cmd/mesh-controller/apply_failing.go

@@ -33,7 +33,7 @@ const packageManagerKey = "the package manager ("
 func watchApplyFailing(f *signalFacts) []conditions.Observation {
 	heard := map[string]bool{}
 	for _, m := range f.machines {
-		if !m.asleep() && !m.lastHeard.IsZero() && f.now.Sub(m.lastHeard) <= heartbeatBound(m.every) {
+		if !m.asleep() && !m.lastHeard.IsZero() && !m.silent(f.now) {
 			heard[m.name] = true
 		}
 	}

cmd/mesh-controller/doctor.go

@@ -120,6 +120,11 @@ var probeRegistry = []probe{
 	{ID: probeDeliveriesID, Asserts: "no delivery is held past its state's bound unsaid: mesh-delivery's " +
 		"`stalled`, each with the transition its table lets healer H2 take", From: "ADR 0239",
 		Kind: kindDeliveryStalled, Phase: 3, run: probeDeliveries},
+	// What the watchman says stopped moving (ADR 0433 §2, issue 1156): each key of its stuck bucket not moved, but a
+	// node's presence, which the silent check takes.
+	{ID: probeStuckID, Asserts: "no key the watchman says stopped moving is left unsaid: each key of its stuck bucket " +
+		"not moved is a condition of the delivery scope until it says moved", From: "ADR 0433 §2, issue 1156",
+		Kind: kindStuck, Phase: 3, run: probeStuck},
 	// The delivery budgets (novox/hq ADR 0282 decision 7): the newest delivery of each class within its budget,
 	// read from mesh-delivery's `times`; a measurement said, never a delivery held.
 	{ID: probeBudgetsID, Asserts: "the newest delivery of a leaf module ran on every machine within three minutes of " +

cmd/mesh-controller/plain_words.go

@@ -610,6 +610,13 @@ var plainWordings = map[string]func(conditions.Observation) words{
 				"did not answer in ten minutes, so nothing of the delivery is built or sent.",
 			Resolved: "Resolved: the backup is done and the delivery goes on"}
 	}),
+	kindStuck: worded(func(o conditions.Observation) words {
+		return words{Headline: "Something in a delivery has stopped moving",
+			Explanation: "The watchman noticed a part of the delivery that did not move when it should have: a build " +
+				"asked and not answered, a check that stopped, or a part that went offline. Nothing is lost, and it is " +
+				"said again until it moves.",
+			Resolved: "Resolved: it moves again"}
+	}),
 	kindSendKeyRefused: worded(func(o conditions.Observation) words {
 		return words{Headline: "A delivery cannot watch a machine for its report",
 			Explanation: "The bus refused the note that makes the mesh notice a machine that never reports on a send. " +

cmd/mesh-controller/probes.go

@@ -629,7 +629,7 @@ func heardMachines(d *doctor) map[string]bool {
 		return out
 	}
 	for _, m := range f.machines {
-		if !m.lastHeard.IsZero() && f.now.Sub(m.lastHeard) <= heartbeatBound(m.every) && !m.asleep() {
+		if !m.lastHeard.IsZero() && !m.silent(f.now) && !m.asleep() {
 			out[m.name] = true
 		}
 	}

cmd/mesh-controller/signals.go

@@ -335,7 +335,7 @@ func watchHeartbeats(f *signalFacts) []conditions.Observation {
 		}
 		bound := heartbeatBound(m.every)
 		silent := f.now.Sub(m.lastHeard)
-		if silent <= bound {
+		if !m.silent(f.now) {
 			continue
 		}
 		severity := conditions.Warning
@@ -357,7 +357,7 @@ func watchReports(f *signalFacts) []conditions.Observation {
 		if m.sentAt.IsZero() || m.reportedCurrent || m.asleep() {
 			continue
 		}
-		if !m.lastHeard.IsZero() && f.now.Sub(m.lastHeard) > heartbeatBound(m.every) {
+		if m.silent(f.now) {
 			continue // silent: S1 says it, and a silent machine reports nothing
 		}
 		bound := max(reportAtLeast, 3*m.lastApply)

