From 20027e53ff773ca0beb9fee5cb16fc59f630e79d Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Sun, 25 Oct 2026 22:00:50 +0100
Subject: [PATCH] Delivery parts: a bucket the bus refuses at start stops a
 part only when it cannot work without it (issue 1945)

Met twice on 2026-10-25: the builder of #48 exited on a refused read of
the gate's source and crash-looped, and its new reasks bucket would have
done the same. A grant reaches the bus with a delivery, so a refusal or a
timeout at start is often only a grant not there yet; exiting for it
stopped the whole part until a hand step on the bus.

Every startup open in the parts is now essential or optional. Essential
ones (a part's own state and the input it exists for) still stop the
start, with an error naming the bucket and its grant. Optional ones are
said and left: watches the bus refuses too. The builder builds trunk keys
without the gate's source, which it opens again at the next candidate
that asks a trunk head; toolchains and previews open again at their next
event, as a missing bucket did. builder_ask_again says that asking a
running step again builds it twice.
---
 .../cmd/mesh-delivery-assigner/main.go        |   6 +-
 .../cmd/mesh-delivery-assigner/main_test.go   |   2 +-
 .../cmd/mesh-delivery-assigner/optional.go    |  27 +++++
 .../cmd/mesh-delivery-builder-tools/main.go   |   3 +-
 .../cmd/mesh-delivery-builder/main.go         |  91 +++++----------
 .../cmd/mesh-delivery-builder/optional.go     | 104 ++++++++++++++++++
 .../cmd/mesh-delivery-builder/standing.go     |   4 +-
 .../mesh-delivery-builder/standing_test.go    |  61 ++++++++++
 .../cmd/mesh-delivery-builder/toolchains.go   |   8 +-
 .../cmd/mesh-delivery-checker/main.go         |  69 +++++-------
 .../cmd/mesh-delivery-checker/optional.go     |  41 +++++++
 .../cmd/mesh-delivery-checker/standing.go     |   4 +-
 .../mesh-delivery-checker/standing_test.go    |  51 +++++++++
 .../cmd/mesh-delivery-checker/toolchains.go   |   8 +-
 .../cmd/mesh-delivery-forge-bridge/main.go    |  23 ++--
 .../mesh-delivery-forge-bridge/main_test.go   |  16 +++
 .../mesh-delivery-forge-bridge/optional.go    |  46 ++++++++
 .../cmd/mesh-delivery-indexer/main.go         |  50 ++++-----
 .../cmd/mesh-delivery-indexer/optional.go     |  41 +++++++
 .../cmd/mesh-delivery-indexer/previews.go     |   8 +-
 .../cmd/mesh-delivery-indexer/standing.go     |   4 +-
 .../cmd/mesh-delivery-indexer/toolchains.go   |   8 +-
 .../mesh-delivery-indexer/toolchains_test.go  |  11 ++
 .../cmd/mesh-delivery-teller/main.go          |  21 ++--
 .../cmd/mesh-delivery-teller/optional.go      |  46 ++++++++
 .../cmd/mesh-delivery-teller/teller_test.go   |  18 +++
 .../cmd/mesh-delivery-watchman/main.go        |  53 +++++----
 .../cmd/mesh-delivery-watchman/main_test.go   |  19 ++++
 .../cmd/mesh-delivery-watchman/optional.go    |  46 ++++++++
 29 files changed, 681 insertions(+), 208 deletions(-)
 create mode 100644 modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/optional.go
 create mode 100644 modules/mesh-delivery-builder/cmd/mesh-delivery-builder/optional.go
 create mode 100644 modules/mesh-delivery-checker/cmd/mesh-delivery-checker/optional.go
 create mode 100644 modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/optional.go
 create mode 100644 modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/optional.go
 create mode 100644 modules/mesh-delivery-teller/cmd/mesh-delivery-teller/optional.go
 create mode 100644 modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/optional.go

diff --git a/modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/main.go b/modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/main.go
index 0c7341d..2f2512d 100644
--- a/modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/main.go
+++ b/modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/main.go
@@ -86,11 +86,11 @@ var keptStates = []announce.State{
 // buckets is every bucket the assigner opened, by name.
 type buckets map[string]jetstream.KeyValue
 
-// open opens every bucket the assigner reads and writes; a bucket it cannot open stops the start, named, since a pass
+// open opens every bucket the assigner reads and writes; a bucket it cannot open stops the start, named with its grant (issue 1945), since a pass
 // without it would write wants from half the mesh. The puts' bucket is the exception: whatever keeps it from opening (it
 // does not exist yet, the credential is not granted it yet, the bus does not answer in time), the assigner writes wants
 // without it and takes no put further until it starts again (ADR 0546).
