load "lib/artdag/cost.sx")
 (load "lib/artdag/serialize.sx")
+(load "lib/artdag/stats.sx")
 (epoch 2)
 (eval "(define artdag-test-pass 0)")
 (eval "(define artdag-test-fail 0)")
diff --git a/lib/artdag/scoreboard.json b/lib/artdag/scoreboard.json
index f46251b7..2b4698d7 100644
--- a/lib/artdag/scoreboard.json
+++ b/lib/artdag/scoreboard.json
@@ -7,9 +7,10 @@
     "optimize": {"pass": 22, "fail": 0},
     "fed": {"pass": 15, "fail": 0},
     "cost": {"pass": 13, "fail": 0},
-    "serialize": {"pass": 13, "fail": 0}
+    "serialize": {"pass": 13, "fail": 0},
+    "stats": {"pass": 12, "fail": 0}
   },
-  "total_pass": 132,
+  "total_pass": 144,
   "total_fail": 0,
-  "total": 132
+  "total": 144
 }
diff --git a/lib/artdag/scoreboard.md b/lib/artdag/scoreboard.md
index 5d1a483c..5e61f292 100644
--- a/lib/artdag/scoreboard.md
+++ b/lib/artdag/scoreboard.md
@@ -12,4 +12,5 @@ _Generated by `lib/artdag/conformance.sh`_
 | fed | 15 | 0 | 15 |
 | cost | 13 | 0 | 13 |
 | serialize | 13 | 0 | 13 |
-| **Total** | **132** | **0** | **132** |
+| stats | 12 | 0 | 12 |
+| **Total** | **144** | **0** | **144** |
diff --git a/lib/artdag/stats.sx b/lib/artdag/stats.sx
new file mode 100644
index 00000000..5ddf1e10
--- /dev/null
+++ b/lib/artdag/stats.sx
@@ -0,0 +1,51 @@
+; lib/artdag/stats.sx — observability over an execution: cache hit ratio and the
+; compute work saved by memoization (weighted by the cost model). An exec is the
+; {:results :recomputed :hits} record returned by artdag/execute. Depends on
+; execute.sx (exec accessors) and cost.sx (artdag/-node-cost).
+
+(define
+  artdag/exec-total
+  (fn (exec) (+ (artdag/recompute-count exec) (artdag/hit-count exec))))
+
+; fraction of executed nodes served from cache (0 when nothing ran).
+(define
+  artdag/hit-ratio
+  (fn
+    (exec)
+    (let
+      ((n (artdag/exec-total exec)))
+      (if (= n 0) 0 (/ (artdag/hit-count exec) n)))))
+
+(define
+  artdag/-sum-cost
+  (fn
+    (dag cost-fn ids)
+    (reduce
+      (fn (s id) (+ s (artdag/-node-cost dag cost-fn id)))
+      0
+      ids)))
+
+; weighted compute work that actually ran this execution.
+(define
+  artdag/work-recomputed
+  (fn
+    (exec dag cost-fn)
+    (artdag/-sum-cost dag cost-fn (get exec :recomputed))))
+
+; weighted compute work avoided by cache hits.
+(define
+  artdag/work-saved
+  (fn (exec dag cost-fn) (artdag/-sum-cost dag cost-fn (get exec :hits))))
+
+; fraction of total weighted work that the cache saved (0 when no work at all).
+(define
+  artdag/savings-ratio
+  (fn
+    (exec dag cost-fn)
+    (let
+      ((saved (artdag/work-saved exec dag cost-fn))
+        (ran (artdag/work-recomputed exec dag cost-fn)))
+      (if (= (+ saved ran) 0) 0 (/ saved (+ saved ran))))))
+
+; compact summary dict for logging.
+(define artdag/exec-summary (fn (exec dag cost-fn) {:work-saved (artdag/work-saved exec dag cost-fn) :recomputed (artdag/recompute-count exec) :total (artdag/exec-total exec) :work-ran (artdag/work-recomputed exec dag cost-fn) :hits (artdag/hit-count exec)}))
diff --git a/lib/artdag/tests/stats.sx b/lib/artdag/tests/stats.sx
new file mode 100644
index 00000000..c143bff1
--- /dev/null
+++ b/lib/artdag/tests/stats.sx
@@ -0,0 +1,150 @@
+; execution stats: hit ratio + memoized work saved (cost-weighted).
+
+(define st-RT (artdag/op-table-runner {:in (fn (p i) (get p :v)) :add (fn (p i) (+ (nth i 0) (nth i 1))) :inc (fn (p i) (+ 1 (first i)))}))
