diff --git a/cmd/mesh-controller/asker.go b/cmd/mesh-controller/asker.go
index 5202fc19..3b28ba5e 100644
--- a/cmd/mesh-controller/asker.go
+++ b/cmd/mesh-controller/asker.go
@@ -84,21 +84,74 @@ type asked struct {
 	// Acted is what the controller did on the warrant: empty before it did anything, "acting" while it acts,
 	// then "done", "failed: …" or "nothing: …". Anything but empty is never acted on again.
 	Acted string `json:"acted,omitempty"`
-	// Drill is an ask started at the controller's terminal (drill.go): about no condition, its answers
+	// Part is which ask of its condition this is (askPart): empty for the one that carries the condition's
+	// answers, or the authorising ones where it has both; "acknowledge" for its acknowledging answers asked
+	// apart (the review of 2026-10-09, M1).
+	Part string `json:"part,omitempty"`
+	// Rehearsal is an ask started at the controller's terminal (rehearse.go): about no condition, its answers
 	// perform nothing, and the reconciling of conditions leaves it alone.
-	Drill bool `json:"drill,omitempty"`
+	Rehearsal bool `json:"rehearsal,omitempty"`
 }
 
-// askedStore keeps the asks (broker.AskedBucket).
+// partKey is an ask's place among what is asked: its condition and its part.
+func partKey(condition, part string) string { return condition + "#" + part }
+
+// partAcknowledge is the part of a condition asked apart for its acknowledging answers.
+const partAcknowledge = "acknowledge"
+
+// askPart is one ask a condition is asked with: its part, what it is about, and its answers.
+type askPart struct {
+	name    string
+	about   string
+	actions []conditions.Action
+}
+
+// levelOf is an action's level as an option offers it: one that says none is never taken for less than
+// approve.
+func levelOf(act conditions.Action) asks.Level {
+	if act.Level == "" {
+		return asks.Approve
+	}
+	return asks.Level(act.Level)
+}
+
+// partsOf is the asks a condition is asked with (the review of 2026-10-09, M1): one, when its answers are all
+// of one kind; else its authorising answers (Release, Stop, Restart) in one ask, about the condition, and its
+// acknowledging ones (Silence) in another. **An acknowledgement never shares an ask with an approval**: a
+// channel that only acknowledges would otherwise answer the ask, and end the approval with it.
+func partsOf(c conditions.Condition) []askPart {
+	var ack, auth []conditions.Action
+	for _, act := range c.Actions {
+		if levelOf(act) == asks.Acknowledge {
+			ack = append(ack, act)
+		} else {
+			auth = append(auth, act)
+		}
+	}
+	if len(ack) == 0 || len(auth) == 0 {
+		return []askPart{{about: c.Key, actions: c.Actions}}
+	}
+	return []askPart{{about: c.Key, actions: auth},
+		{name: partAcknowledge, about: c.Key + "." + partAcknowledge, actions: ack}}
+}
+
+// askedStore keeps the asks (broker.AskedBucket). **Every write after the first is a compare-and-set** (the
+// review of 2026-10-09, L2): an ask is created once, and changed only over the revision it was read at, the
+// change decided again on what is read — so two controllers, or two deliveries of one warrant, never write
+// over each other, and of two that would act only the one whose write stands does.
 type askedStore interface {
 	Get(ctx context.Context, id string) (*asked, error)
-	Put(ctx context.Context, a asked) error
+	// Create keeps a new ask, and refuses one already kept under its id.
+	Create(ctx context.Context, a asked) error
+	// Change applies change to the ask kept under id, by compare-and-set, and says whether its write stood.
+	// change says whether to write at all; on a write that came between, it is asked again on what is read.
+	Change(ctx context.Context, id string, change func(*asked) bool) (bool, error)
 	All(ctx context.Context) ([]asked, error)
-	// Claim marks an open ask acting, by compare-and-set, and says whether this write stood: of two
-	// deliveries of one warrant, or two controllers, only the one whose write stands acts.
-	Claim(ctx context.Context, id string, w asks.Warrant) (bool, error)
 }
 
+// askChangeTries is how often a change is read and tried again when another write came between.
+const askChangeTries = 5
+
 // asker is the controller asking the operator and acting on the answer.
 type asker struct {
 	open    func(ctx context.Context) ([]conditions.Condition, error)
@@ -217,11 +270,12 @@ func (a *asker) reconcile(ctx context.Context) error {
 	if err != nil {
 		return err
 	}
-	byCondition := map[string]asked{}
+	byCondition := map[string]asked{} // by partKey
 	for _, r := range all {
-		if r.State == askOpen && !r.Drill {
-			if prior, held := byCondition[r.Condition]; !held || r.Opened.After(prior.Opened) {
-				byCondition[r.Condition] = r
+		if r.State == askOpen && !r.Rehearsal {
+			k := partKey(r.Condition, r.Part)
+			if prior, held := byCondition[k]; !held || r.Opened.After(prior.Opened) {
+				byCondition[k] = r
 			}
 		}
 	}
@@ -243,8 +297,8 @@ func (a *asker) reconcile(ctx context.Context) error {
 		}
 		byCondition = map[string]asked{}
 		for _, r := range all {
-			if r.State == askOpen && !r.Drill {
-				byCondition[r.Condition] = r
+			if r.State == askOpen && !r.Rehearsal {
+				byCondition[partKey(r.Condition, r.Part)] = r
 			}
 		}
 	}
@@ -252,12 +306,13 @@ func (a *asker) reconcile(ctx context.Context) error {
 	// newest first: not asked again until the answers or the channels change.
 	answered, refused := map[string]asked{}, map[string]asked{}
 	for _, r := range all {
+		k := partKey(r.Condition, r.Part)
 		if r.State == string(asks.OutcomeChosen) && now.Sub(r.Ended) < askAgainAfterAnswer {
-			answered[r.Condition] = r
+			answered[k] = r
 		}
 		if r.State == string(asks.OutcomeRefused) {
-			if prior, has := refused[r.Condition]; !has || r.Opened.After(prior.Opened) {
-				refused[r.Condition] = r
+			if prior, has := refused[k]; !has || r.Opened.After(prior.Opened) {
+				refused[k] = r
 			}
 		}
 	}
@@ -277,54 +332,70 @@ func (a *asker) reconcile(ctx context.Context) error {
 	})
 	openNow := 0
 	for _, c := range open {
-		if r, held := byCondition[c.Key]; held && wants(c, now) && sameAsked(r.Actions, c.Actions) && now.Before(r.Ask.Expires) {
-			openNow++
+		if !wants(c, now) {
+			continue
+		}
+		for _, p := range partsOf(c) {
+			if r, held := byCondition[partKey(c.Key, p.name)]; held && sameAsked(r.Actions, p.actions) && now.Before(r.Ask.Expires) {
+				openNow++
+			}
 		}
 	}
 	for _, c := range open {
 		if !wants(c, now) {
 			continue
 		}
-		wanted[c.Key] = true
-		if r, was := refused[c.Key]; was && sameAsked(r.Actions, c.Actions) && r.Channels == channels {
-			if _, held := byCondition[c.Key]; !held {
-				unasked = append(unasked, c)
-				if r.Warrant != nil && r.Warrant.Words != "" {
-					refusedWords = append(refusedWords, r.Warrant.Words)
+		saidUnasked := false
+		for _, p := range partsOf(c) {
+			key := partKey(c.Key, p.name)
+			wanted[key] = true
+			if r, was := refused[key]; was && sameAsked(r.Actions, p.actions) && r.Channels == channels {
+				if _, held := byCondition[key]; !held {
+					if !saidUnasked {
+						unasked, saidUnasked = append(unasked, c), true
+					}
+					if r.Warrant != nil && r.Warrant.Words != "" {
+						refusedWords = append(refusedWords, r.Warrant.Words)
+					}
+					continue // refused, and nothing it was refused for has changed
 				}
-				continue // refused, and nothing it was refused for has changed
 			}
-		}
-		if r, done := answered[c.Key]; done && sameAsked(r.Actions, c.Actions) {
-			if _, held := byCondition[c.Key]; !held {
+			if r, done := answered[key]; done && sameAsked(r.Actions, p.actions) {
+				if _, held := byCondition[key]; !held {
+					continue
+				}
+			}
+			if r, held := byCondition[key]; held {
+				switch {
+				case !sameAsked(r.Actions, p.actions):
+					if err := a.cancel(ctx, r, "its answers changed"); err != nil {
+						return err
+					}
+				case !now.Before(r.Ask.Expires):
+					// Expired unanswered: the router says so too; asked again below while it lasts.
+					if _, err := a.store.Change(ctx, r.ID, func(x *asked) bool {
+						if x.State != askOpen {
+							return false
+						}
+						x.State, x.Ended = string(asks.OutcomeExpired), now
+						return true
+					}); err != nil {
+						return err
+					}
+					openNow--
+				default:
+					continue
+				}
+			}
+			if openNow >= askMostOpen {
+				continue // asked when one of the open ones ends, most urgent first
+			}
+			if err := a.ask(ctx, c, p, channels); err != nil {
+				a.logf("the operator could not be asked about %s: %v", c.Key, err)
 				continue
 			}
+			openNow++
 		}
-		if r, held := byCondition[c.Key]; held {
-			switch {
-			case !sameAsked(r.Actions, c.Actions):
-				if err := a.cancel(ctx, r, "its answers changed"); err != nil {
-					return err
-				}
-			case !now.Before(r.Ask.Expires):
-				// Expired unanswered: the router says so too; asked again below while it lasts.
-				r.State, r.Ended = string(asks.OutcomeExpired), now
-				if err := a.store.Put(ctx, r); err != nil {
-					return err
-				}
-				openNow--
-			default:
-				continue
-			}
-		}
-		if openNow >= askMostOpen {
-			continue // asked when one of the open ones ends, most urgent first
-		}
-		if err := a.ask(ctx, c, channels); err != nil {
-			a.logf("the operator could not be asked about %s: %v", c.Key, err)
-			continue
-		}
-		openNow++
 	}
 	for key, r := range byCondition {
 		if !wanted[key] {
@@ -420,18 +491,15 @@ func askText(s string) string {
 	return strings.ReplaceAll(s, "..", ".")
 }
 