-func open(ctx context.Context, js jetstream.JetStream, logf func(string, ...any)) (buckets, error) {
+func open(ctx context.Context, js bucketOpener, logf func(string, ...any)) (buckets, error) {
 	out := buckets{}
 	for _, name := range append(append([]string{}, readBuckets...), ownBuckets...) {
 		kv, err := js.KeyValue(ctx, name)
@@ -99,7 +99,7 @@ func open(ctx context.Context, js jetstream.JetStream, logf func(string, ...any)
 			continue
 		}
 		if err != nil {
-			return nil, fmt.Errorf("the bucket %s cannot be opened: %w", name, err)
+			return nil, essentialErr(name, "write a want from the whole mesh", err)
 		}
 		out[name] = kv
 	}
diff --git a/modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/main_test.go b/modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/main_test.go
index 3c346ab..75d7411 100644
--- a/modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/main_test.go
+++ b/modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/main_test.go
@@ -73,7 +73,7 @@ func TestOpensWhatItsManifestNames(t *testing.T) {
 		switch {
 		case c.starts && (err != nil || kvs[c.missing] != nil || len(kvs) != len(readBuckets)+len(ownBuckets)-1 || !strings.Contains(logged, "no put is taken further")):
 			t.Errorf("%s refused with %v: the start answered %v, %d buckets, logged %q", c.missing, c.err, err, len(kvs), logged)
-		case !c.starts && (err == nil || !strings.Contains(err.Error(), c.missing)):
+		case !c.starts && (err == nil || !strings.Contains(err.Error(), "grant of "+c.missing)): // 1945: named with its grant
 			t.Errorf("%s refused with %v: the start answered %v", c.missing, c.err, err)
 		}
 	}
diff --git a/modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/optional.go b/modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/optional.go
new file mode 100644
index 0000000..0267144
--- /dev/null
+++ b/modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/optional.go
@@ -0,0 +1,27 @@
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// **A part does not stop for a bucket it can work without** (novox/hq issue 1945, met twice on 2026-10-25: the builder of
+// mesh-delivery #48 exited on a refused read of the gate's source, and its new reasks bucket would have done the same). A
+// grant reaches the bus with a delivery, so a bucket the bus refuses, or times out on, at start is often only not granted
+// yet: exiting for it stops the part until a person's hand. The assigner works without none of its buckets but the Go build
+// module's steps, so the others stop the start, naming the grant to look at. (The same two functions are in each delivery part;
+// they belong in mesh-sdk.)
+
+// bucketOpener is the part of the bus a start opens buckets with.
+type bucketOpener interface {
+	KeyValue(ctx context.Context, bucket string) (jetstream.KeyValue, error)
+}
+
+// essentialErr is the error of a bucket the part cannot work without: it names the bucket and the grant.