+
+(define
+  st-D
+  (artdag/build
+    (list
+      (list "p" "in" (list) {:v 10})
+      (list "q" "in" (list) {:v 20})
+      (list "b" "inc" (list "p") {})
+      (list "c" "inc" (list "q") {})
+      (list "d" "add" (list "b" "c") {} true))))
+
+; same shape, leaf q changed -> dirty closure {q,c,d}
+(define
+  st-D2
+  (artdag/build
+    (list
+      (list "p" "in" (list) {:v 10})
+      (list "q" "in" (list) {:v 21})
+      (list "b" "inc" (list "p") {})
+      (list "c" "inc" (list "q") {})
+      (list "d" "add" (list "b" "c") {} true))))
+
+(define st-W (artdag/op-cost {:add 5 :inc 2}))
+
+; ---- cold run ----
+
+(artdag-test
+  "cold run: hit ratio is zero"
+  (let
+    ((cache (persist/open)))
+    (artdag/hit-ratio (artdag/run st-D st-RT cache)))
+  0)
+
+(artdag-test
+  "cold run: nothing saved"
+  (let
+    ((cache (persist/open)))
+    (artdag/work-saved (artdag/run st-D st-RT cache) st-D artdag/const-cost))
+  0)
+
+(artdag-test
+  "cold run: all work runs"
+  (let
+    ((cache (persist/open)))
+    (artdag/work-recomputed
+      (artdag/run st-D st-RT cache)
+      st-D
+      artdag/const-cost))
+  5)
+
+(artdag-test
+  "cold run: weighted work ran"
+  (let
+    ((cache (persist/open)))
+    (artdag/work-recomputed (artdag/run st-D st-RT cache) st-D st-W))
+  11)
+
+; ---- warm rerun ----
+
+(artdag-test
+  "warm rerun: hit ratio is one"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run st-D st-RT cache)
+      (artdag/hit-ratio (artdag/run st-D st-RT cache))))
+  1)
+
+(artdag-test
+  "warm rerun: savings ratio is one"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run st-D st-RT cache)
+      (artdag/savings-ratio
+        (artdag/run st-D st-RT cache)
+        st-D
+        artdag/const-cost)))
+  1)
+
+(artdag-test
+  "warm rerun: all weighted work saved"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run st-D st-RT cache)
+      (artdag/work-saved (artdag/run st-D st-RT cache) st-D st-W)))
+  11)
+
+; ---- partial (incremental) ----
+
+(artdag-test
+  "incremental: total is every node"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run st-D st-RT cache)
+      (artdag/exec-total (artdag/run st-D2 st-RT cache))))
+  5)
+
+(artdag-test
+  "incremental: saved work counts unchanged nodes"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run st-D st-RT cache)
+      (artdag/work-saved
+        (artdag/run st-D2 st-RT cache)
+        st-D2
+        artdag/const-cost)))
+  2)
+
+(artdag-test
+  "incremental: ran work counts dirty closure"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run st-D st-RT cache)
+      (artdag/work-recomputed
+        (artdag/run st-D2 st-RT cache)
+        st-D2
+        artdag/const-cost)))
+  3)
+
+(artdag-test
+  "summary reports recompute count"
+  (let
+    ((cache (persist/open)))
+    (get
+      (artdag/exec-summary
+        (artdag/run st-D st-RT cache)
+        st-D
+        artdag/const-cost)
+      :recomputed))
+  5)
+
+(artdag-test
+  "summary reports total"
+  (let
+    ((cache (persist/open)))
+    (get
+      (artdag/exec-summary
+        (artdag/run st-D st-RT cache)
+        st-D
+        artdag/const-cost)
+      :total))
+  5)
diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index b8019bee..1a105d98 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -30,7 +30,7 @@ edges.
 