-// askOf is the ask a condition is asked with.
-func askOf(id string, c conditions.Condition, now time.Time) (asks.Ask, map[string]int) {
+// askOf is the ask one part of a condition is asked with.
+func askOf(id string, c conditions.Condition, p askPart, now time.Time) (asks.Ask, map[string]int) {
 	q := asks.Ask{ID: id, Headline: c.Headline, Explanation: askText(c.Explanation), Who: asks.Operator,
-		OnExpiry: "nothing is done, and you are asked again while it lasts", About: c.Key,
+		OnExpiry: "nothing is done, and you are asked again while it lasts", About: p.about,
 		Urgent: c.Severity == conditions.Urgent}
 	options := map[string]int{}
 	approves := false
-	for i, act := range c.Actions {
-		level := asks.Level(act.Level)
-		if level == "" {
-			level = asks.Approve // an action that says nothing of its level is never taken for less
-		}
+	for i, act := range p.actions {
+		level := levelOf(act) // an action that says nothing of its level is never taken for less than approve
 		approves = approves || level != asks.Acknowledge
 		oid := optionID(act.Label)
 		options[oid] = i
@@ -448,10 +516,14 @@ func askOf(id string, c conditions.Condition, now time.Time) (asks.Ask, map[stri
 	return q, options
 }
 
-// boundAct is what an option's Binds digests: the act exactly as the controller will perform it, with its
-// level, and never its label or words.
-func boundAct(act conditions.Action) map[string]any {
-	return map[string]any{"verb": act.Verb, "machine": act.Machine, "arguments": act.Arguments, "level": act.Level}
+// boundAct is what an option's Binds digests: the act exactly as the controller will perform it — its verb,
+// machine, level, and each argument as "arg.<name>" — and never its label or words.
+func boundAct(act conditions.Action) asks.Act {
+	out := asks.Act{"verb": act.Verb, "machine": act.Machine, "level": act.Level}
+	for k, v := range act.Arguments {
+		out["arg."+k] = v
+	}
+	return out
 }
 
 func newAskID() string {
@@ -460,11 +532,15 @@ func newAskID() string {
 	return "c" + hex.EncodeToString(b[:])
 }
 
-// ask publishes one ask about a condition, and keeps it.
-func (a *asker) ask(ctx context.Context, c conditions.Condition, channels string) error {
+// askUnsent is an ask kept and never published: asked again at the next look.
+const askUnsent = "unsent"
+
+// ask publishes one ask about a part of a condition, kept before it is published (the review of 2026-10-09,
+// L3): a warrant for it then always finds it, and one whose publishing failed is marked so and asked again.
+func (a *asker) ask(ctx context.Context, c conditions.Condition, p askPart, channels string) error {
 	now := a.now()
 	id := newAskID()
-	q, options := askOf(id, c, now)
+	q, options := askOf(id, c, p, now)
 	if err := q.Check(now); err != nil {
 		return err
 	}
@@ -472,24 +548,47 @@ func (a *asker) ask(ctx context.Context, c conditions.Condition, channels string
 	if err != nil {
 		return err
 	}
+	if err := a.store.Create(ctx, asked{ID: id, Condition: c.Key, Part: p.name, Ask: q, Actions: p.actions,
+		Options: options, State: askOpen, Opened: now, Channels: channels}); err != nil {
+		return fmt.Errorf("the ask could not be kept, so it was not asked: %w", err)
+	}
 	if err := a.publish(ctx, asks.AskSubject(askerName), body, "ask."+id); err != nil {
+		if _, cerr := a.store.Change(ctx, id, func(x *asked) bool {
+			if x.State != askOpen || x.Acted != "" {
+				return false
+			}
+			x.State, x.Ended, x.Acted = askUnsent, a.now(), "nothing: it could not be published: "+err.Error()
+			return true
+		}); cerr != nil {
+			a.logf("the ask %s could not be published, and could not be marked so: %v", id, cerr)
+		}
 		return err
 	}
 	a.logf("asked the operator about %s (%s): %d answer(s)", c.Key, id, len(q.Options))
-	return a.store.Put(ctx, asked{ID: id, Condition: c.Key, Ask: q, Actions: c.Actions, Options: options,
-		State: askOpen, Opened: now, Channels: channels})
+	return nil
 }
 
-// cancel takes an ask back.
+// cancel takes an ask back: kept cancelled first, so a warrant that comes after is refused, then said to the
+// router; a cancel the router did not hear leaves the ask to expire there, and nothing is done on it here.
 func (a *asker) cancel(ctx context.Context, r asked, why string) error {
+	stood, err := a.store.Change(ctx, r.ID, func(x *asked) bool {
+		if x.State != askOpen {
+			return false
+		}
+		x.State, x.Ended = askCancelled, a.now()
+		return true
+	})
+	if err != nil || !stood {
+		return err
+	}
 	body, _ := json.Marshal(map[string]string{"id": r.ID})
 	if err := a.publish(ctx, asks.CancelSubject(askerName), body, "cancel."+r.ID); err != nil {
-		a.logf("the ask %s about %s could not be taken back (%v); taken back at the next look", r.ID, r.Condition, err)
+		a.logf("the ask %s about %s is taken back here, and the router could not be told (%v): it expires there, "+
+			"and no answer to it is acted on", r.ID, r.Condition, err)
 		return nil
 	}
 	a.logf("took back the ask %s about %s: %s", r.ID, r.Condition, why)
-	r.State, r.Ended = askCancelled, a.now()
-	return a.store.Put(ctx, r)
+	return nil
 }
 
