Merge pull request 'mesh-build-node tests: never install a toolchain from the registry in the integration level; skip as NOT RUN when none is installed (issue 890)' (#491) from fix/build-node-tests-offline into main

On ace, which holds no Node build module, five integration tests each spent 70 s in npm's network retries and failed every mesh-catalog check run there (five verdicts since 00:07). The tests now copy the node's installed toolchain or are skipped as NOT RUN; the registry is never reached. Three tests sharing the fixture are one, so the toolchain is copied three times instead of five (10 integration tests in the module, now 8).

modules/desk-channel/cmd/desk-channel/desk.go

@@ -15,6 +15,13 @@ package main
 //     the desk says in its standing when that happened (`answers-lost-at`), and the router, which alone knows
 //     what is still open and unanswered, says that again under its handle — replacing the notification in place,
 //     so its buttons work again. Nothing resolved, silenced or cancelled comes back.
+//   - **A store that does not answer does not lose where a message is shown, while the desk runs.** A message
+//     is shown first and its notification ids kept after; when the state store does not answer then (the bus
+//     reloading its accounts, 2026-10-26 09:18: the very outage that raised the condition), the work is taken
+//     all the same and the ids are held in memory, recalled before the store, and kept at the start of the next
+//     work and at the minute's standing. Otherwise the clearing of that message finds no notification to
+//     replace and the urgent one stays on screen for good. A desk that restarts while it still holds some loses
+//     where those are shown; the log says so when they are held.
 //   - **Standing**: it can send when machines are named in its settings; which of them answered last is in its
 //     status. A message no machine took is said to the router as failed, and tried again by it.
 
@@ -93,6 +100,9 @@ type Desk struct {
 	pause     map[string]pauseSeen
 	// lost is when each machine's notifier last started again: the answers its notifications waited for are lost.
 	lost map[string]time.Time
+	// unkept is what was shown and not yet kept in the store, because it did not answer: recalled from here
+	// before the store, and kept at the next piece of work.
+	unkept map[string]Shown
 }
 
 func (d *Desk) init() {
@@ -107,6 +117,9 @@ func (d *Desk) init() {
 	if d.lost == nil {
 		d.lost = map[string]time.Time{}
 	}
+	if d.unkept == nil {
+		d.unkept = map[string]Shown{}
+	}
 	if d.Now == nil {
 		d.Now = time.Now
 	}
@@ -138,6 +151,7 @@ func (d *Desk) Take(subject string, body json.RawMessage) error {
 		d.Logf("[desk-channel] work on %s could not be read; taken and dropped", subject)
 		return nil
 	}
+	d.KeepUnkept()
 	machines := d.Machines()
 	if m.Secret {
 		// Shown only where the notifier said lately it is not paused (the review of 2026-10-09): one held back
@@ -167,12 +181,16 @@ func (d *Desk) Take(subject string, body json.RawMessage) error {
 	switch {
 	case edit:
 		var err error
-		if before, err = d.Store.Get(m.Handle); err != nil {
+		if before, err = d.recall(m.Handle); err != nil {
 			return err
 		}
+		if before == nil {
+			d.Logf("[desk-channel] an edit of %s, which nothing here records as shown: shown as a new message; "+
+				"a notification it was to replace, if any, stays", m.Handle)
+		}
 	case !m.Secret:
 		var err error
-		if before, err = d.Store.Get(m.Handle); err != nil {
+		if before, err = d.recall(m.Handle); err != nil {
 			d.Logf("[desk-channel] what is shown under this handle could not be read (%v): shown as a new message", err)
 			before = nil
 		}
@@ -218,12 +236,91 @@ func (d *Desk) Take(subject string, body json.RawMessage) error {
 		// Shown once and kept nowhere of this module's (a link's code): no edit or re-showing reaches it.
 		return nil
 	}
-	if err := d.Store.Put(m.Handle, s); err != nil {
-		d.Logf("[desk-channel] shown, and what was shown could not be kept: an edit of it will not reach it: %v", err)
-	}
+	d.keep(m.Handle, s)
 	return nil
 }
 