cmd/mesh-controller/stuck_probe.go

@@ -0,0 +1,208 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sort"
+	"time"
+
+	sdkdelivery "git.novox.be/novox/mesh-sdk/go/delivery"
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/jetstream"
+
+	"github.com/novox/mesh-controller/internal/conditions"
+)
+
+// What stopped moving (novox/hq ADR 0433 §2, §3, issue 1156). The watchman writes `stuck.<bucket>.<key>` in its own
+// bucket for each key whose pulse expired, and again as moved when the key moves; it never deletes one. The controller
+// reads that bucket in two places and holds no timer for either: a probe of the self-check raises each key not moved as
+// a condition of the delivery scope, and the check that a machine is silent takes a node's presence key as its verdict.
+const (
+	kindStuck    = "stuck"
+	probeStuckID = "DM"
+)
+
+// presenceVerdict is the watchman's word on whether a machine is online, from its stuck presence key.
+type presenceVerdict int
+
+const (
+	// presenceUnsaid: the watchman has written nothing for the machine; the heartbeat rule judges it, as before.
+	presenceUnsaid presenceVerdict = iota
+	// presenceHeard: the key says moved, the machine is back online.
+	presenceHeard
+	// presenceSilent: the key says not moved, the machine was offline past its bound.
+	presenceSilent
+)
+
+// applyPresence sets what the watchman says of a machine: the verdict of its stuck presence key (nil when there is none)
+// and, when presence.<node> has an entry, its time as when the machine was last heard from. Without a presence entry,
+// last heard stays the store's last_seen.
+func applyPresence(m *machineFacts, stuck *sdkdelivery.Stuck, at time.Time) {
+	switch {
+	case stuck == nil:
+		m.presence = presenceUnsaid
+	case stuck.Moved:
+		m.presence = presenceHeard
+	default:
+		m.presence = presenceSilent
+	}
+	if !at.IsZero() {
+		m.lastHeard = at
+	}
+}
+
+// silent says the machine is silent: the watchman's verdict where it gave one, else the heartbeat rule. A machine never
+// heard from is not silent, it has not joined.
+func (m machineFacts) silent(now time.Time) bool {
+	switch m.presence {
+	case presenceSilent:
+		return true
+	case presenceHeard:
+		return false
+	}
+	return !m.lastHeard.IsZero() && now.Sub(m.lastHeard) > heartbeatBound(m.every)
+}
+
+// stuckObservations are the conditions of what stopped moving: one for each key not moved, in the delivery scope, kind
+// stuck, naming the key and what it waited for. A node's presence key is left to the silent check; a moved key raises
+// nothing, so its condition clears.
+func stuckObservations(entries map[string]sdkdelivery.Stuck) []conditions.Observation {
+	keys := make([]string, 0, len(entries))
+	for k := range entries {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	var out []conditions.Observation
+	for _, k := range keys {
+		s := entries[k]
+		if s.Moved {
+			continue
+		}
+		if s.Bucket == sdkdelivery.PresenceBucket {
+			if node, _, _, err := sdkdelivery.ParsePresenceKey(s.Key); err == nil && node != "" {
+				continue
+			}
+		}
+		waited := s.Waited
+		if waited == "" {
+			waited = "a move"
+		}
+		out = append(out, conditions.Observation{Scope: conditions.ScopeDelivery, ID: k, Kind: kindStuck,
+			Severity: conditions.Warning,
+			Summary: fmt.Sprintf("%s has not moved since %s: it waited for %s", k, s.Since.UTC().Format("2006-01-02 15:04 MST"),
+				waited),
+			Said: fmt.Sprintf("%s: waiting for %s since %s", k, waited, s.Since.UTC().Format(time.RFC3339))})
+	}
+	return out
+}
+
+// readStuck is every key of the stuck bucket and its value; none when the bucket is not there yet (the watchman not
+// delivered). A value of another version is left out, said.
+func readStuck(ctx context.Context, conn *nats.Conn) (map[string]sdkdelivery.Stuck, error) {
+	api, err := jetstream.New(conn)
+	if err != nil {
+		return nil, err
+	}
+	kv, err := api.KeyValue(ctx, sdkdelivery.StuckBucket)
+	if errors.Is(err, jetstream.ErrBucketNotFound) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("the watchman's stuck bucket: %w", err)
+	}
+	keys, err := boundedCall(ctx, "listing the stuck keys", func(ctx context.Context) ([]string, error) { return kv.Keys(ctx) })
+	if errors.Is(err, jetstream.ErrNoKeysFound) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	out := map[string]sdkdelivery.Stuck{}
+	for _, key := range keys {
+		e, err := kv.Get(ctx, key)
+		if errors.Is(err, jetstream.ErrKeyNotFound) {
+			continue
+		}
+		if err != nil {
+			return nil, err
+		}
+		s, err := sdkdelivery.DecodeStuck(e.Value())
+		if err != nil {
+			fmt.Printf("the stuck key %s is not read: %v\n", key, err)
+			continue
+		}
+		out[key] = s
+	}
+	return out, nil
+}
+
+// readPresenceTimes is, by node, the time of presence.<node>'s entry; a node without an entry is left out.
+func readPresenceTimes(ctx context.Context, conn *nats.Conn, nodes []string) (map[string]time.Time, error) {
+	api, err := jetstream.New(conn)
+	if err != nil {
+		return nil, err
+	}
+	kv, err := api.KeyValue(ctx, sdkdelivery.PresenceBucket)
+	if errors.Is(err, jetstream.ErrBucketNotFound) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("the watchman's presence bucket: %w", err)
+	}
+	out := map[string]time.Time{}
+	for _, node := range nodes {
+		key, err := sdkdelivery.PresenceNodeKey(node)
+		if err != nil {
+			continue
+		}
+		e, err := kv.Get(ctx, key)
+		if errors.Is(err, jetstream.ErrKeyNotFound) {
+			continue
+		}
+		if err != nil {
+			return nil, err
+		}
+		out[node] = e.Created()
+	}
+	return out, nil
+}
+
+// withPresence says of each machine what the watchman says: its stuck presence key and its presence entry's time.
+func withPresence(ctx context.Context, conn *nats.Conn, machines []machineFacts) error {
+	stuck, err := readStuck(ctx, conn)
+	if err != nil {
+		return err
+	}
+	names := make([]string, len(machines))
+	for i, m := range machines {
+		names[i] = m.name
+	}
+	times, err := readPresenceTimes(ctx, conn, names)
+	if err != nil {
+		return err
+	}
+	for i := range machines {
+		var said *sdkdelivery.Stuck
+		if key, err := sdkdelivery.StuckKey(sdkdelivery.PresenceBucket, machines[i].name); err == nil {
+			if s, ok := stuck[key]; ok {
+				said = &s
+			}
+		}
+		applyPresence(&machines[i], said, times[machines[i].name])
+	}
+	return nil
+}
+
+// probeStuck is DM: every key the watchman says stopped moving is raised, but a node's presence, which the silent check
+// takes.
+func probeStuck(ctx context.Context, d *doctor) ([]conditions.Observation, error) {
+	if d.js == nil {
+		return nil, nil
+	}
+	entries, err := readStuck(ctx, d.js.Conn())
+	if err != nil {
+		return nil, err
+	}
+	return stuckObservations(entries), nil
+}