 // Decided takes the router's word on one of the controller's asks (link.Decider). An error is returned only
@@ -517,13 +616,21 @@ func (a *asker) Decided(ctx context.Context, body []byte) error {
 	}
 	now := a.now()
 	if w.Outcome != asks.OutcomeChosen {
-		r.State, r.Ended, r.Warrant = string(w.Outcome), now, &w
-		r.Acted = "nothing: the ask " + string(w.Outcome)
+		acted := "nothing: the ask " + string(w.Outcome)
 		if w.Words != "" {
-			r.Acted += ": " + w.Words
+			acted += ": " + w.Words
+		}
+		if _, err := a.store.Change(ctx, r.ID, func(x *asked) bool {
+			if x.Acted != "" {
+				return false
+			}
+			x.State, x.Ended, x.Warrant, x.Acted = string(w.Outcome), now, &w, acted
+			return true
+		}); err != nil {
+			return err
 		}
 		a.logf("the ask %s about %s ended %s; nothing is done", r.ID, r.Condition, w.Outcome)
-		return a.store.Put(ctx, *r)
+		return nil
 	}
 	if r.State != askOpen {
 		// Cancelled, replaced or expired in the controller's own record: no answer to it is acted on.
@@ -547,24 +654,39 @@ func (a *asker) Decided(ctx context.Context, body []byte) error {
 		a.logf("REFUSED a warrant for the ask %s: %v", r.ID, err)
 		return nil
 	}
-	r.State, r.Warrant = string(asks.OutcomeChosen), &w
 	open, err := a.open(ctx)
 	if err != nil {
 		return err
 	}
-	stillOpen := r.Drill // a drill is about no condition
+	stillOpen := r.Rehearsal // a rehearsal is about no condition
 	for _, c := range open {
 		stillOpen = stillOpen || c.Key == r.Condition
 	}
 	if !stillOpen {
 		// The asker checks the state is still what it asked about before it acts (to-be 46 §10, step 7).
-		r.Ended, r.Acted = now, "nothing: the condition ended before the answer"
+		if _, err := a.store.Change(ctx, r.ID, func(x *asked) bool {
+			if x.State != askOpen || x.Acted != "" {
+				return false
+			}
+			x.State, x.Warrant, x.Ended, x.Acted = string(asks.OutcomeChosen), &w, now,
+				"nothing: the condition ended before the answer"
+			return true
+		}); err != nil {
+			return err
+		}
 		a.logf("%s, for %s, which ended meanwhile: nothing is done", w.Says(), r.Condition)
-		return a.store.Put(ctx, *r)
+		return nil
 	}
 	// Claimed before acting, by compare-and-set: only the delivery whose write stands acts (security review
-	// of 2026-10-08, finding 9).
-	claimed, err := a.store.Claim(ctx, r.ID, w)
+	// of 2026-10-08, finding 9). Not by the warrant's message id, which another publisher could take first:
+	// the controller's own record decides.
+	claimed, err := a.store.Change(ctx, r.ID, func(x *asked) bool {
+		if x.State != askOpen || x.Acted != "" {
+			return false
+		}
+		x.State, x.Warrant, x.Acted = string(asks.OutcomeChosen), &w, "acting"
+		return true
+	})
 	if err != nil {
 		return err
 	}
@@ -584,20 +706,26 @@ func (a *asker) Decided(ctx context.Context, body []byte) error {
 	}
 	var acted error
 	switch {
-	case r.Drill && act.Verb == drillVerb:
-		// A drill's answer performs nothing: it is recorded below as the operator's decision.
+	case r.Rehearsal && act.Verb == rehearsalVerb:
+		// A rehearsal's answer performs nothing: it is recorded below as the operator's decision.
 	case act.Arguments["silence"] != "":
 		acted = a.silence(ctx, act.Arguments["silence"], conditions.MaxSilence, byWords(w), why)
 	default:
 		acted = a.call(ctx, act, args)
 	}
-	r.Ended = a.now()
-	r.Acted = "done"
+	ended, outcome := a.now(), "done"
 	if acted != nil {
-		r.Acted = "failed: " + acted.Error()
+		outcome = "failed: " + acted.Error()
 	}
-	if err := a.store.Put(ctx, *r); err != nil {
-		return err
+	r.Ended, r.Acted = ended, outcome
+	if _, err := a.store.Change(ctx, r.ID, func(x *asked) bool {
+		if x.Acted != "acting" {
+			return false
+		}
+		x.Ended, x.Acted = ended, outcome
+		return true
+	}); err != nil {
+		a.logf("%s was acted on (%s), and how it ended could NOT be kept: %v", r.ID, outcome, err)
 	}
 	verbArgs := []string{act.Verb}
 	if act.Machine != "" {
diff --git a/cmd/mesh-controller/asker_bus_test.go b/cmd/mesh-controller/asker_bus_test.go
new file mode 100644
index 00000000..0e22c949
--- /dev/null
+++ b/cmd/mesh-controller/asker_bus_test.go
@@ -0,0 +1,151 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-sdk/go/asks"
+
+	"github.com/novox/mesh-controller/internal/broker"
+	"github.com/novox/mesh-controller/internal/conditions"
+	"github.com/novox/mesh-controller/internal/link"
+	"github.com/novox/mesh-controller/internal/testbus"
+)
+
+// busAsker is an asker on a real bus's `asked` bucket, counting what it performs: two of them are two
+// controllers sharing one record.
+type busAskerRig struct {
+	mu     sync.Mutex
+	called int
+	acts   int
+	open   []conditions.Condition
+	sent   [][]byte
+}
+
+func (rig *busAskerRig) asker(t *testing.T, conn *nats.Conn, now time.Time) *asker {
+	return &asker{
+		open: func(context.Context) ([]conditions.Condition, error) {
+			rig.mu.Lock()
+			defer rig.mu.Unlock()
+			return rig.open, nil
+		},
+		silence: func(context.Context, string, time.Duration, string, string) error { return nil },
+		store:   busAsked{conn: conn},
+		publish: func(_ context.Context, subject string, body []byte, _ string) error {
+			rig.mu.Lock()
+			defer rig.mu.Unlock()
+			if subject == asks.AskSubject(askerName) {
+				rig.sent = append(rig.sent, body)
+			}
+			return nil
+		},
+		call: func(context.Context, conditions.Action, map[string]string) error {
+			time.Sleep(20 * time.Millisecond) // long enough for the other delivery to arrive meanwhile
+			rig.mu.Lock()
+			defer rig.mu.Unlock()
+			rig.called++
+			return nil
+		},
+		record: func(context.Context, link.HandAct) error {
+			rig.mu.Lock()
+			defer rig.mu.Unlock()
+			rig.acts++
+			return nil
+		},
+		now:  func() time.Time { return now },
+		logf: t.Logf,
+	}
+}
+
+func askedBus(t *testing.T) *nats.Conn {
+	t.Helper()
+	conn, err := nats.Connect(testbus.URL(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(conn.Close)
+	js, err := jetstream.New(conn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := js.CreateKeyValue(context.Background(), jetstream.KeyValueConfig{Bucket: broker.AskedBucket}); err != nil {
+		t.Fatal(err)
+	}
+	return conn
+}
+
+// The review of 2026-10-09 (L7): two deliveries of one warrant, to two controllers at once, perform its act
+// exactly once and record it once — the record's compare-and-set decides, never the warrant's message id.
+func TestTwoAnswersAtOnceActOnce(t *testing.T) {
+	conn := askedBus(t)
+	now := time.Date(2026, 10, 9, 14, 0, 0, 0, time.UTC)
+	rig := &busAskerRig{open: []conditions.Condition{heldCondition()}}
+	first, second := rig.asker(t, conn, now), rig.asker(t, conn, now)
+	if err := first.reconcile(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	if len(rig.sent) != 1 {
+		t.Fatalf("asked %d times", len(rig.sent))
+	}
+	var q asks.Ask
+	_ = json.Unmarshal(rig.sent[0], &q)
+	release, _ := q.Option("release")
+	w := asks.Warrant{Ask: q.ID, Asker: askerName, About: q.About, Outcome: asks.OutcomeChosen, Option: release.ID,
+		Label: release.Label, Level: release.Level, Channel: "telegram", Proofs: []string{"P1"}, At: now,
+		AskDigest: q.Digest(), By: &asks.Person{Who: asks.Operator, Kind: "telegram", Identity: "42", Verified: "user id verified"}}
+	body, _ := json.Marshal(w)
+	var wg sync.WaitGroup
+	for _, a := range []*asker{first, second, first, second} {
+		wg.Add(1)
+		go func(a *asker) {
+			defer wg.Done()
+			if err := a.Decided(context.Background(), body); err != nil {
+				t.Error(err)
+			}
+		}(a)
+	}
+	wg.Wait()
+	if rig.called != 1 || rig.acts != 1 {
+		t.Fatalf("performed %d time(s), recorded %d time(s)", rig.called, rig.acts)
+	}
+	got, err := busAsked{conn: conn}.Get(context.Background(), q.ID)
+	if err != nil || got == nil || got.Acted != "done" {
+		t.Fatalf("kept as %+v (%v)", got, err)
+	}
+}
+
+// The review of 2026-10-09 (L2): a write decided on a record read earlier never lands over one made since. A
+// cancel read before the answer was acted on leaves the act's record as it is.
+func TestAStaleCancelDoesNotWriteOverAnAct(t *testing.T) {
+	conn := askedBus(t)
+	now := time.Date(2026, 10, 9, 14, 0, 0, 0, time.UTC)
+	rig := &busAskerRig{open: []conditions.Condition{heldCondition()}}
+	a := rig.asker(t, conn, now)
+	if err := a.reconcile(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	var q asks.Ask
+	_ = json.Unmarshal(rig.sent[0], &q)
+	stale, _ := busAsked{conn: conn}.Get(context.Background(), q.ID)
+	release, _ := q.Option("release")
+	w := asks.Warrant{Ask: q.ID, Asker: askerName, About: q.About, Outcome: asks.OutcomeChosen, Option: release.ID,
+		Label: release.Label, Level: release.Level, Channel: "telegram", At: now, AskDigest: q.Digest(),
+		By: &asks.Person{Who: asks.Operator, Kind: "telegram", Identity: "42", Verified: "user id verified"}}
+	body, _ := json.Marshal(w)
+	if err := a.Decided(context.Background(), body); err != nil {
+		t.Fatal(err)
+	}
+	if err := a.cancel(context.Background(), *stale, "the condition ended"); err != nil {
+		t.Fatal(err)
+	}
+	got, _ := busAsked{conn: conn}.Get(context.Background(), q.ID)
+	if got.State != string(asks.OutcomeChosen) || got.Acted != "done" {
+		t.Errorf("a stale cancel wrote over the act: %+v", got)
+	}
+}
diff --git a/cmd/mesh-controller/asker_test.go b/cmd/mesh-controller/asker_test.go
index 5e40c9c4..024fd1fd 100644
--- a/cmd/mesh-controller/asker_test.go
+++ b/cmd/mesh-controller/asker_test.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 
@@ -19,24 +20,40 @@ import (
 