+// keep keeps what a handle shows in the store. When the store does not answer it is held in memory, where an
+// edit, a reminder and a click still find it, and kept later (KeepUnkept). The work is taken either way: offered
+// again it would race the message's own later edits, and a redelivery is bounded where an outage is not.
+func (d *Desk) keep(handle string, s Shown) {
+	err := d.Store.Put(handle, s)
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if err == nil {
+		delete(d.unkept, handle)
+		return
+	}
+	d.unkept[handle] = s
+	d.Logf("[desk-channel] shown, and where it is shown could not be kept yet (%v): held in memory, so its edit "+
+		"and clearing still reach it, and kept when the store answers; %d held, lost if the desk restarts first",
+		err, len(d.unkept))
+}
+
+// KeepUnkept keeps in the store what it did not answer for before: at the start of each piece of work and at
+// the minute's standing. It stops at the first write the store does not answer, so one call waits on it once.
+func (d *Desk) KeepUnkept() {
+	d.init()
+	d.mu.Lock()
+	held := make(map[string]Shown, len(d.unkept))
+	for h, s := range d.unkept {
+		held[h] = s
+	}
+	d.mu.Unlock()
+	for h, s := range held {
+		if err := d.Store.Put(h, s); err != nil {
+			return
+		}
+		d.mu.Lock()
+		if cur, ok := d.unkept[h]; ok && sameShown(cur, s) {
+			delete(d.unkept, h)
+		}
+		d.mu.Unlock()
+		d.Logf("[desk-channel] where %s is shown is kept now", h)
+	}
+}
+
+func (d *Desk) unkeptOf(handle string) (Shown, bool) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	s, ok := d.unkept[handle]
+	return s, ok
+}
+
+// recall is what a handle shows: from memory when the store did not keep it yet, else from the store.
+func (d *Desk) recall(handle string) (*Shown, error) {
+	if s, ok := d.unkeptOf(handle); ok {
+		return &s, nil
+	}
+	return d.Store.Get(handle)
+}
+
+// handles is every handle shown: the store's and those held in memory.
+func (d *Desk) handles() ([]string, error) {
+	hs, err := d.Store.Handles()
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	seen := map[string]bool{}
+	for _, h := range hs {
+		seen[h] = true
+	}
+	for h := range d.unkept {
+		if !seen[h] {
+			hs = append(hs, h)
+		}
+	}
+	if err != nil && len(d.unkept) == 0 {
+		return nil, err
+	}
+	return hs, nil
+}
+
+func sameShown(a, b Shown) bool {
+	x, err1 := json.Marshal(a)
+	y, err2 := json.Marshal(b)
+	return err1 == nil && err2 == nil && string(x) == string(y)
+}
+
 // show puts one message on one machine's notifier, in place of `replace` when it names one.
 func (d *Desk) show(machine string, m asks.Message, replace int) (int, error) {
 	urgency := "normal"
@@ -308,12 +405,12 @@ func (d *Desk) Chosen(event, machine, ticket string) {
 }
 