cmd/mesh-controller/stuck_probe_integration_test.go

@@ -0,0 +1,82 @@
+//go:build integration
+
+package main
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	sdkdelivery "git.novox.be/novox/mesh-sdk/go/delivery"
+	"github.com/nats-io/nats.go/jetstream"
+
+	"github.com/novox/mesh-controller/internal/broker"
+	"github.com/novox/mesh-controller/internal/testbus"
+)
+
+// 1156/AC4: on the embedded bus with the watchman's buckets, a stuck key written raises a condition and written as moved
+// clears it; a node's presence key not moved says the machine silent through the facts, and moved says it heard.
+func TestAStuckKeyWrittenAndThenMovedRaisesAndClearsACondition(t *testing.T) { // 1156/AC4
+	js, err := broker.Dial(testbus.URL(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(js.Close)
+	if _, err := broker.RaiseBuckets(js, []broker.Bucket{
+		{Module: sdkdelivery.WatchmanModule, Name: "stuck"},
+		{Module: sdkdelivery.WatchmanModule, Name: "presence", History: sdkdelivery.PresenceHistory},
+	}); err != nil {
+		t.Fatal(err)
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	api, err := jetstream.New(js.Conn())
+	if err != nil {
+		t.Fatal(err)
+	}
+	kv, err := api.KeyValue(ctx, sdkdelivery.StuckBucket)
+	if err != nil {
+		t.Fatal(err)
+	}
+	write := func(bucket, key string, moved bool) string {
+		t.Helper()
+		stuckKey, err := sdkdelivery.StuckKey(bucket, key)
+		if err != nil {
+			t.Fatal(err)
+		}
+		body, err := sdkdelivery.EncodeStuck(sdkdelivery.Stuck{Bucket: bucket, Key: key, Waited: "an answer", Since: time.Now().UTC(), Moved: moved})
+		if err != nil {
+			t.Fatal(err)
+		}
+		if _, err := kv.Put(ctx, stuckKey, body); err != nil {
+			t.Fatal(err)
+		}
+		return stuckKey
+	}
+	d := &doctor{js: js}
+	stuckKey := write(sdkdelivery.PulseBucket, "builds.x", false)
+	write(sdkdelivery.PresenceBucket, "ace", false)
+	got, err := probeStuck(ctx, d)
+	if err != nil || len(got) != 1 || got[0].ID != stuckKey || got[0].Kind != kindStuck {
+		t.Fatalf("a stuck key written: %+v %v", got, err)
+	}
+	machines := []machineFacts{{name: "ace", lastHeard: time.Now()}}
+	if err := withPresence(ctx, js.Conn(), machines); err != nil {
+		t.Fatal(err)
+	}
+	if !machines[0].silent(time.Now()) {
+		t.Fatal("a presence key not moved did not say the machine silent")
+	}
+	write(sdkdelivery.PulseBucket, "builds.x", true)
+	write(sdkdelivery.PresenceBucket, "ace", true)
+	if got, err := probeStuck(ctx, d); err != nil || len(got) != 0 {
+		t.Fatalf("a stuck key written as moved: %+v %v", got, err)
+	}
+	machines = []machineFacts{{name: "ace", lastHeard: time.Now().Add(-time.Hour), every: time.Minute}}
+	if err := withPresence(ctx, js.Conn(), machines); err != nil {
+		t.Fatal(err)
+	}
+	if machines[0].silent(time.Now()) {
+		t.Fatal("a presence key that moved still says the machine silent")
+	}
+}