 type memAskedStore map[string]asked
 
+// memAskedMu guards every memAskedStore: Change is a compare-and-set as the bus's is.
+var memAskedMu sync.Mutex
+
 func (m memAskedStore) Get(_ context.Context, id string) (*asked, error) {
+	memAskedMu.Lock()
+	defer memAskedMu.Unlock()
 	r, ok := m[id]
 	if !ok {
 		return nil, nil
 	}
 	return &r, nil
 }
-func (m memAskedStore) Put(_ context.Context, r asked) error { m[r.ID] = r; return nil }
-func (m memAskedStore) Claim(_ context.Context, id string, w asks.Warrant) (bool, error) {
+func (m memAskedStore) Create(_ context.Context, r asked) error {
+	memAskedMu.Lock()
+	defer memAskedMu.Unlock()
+	if _, kept := m[r.ID]; kept {
+		return errors.New("an ask is kept under that id")
+	}
+	m[r.ID] = r
+	return nil
+}
+func (m memAskedStore) Change(_ context.Context, id string, change func(*asked) bool) (bool, error) {
+	memAskedMu.Lock()
+	defer memAskedMu.Unlock()
 	r, ok := m[id]
-	if !ok || r.State != askOpen || r.Acted != "" {
+	if !ok || !change(&r) {
 		return false, nil
 	}
-	r.State, r.Warrant, r.Acted = string(asks.OutcomeChosen), &w, "acting"
 	m[id] = r
 	return true, nil
 }
 func (m memAskedStore) All(context.Context) ([]asked, error) {
+	memAskedMu.Lock()
+	defer memAskedMu.Unlock()
 	var out []asked
 	for _, r := range m {
 		out = append(out, r)
@@ -437,7 +454,7 @@ func TestTheAskDropsWhereItIsAnsweredAndTheConditionKeepsIt(t *testing.T) {
 	if !strings.Contains(c.Explanation, FromMeshMCPServer) {
 		t.Fatalf("the condition lost where it is answered: %q", c.Explanation)
 	}
-	q, _ := askOf("x", c, time.Now())
+	q, _ := askOf("x", c, partsOf(c)[0], time.Now())
 	if strings.Contains(q.Explanation, "mesh MCP server") || !strings.HasPrefix(q.Explanation, "Needs you: release it, or stop it.") {
 		t.Errorf("the ask says %q", q.Explanation)
 	}
@@ -507,7 +524,7 @@ func TestAWarrantPerformsOnlyTheActItsOptionBound(t *testing.T) {
 		})
 	}
 	// Every option of an ask binds its act.
-	q, _ := askOf("x", heldCondition(), time.Now())
+	q, _ := askOf("x", heldCondition(), partsOf(heldCondition())[0], time.Now())
 	for _, o := range q.Options {
 		if o.Binds == "" {
 			t.Errorf("the option %s binds nothing", o.ID)
@@ -563,3 +580,65 @@ func TestAnAskThatCannotBeDeliveredIsSaid(t *testing.T) {
 		t.Errorf("nothing needs asking, and still said: %+v", got)
 	}
 }
+
+// The review of 2026-10-09 (M1): an acknowledging answer never shares an ask with an authorising one. A
+// condition offering Restart and Silence is asked twice — Restart alone, about the condition, and Silence
+// alone, apart — so Silence chosen on a channel that only acknowledges leaves the Restart ask open.
+func TestAnAcknowledgementNeverSharesAnAskWithAnApproval(t *testing.T) {
+	r := newAskerRig(t)
+	key := "module.shanks.plex.down"
+	c := conditions.Condition{Key: key, Kind: "module-down", Severity: conditions.Urgent, Headline: "Plex down on shanks",
+		Explanation: "Needs you: restart it, or silence this.", Needs: "restart it, or silence this.",
+		Actions: []conditions.Action{
+			{Label: "Restart", Verb: "node-service-manager.restart", Machine: "shanks", Level: conditions.LevelApprove,
+				Arguments: map[string]string{"unit": "plex"}},
+			conditions.SilenceAction(key)}}
+	r.open = []conditions.Condition{c}
+	if err := r.a.reconcile(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	sent := r.asksSent(t)
+	if len(sent) != 2 {
+		t.Fatalf("asked %d time(s): %+v", len(sent), sent)
+	}
+	for _, q := range sent {
+		if err := q.Check(r.now); err != nil {
+			t.Errorf("%s: %v", q.About, err)
+		}
+		levels := map[asks.Level]bool{}
+		for _, o := range q.Options {
+			levels[o.Level] = true
+		}
+		if len(levels) != 1 {
+			t.Errorf("the ask about %s mixes levels: %+v", q.About, q.Options)
+		}
+	}
+	byAbout := map[string]asks.Ask{}
+	for _, q := range sent {
+		byAbout[q.About] = q
+	}
+	if q := byAbout[key]; len(q.Options) != 1 || q.Options[0].Label != "Restart" {
+		t.Errorf("the condition's own ask: %+v", q)
+	}
+	if q := byAbout[key+".acknowledge"]; len(q.Options) != 1 || q.Options[0].Level != asks.Acknowledge {
+		t.Errorf("the acknowledging ask: %+v", q)
+	}
+	// Silence chosen: performed, and the Restart ask stays open, never asked twice.
+	answerWith(t, r, r.warrantFor(t, key, "Silence for a week"))
+	if len(r.silenced) != 1 || len(r.called) != 0 {
+		t.Fatalf("silenced %v called %v", r.silenced, r.called)
+	}
+	_ = r.a.reconcile(context.Background())
+	open := 0
+	for _, a := range r.store {
+		if a.State == askOpen && a.Condition == key {
+			open++
+			if a.Part != "" || a.Ask.Options[0].Label != "Restart" {
+				t.Errorf("the open ask is %+v", a)
+			}
+		}
+	}
+	if open != 1 || len(r.asksSent(t)) != 2 {
+		t.Errorf("after the silence: %d open, %d asked", open, len(r.asksSent(t)))
+	}
+}
diff --git a/cmd/mesh-controller/asker_wire.go b/cmd/mesh-controller/asker_wire.go
index dd7ba87a..454986c8 100644
--- a/cmd/mesh-controller/asker_wire.go
+++ b/cmd/mesh-controller/asker_wire.go
@@ -57,7 +57,8 @@ func (b busAsked) Get(ctx context.Context, id string) (*asked, error) {
 	return &r, json.Unmarshal(e.Value(), &r)
 }
 