 func (d *Desk) find(ticket string) (string, *Shown) {
-	handles, err := d.Store.Handles()
+	handles, err := d.handles()
 	if err != nil {
 		return "", nil
 	}
 	for _, h := range handles {
-		s, err := d.Store.Get(h)
+		s, err := d.recall(h)
 		if err != nil || s == nil {
 			continue
 		}
@@ -356,9 +453,9 @@ func (d *Desk) Started(event, machine string) int {
 	d.lost[machine] = d.Now()
 	d.mu.Unlock()
 	n := 0
-	if handles, err := d.Store.Handles(); err == nil {
+	if handles, err := d.handles(); err == nil {
 		for _, h := range handles {
-			if s, err := d.Store.Get(h); err == nil && s != nil && len(s.Message.Buttons) > 0 {
+			if s, err := d.recall(h); err == nil && s != nil && len(s.Message.Buttons) > 0 {
 				if _, here := s.On[machine]; here {
 					n++
 				}
@@ -472,6 +569,7 @@ func (d *Desk) Status() map[string]any {
 			"it proves nothing about who clicked: any process of the operator's account can choose an action, so it answers acknowledgements only",
 			"an answer is taken only on a machine its message was shown on; a message with buttons stays until dismissed",
 			"what it remembers is never shown again: when a notifier started again, the answers its notifications waited for are lost; the desk says when in its standing (answers-lost-at), and the router says again what is still open and unanswered, replacing those notifications in place — nothing resolved, silenced or cancelled comes back (issue 384)",
+			"a store that does not answer does not lose where a message is shown while the desk runs: it is held in memory, its edit and clearing still replace it in place, and it is kept when the store answers again; a desk restarted before then loses where those are shown, and its log said how many it held",
 			"it can send while a named machine's notifier said lately that it is not paused; a link's code is shown only on such a machine, kept nowhere, and sent secret so the notifier keeps it out of its history",
 		}}
 	if s.Why != "" {

modules/desk-channel/cmd/desk-channel/desk_test.go

@@ -3,6 +3,7 @@ package main
 import (
 	"encoding/json"
 	"errors"
+	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -363,9 +364,64 @@ func TestAMessageSaidAgainUnderItsHandleReplacesItsNotification(t *testing.T) {
 	}
 }
 
+// downStore is a store that does not answer while down: the bus reloading its accounts (2026-10-26 09:18).
+type downStore struct {
+	memShown
+	down *bool
+}
+
+func (s downStore) Get(h string) (*Shown, error) {
+	if *s.down {
+		return nil, errors.New("nats: no responders available for request")
+	}
+	return s.memShown.Get(h)
+}
+func (s downStore) Put(h string, v Shown) error {
+	if *s.down {
+		return errors.New("nats: no responders available for request")
+	}
+	return s.memShown.Put(h, v)
+}
+
 // The review of PR 176: a replace that fails on a machine keeps that machine's notification on record, so a
-// later edit or clearing still reaches it; failing everywhere, it is said to the router as failed.
+// later edit or clearing still reaches it; failing everywhere, it is said to the router as failed. And
+// (2026-10-26 09:18, an urgent "A new build of mesh-controller cannot be delivered" left on screen for hours
+// after its clearing): a message shown while the store does not answer keeps where it is shown in memory, its
+// work is taken, its clearing replaces it in place, and it is kept once the store answers.
 func TestAFailedReplaceKeepsTheNotificationItWasToReplace(t *testing.T) {
+	// The raise, then its clearing, taken while the store does not answer; the store then stays down or comes
+	// back. Each is taken (never offered again, where a redelivered raise would follow its clearing), the
+	// clearing replaces the urgent notification in place, and the screen and the store end on the clearing.
+	for _, back := range []bool{false, true} {
+		t.Run(fmt.Sprintf("the store does not answer, back %v", back), func(t *testing.T) {
+			d, shown, _, store := newDesk(t, "laptop")
+			down := true
+			d.Store = downStore{store, &down}
+			raised, _ := json.Marshal(asks.Message{Handle: "m9", Title: "A new build cannot be delivered", Urgent: true})
+			if err := d.Take(asks.ChannelSubject(asks.Send, Kind), raised); err != nil {
+				t.Fatalf("the raise was not taken: %v", err)
+			}
+			cleared, _ := json.Marshal(asks.Message{Handle: "m9", Title: "Cleared: a new build can be delivered"})
+			if err := d.Take(asks.ChannelSubject(asks.Edit, Kind), cleared); err != nil {
+				t.Fatalf("the clearing was not taken: %v", err)
+			}
+			d.KeepUnkept() // the minute's standing, store still down
+			down = !back
+			d.KeepUnkept()
+			take(t, d, asks.Send, asks.Message{Handle: "m10", Title: "another"})
+			if len(*shown) != 3 || (*shown)[1].args["replace_id"] != 1 || (*shown)[1].args["summary"] != "Cleared: a new build can be delivered" {
+				t.Fatalf("the clearing did not replace the urgent notification: %+v", *shown)
+			}
+			s, kept := store["m9"]
+			if back != kept || (kept && s.Message.Title != "Cleared: a new build can be delivered") {
+				t.Fatalf("store back %v, kept %v: %+v", back, kept, store)
+			}
+			if got, _ := d.recall("m9"); got == nil || got.Message.Title != "Cleared: a new build can be delivered" {
+				t.Fatalf("recalled %+v", got)
+			}
+		})
+	}
+
 	d, shown, said, store := newDesk(t, "laptop", "desktop")
 	take(t, d, asks.Send, asks.Message{Handle: "m1", Title: "2 failed services on shanks"})
 	first := store["m1"].On