 ## Status (rolling)
 
-`bash lib/artdag/conformance.sh` → **132/132** (8 suites: dag, analyze, plan, execute, optimize, fed, cost, serialize)
+`bash lib/artdag/conformance.sh` → **144/144** (9 suites: dag, analyze, plan, execute, optimize, fed, cost, serialize, stats)
 
 Base roadmap (Phases 1–6) COMPLETE. Now extending.
 
@@ -138,6 +138,12 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
+- **Ext: execution stats / cache analytics** (stats suite 12/12, total 144/144).
+  `lib/artdag/stats.sx` over an exec record: `hit-ratio`, `work-recomputed`/`work-saved`
+  (cost-weighted via the cost model), `savings-ratio`, and `exec-summary`. Cold run =
+  0 hit ratio / all work ran; warm rerun = ratio 1 / all work saved; incremental = saved
+  work counts unchanged nodes, ran work counts the dirty closure.
+
 - **Ext: optimize composition pass** (optimize suite 22/22, total 132/132).
   `artdag/optimize entries outputs fusible?` fuses the entry list then DCEs against
   the output names (sinks survive fusion since they're never absorbed) — fewer nodes,

From 28fed7c7994ff9d4d3f53fb2494669bb272d7e0f Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 12:32:14 +0000
Subject: [PATCH 11/13] =?UTF-8?q?artdag:=20fault-tolerant=20execution=20?=
 =?UTF-8?q?=E2=80=94=20confined=20failure,=20cache=20never=20poisoned=20+?=
 =?UTF-8?q?=2014=20tests?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

fault.sx run-safe: a node op may return (artdag/fail reason); failure is confined
to that node + downstream dependents while independent branches compute, and failed
results are never cached, so retry after a fix recomputes only the failed closure
and hits the good nodes. fault 14/14, total 158/158.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/conformance.sh  |   3 +-
 lib/artdag/fault.sx        |  56 +++++++++++++++
 lib/artdag/scoreboard.json |   7 +-
 lib/artdag/scoreboard.md   |   3 +-
 lib/artdag/tests/fault.sx  | 144 +++++++++++++++++++++++++++++++++++++
 plans/artdag-on-sx.md      |   9 ++-
 6 files changed, 216 insertions(+), 6 deletions(-)
 create mode 100644 lib/artdag/fault.sx
 create mode 100644 lib/artdag/tests/fault.sx

diff --git a/lib/artdag/conformance.sh b/lib/artdag/conformance.sh
index c2d19bba..7efa9077 100755
--- a/lib/artdag/conformance.sh
+++ b/lib/artdag/conformance.sh
@@ -13,7 +13,7 @@ if [ ! -x "$SX_SERVER" ]; then
   exit 1
 fi
 
-SUITES=(dag analyze plan execute optimize fed cost serialize stats)
+SUITES=(dag analyze plan execute optimize fed cost serialize stats fault)
 