cmd/mesh-controller/stuck_probe_test.go

@@ -0,0 +1,108 @@
+package main
+
+import (
+	"strings"
+	"testing"
+	"time"
+
+	sdkdelivery "git.novox.be/novox/mesh-sdk/go/delivery"
+
+	"github.com/novox/mesh-controller/internal/conditions"
+	"github.com/novox/mesh-controller/internal/link"
+)
+
+func aStuckKey(t *testing.T, bucket, key string) string {
+	t.Helper()
+	k, err := sdkdelivery.StuckKey(bucket, key)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return k
+}
+
+// 1156/AC1: each not-moved stuck key that is not a node's presence is an observation of the delivery scope, kind stuck,
+// naming the key and what it waited for; a moved key raises nothing, so its condition clears.
+func TestEachStuckKeyThatHasNotMovedIsAConditionOfTheDeliveryScope(t *testing.T) { // 1156/AC1
+	since := time.Date(2026, 10, 18, 19, 0, 0, 0, time.UTC)
+	pulse := aStuckKey(t, sdkdelivery.PulseBucket, "x")
+	moved := aStuckKey(t, sdkdelivery.HaveBucket, "ace.zsh")
+	node := aStuckKey(t, sdkdelivery.PresenceBucket, "ace")
+	part := aStuckKey(t, sdkdelivery.PresenceBucket, "part.mesh-controller.one")
+	entries := map[string]sdkdelivery.Stuck{
+		pulse: {Bucket: sdkdelivery.PulseBucket, Key: "x", Waited: "the build of zsh to be answered", Since: since},
+		moved: {Bucket: sdkdelivery.HaveBucket, Key: "ace.zsh", Waited: "a want", Since: since, Moved: true},
+		node:  {Bucket: sdkdelivery.PresenceBucket, Key: "ace", Waited: "its return", Since: since},
+		part:  {Bucket: sdkdelivery.PresenceBucket, Key: "part.mesh-controller.one", Waited: "its return", Since: since},
+	}
+	got := stuckObservations(entries)
+	if len(got) != 2 {
+		t.Fatalf("observations %+v, want the pulse key and the part's presence", got)
+	}
+	byID := map[string]conditions.Observation{}
+	for _, o := range got {
+		if o.Scope != conditions.ScopeDelivery || o.Kind != kindStuck {
+			t.Errorf("%+v is not a stuck condition of the delivery scope", o)
+		}
+		byID[o.ID] = o
+	}
+	o, ok := byID[pulse]
+	if !ok || !strings.Contains(o.Summary, pulse) || !strings.Contains(o.Summary, "the build of zsh to be answered") {
+		t.Fatalf("the condition does not name the key and what it waited for: %+v", got)
+	}
+	if _, ok := byID[part]; !ok {
+		t.Errorf("a part's presence is left out: %v", byID)
+	}
+	// Moved again: the same key, written as moved, raises nothing.
+	entries[pulse] = sdkdelivery.Stuck{Bucket: sdkdelivery.PulseBucket, Key: "x", Since: since, Moved: true}
+	if got := stuckObservations(entries); len(got) != 1 {
+		t.Fatalf("a moved key still raises: %+v", got)
+	}
+}
+
+func aMachineHeardAt(now time.Time, ago time.Duration) machineFacts {
+	return machineFacts{name: "laptop", lastHeard: now.Add(-ago), every: time.Minute}
+}
+
+// 1156/AC2: a node's stuck presence key not moved makes the machine silent, unless it sleeps; moved, it is heard; no
+// timer is armed (the verdict is the key's, whatever the time of the last word).
+func TestAStuckPresenceKeyIsTheSilentVerdict(t *testing.T) { // 1156/AC2
+	now := time.Now()
+	f := calm(now)
+	f.machines = append(f.machines, aMachineHeardAt(now, 10*time.Second))
+	notMoved := sdkdelivery.Stuck{Bucket: sdkdelivery.PresenceBucket, Key: "laptop", Waited: "its return", Since: now.Add(-3 * time.Minute)}
+	applyPresence(&f.machines[1], &notMoved, now.Add(-3*time.Minute))
+	got := watchHeartbeats(f)
+	if len(got) != 1 || got[0].Machine != "laptop" || got[0].Kind != "silent" {
+		t.Fatalf("a presence key not moved: %+v", got)
+	}
+	// Asleep: not silent.
+	f.machines[1].power = link.PowerState{State: "sleeping", At: now.Add(-time.Hour)}
+	if got := watchHeartbeats(f); len(got) != 0 {
+		t.Fatalf("a sleeping machine raised %+v", got)
+	}
+	// Moved: heard, whatever the store's last word says.
+	f.machines[1].power = link.PowerState{}
+	f.machines[1].lastHeard = now.Add(-2 * time.Hour)
+	moved := notMoved
+	moved.Moved = true
+	applyPresence(&f.machines[1], &moved, now.Add(-time.Minute))
+	if got := watchHeartbeats(f); len(got) != 0 {
+		t.Fatalf("a presence key that moved raised %+v", got)
+	}
+}
+
+// 1156/AC3: a machine's last heard is the presence key's entry time when there is one, and last_seen when there is none.
+func TestLastHeardIsThePresenceKeysTimeWhenThereIsOne(t *testing.T) { // 1156/AC3
+	now := time.Now()
+	seen := now.Add(-time.Hour)
+	m := machineFacts{name: "laptop", lastHeard: seen}
+	applyPresence(&m, nil, time.Time{})
+	if !m.lastHeard.Equal(seen) {
+		t.Fatalf("with no presence key last heard is %v, want last_seen %v", m.lastHeard, seen)
+	}
+	at := now.Add(-5 * time.Minute)
+	applyPresence(&m, nil, at)
+	if !m.lastHeard.Equal(at) {
+		t.Fatalf("with a presence key last heard is %v, want %v", m.lastHeard, at)
+	}
+}