modules/desk-channel/cmd/desk-channel/main.go

@@ -100,6 +100,7 @@ func run(d *Desk) {
 	}()
 	go func() {
 		for {
+			d.KeepUnkept()
 			d.SayStanding()
 			time.Sleep(time.Minute)
 		}

modules/mesh-build-node/cmd/mesh-build-node/build_integration_test.go

@@ -17,11 +17,11 @@ import (
 	"git.novox.be/novox/mesh-sdk/go/forgekey"
 )
 
-// realMachine gives the tests the real toolchain of the module's own lock and makes two workspaces holding one fixture
-// bundle. The toolchain is the one this node's installed Node build module keeps (ADR 0533 §1): the integration level
-// is given its toolchains read-only and no network, so it is copied into the test's own cache from there. Only where
-// no toolchain is installed (a desk) is it installed with `npm ci --ignore-scripts` from the mesh's registry, as the
-// module does, which needs the network.
+// realMachine gives the tests the real toolchain of the module's own lock and makes three workspaces holding one fixture
+// bundle. The toolchain is the one this node's installed Node build module keeps (ADR 0533 §1), copied into the test's
+// own cache: the integration level is given its toolchains read-only and no network, so it is never installed from the
+// registry here. Where no Node build module has installed one (a node without it, a desk), the test is skipped by
+// name: an install from the public registry inside a shut-off level only fails, after 70 s of npm's retries.
 func realMachine(t *testing.T) (*Module, string) {
 	t.Helper()
 	for _, p := range []string{"node", "npm", "bwrap"} { // bwrap: tsc, esbuild and the scripts run shut off (1309)
@@ -44,16 +44,19 @@ func realMachine(t *testing.T) (*Module, string) {
 	run := forgekey.ExecRunnerFor(0)
 	m := &Module{Node: "ace", Recipe: lock, Work: work, Run: run, Ctx: context.Background(),
 		Toolchain: &Toolchain{Paths: Paths{Home: home, Cache: cache}, Run: run, Registry: func() (Registry, error) {
-			return Registry{URL: "https://git.novox.be/api/packages/novox/npm/"}, nil
+			return Registry{}, fmt.Errorf("the integration test installs no toolchain from a registry: it has no network")
 		}}}
 	withStore(t, m)
-	if from := installedToolchain(t, filepath.Join(CacheDir, "toolchain"), filepath.Join(home, "toolchain", "package-lock.json")); from != "" {
-		copyToolchain(t, from, m.Toolchain.Paths.Dir(m.Recipe.Version()))
+	from := installedToolchain(t, filepath.Join(CacheDir, "toolchain"), filepath.Join(home, "toolchain", "package-lock.json"))
+	if from == "" {
+		t.Skipf("NOT RUN: no Node toolchain is installed under %s for this account to read (no Node build module on this node); "+
+			"the integration level has no network to install one, so this runs on a node that holds the Node build module", filepath.Join(CacheDir, "toolchain"))
 	}
-	if err := m.Toolchain.Ensure(context.Background(), m.Recipe.Version()); err != nil {
-		t.Fatalf("no toolchain of this lock is installed under %s, and installing it from the registry failed: %v", filepath.Join(CacheDir, "toolchain"), err)
+	copyToolchain(t, from, m.Toolchain.Paths.Dir(m.Recipe.Version()))
+	if err := m.Toolchain.Ensure(context.Background(), m.Recipe.Version()); err != nil { // present: opens it, installs nothing
+		t.Fatalf("the toolchain copied from %s cannot be used: %v", from, err)
 	}
-	for _, id := range []string{"w1", "w2"} {
+	for _, id := range []string{"w1", "w2", "w3"} {
 		for p, body := range map[string]string{
 			"modules/m/module.json":    `{"module":"m","build":{"artifacts":[{"name":"tools","kind":"bundle","language":"typescript","entrypoints":["tools/index.js"]}]}}`,
 			"modules/m/package.json":   `{"name":"m","type":"module","scripts":{"test":"node -e \"process.exit(0)\""}}`,
@@ -65,10 +68,36 @@ func realMachine(t *testing.T) (*Module, string) {
 	return m, work
 }
 