 OUT_JSON="lib/artdag/scoreboard.json"
 OUT_MD="lib/artdag/scoreboard.md"
@@ -50,6 +50,7 @@ run_suite() {
 (load "lib/artdag/cost.sx")
 (load "lib/artdag/serialize.sx")
 (load "lib/artdag/stats.sx")
+(load "lib/artdag/fault.sx")
 (epoch 2)
 (eval "(define artdag-test-pass 0)")
 (eval "(define artdag-test-fail 0)")
diff --git a/lib/artdag/fault.sx b/lib/artdag/fault.sx
new file mode 100644
index 00000000..fb579199
--- /dev/null
+++ b/lib/artdag/fault.sx
@@ -0,0 +1,56 @@
+; lib/artdag/fault.sx — fault-tolerant execution. A node op may fail by returning
+; (artdag/fail reason); the failure is confined to that node and its transitive
+; dependents (which cannot run without it), while independent branches still
+; compute. Failed results are NEVER cached, so a later run with the fault fixed
+; recomputes only the failed closure. Depends on execute.sx and plan.sx.
+
+(define artdag/fail (fn (reason) {:artdag-fail true :reason reason}))
+(define artdag/failed? (fn (v) (and (dict? v) (has-key? v :artdag-fail))))
+
+(define
+  artdag/-exec-safe-node
+  (fn
+    (dag runner cache acc id)
+    (let
+      ((node (artdag/dag-get dag id)))
+      (let
+        ((ins (artdag/node-inputs node)))
+        (if
+          (some (fn (in) (artdag/member? in (get acc :failed))) ins)
+          (assoc acc :failed (concat (get acc :failed) (list id)))
+          (if
+            (persist/kv-has? cache id)
+            (assoc
+              acc
+              :results (assoc (get acc :results) id (persist/kv-get cache id))
+              :hits (concat (get acc :hits) (list id)))
+            (let
+              ((inputs (map (fn (in) (artdag/-input-result (get acc :results) cache in)) ins)))
+              (let
+                ((result (runner (artdag/node-op node) (artdag/node-params node) inputs)))
+                (if
+                  (artdag/failed? result)
+                  (assoc acc :failed (concat (get acc :failed) (list id)))
+                  (begin
+                    (persist/kv-put cache id result)
+                    (assoc
+                      acc
+                      :results (assoc (get acc :results) id result)
+                      :recomputed (concat (get acc :recomputed) (list id)))))))))))))
+
+(define
+  artdag/run-safe
+  (fn
+    (dag runner cache)
+    (reduce
+      (fn (acc id) (artdag/-exec-safe-node dag runner cache acc id))
+      {:recomputed (list) :results {} :hits (list) :failed (list)}
+      (artdag/plan-flatten (artdag/plan dag 0)))))
+
+(define
+  artdag/failed-nodes
+  (fn (exec) (artdag/sort-strings (get exec :failed))))
+(define artdag/failure-count (fn (exec) (len (get exec :failed))))
+(define
+  artdag/all-ok?
+  (fn (exec) (= (len (get exec :failed)) 0)))
diff --git a/lib/artdag/scoreboard.json b/lib/artdag/scoreboard.json
index 2b4698d7..52d1d93b 100644
--- a/lib/artdag/scoreboard.json
+++ b/lib/artdag/scoreboard.json
@@ -8,9 +8,10 @@
     "fed": {"pass": 15, "fail": 0},
     "cost": {"pass": 13, "fail": 0},
     "serialize": {"pass": 13, "fail": 0},
-    "stats": {"pass": 12, "fail": 0}
+    "stats": {"pass": 12, "fail": 0},
+    "fault": {"pass": 14, "fail": 0}
   },
-  "total_pass": 144,
+  "total_pass": 158,
   "total_fail": 0,
-  "total": 144
+  "total": 158
 }
diff --git a/lib/artdag/scoreboard.md b/lib/artdag/scoreboard.md
index 5e61f292..ea91478b 100644
--- a/lib/artdag/scoreboard.md
+++ b/lib/artdag/scoreboard.md
@@ -13,4 +13,5 @@ _Generated by `lib/artdag/conformance.sh`_
 | cost | 13 | 0 | 13 |
 | serialize | 13 | 0 | 13 |
 | stats | 12 | 0 | 12 |
-| **Total** | **144** | **0** | **144** |
+| fault | 14 | 0 | 14 |
+| **Total** | **158** | **0** | **158** |
diff --git a/lib/artdag/tests/fault.sx b/lib/artdag/tests/fault.sx
new file mode 100644
index 00000000..a7bcbc0a
--- /dev/null
+++ b/lib/artdag/tests/fault.sx
@@ -0,0 +1,144 @@