cmd/mesh-controller/watchdogs.go

@@ -155,6 +155,8 @@ type machineFacts struct {
 	tools      bool
 	toolsHeard time.Time
 	toolsEvery time.Duration
+	// presence is the watchman's word on whether it is online (novox/hq ADR 0433 §3); unsaid, the heartbeat rule judges.
+	presence presenceVerdict
 }
 
 // asleep says the machine said it would be away and has not said it is back (ADR 0211).
@@ -470,7 +472,7 @@ func (w *watchdogs) gatherMachines(ctx context.Context, inv *inventory.Inventory
 			}
 			m.reportedCurrent = r.Current
 		}
-		if !m.lastHeard.IsZero() && now.Sub(m.lastHeard) > heartbeatBound(m.every) {
+		if m.silent(now) {
 			anyPast = true
 		}
 		if m.tools && now.Sub(later(m.toolsHeard, link.ToolsBeats.Started())) > heartbeatBound(m.toolsEvery) {
@@ -478,6 +480,19 @@ func (w *watchdogs) gatherMachines(ctx context.Context, inv *inventory.Inventory
 		}
 		out = append(out, m)
 	}
+	// What the watchman says of each machine: its stuck presence key is the silent verdict, and presence.<node>'s time when
+	// it was last heard (ADR 0433 §3). Unreadable is said, and the heartbeat rule judges as before.
+	if w.js != nil {
+		if err := withPresence(ctx, w.js.Conn(), out); err != nil {
+			fmt.Printf("what the watchman says of the machines' presence cannot be read: %v\n", err)
+		} else {
+			for _, m := range out {
+				if m.silent(now) {
+					anyPast = true
+				}
+			}
+		}
+	}
 	// What a machine past its bound last said of its power, read only then: a machine that said it
 	// is asleep is not lost (ADR 0211). Unreadable is said: a sleeping laptop is then called silent,
 	// which is the louder mistake and the right one to make.