-// 1490/AC2: a fixture TypeScript bundle importing @novox/mesh-sdk, built twice by the real tsc and esbuild, has equal
-// digests, and its archive holds the bundled .js, the .serve.mjs launcher and package.json.
-func TestAFixtureBundleBuiltTwiceHasOneDigest(t *testing.T) {
+// 1490/AC2, 1491 and issue 1869, in one test so the toolchain is copied once: the real type-check and test script of the
+// fixture pass the unit level; a package whose test imports its own build output (as mesh-sdk's do) passes the unit level,
+// the test step emitting it with the real tsc, shut off, before the test script runs; and the fixture TypeScript bundle
+// importing @novox/mesh-sdk, built twice by the real tsc and esbuild, has equal digests, its archive holding the bundled
+// .js, the .serve.mjs launcher and package.json. The unit levels run in w3, so the two builds' workspaces stay alike.
+func TestTheFixturePassesTheUnitLevelAndBuildsTwiceToOneDigest(t *testing.T) {
 	m, work := realMachine(t)
+	out, err := m.test(context.Background(), map[string]any{"workspace": "w3", "module": "modules/m", "level": "unit"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if r := out.(*TestResult); !r.Passed || r.NoTests || len(r.Ran) != 2 {
+		t.Errorf("the fixture's unit level: result = %+v", r)
+	}
+	for p, body := range map[string]string{
+		"modules/p/package.json":  `{"name":"p","type":"module","scripts":{"build":"tsc","test":"node --test test/a.test.mjs","prepare":"tsc"}}`,
+		"modules/p/tsconfig.json": `{"compilerOptions":{"module":"NodeNext","moduleResolution":"NodeNext","target":"ES2022","outDir":"dist","rootDir":"src"},"include":["src"]}`,
+		"modules/p/src/index.ts":  "export const answer: number = 42;\n",
+		"modules/p/test/a.test.mjs": "import { test } from 'node:test';\nimport assert from 'node:assert';\nimport { answer } from '../dist/index.js';\n" +
+			"test('the build is there', () => assert.equal(answer, 42));\n",
+	} {
+		write(t, filepath.Join(work, "w3", "tree", filepath.FromSlash(p)), body, 0o644)
+	}
+	out, err = m.test(context.Background(), map[string]any{"workspace": "w3", "module": "modules/p", "level": "unit"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if r := out.(*TestResult); !r.Passed || !slices.Equal(r.Ran, []string{"build", "test"}) {
+		t.Errorf("the package importing its build: result = %+v", r)
+	}
 	var digests []string
 	for _, id := range []string{"w1", "w2"} {
 		out, err := m.build(context.Background(), map[string]any{"workspace": id, "module": "modules/m", "artifact": "tools"})
@@ -89,43 +118,6 @@ func TestAFixtureBundleBuiltTwiceHasOneDigest(t *testing.T) {
 	}
 }
 