-func (b busAsked) Put(ctx context.Context, r asked) error {
+// Create keeps a new ask under its id, and only where none is kept: never over another.
+func (b busAsked) Create(ctx context.Context, r asked) error {
 	kv, err := b.kv(ctx)
 	if err != nil {
 		return err
@@ -66,10 +67,49 @@ func (b busAsked) Put(ctx context.Context, r asked) error {
 	if err != nil {
 		return err
 	}
-	_, err = kv.Put(ctx, r.ID, body)
+	_, err = kv.Create(ctx, r.ID, body)
 	return err
 }
 
+// Change applies change to the ask kept under id by compare-and-set on its key's revision (the review of
+// 2026-10-09, L2): read, changed, and written only over the revision read; when another write came between,
+// read again and asked again, at most askChangeTries times. change says whether to write at all.
+func (b busAsked) Change(ctx context.Context, id string, change func(*asked) bool) (bool, error) {
+	kv, err := b.kv(ctx)
+	if err != nil {
+		return false, err
+	}
+	for try := 0; try < askChangeTries; try++ {
+		e, err := kv.Get(ctx, id)
+		if errors.Is(err, jetstream.ErrKeyNotFound) {
+			return false, nil
+		}
+		if err != nil {
+			return false, err
+		}
+		var r asked
+		if err := json.Unmarshal(e.Value(), &r); err != nil {
+			return false, err
+		}
+		if !change(&r) {
+			return false, nil
+		}
+		body, err := json.Marshal(r)
+		if err != nil {
+			return false, err
+		}
+		if _, err := kv.Update(ctx, id, body, e.Revision()); err != nil {
+			var api *jetstream.APIError
+			if errors.Is(err, jetstream.ErrKeyExists) || (errors.As(err, &api) && api.ErrorCode == jetstream.JSErrCodeStreamWrongLastSequence) {
+				continue
+			}
+			return false, err
+		}
+		return true, nil
+	}
+	return false, fmt.Errorf("the ask %s changed under every one of %d tries", id, askChangeTries)
+}
+
 func (b busAsked) All(ctx context.Context) ([]asked, error) {
 	kv, err := b.kv(ctx)
 	if err != nil {
@@ -94,41 +134,6 @@ func (b busAsked) All(ctx context.Context) ([]asked, error) {
 	return out, nil
 }
 