+func essentialErr(name, does string, err error) error {
+	return fmt.Errorf("the bucket %s cannot be read (%v): the assigner cannot %s without it, so it stops; where the bus "+
+		"refused it or did not answer, this module's grant of %s (its manifest's reads or state, issued with its credential) "+
+		"has not reached the bus yet", name, err, does, name)
+}
diff --git a/modules/mesh-delivery-builder/cmd/mesh-delivery-builder-tools/main.go b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder-tools/main.go
index 852cb29..acc2bfe 100644
--- a/modules/mesh-delivery-builder/cmd/mesh-delivery-builder-tools/main.go
+++ b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder-tools/main.go
@@ -31,7 +31,8 @@ func Tools(r build.StuckReader, askAgain func(key string, value []byte) error, n
 		{Name: build.AskAgainTool,
 			Description: "Ask a waiting build key's asks again now, under new ids the key then names, as the builder does by itself for an ask its build " +
 				"seat's stream gave up on. The builder answers in the reasks state, which " + build.StuckTool + " shows beside the key; a key no ask of " +
-				"which waits is answered so and nothing is asked.",
+				"which waits is answered so and nothing is asked. An ask whose step already runs on a node is asked again too: it is then " +
+				"built twice, the first run's work wasted and its end read by nobody, never a wrong key; builder_stuck shows whether a step runs.",
 			Input: map[string]any{"type": "object", "required": []string{"module", "fp", "why"}, "properties": map[string]any{
 				"module": map[string]any{"type": "string", "description": "the module's name"},
 				"fp":     map[string]any{"type": "string", "description": "its new-form fingerprint, src2:<hex>, as builder_stuck shows it"},
diff --git a/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/main.go b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/main.go
index 3d867ce..d6b2e9f 100644
--- a/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/main.go
+++ b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/main.go
@@ -124,29 +124,20 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	if err != nil {
 		return err
 	}
-	bucket := func(name string) (jetstream.KeyValue, error) {
-		kv, err := js.KeyValue(ctx, name)
-		if err != nil {
-			return nil, fmt.Errorf("the bucket %s: %w", name, err)
-		}
-		return kv, nil
-	}
-	builds, err := bucket(delivery.BuilderBuildsBucket)
+	builds, err := essentialBucket(ctx, js, delivery.BuilderBuildsBucket, "claim or write a build key")
 	if err != nil {
 		return err
 	}
-	modules, err := bucket(delivery.ModulesBucket)
+	modules, err := essentialBucket(ctx, js, delivery.ModulesBucket, "know any fingerprint to build")
 	if err != nil {
 		return err
 	}
-	manifests, err := bucket(delivery.ManifestsBucket)
-	if err != nil {
-		return err
-	}
-	candidates, err := bucket(delivery.CandidatesBucket)
+	manifests, err := essentialBucket(ctx, js, delivery.ManifestsBucket, "read what a module builds")
 	if err != nil {
 		return err
 	}
+	// The candidates' fingerprints are built too (issue 1684): a builder that cannot read them builds the trunk's.
+	candidates := optionalBucket(ctx, js, delivery.CandidatesBucket, "no candidate's fingerprint is built until the builder starts again; the trunk's are", logger.Printf)
 	bound := defaultStepBound
 	if v := strings.TrimSpace(getenv("MESH_BUILDER_STEP_BOUND")); v != "" {
 		if bound, err = time.ParseDuration(v); err != nil {
@@ -181,26 +172,13 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 		Stored:     storedVia(calls.Call),
 	}
 	// A candidate's preview is merged onto the trunk head the indexer previewed it onto: source.main at the candidate's base
-	// revision (the gate's source state). Where the bucket is not there yet no candidate's fingerprint is built, and said.
-	// The source's revisions are watched with their history (a direct get of one revision is not what a read grants): a
-	// revision heard after the candidate that names it builds that candidate then.
-	trunks := &sourceHeads{}
-	var sw jetstream.KeyWatcher
-	switch kv, err := js.KeyValue(ctx, delivery.SourceBucket); {
-	case errors.Is(err, jetstream.ErrBucketNotFound):
-		logger.Printf("the bucket %s does not exist yet: no candidate's fingerprint is built until the builder starts again", delivery.SourceBucket)
-	case err != nil:
-		return fmt.Errorf("the bucket %s: %w", delivery.SourceBucket, err)
-	default:
-		w, err := kv.Watch(ctx, delivery.SourceMainKey, jetstream.IncludeHistory())
-		if err != nil {
-			return fmt.Errorf("the bucket %s cannot be watched: %w", delivery.SourceBucket, err)
-		}
-		if sw, err = settled(ctx, w, func(e jetstream.KeyValueEntry) { trunks.put(e) }); err != nil {
-			return err
-		}
-		b.Trunk = trunks.head
-	}
+	// revision (the gate's source state). The source's revisions are watched with their history (a direct get of one revision
+	// is not what a read grants): a revision heard after the candidate that names it builds that candidate then. Where it
+	// cannot be read the trunk's keys are built and the candidates wait (issue 1945).