-// 1491: the real type-check and test script of the same fixture pass the unit level.
-func TestTheFixturePassesTheUnitLevel(t *testing.T) {
-	m, _ := realMachine(t)
-	out, err := m.test(context.Background(), map[string]any{"workspace": "w1", "module": "modules/m", "level": "unit"})
-	if err != nil {
-		t.Fatal(err)
-	}
-	if r := out.(*TestResult); !r.Passed || r.NoTests || len(r.Ran) != 2 {
-		t.Errorf("result = %+v", r)
-	}
-}
-
-// Issue 1869: a package whose test imports its own build output (as mesh-sdk's do) passes the unit level: the test step
-// emits it with the real tsc, shut off, before the test script runs.
-func TestAPackageWhoseTestsImportItsBuildPassesTheUnitLevel(t *testing.T) {
-	if _, err := exec.LookPath("bwrap"); err != nil {
-		t.Skip("NOT RUN: no bubblewrap installed where this check runs; every build node has it (the module declares it)")
-	}
-	m, work := realMachine(t)
-	for p, body := range map[string]string{
-		"modules/p/package.json":  `{"name":"p","type":"module","scripts":{"build":"tsc","test":"node --test test/a.test.mjs","prepare":"tsc"}}`,
-		"modules/p/tsconfig.json": `{"compilerOptions":{"module":"NodeNext","moduleResolution":"NodeNext","target":"ES2022","outDir":"dist","rootDir":"src"},"include":["src"]}`,
-		"modules/p/src/index.ts":  "export const answer: number = 42;\n",
-		"modules/p/test/a.test.mjs": "import { test } from 'node:test';\nimport assert from 'node:assert';\nimport { answer } from '../dist/index.js';\n" +
-			"test('the build is there', () => assert.equal(answer, 42));\n",
-	} {
-		write(t, filepath.Join(work, "w1", "tree", filepath.FromSlash(p)), body, 0o644)
-	}
-	out, err := m.test(context.Background(), map[string]any{"workspace": "w1", "module": "modules/p", "level": "unit"})
-	if err != nil {
-		t.Fatal(err)
-	}
-	if r := out.(*TestResult); !r.Passed || !slices.Equal(r.Ran, []string{"build", "test"}) {
-		t.Errorf("result = %+v", r)
-	}
-}
-
 // installedToolchain is the toolchain directory under toolchains that this node's Node build module installed: the
 // one installed from the lock at lockPath, byte for byte, or, when the change carries a lock no delivered release has
 // installed yet, the one installed last, said in the test's log (ADR 0533 §3: a new lock is proven by the module that

modules/mesh-knowledge/cmd/mesh-knowledge/kb.go

@@ -515,6 +515,9 @@ func (k *KB) accept(ctx context.Context, held *Entry, w *Record, by, why, warran
 
 // judgeSet holds the whole record set to its 4 rules and keeps what fails, which the module's health answers.
 func (k *KB) judgeSet(ctx context.Context) []Finding {
+	if _, err := k.RecomputeMarks(ctx); err != nil {
+		k.logf("[mesh-knowledge] %v", err)
+	}
 	all, err := k.Store.All(ctx)
 	if err != nil {
 		k.logf("[mesh-knowledge] the whole record set cannot be read to judge it: %v", err)

modules/mesh-knowledge/cmd/mesh-knowledge/main.go

@@ -99,7 +99,7 @@ func serve(k *KB, status string) {
 	k.kick = make(chan struct{}, 1)
 	go hear(k)
 	go background(k)
-	if err := stdio.Serve("", append(Tools(k, callerOf), healthTool(status, k.now), highestTool(k))); err != nil {
+	if err := stdio.Serve("", append(Tools(k, callerOf), healthTool(status, k.now), highestTool(k), marksTool(k))); err != nil {
 		logf("%v", err)
 		os.Exit(1)
 	}

modules/mesh-knowledge/cmd/mesh-knowledge/manifest_test.go

@@ -119,7 +119,7 @@ func TestItsProcessesAreThePreparationTheActAndTheJudge(t *testing.T) {
 	}
 	h, _ := watch["health"].(map[string]any)
 	if watch == nil || watch["run"].([]any)[1] != "watch" || h["kind"] != "tool" || h["tool"] != HealthTool ||
-		!reflect.DeepEqual(m.Tools, []string{HealthTool, HighestTool}) {
+		!reflect.DeepEqual(m.Tools, []string{HealthTool, HighestTool, MarksTool}) {
 		t.Fatalf("watch %v, tools %v", watch, m.Tools)
 	}
 	// The watch's verdict is whether the database serves, so its check names the provision it exercises: while the