-// Claim marks an open ask acting, by compare-and-set on its key's revision: only the write that stands acts.
-func (b busAsked) Claim(ctx context.Context, id string, w asks.Warrant) (bool, error) {
-	kv, err := b.kv(ctx)
-	if err != nil {
-		return false, err
-	}
-	e, err := kv.Get(ctx, id)
-	if errors.Is(err, jetstream.ErrKeyNotFound) {
-		return false, nil
-	}
-	if err != nil {
-		return false, err
-	}
-	var r asked
-	if err := json.Unmarshal(e.Value(), &r); err != nil {
-		return false, err
-	}
-	if r.State != askOpen || r.Acted != "" {
-		return false, nil
-	}
-	r.State, r.Warrant, r.Acted = string(asks.OutcomeChosen), &w, "acting"
-	body, err := json.Marshal(r)
-	if err != nil {
-		return false, err
-	}
-	if _, err := kv.Update(ctx, id, body, e.Revision()); err != nil {
-		var api *jetstream.APIError
-		if errors.Is(err, jetstream.ErrKeyExists) || (errors.As(err, &api) && api.ErrorCode == jetstream.JSErrCodeStreamWrongLastSequence) {
-			return false, nil
-		}
-		return false, err
-	}
-	return true, nil
-}
-
 // callAction performs an action's verb as the controller, through the grant that names it.
 func callAction(conn *nats.Conn) func(ctx context.Context, a conditions.Action, args map[string]string) error {
 	return func(ctx context.Context, a conditions.Action, args map[string]string) error {
diff --git a/cmd/mesh-controller/drill.go b/cmd/mesh-controller/drill.go
deleted file mode 100644
index 1db79cf8..00000000
--- a/cmd/mesh-controller/drill.go
+++ /dev/null
@@ -1,110 +0,0 @@
-package main
-
-// The drill of the operator's answers (novox/hq ADR 0259, the live acceptance after rollout): an ask the
-// operator starts at the controller's terminal, answered on the phone, whose approval changes nothing and is
-// recorded as a person's decision like any other.
-//
-//	mesh-controller drill [--for 15m]
-//
-// It asks with two answers — Approve (an approval, so only a channel that proves who answered carries it) and
-// Decline (an acknowledgement) — each bound to the drill's own act. The serving controller acts on the warrant
-// as on any other: it claims the ask once, checks the act is the one bound, performs nothing, and records the
-// hand-act `warrant` with who answered, through which channel, and the proofs. `hand-acts` then shows it.
-//
-// **The terminal's alone**: a command a verb runs (MESH_VERB set) is refused, so no agent starts a drill — a
-// drill is a question the operator expects, and one an agent could start would teach them to approve what they
-// did not ask for.
-
-import (
-	"context"
-	"encoding/json"
-	"errors"
-	"flag"
-	"fmt"
-	"os"
-	"time"
-
-	"github.com/nats-io/nats.go"
-
-	"git.novox.be/novox/mesh-sdk/go/asks"
-
-	"github.com/novox/mesh-controller/internal/conditions"
-)
-
-// drillVerb is the act a drill's answers bind: nothing is called.
-const drillVerb = "drill"
-
-// drillActions are the drill's two answers.
-func drillActions() []conditions.Action {
-	return []conditions.Action{
-		{Label: "Approve", Verb: drillVerb, Level: conditions.LevelApprove, Arguments: map[string]string{"drill": "approve"}},
-		{Label: "Decline", Verb: drillVerb, Level: conditions.LevelAcknowledge, Arguments: map[string]string{"drill": "decline"}},
-	}
-}
-
-// drillAsk is the drill's ask, as the router is sent it.
-func drillAsk(id string, now time.Time, lasts time.Duration) (asks.Ask, map[string]int) {
-	q := asks.Ask{ID: id, Headline: "Drill: approve this test question?", Who: asks.Operator,
-		Explanation: "Needs you: approve or decline. You started this drill at the controller's terminal. Approving " +
-			"changes nothing on the mesh; it is recorded as your decision, so you can check the record.",
-		OnExpiry: "nothing is done", Expires: now.Add(lasts), About: "drill." + id}
-	options := map[string]int{}
-	for i, act := range drillActions() {
-		binds, _ := asks.ActDigest(boundAct(act))
-		oid := optionID(act.Label)
-		options[oid] = i
-		q.Options = append(q.Options, asks.Option{ID: oid, Label: act.Label, Does: doesDrill(act), Level: asks.Level(act.Level),
-			Binds: binds})
-	}
-	return q, options
-}
-
-func doesDrill(act conditions.Action) string {
-	if act.Arguments["drill"] == "approve" {
-		return "nothing changes; your approval is recorded"
-	}
-	return "nothing changes; your answer is recorded"
-}
-
-func drillCommand(ctx context.Context, args []string) error {
-	if os.Getenv(verbVar) != "" {
-		return errors.New("drill is the controller's terminal's alone: a verb may not start one, so no agent asks " +
-			"the operator a question they did not start (novox/hq ADR 0259)")
-	}
-	set := flag.NewFlagSet("drill", flag.ContinueOnError)
-	lasts := set.Duration("for", 15*time.Minute, "how long the question waits for an answer")
-	if err := set.Parse(args); err != nil {
-		return err
-	}
-	if *lasts < time.Minute || *lasts > askApproveFor {
-		return fmt.Errorf("a drill waits between a minute and %s", askApproveFor)
-	}
-	js, err := aBus()
-	if err != nil {
-		return err
-	}
-	defer js.Close()
-	now := time.Now()
-	id := newAskID()
-	q, options := drillAsk(id, now, *lasts)
-	if err := q.Check(now); err != nil {
-		return err
-	}
-	store := busAsked{conn: js.Conn()}
-	// Kept before it is published, as the asker keeps every ask, so a warrant always finds it.
-	if err := store.Put(ctx, asked{ID: id, Condition: q.About, Ask: q, Actions: drillActions(), Options: options,
-		State: askOpen, Opened: now, Drill: true}); err != nil {
-		return fmt.Errorf("the drill could not be kept in the controller's asks: %w", err)
-	}
-	body, err := json.Marshal(q)
-	if err != nil {
-		return err
-	}
-	if _, err := js.Context().Publish(asks.AskSubject(askerName), body, nats.MsgId("ask."+id), nats.Context(ctx)); err != nil {
-		return fmt.Errorf("the drill could not be asked: %w", err)
-	}
-	fmt.Printf("drill %s asked: answer it on your phone before %s. Then `mesh-controller hand-acts` shows the "+
-		"answer as a warrant, with who answered, through which channel and the proofs; nothing else changes.\n",
-		id, q.Expires.Local().Format("15:04"))
-	return nil
-}
diff --git a/cmd/mesh-controller/drill_test.go b/cmd/mesh-controller/drill_test.go
deleted file mode 100644
index 074abd4b..00000000
--- a/cmd/mesh-controller/drill_test.go
+++ /dev/null
@@ -1,60 +0,0 @@
-package main
-
-import (
-	"context"
-	"strings"
-	"testing"
-	"time"
-
-	"git.novox.be/novox/mesh-sdk/go/asks"
-)
-
-// A drill (the live acceptance of novox/hq ADR 0259): its approval is a warrant like any other — claimed once,
-// its act checked against what the option bound, recorded as the operator's decision with who, how and the
-// proofs — and it performs nothing. The reconciling of conditions leaves it open.
-func TestADrillsApprovalIsRecordedAndPerformsNothing(t *testing.T) {
-	r := newAskerRig(t)
-	q, options := drillAsk("cdrill", r.now, askerDrillFor)
-	if err := q.Check(r.now); err != nil {
-		t.Fatalf("the drill's ask is refused: %v", err)
-	}
-	r.store["cdrill"] = asked{ID: "cdrill", Condition: q.About, Ask: q, Actions: drillActions(), Options: options,
-		State: askOpen, Opened: r.now, Drill: true}
-	if err := r.a.reconcile(context.Background()); err != nil {
-		t.Fatal(err)
-	}
-	if got := r.store["cdrill"]; got.State != askOpen {
-		t.Fatalf("the reconciling of conditions ended the drill: %+v", got)
-	}
-	approve, _ := q.Option("approve")
-	w := asks.Warrant{Ask: "cdrill", Asker: "mesh-controller", Outcome: asks.OutcomeChosen, Option: approve.ID,
-		Label: approve.Label, Level: approve.Level, Channel: "telegram", Proofs: []string{"P1"}, At: r.now,
-		AskDigest: q.Digest(), By: &asks.Person{Who: asks.Operator, Kind: "telegram", Identity: "42", Verified: "user id verified"}}
-	answerWith(t, r, w)
-	answerWith(t, r, w) // heard again
-	if len(r.called)+len(r.silenced) != 0 {
-		t.Errorf("a drill performed something: %v %v", r.called, r.silenced)
-	}
-	if len(r.acts) != 1 {
-		t.Fatalf("hand-acts %+v", r.acts)
-	}
-	act := r.acts[0]
-	if act.Verb != handActWarrant || act.By != "the operator, as telegram identity 42" || act.Ask != "cdrill" ||
-		strings.Join(act.Args, " ") != "drill drill=approve" || act.Outcome != "done" || strings.Join(act.Proofs, ",") != "P1" {
-		t.Errorf("the drill's record: %+v", act)
-	}
-	if !personsDecision(act) {
-		t.Error("a drill's answer counts as a repair")
-	}
-}
-
-// Only the terminal starts a drill: a verb's process is refused before anything is asked.
-func TestADrillIsTheTerminalsAlone(t *testing.T) {
-	t.Setenv(verbVar, "mesh-controller.command")
-	if err := drillCommand(context.Background(), nil); err == nil || !strings.Contains(err.Error(), "terminal") {
-		t.Fatalf("a verb started a drill: %v", err)
-	}
-}
-
-// askerDrillFor is how long the test's drill waits.
-const askerDrillFor = 15 * time.Minute
diff --git a/cmd/mesh-controller/main.go b/cmd/mesh-controller/main.go
index 6a085307..81e86c87 100644
--- a/cmd/mesh-controller/main.go
+++ b/cmd/mesh-controller/main.go
@@ -78,8 +78,8 @@ func run() error {
 		return rotateCommand(ctx, args[1:])
 	case "ask":
 		return askCommand(ctx, args[1:])
-	case "drill":
-		return drillCommand(ctx, args[1:])
+	case "rehearse":
+		return rehearseCommand(ctx, args[1:])
 	case "builds":
 		return buildsCommand(ctx, args[1:])
 	// The build queue, controlled by hand (novox/hq ADR 0219).
diff --git a/cmd/mesh-controller/rehearse.go b/cmd/mesh-controller/rehearse.go
new file mode 100644
index 00000000..5ec46044
--- /dev/null
+++ b/cmd/mesh-controller/rehearse.go
@@ -0,0 +1,111 @@
+package main
+
+// The rehearsal of the operator's answers — not a drill, which in the glossary is something broken on purpose (novox/hq ADR 0259, the live acceptance after rollout): an ask the
+// operator starts at the controller's terminal, answered on the phone, whose approval changes nothing and is
+// recorded as a person's decision like any other.
+//
+//	mesh-controller rehearse [--for 15m]
+//
+// It asks with two answers, Approve and Decline, each bound to the rehearsal's own act and **both at the level
+// approve** (the review of 2026-10-09, M1: an acknowledgement never shares an ask with an approval), so only a
+// channel that proves who answered carries either — the rehearsal is of exactly that. The serving controller acts on the warrant
+// as on any other: it claims the ask once, checks the act is the one bound, performs nothing, and records the
+// hand-act `warrant` with who answered, through which channel, and the proofs. `hand-acts` then shows it.
+//
+// **The terminal's alone**: a command a verb runs (MESH_VERB set) is refused, so no agent starts a rehearsal — a
+// rehearsal is a question the operator expects, and one an agent could start would teach them to approve what they
+// did not ask for.
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/nats-io/nats.go"
+
+	"git.novox.be/novox/mesh-sdk/go/asks"
+
+	"github.com/novox/mesh-controller/internal/conditions"
+)
+
+// rehearsalVerb is the act a rehearsal's answers bind: nothing is called.
+const rehearsalVerb = "rehearsal"
+
+// rehearsalActions are the rehearsal's two answers.
+func rehearsalActions() []conditions.Action {
+	return []conditions.Action{
+		{Label: "Approve", Verb: rehearsalVerb, Level: conditions.LevelApprove, Arguments: map[string]string{"rehearsal": "approve"}},
+		{Label: "Decline", Verb: rehearsalVerb, Level: conditions.LevelApprove, Arguments: map[string]string{"rehearsal": "decline"}},
+	}
+}
+
+// rehearsalAsk is the rehearsal's ask, as the router is sent it.
+func rehearsalAsk(id string, now time.Time, lasts time.Duration) (asks.Ask, map[string]int) {
+	q := asks.Ask{ID: id, Headline: "Rehearsal: approve this test question?", Who: asks.Operator,
+		Explanation: "Needs you: approve or decline. You started this rehearsal at the controller's terminal. Approving " +
+			"changes nothing on the mesh; it is recorded as your decision, so you can check the record.",
+		OnExpiry: "nothing is done", Expires: now.Add(lasts), About: "rehearsal." + id}
+	options := map[string]int{}
+	for i, act := range rehearsalActions() {
+		binds, _ := asks.ActDigest(boundAct(act))
+		oid := optionID(act.Label)
+		options[oid] = i
+		q.Options = append(q.Options, asks.Option{ID: oid, Label: act.Label, Does: doesRehearsal(act), Level: asks.Level(act.Level),
+			Binds: binds})
+	}
+	return q, options
+}
+
+func doesRehearsal(act conditions.Action) string {
+	if act.Arguments["rehearsal"] == "approve" {
+		return "nothing changes; your approval is recorded"
+	}
+	return "nothing changes; your answer is recorded"
+}
+
+func rehearseCommand(ctx context.Context, args []string) error {
+	if os.Getenv(verbVar) != "" {
+		return errors.New("rehearse is the controller's terminal's alone: a verb may not start one, so no agent asks " +
+			"the operator a question they did not start (novox/hq ADR 0259)")
+	}
+	set := flag.NewFlagSet("rehearse", flag.ContinueOnError)
+	lasts := set.Duration("for", 15*time.Minute, "how long the question waits for an answer")
+	if err := set.Parse(args); err != nil {
+		return err
+	}
+	if *lasts < time.Minute || *lasts > askApproveFor {
+		return fmt.Errorf("a rehearsal waits between a minute and %s", askApproveFor)
+	}
+	js, err := aBus()
+	if err != nil {
+		return err
+	}
+	defer js.Close()
+	now := time.Now()
+	id := newAskID()
+	q, options := rehearsalAsk(id, now, *lasts)
+	if err := q.Check(now); err != nil {
+		return err
+	}
+	store := busAsked{conn: js.Conn()}
+	// Kept before it is published, as the asker keeps every ask, so a warrant always finds it.
+	if err := store.Create(ctx, asked{ID: id, Condition: q.About, Ask: q, Actions: rehearsalActions(), Options: options,
+		State: askOpen, Opened: now, Rehearsal: true}); err != nil {
+		return fmt.Errorf("the rehearsal could not be kept in the controller's asks: %w", err)
+	}
+	body, err := json.Marshal(q)
+	if err != nil {
+		return err
+	}
+	if _, err := js.Context().Publish(asks.AskSubject(askerName), body, nats.MsgId("ask."+id), nats.Context(ctx)); err != nil {
+		return fmt.Errorf("the rehearsal could not be asked: %w", err)
+	}
+	fmt.Printf("rehearsal %s asked: answer it on your phone before %s. Then `mesh-controller hand-acts` shows the "+
+		"answer as a warrant, with who answered, through which channel and the proofs; nothing else changes.\n",
+		id, q.Expires.Local().Format("15:04"))
+	return nil
+}
diff --git a/cmd/mesh-controller/rehearse_test.go b/cmd/mesh-controller/rehearse_test.go
new file mode 100644
index 00000000..4cfdeb20
--- /dev/null
+++ b/cmd/mesh-controller/rehearse_test.go
@@ -0,0 +1,60 @@
+package main
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/asks"
+)
+
+// A rehearsal (the live acceptance of novox/hq ADR 0259): its approval is a warrant like any other — claimed once,
+// its act checked against what the option bound, recorded as the operator's decision with who, how and the
+// proofs — and it performs nothing. The reconciling of conditions leaves it open.
+func TestARehearsalsApprovalIsRecordedAndPerformsNothing(t *testing.T) {
+	r := newAskerRig(t)
+	q, options := rehearsalAsk("crehearsal", r.now, askerRehearsalFor)
+	if err := q.Check(r.now); err != nil {
+		t.Fatalf("the rehearsal's ask is refused: %v", err)
+	}
+	r.store["crehearsal"] = asked{ID: "crehearsal", Condition: q.About, Ask: q, Actions: rehearsalActions(), Options: options,
+		State: askOpen, Opened: r.now, Rehearsal: true}
+	if err := r.a.reconcile(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	if got := r.store["crehearsal"]; got.State != askOpen {
+		t.Fatalf("the reconciling of conditions ended the rehearsal: %+v", got)
+	}
+	approve, _ := q.Option("approve")
+	w := asks.Warrant{Ask: "crehearsal", Asker: "mesh-controller", Outcome: asks.OutcomeChosen, Option: approve.ID,
+		Label: approve.Label, Level: approve.Level, Channel: "telegram", Proofs: []string{"P1"}, At: r.now,
+		AskDigest: q.Digest(), By: &asks.Person{Who: asks.Operator, Kind: "telegram", Identity: "42", Verified: "user id verified"}}
+	answerWith(t, r, w)
+	answerWith(t, r, w) // heard again
+	if len(r.called)+len(r.silenced) != 0 {
+		t.Errorf("a rehearsal performed something: %v %v", r.called, r.silenced)
+	}
+	if len(r.acts) != 1 {
+		t.Fatalf("hand-acts %+v", r.acts)
+	}
+	act := r.acts[0]
+	if act.Verb != handActWarrant || act.By != "the operator, as telegram identity 42" || act.Ask != "crehearsal" ||
+		strings.Join(act.Args, " ") != "rehearsal rehearsal=approve" || act.Outcome != "done" || strings.Join(act.Proofs, ",") != "P1" {
+		t.Errorf("the rehearsal's record: %+v", act)
+	}
+	if !personsDecision(act) {
+		t.Error("a rehearsal's answer counts as a repair")
+	}
+}
+
+// Only the terminal starts a rehearsal: a verb's process is refused before anything is asked.
+func TestARehearsalIsTheTerminalsAlone(t *testing.T) {
+	t.Setenv(verbVar, "mesh-controller.command")
+	if err := rehearseCommand(context.Background(), nil); err == nil || !strings.Contains(err.Error(), "terminal") {
+		t.Fatalf("a verb started a rehearsal: %v", err)
+	}
+}
+
+// askerRehearsalFor is how long the test's rehearsal waits.
+const askerRehearsalFor = 15 * time.Minute
diff --git a/go.mod b/go.mod
index 5da9ba9f..a6b3c201 100644
--- a/go.mod
+++ b/go.mod
@@ -3,7 +3,7 @@ module github.com/novox/mesh-controller
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261009081503-d4077b473ea8
+	git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261009095928-76902998cd39
 	github.com/jackc/pgx/v5 v5.10.0
 	github.com/nats-io/nats-server/v2 v2.11.17
 	github.com/nats-io/nats.go v1.54.0
diff --git a/go.sum b/go.sum
index eadf28cd..eb765ca2 100644
--- a/go.sum
+++ b/go.sum
@@ -1,13 +1,7 @@
-git.novox.be/novox/mesh-host v0.0.0-20261007162834-56e2ebec4bac h1:yLtFS0pDCCqIE9Zx8hgXEFG9fUWzf8L9WQoKV+Amk1E=
-git.novox.be/novox/mesh-host v0.0.0-20261007162834-56e2ebec4bac/go.mod h1:VlilMCRZ5yyNXg7SNigNBLr0Gt32jrGw5KSNq5JAVYs=
 git.novox.be/novox/mesh-host v0.0.0-20261009081005-b28d7bbcbff4 h1:f4rBnKSemuN0Z9dTtRJMigIGfEs6ltFPOILJGHGab74=
 git.novox.be/novox/mesh-host v0.0.0-20261009081005-b28d7bbcbff4/go.mod h1:72ZATZjxMLaJfWdvlSDJrygIoBzCmKIjCDMhEXxVzTo=
-git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261008145004-62367ce15ad6 h1:JT7xM1bnLNInW7/oImV2OlXTrcQ4/GSM0Y8tAb+AhmY=
-git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261008145004-62367ce15ad6/go.mod h1:GFuZUElBZ9A++mxgIKo97aXXo+kV0uJ/UkbhQPPIbrY=
-git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261008162031-55090da7e08f h1:BNvyWq899GwP7F3sY4ACieB5a5fnFAq+sJ9lP6HQ5qI=
-git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261008162031-55090da7e08f/go.mod h1:GFuZUElBZ9A++mxgIKo97aXXo+kV0uJ/UkbhQPPIbrY=
-git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261009081503-d4077b473ea8 h1:soqhLNpEXThdq6PdiPy6ExxjJ+yjhh1N1n9E3j1CtrM=
-git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261009081503-d4077b473ea8/go.mod h1:GFuZUElBZ9A++mxgIKo97aXXo+kV0uJ/UkbhQPPIbrY=
+git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261009095928-76902998cd39 h1:WHW6CgbuTxP7M+qRBOgzsiG9vT49xdkZ/rarc9/vKMA=
+git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261009095928-76902998cd39/go.mod h1:GFuZUElBZ9A++mxgIKo97aXXo+kV0uJ/UkbhQPPIbrY=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op/go.mod h1:FQyySiasQQM8735Ddel3MRojmy4dA1IqCeyJ5jmPMbI=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
diff --git a/internal/inventory/asks_lab_test.go b/internal/inventory/asks_lab_test.go
index 62593d54..a96a9a73 100644
--- a/internal/inventory/asks_lab_test.go
+++ b/internal/inventory/asks_lab_test.go
@@ -98,7 +98,13 @@ func TestTheAsksLabBus(t *testing.T) {
 			Emits: own.Emits, Serves: own.Serves}
 	}
 	records := broker.Records{Nodes: []string{labMachine}, Assigned: map[string][]broker.Declared{},
-		People: map[string][]string{}, Interchangeable: map[string]bool{}}
+		People: map[string][]string{}, Interchangeable: map[string]bool{}, RootFree: map[string]bool{}}
+	// Whether the lab's machine is root-free is the lab's to say (MESH_LAB_ASKS_ROOT_FREE=true): it has no
+	// node-engine to judge it. Unsaid, it is not, and no kind is composed with verified-sender — as a push
+	// composes on a machine that is not (novox/hq ADR 0259 §8).
+	if os.Getenv("MESH_LAB_ASKS_ROOT_FREE") == "true" {
+		records.RootFree[labMachine] = true
+	}
 	var buckets []broker.Bucket
 	var trafficSeats []broker.Seat
 	for _, m := range manifests {
diff --git a/vendor/git.novox.be/novox/mesh-sdk/go/asks/asks.go b/vendor/git.novox.be/novox/mesh-sdk/go/asks/asks.go
index ca2e8006..efe2a661 100644
--- a/vendor/git.novox.be/novox/mesh-sdk/go/asks/asks.go
+++ b/vendor/git.novox.be/novox/mesh-sdk/go/asks/asks.go
@@ -8,10 +8,11 @@ package asks
 import (
 	"crypto/sha256"
 	"encoding/hex"
-	"encoding/json"
 	"errors"
 	"fmt"
 	"regexp"
+	"sort"
+	"strconv"
 	"strings"
 	"time"
 )
@@ -107,25 +108,67 @@ type Option struct {
 	Binds string `json:"binds,omitempty"`
 }
 