+	errs := make(chan error, 4)
+	trunks := &trunkSource{ctx: ctx, js: js, heads: &sourceHeads{}, moved: b.TrunkMoved, errs: errs, logf: logger.Printf}
+	trunks.start()
+	b.Trunk = trunks.head
 	b.Said = func(e build.AskedAgain) {
 		if err := emitAskedAgain(context.WithoutCancel(ctx), js, cred, e); err != nil {
 			logger.Printf("%v", err)
@@ -210,11 +188,8 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	// controller delivers from this builder's keys only while an instance says it writes references. A bucket not there
 	// yet (the manifest's state not made) is said, and the controller's plan waits for the keys, named (no build-agent
 	// is asked since R4g, ADR 0524 §7).
-	switch kv, err := js.KeyValue(ctx, instancesBucket); {
-	case errors.Is(err, jetstream.ErrBucketNotFound):
-		logger.Printf("the bucket %s does not exist yet: the controller is not told that this builder writes references until it starts again", instancesBucket)
-	case err != nil:
-		return fmt.Errorf("the bucket %s: %w", instancesBucket, err)
+	switch kv := optionalBucket(ctx, js, instancesBucket, "the controller is not told that this builder writes references until it starts again", logger.Printf); {
+	case kv == nil:
 	default:
 		says := newSayer(ctx, kv, cred.Node, []string{buildrun.GoBuildModule, buildrun.NodeBuildModule, build.ImageBuildModule}, logger.Printf)
 		b.Answered = says.Answered
@@ -294,38 +269,26 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 			b.ForgetCandidate(e.Key())
 		}
 	}
-	cw, err := settle(ctx, candidates, eachCandidate)
-	if err != nil {
-		return err
+	if candidates != nil {
+		cw, err := settle(ctx, candidates, eachCandidate)
+		if err != nil {
+			logger.Printf("the bucket %s cannot be watched (%v): no candidate's fingerprint is built until the builder starts again", delivery.CandidatesBucket, err)
+		} else {
+			go func() { errs <- follow(ctx, cw, eachCandidate) }()
+		}
 	}
 	// A person asks a key's build again with builder_ask_again, which writes the reasks state (issue 1945): watched, as
-	// every other input. A bucket not there yet (the manifest's state not made) is said.
-	errs := make(chan error, 4)
-	switch kv, err := js.KeyValue(ctx, build.ReAsksBucket); {
-	case errors.Is(err, jetstream.ErrBucketNotFound):
-		logger.Printf("the bucket %s does not exist yet: builder_ask_again is not heard until the builder starts again", build.ReAsksBucket)
-	case err != nil:
-		return fmt.Errorf("the bucket %s: %w", build.ReAsksBucket, err)
-	default:
+	// every other input. The builder asks again by itself without it.
+	if kv := optionalBucket(ctx, js, build.ReAsksBucket, "builder_ask_again is not heard until the builder starts again; an ask that can no longer be answered is still asked again by itself", logger.Printf); kv != nil {
 		eachReAsk := func(e jetstream.KeyValueEntry) { reAsked(ctx, b, kv, e, logger.Printf) }
-		rw, err := settle(ctx, kv, eachReAsk)
-		if err != nil {
-			return err
+		if rw, err := settle(ctx, kv, eachReAsk); err != nil {
+			logger.Printf("the bucket %s cannot be watched (%v): builder_ask_again is not heard until the builder starts again", build.ReAsksBucket, err)
+		} else {
+			go func() { errs <- follow(ctx, rw, eachReAsk) }()
 		}
-		go func() { errs <- follow(ctx, rw, eachReAsk) }()
 	}
 	logger.Printf("started on %s", cred.Node)
 	go func() { errs <- follow(ctx, w, each) }()
-	go func() { errs <- follow(ctx, cw, eachCandidate) }()
-	if sw != nil {
-		go func() {
-			errs <- follow(ctx, sw, func(e jetstream.KeyValueEntry) {
-				if trunks.put(e) {
-					b.TrunkMoved(ctx)
-				}
-			})
-		}()
-	}
 	select {
 	case <-ctx.Done():
 		b.Wait()
diff --git a/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/optional.go b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/optional.go
new file mode 100644
index 0000000..bd2542e
--- /dev/null
+++ b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/optional.go
@@ -0,0 +1,104 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"sync"
+
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-sdk/go/delivery"
+)
+
+// **A part does not stop for a bucket it can work without** (novox/hq issue 1945, met twice on 2026-10-25: the builder of
+// mesh-delivery #48 exited on a refused read of the gate's source, and its reasks bucket would have done the same). A grant
+// reaches the bus with a delivery, so a bucket the bus refuses, or times out on, at start is often only not granted yet:
+// exiting for it stops every build until a person's hand. A bucket the builder cannot build at all without (its builds,
+// the indexer's modules and manifests) still stops the start, naming the grant to look at; every other is said and left,
+// and opened again at the next event that needs it where there is one.