modules/mesh-knowledge/cmd/mesh-knowledge/marks.go

@@ -0,0 +1,137 @@
+package main
+
+// The marks on a clause (changed, and by what) follow the accepted links, both ways: an acceptance that adds a
+// changes link sets the mark (accept), and a later accepted version that drops the link withdraws it here. Without
+// this a mark outlived its link, so holds and the whole-set rule `partial` said "changed" while links and get said
+// nothing (ADR 0536 v6 changed ADR 0525 §10; v12 only cited it).
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+	"strings"
+
+	stdio "git.novox.be/novox/mesh-sdk/go"
+)
+
+// MarksTool is the module's tool that recomputes every mark now.
+const MarksTool = "knowledge_marks"
+
+// markedBy reads "ADR 0536 §4" or "research 045" as the record it names.
+func markedBy(s string) (Key, bool) {
+	f := strings.Fields(s)
+	if len(f) < 2 {
+		return Key{}, false
+	}
+	n, err := strconv.Atoi(f[1])
+	if err != nil {
+		return Key{}, false
+	}
+	switch strings.ToLower(f[0]) {
+	case "adr":
+		return Key{KindDecision, n}, true
+	case "research":
+		return Key{KindResearch, n}, true
+	}
+	return Key{}, false
+}
+
+// StaleMarks drops, on every record of the set, each "changed by" mark whose changing record is accepted and no
+// longer links the clause with a changes link; a clause left with no mark is in force again. A mark of a record
+// not accepted (a change confirmed ahead of its acceptance) or of a record not held stays. It changes the
+// records in place and answers the keys it changed with what it did.
+func StaleMarks(set []*Record) map[Key][]string {
+	byKey := map[Key]*Record{}
+	for _, r := range set {
+		byKey[r.Key()] = r
+	}
+	did := map[Key][]string{}
+	for _, t := range set {
+		if t.Status == StatusSuperseded {
+			continue
+		}
+		for i := range t.Clauses {
+			c := &t.Clauses[i]
+			if c.Status != ClauseChanged {
+				continue
+			}
+			var kept []string
+			for _, by := range c.ChangedBy {
+				from, ok := markedBy(by)
+				src := byKey[from]
+				if !ok || src == nil || !src.Accepted() || changesClause(src, t.Key(), c.N) {
+					kept = append(kept, by)
+					continue
+				}
+				did[t.Key()] = append(did[t.Key()], fmt.Sprintf("§%d no longer changed by %s", c.N, by))
+			}
+			if len(kept) != len(c.ChangedBy) {
+				c.ChangedBy = kept
+				if len(kept) == 0 {
+					c.Status = ClauseInForce
+				}
+			}
+		}
+	}
+	return did
+}
+
+func changesClause(src *Record, to Key, clause int) bool {
+	for _, l := range src.Links {
+		if k, ok := l.To.Record(); ok && l.Kind == LinkChanges && k == to && l.To.Clause == clause {
+			return true
+		}
+	}
+	return false
+}
+
+// RecomputeMarks withdraws every stale mark of the record set now, each a new version of the record it frees, and
+// says what it withdrew. judgeSet runs it first, so an acceptance, the background work every few minutes and a
+// start all agree with the links.
+func (k *KB) RecomputeMarks(ctx context.Context) ([]string, error) {
+	all, err := k.Store.All(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("the record set cannot be read to recompute its marks: %v", err)
+	}
+	set := make([]*Record, len(all))
+	for i, e := range all {
+		set[i] = e.Current.Clone()
+	}
+	did := StaleMarks(set)
+	var said []string
+	for i, e := range all {
+		what := did[e.Current.Key()]
+		if len(what) == 0 {
+			continue
+		}
+		why := strings.Join(what, "; ") + " (its changing record's accepted links no longer change it)"
+		if err := k.Store.Save(ctx, Version{By: "the knowledge base", At: k.now(), Why: why, Record: set[i]}, true, false, e.Revision); err != nil {
+			k.logf("[mesh-knowledge] the marks of %s could not be recomputed (%v): the next judgement tries again", e.Current.Key(), err)
+			continue
+		}
+		k.emit(EventChanged, set[i], "the knowledge base", why, e.Versions+1)
+		said = append(said, fmt.Sprintf("%s: %s", e.Current.Key(), why))
+	}
+	return said, nil
+}
+
+func marksTool(k *KB) stdio.Tool {
+	return stdio.Tool{Name: MarksTool,
+		Description: "Recompute every clause's changed and changed-by marks from the accepted links now, withdrawing each mark whose " +
+			"changing record no longer links the clause (the clause is in force again), and answer what it withdrew. The " +
+			"knowledge base does this on every acceptance and every few minutes; this runs it at once.",
+		Input: schema(nil, map[string]any{}),
+		Run: func(m map[string]any) (any, error) {
+			if _, err := readArgs(MarksTool, m); err != nil {
+				return nil, err
+			}
+			k.mu.Lock()
+			said, err := k.RecomputeMarks(context.Background())
+			k.mu.Unlock()
+			if err != nil {
+				return nil, err
+			}
+			findings := k.judgeSet(context.Background())
+			return map[string]any{"withdrawn": said, "findings": len(findings)}, nil
+		}}
+}