-// ActDigest is the digest an asker puts in Option.Binds: SHA-256 over the act's JSON (Go's encoding sorts a
-// map's keys, so the same act gives the same digest), written "sha256:<hex>".
-func ActDigest(act any) (string, error) {
-	raw, err := json.Marshal(act)
-	if err != nil {
-		return "", fmt.Errorf("the act cannot be digested: %w", err)
+// An Act is what an option binds: named fields, each a string — the verb, the machine, the level, and each
+// argument under a name of its own ("arg.delivery"). Flat on purpose: its digest is over these names and
+// values alone, never over how a language happens to encode a struct.
+type Act map[string]string
+
+// ActDigest is the digest an asker puts in Option.Binds: SHA-256 over the act's canonical encoding (canonical),
+// written "sha256:<hex>". The same names and values give the same digest in any language, whatever order
+// they were set in; a field renamed, added or emptied gives another.
+func ActDigest(act Act) (string, error) {
+	if len(act) == 0 {
+		return "", fmt.Errorf("the act cannot be digested: it names nothing")
 	}
-	sum := sha256.Sum256(raw)
+	keys := make([]string, 0, len(act))
+	for k := range act {
+		if k == "" {
+			return "", fmt.Errorf("the act cannot be digested: a field has no name")
+		}
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	var b strings.Builder
+	b.WriteString("novox.act.v1\n")
+	for _, k := range keys {
+		canonical(&b, k)
+		canonical(&b, act[k])
+	}
+	sum := sha256.Sum256([]byte(b.String()))
 	return "sha256:" + hex.EncodeToString(sum[:]), nil
 }
 