+
+// essentialBucket opens a bucket the builder cannot work without; its error names the bucket and the grant.
+func essentialBucket(ctx context.Context, js bucketOpener, name, does string) (jetstream.KeyValue, error) {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		return nil, essentialErr(name, does, err)
+	}
+	return kv, nil
+}
+
+// essentialErr is the error of a bucket the part cannot work without: it names the bucket and the grant.
+func essentialErr(name, does string, err error) error {
+	return fmt.Errorf("the bucket %s cannot be read (%v): the builder cannot %s without it, so it stops; where the bus "+
+		"refused it or did not answer, this module's grant of %s (its manifest's reads or state, issued with its credential) "+
+		"has not reached the bus yet", name, err, does, name)
+}
+
+// optionalBucket opens a bucket the builder works without: any error is said with what is not heard, and nil answered.
+func optionalBucket(ctx context.Context, js bucketOpener, name, without string, logf func(string, ...any)) jetstream.KeyValue {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		logf("the bucket %s cannot be read (%v): %s", name, err, without)
+		return nil
+	}
+	return kv
+}
+
+// trunkSource is the gate's source history the candidates' previews are merged onto (sourceHeads), opened at start and,
+// while it cannot be, again at the next candidate that asks a trunk head: a builder without it builds the trunk's keys,
+// and a candidate's preview waits, saying why.
+type trunkSource struct {
+	ctx   context.Context
+	js    bucketOpener
+	heads *sourceHeads
+	moved func(context.Context)
+	errs  chan<- error
+	logf  func(string, ...any)
+
+	mu     sync.Mutex
+	opened bool
+}
+
+// ensure opens and settles the source's watch once, and follows it; an error leaves it closed for the next ask.
+func (t *trunkSource) ensure() error {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	if t.opened {
+		return nil
+	}
+	kv, err := t.js.KeyValue(t.ctx, delivery.SourceBucket)
+	if err != nil {
+		return fmt.Errorf("the bucket %s cannot be read (%v)", delivery.SourceBucket, err)
+	}
+	w, err := kv.Watch(t.ctx, delivery.SourceMainKey, jetstream.IncludeHistory())
+	if err != nil {
+		return fmt.Errorf("the bucket %s cannot be watched (%v)", delivery.SourceBucket, err)
+	}
+	sw, err := settled(t.ctx, w, func(e jetstream.KeyValueEntry) { t.heads.put(e) })
+	if err != nil {
+		return fmt.Errorf("the bucket %s: %w", delivery.SourceBucket, err)
+	}
+	t.opened = true
+	go func() {
+		t.errs <- follow(t.ctx, sw, func(e jetstream.KeyValueEntry) {
+			if t.heads.put(e) && t.moved != nil {
+				t.moved(t.ctx)
+			}
+		})
+	}()
+	return nil
+}
+
+// start opens the source at start; one that cannot be is said, and the builder goes on.
+func (t *trunkSource) start() {
+	if err := t.ensure(); err != nil {
+		t.logf("%v: the trunk's keys are built, and a candidate's preview waits until the source can be read, tried again at its next candidate", err)
+	}
+}
+
+// head is Builder.Trunk: the head of repository at source revision rev, opening the source first if it is not yet.