+; fault-tolerant execution: failure confined to its closure, cache never poisoned.
+
+(define ft-BAD (artdag/op-table-runner {:boom (fn (p i) (artdag/fail "kaboom")) :in (fn (p i) (get p :v)) :add (fn (p i) (+ (nth i 0) (nth i 1))) :inc (fn (p i) (+ 1 (first i)))}))
+
+(define ft-GOOD (artdag/op-table-runner {:boom (fn (p i) 99) :in (fn (p i) (get p :v)) :add (fn (p i) (+ (nth i 0) (nth i 1))) :inc (fn (p i) (+ 1 (first i)))}))
+
+; p,q leaves; b=inc(p) (independent); c=boom(q); d=add(b,c)
+(define
+  ft-D
+  (artdag/build
+    (list
+      (list "p" "in" (list) {:v 10})
+      (list "q" "in" (list) {:v 20})
+      (list "b" "inc" (list "p") {})
+      (list "c" "boom" (list "q") {})
+      (list "d" "add" (list "b" "c") {} true))))
+
+; ---- markers ----
+
+(artdag-test
+  "fail constructor is detected"
+  (artdag/failed? (artdag/fail "x"))
+  true)
+
+(artdag-test
+  "plain values are not failures"
+  (artdag/failed? 42)
+  false)
+
+; ---- failure confinement ----
+
+(artdag-test
+  "failure count covers node and its dependents"
+  (let
+    ((cache (persist/open)))
+    (artdag/failure-count (artdag/run-safe ft-D ft-BAD cache)))
+  2)
+
+(artdag-test
+  "failed set is exactly c and d"
+  (let
+    ((cache (persist/open)))
+    (artdag/failed-nodes (artdag/run-safe ft-D ft-BAD cache)))
+  (artdag/sort-strings
+    (list (artdag/dag-id ft-D "c") (artdag/dag-id ft-D "d"))))
+
+(artdag-test
+  "independent branch still computes"
+  (let
+    ((cache (persist/open)))
+    (artdag/recompute-count (artdag/run-safe ft-D ft-BAD cache)))
+  3)
+
+(artdag-test
+  "independent node result is available"
+  (let
+    ((cache (persist/open)))
+    (artdag/result-of
+      (artdag/run-safe ft-D ft-BAD cache)
+      (artdag/dag-id ft-D "b")))
+  11)
+
+(artdag-test
+  "all-ok? is false when something failed"
+  (let
+    ((cache (persist/open)))
+    (artdag/all-ok? (artdag/run-safe ft-D ft-BAD cache)))
+  false)
+
+(artdag-test
+  "all-ok? is true on a clean run"
+  (let
+    ((cache (persist/open)))
+    (artdag/all-ok? (artdag/run-safe ft-D ft-GOOD cache)))
+  true)
+
+; ---- cache integrity ----
+
+(artdag-test
+  "good node is cached"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run-safe ft-D ft-BAD cache)
+      (persist/kv-has? cache (artdag/dag-id ft-D "b"))))
+  true)
+
+(artdag-test
+  "failed node is never cached"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run-safe ft-D ft-BAD cache)
+      (persist/kv-has? cache (artdag/dag-id ft-D "c"))))
+  false)
+
+; ---- retry after fix ----
+
+(artdag-test
+  "retry recomputes only the failed closure"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run-safe ft-D ft-BAD cache)
+      (artdag/recompute-count (artdag/run-safe ft-D ft-GOOD cache))))
+  2)
+
+(artdag-test
+  "retry reuses the good nodes from cache"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run-safe ft-D ft-BAD cache)
+      (artdag/hit-count (artdag/run-safe ft-D ft-GOOD cache))))
+  3)
+
+(artdag-test
+  "retry produces the correct result"
+  (let
+    ((cache (persist/open)))
+    (begin
+      (artdag/run-safe ft-D ft-BAD cache)
+      (artdag/result-of
+        (artdag/run-safe ft-D ft-GOOD cache)
+        (artdag/dag-id ft-D "d"))))
+  110)
+
+; ---- transitive cascade ----
+
+(artdag-test
+  "failure cascades through a deep chain"
+  (let
+    ((cache (persist/open)))
+    (artdag/failure-count
+      (artdag/run-safe
+        (artdag/build
+          (list
+            (list "a" "in" (list) {:v 1})
+            (list "b" "boom" (list "a") {})
+            (list "c" "inc" (list "b") {})
+            (list "d" "inc" (list "c") {})))
+        ft-BAD
+        cache)))
+  3)
diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index 1a105d98..f5f7cbab 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -30,7 +30,7 @@ edges.
 