modules/mesh-knowledge/cmd/mesh-knowledge/wholeset_test.go

@@ -117,6 +117,37 @@ func TestARecordAcceptedCitingANewDecisionLetsItBeAcceptedAndDroppingTheLinkIsLo
 	})
 }
 
+// A mark follows the accepted links: a later accepted version that drops a changes link withdraws the clause's
+// mark, so holds, get and the rule `partial` agree with links (ADR 0536 v6 changed ADR 0525 §10; v12 only cited it).
+func TestACorrectionThatDropsAChangesLinkWithdrawsTheClausesMark(t *testing.T) {
+	eachStore(t, func(t *testing.T, s Store) {
+		w := imported(t, s)
+		n := w.reserved(t, "author@g14")
+		a := valid(n) // changes 0276 §1
+		w.accepted(t, "author@g14", a)
+		if c := mustGet(t, s, Key{KindDecision, 276}).Current.Clause(1); c.Status != ClauseChanged || len(c.ChangedBy) != 1 {
+			t.Fatalf("0276 §1 is not marked changed by the acceptance: %+v", c)
+		}
+		a.Links = a.Links[:1] // only extends 0276 now
+		a.Insight = "it no longer changes 0276 §1"
+		w.accepted(t, "author@g14", a)
+		c := mustGet(t, s, Key{KindDecision, 276}).Current.Clause(1)
+		if c.Status != ClauseInForce || len(c.ChangedBy) != 0 {
+			t.Fatalf("0276 §1 keeps a mark no accepted link makes: %+v", c)
+		}
+		f, _ := s.Findings(context.Background())
+		for _, x := range f {
+			if x.Rule == "partial" {
+				t.Fatalf("a stale mark is still a finding: %+v", x)
+			}
+		}
+		// Recomputing again changes nothing.
+		if said, err := w.k.RecomputeMarks(context.Background()); err != nil || len(said) != 0 {
+			t.Fatalf("a second recompute withdrew %v (%v)", said, err)
+		}
+	})
+}
+
 // Each of the 4 whole-set rules, failing on a record set made to break it.
 func TestEachWholeSetRuleFails(t *testing.T) {
 	acc := func(n int, links ...Link) *Record {

modules/mesh-knowledge/module.json

@@ -58,7 +58,8 @@
   ],
   "tools": [
     "knowledge_health",
-    "knowledge_highest"
+    "knowledge_highest",
+    "knowledge_marks"
   ],
   "emits": [
     "reserved",