+func (t *trunkSource) head(ctx context.Context, rev uint64, repository string) (string, error) {
+	if err := t.ensure(); err != nil {
+		return "", err
+	}
+	return t.heads.head(ctx, rev, repository)
+}
diff --git a/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/standing.go b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/standing.go
index 3d6decf..9a06cec 100644
--- a/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/standing.go
+++ b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/standing.go
@@ -193,7 +193,9 @@ func watchAssignments(ctx context.Context, js bucketOpener, gate *toolchainGate,
 	each := func(e jetstream.KeyValueEntry) { gate.Assignment(e.Key(), e.Value(), !opOf(e), e.Created()) }
 	w, err := settle(ctx, kv, each)
 	if err != nil {
-		return nil, fmt.Errorf("the bucket %s: %w", provider.AssignmentsBucket, err)
+		// Not fatal either (issue 1945): a watch the bus refuses is the same missing grant as a refused read.
+		logger.Printf("the bucket %s cannot be watched, so every node's toolchain report counts, an unassigned build node's too (issue 1940): %v", provider.AssignmentsBucket, err)
+		return errs, nil
 	}
 	if gate.Settled() {
 		changed(ctx)
diff --git a/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/standing_test.go b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/standing_test.go
index 28fccc4..ae19091 100644
--- a/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/standing_test.go
+++ b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/standing_test.go
@@ -3,11 +3,17 @@ package main
 // The same in mesh-delivery-indexer, mesh-delivery-builder and mesh-delivery-checker, as standing.go is (issue 1940).
 
 import (
+	"bytes"
+	"context"
+	"errors"
 	"fmt"
+	"log"
 	"strings"
 	"testing"
 	"time"
 
+	"github.com/nats-io/nats.go/jetstream"
+
 	"git.novox.be/novox/mesh-sdk/go/delivery"
 	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
@@ -89,6 +95,61 @@ func TestAnUnassignedBuildNodesReportIsNoBuilder(t *testing.T) {
 	if n := len(set.Entries("typescript")); n != 2 {
 		t.Fatalf("novox and shanks are left; got %d entries", n)
 	}
+
+	// 1945 (a part exits at start for a bucket it works without): a bus that refuses the assignments' watch, or every
+	// toolchains bucket, leaves the watches unstarted and the part running, said; a refused bucket it cannot work without
+	// is an error naming the bucket and its grant.
+	var logs bytes.Buffer
+	logger := log.New(&logs, "", 0)
+	refused := refusingBus{err: errors.New("nats: permissions violation for publish to $JS.API.CONSUMER.CREATE.KV_mesh-controller_assignments")}
+	if _, err := watchAssignments(context.Background(), refused, newToolchainGate(nil, set.Put, t.Logf), func(context.Context) {}, logger); err != nil {
+		t.Errorf("a refused watch of the assignments stopped the start: %v", err)
+	}
+	if err := newToolchainWatch(context.Background(), refusingBus{refuseOpen: true, err: refused.err}, set, func(context.Context) {}, logger).start(); err != nil {
+		t.Errorf("a refused toolchains bucket stopped the start: %v", err)
+	}
+	if !strings.Contains(logs.String(), "cannot be watched") || !strings.Contains(logs.String(), "cannot be read") {
+		t.Errorf("the refusals were not said: %q", logs.String())
+	}
+	if _, err := essentialBucket(context.Background(), refusingBus{refuseOpen: true, err: refused.err}, "mesh-delivery-indexer_modules", "work"); err == nil ||
+		!strings.Contains(err.Error(), "grant of mesh-delivery-indexer_modules") {
+		t.Errorf("a refused bucket the part needs: %v, want an error naming its grant", err)
+	}
+	// The gate's source (the previews' trunk heads): refused at start, the builder goes on, and a candidate asking a trunk
+	// head is told why and opens it again then.