 ## Status (rolling)
 
-`bash lib/artdag/conformance.sh` → **144/144** (9 suites: dag, analyze, plan, execute, optimize, fed, cost, serialize, stats)
+`bash lib/artdag/conformance.sh` → **158/158** (10 suites: dag, analyze, plan, execute, optimize, fed, cost, serialize, stats, fault)
 
 Base roadmap (Phases 1–6) COMPLETE. Now extending.
 
@@ -138,6 +138,13 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
+- **Ext: fault-tolerant execution** (fault suite 14/14, total 158/158).
+  `lib/artdag/fault.sx`: a node op may fail via `(artdag/fail reason)`; `run-safe`
+  confines the failure to that node + its transitive dependents (independent branches
+  still compute) and NEVER caches a failed result, so a later run with the fault fixed
+  recomputes only the failed closure and cache-hits the good nodes. `failed?`/`fail`
+  markers, `failed-nodes`/`failure-count`/`all-ok?`.
+
 - **Ext: execution stats / cache analytics** (stats suite 12/12, total 144/144).
   `lib/artdag/stats.sx` over an exec record: `hit-ratio`, `work-recomputed`/`work-saved`
   (cost-weighted via the cost model), `savings-ratio`, and `exec-summary`. Cold run =

From cfc784e45ae1410826f0665cbf0a33a1ce6b142e Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 12:34:07 +0000
Subject: [PATCH 12/13] =?UTF-8?q?artdag:=20public=20API=20facade=20lib/art?=
 =?UTF-8?q?dag/api.sx=20=E2=80=94=20load=20list=20+=20surface=20index?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Reference index (matching datalog/persist convention): canonical load order and
the full public surface across all 10 modules, plus artdag/version. Wired into the
conformance load list. Total 158/158 unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 lib/artdag/api.sx         | 91 +++++++++++++++++++++++++++++++++++++++
 lib/artdag/conformance.sh |  1 +
 2 files changed, 92 insertions(+)
 create mode 100644 lib/artdag/api.sx