+// canonical writes one value as its length in bytes, a colon, the bytes and a newline: no value can be read
+// as another's end or start, so two different sequences of values never encode the same.
+func canonical(b *strings.Builder, v string) {
+	b.WriteString(strconv.Itoa(len(v)))
+	b.WriteByte(':')
+	b.WriteString(v)
+	b.WriteByte('\n')
+}
+
 // Digest is the digest of the ask exactly as its asker published it: its id, words, options with what each
 // binds, who answers, and its expiry. The router puts it in the warrant (Warrant.AskDigest), and an asker
 // acts only on a warrant whose digest is that of the ask it keeps — so a warrant answers one ask, as the
 // person was shown it, and nothing published under the same id before or after.
+//
+// It is over the ask's named fields in a fixed order, each written canonically, and the expiry as UTC
+// RFC 3339 to the nanosecond — never over a language's encoding of the struct, so a field added to Ask
+// later changes no digest until it is added here, on purpose.
 func (a Ask) Digest() string {
-	a.Expires = a.Expires.UTC()
-	raw, _ := json.Marshal(a)
-	sum := sha256.Sum256(raw)
+	var b strings.Builder
+	b.WriteString("novox.ask.v1\n")
+	for _, v := range []string{a.ID, a.Headline, a.Explanation, a.Who,
+		a.Expires.UTC().Format(time.RFC3339Nano), a.OnExpiry, a.About, strconv.FormatBool(a.Urgent),
+		strconv.Itoa(len(a.Options))} {
+		canonical(&b, v)
+	}
+	for _, o := range a.Options {
+		for _, v := range []string{o.ID, o.Label, o.Does, string(o.Level), o.Binds} {
+			canonical(&b, v)
+		}
+	}
+	sum := sha256.Sum256([]byte(b.String()))
 	return "sha256:" + hex.EncodeToString(sum[:])
 }
 
@@ -341,7 +384,7 @@ func (w Warrant) For(asker string, a Ask) (Option, error) {
 
 // Performs checks that the act an asker is about to perform is the one the chosen option bound when it
 // asked: the act's digest equals the option's Binds. An acknowledge option that bound nothing passes.
-func (o Option) Performs(act any) error {
+func (o Option) Performs(act Act) error {
 	if o.Binds == "" && o.Level == Acknowledge {
 		return nil
 	}
diff --git a/vendor/modules.txt b/vendor/modules.txt
index f3c9f514..af68ed2c 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -1,4 +1,4 @@
-# git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261009081503-d4077b473ea8
+# git.novox.be/novox/mesh-sdk/go v0.1.8-0.20261009095928-76902998cd39
 ## explicit; go 1.22
 git.novox.be/novox/mesh-sdk/go/asks
 # github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op