diff --git a/lib/artdag/api.sx b/lib/artdag/api.sx
new file mode 100644
index 00000000..39520b0e
--- /dev/null
+++ b/lib/artdag/api.sx
@@ -0,0 +1,91 @@
+; lib/artdag/api.sx — public API index for the artdag content-addressed dataflow
+; DAG engine. Reference-only: `load` is an epoch-protocol command, not an SX
+; function, so this file cannot reload the modules from inside another `.sx`. To
+; set up a session, issue these loads in order (after spec/stdlib.sx + lib/r7rs.sx,
+; the lib/datalog/* modules, and the lib/persist/* modules):
+;
+;   (load "lib/artdag/dag.sx")
+;   (load "lib/artdag/analyze.sx")      ; requires lib/datalog/*
+;   (load "lib/artdag/plan.sx")
+;   (load "lib/artdag/execute.sx")      ; requires lib/persist/*
+;   (load "lib/artdag/optimize.sx")
+;   (load "lib/artdag/federation.sx")
+;   (load "lib/artdag/cost.sx")
+;   (load "lib/artdag/serialize.sx")
+;   (load "lib/artdag/stats.sx")
+;   (load "lib/artdag/fault.sx")
+;
+; (lib/artdag/conformance.sh runs this load list automatically.)
+;
+; ── Public API surface ─────────────────────────────────────────────
+;
+;   Model / content addressing (dag.sx):
+;     (artdag/node op inputs params)        node spec (non-commutative)
+;     (artdag/cnode op inputs params)       commutative node spec
+;     (artdag/content-id node)              structural digest "node:..."
+;     (artdag/build entries)                {:ok :nodes :names :order} | {:ok false :error}
+;       entry = (name op (input-names...) params [commutative?])
+;     (artdag/dag-id dag name)              local name -> content-id
+;     (artdag/dag-get dag id)               content-id -> node
+;     (artdag/dag-node-by-name dag name)    name -> node
+;     (artdag/dag-order dag)                topo-ordered content-ids
+;     (artdag/node-count dag)               distinct node count
+;
+;   Analyze on Datalog (analyze.sx):
+;     (artdag/analyze dag)                  -> datalog db
+;     (artdag/deps-of db id)                direct dependencies
+;     (artdag/dependents-of db id)          direct dependents
+;     (artdag/reachable-from db id)         transitive dependents
+;     (artdag/ancestors-of db id)           transitive dependencies
+;     (artdag/dirty-closure dag changed)    changed nodes + all dependents
+;
+;   Plan (plan.sx):
+;     (artdag/plan dag cap)                 topo batches under width cap (0 = unlimited)
+;     (artdag/plan-dirty dag changed cap)   incremental plan over the dirty closure
+;     (artdag/plan-batches/-width/-size/-flatten plan)
+;
+;   Execute (execute.sx):
+;     (artdag/op-table-runner table)        runner from op-name -> (fn (params inputs))
+;     (artdag/run dag runner cache)         full memoized run
+;     (artdag/run-dirty dag changed runner cache)
+;     (artdag/execute dag plan runner cache) -> {:results :recomputed :hits}
+;     (artdag/result-of/recompute-count/hit-count/recomputed exec)
+;       cache = a lib/persist kv backend (persist/open)
+;
+;   Optimize (optimize.sx):
+;     (artdag/dce dag outputs)              drop nodes not feeding the outputs
+;     (artdag/cse entries)                  == build (sharing is free from content ids)
+;     (artdag/fuse entries fusible?)        collapse fusible unary chains -> pipeline nodes
+;     (artdag/fusing-runner base-runner)    runner that replays pipeline stages
+;     (artdag/optimize entries outputs fusible?)  fuse then dce
+;
+;   Federation (federation.sx):
+;     (artdag/fed-open)                     {:cache :prov}
+;     (artdag/fed-run fed dag runner)       run against the instance cache
+;     (artdag/fed-export fed peer-id)       bundle of {:cid :result :peer}
+;     (artdag/fed-import fed bundle trusted?)  trust-gated import + provenance
+;     (artdag/fed-pull fed fetch-fn peer-id trusted?)  pull via injected transport
+;     (artdag/fed-invalidate fed peer-id)   drop a peer's results (peer-scoped)
+;
+;   Cost / scheduling (cost.sx):
+;     (artdag/const-cost) (artdag/op-cost table)   cost-fn (op params) -> number
+;     (artdag/critical-path dag cost-fn)    longest weighted path
+;     (artdag/makespan dag plan cost-fn)    estimated wall-clock under a plan
+;     (artdag/total-work dag cost-fn) (artdag/speedup dag plan cost-fn)
+;
+;   Serialize (serialize.sx):
+;     (artdag/dag->wire dag) (artdag/wire->dag records)  portable record form
+;     (artdag/wire-verify records)          content-id integrity check
+;     (artdag/dag->string dag) (artdag/string->dag s)    text transport
+;
+;   Stats (stats.sx):
+;     (artdag/hit-ratio exec)
+;     (artdag/work-recomputed/work-saved exec dag cost-fn)
+;     (artdag/savings-ratio exec dag cost-fn) (artdag/exec-summary exec dag cost-fn)
+;
+;   Fault tolerance (fault.sx):
+;     (artdag/fail reason) (artdag/failed? v)
+;     (artdag/run-safe dag runner cache)    -> {:results :recomputed :hits :failed}
+;     (artdag/failed-nodes/failure-count/all-ok? exec)
+
+(define artdag/version "1.0")
diff --git a/lib/artdag/conformance.sh b/lib/artdag/conformance.sh
index 7efa9077..f71d193a 100755
--- a/lib/artdag/conformance.sh
+++ b/lib/artdag/conformance.sh
@@ -51,6 +51,7 @@ run_suite() {
 (load "lib/artdag/serialize.sx")
 (load "lib/artdag/stats.sx")
 (load "lib/artdag/fault.sx")
+(load "lib/artdag/api.sx")
 (epoch 2)
 (eval "(define artdag-test-pass 0)")
 (eval "(define artdag-test-fail 0)")

From 298621e2be5226de1ded4c300718b7311bd1128d Mon Sep 17 00:00:00 2001
From: giles <giles.bradshaw@rose-ash.com>
Date: Sun, 7 Jun 2026 12:34:30 +0000
Subject: [PATCH 13/13] artdag: log api facade in plan progress

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 plans/artdag-on-sx.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index f5f7cbab..1f005f50 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -138,6 +138,10 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
+- **Ext: public API facade** (`lib/artdag/api.sx`, total 158/158 unchanged).
+  Reference index matching the datalog/persist convention: canonical load order +
+  the full public surface across all 10 modules + `artdag/version`.
+
 - **Ext: fault-tolerant execution** (fault suite 14/14, total 158/158).
   `lib/artdag/fault.sx`: a node op may fail via `(artdag/fail reason)`; `run-safe`
   confines the failure to that node + its transitive dependents (independent branches