+	src := &trunkSource{ctx: context.Background(), js: refusingBus{refuseOpen: true, err: refused.err}, heads: &sourceHeads{}, errs: make(chan error, 1), logf: logger.Printf}
+	src.start()
+	if _, err := src.head(context.Background(), 7, "novox/mesh-catalog"); err == nil || !strings.Contains(err.Error(), delivery.SourceBucket) {
+		t.Errorf("a trunk head with the source refused: %v, want why", err)
+	}
+	if src.opened {
+		t.Error("a refused source counts as opened, so it is never opened again")
+	}
+}
+
+// refusingBus is a bus that refuses: every open (refuseOpen), or every watch of a bucket it opens, with err.
+type refusingBus struct {
+	refuseOpen bool
+	err        error
+}
+
+func (r refusingBus) KeyValue(context.Context, string) (jetstream.KeyValue, error) {
+	if r.refuseOpen {
+		return nil, r.err
+	}
+	return refusedWatch{err: r.err}, nil
+}
+
+type refusedWatch struct {
+	jetstream.KeyValue
+	err error
+}
+
+func (r refusedWatch) WatchAll(context.Context, ...jetstream.WatchOpt) (jetstream.KeyWatcher, error) {
+	return nil, r.err
+}
+func (r refusedWatch) Watch(context.Context, string, ...jetstream.WatchOpt) (jetstream.KeyWatcher, error) {
+	return nil, r.err
 }
 
 // A build node's report counts from the first one it writes since its assignment: a newly assigned node that has not
diff --git a/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/toolchains.go b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/toolchains.go
index 69faff2..f574c2d 100644
--- a/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/toolchains.go
+++ b/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/toolchains.go
@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"errors"
-	"fmt"
 	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 	"log"
 	"strings"
@@ -62,11 +61,14 @@ func (w *toolchainWatch) ensure(module string) error {
 		w.logger.Printf("the bucket %s does not exist yet: it is watched when %s reports a toolchain", name, module)
 		return nil
 	case err != nil:
-		return fmt.Errorf("the bucket %s: %w", name, err)
+		// Refused or not answered (its grant not on the bus yet, issue 1945): said, and opened again at the module's next report.
+		w.logger.Printf("the bucket %s cannot be read (%v): %s's toolchains are not heard until its next report", name, err, module)
+		return nil
 	}
 	watcher, err := settle(w.ctx, kv, func(e jetstream.KeyValueEntry) { w.put(module, e.Key(), e.Value(), !opOf(e)) })
 	if err != nil {
-		return err
+		w.logger.Printf("the bucket %s cannot be watched (%v): %s's toolchains are not heard until its next report", name, err, module)
+		return nil
 	}
 	w.watched[module] = true
 	go func() {
diff --git a/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/main.go b/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/main.go
index 297cfce..7b97f0d 100644
--- a/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/main.go
+++ b/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/main.go
@@ -152,17 +152,12 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	if err != nil {
 		return err
 	}
-	bucket := func(name string) (jetstream.KeyValue, error) {
-		kv, err := js.KeyValue(ctx, name)
-		if err != nil {
-			return nil, fmt.Errorf("the bucket %s: %w", name, err)
-		}
-		return kv, nil
-	}
+	// Its own states, the candidates it checks, and the modules and manifests that say which build modules judge a repository:
+	// a check without one of them would be wrong or unwritten, so each stops the start, naming its grant (issue 1945).
 	buckets := map[string]jetstream.KeyValue{}
 	for _, name := range []string{delivery.CheckerVerdictsBucket, delivery.CheckerKeptBucket, delivery.CheckerOwedBucket, delivery.PreviewsBucket,
 		delivery.CandidatesBucket, delivery.ModulesBucket, delivery.ManifestsBucket, check.TriesBucket} {
-		if buckets[name], err = bucket(name); err != nil {
+		if buckets[name], err = essentialBucket(ctx, js, name, "judge or keep a check"); err != nil {
 			return err
 		}
 	}
@@ -212,12 +207,7 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	// The builder's builds say how the candidates' fingerprints stand (issue 1684); where its bucket is not there yet the line
 	// says nothing of the builds, until the checker starts again.
 	var builds check.BuildStates
-	switch kv, err := js.KeyValue(ctx, delivery.BuilderBuildsBucket); {
-	case errors.Is(err, jetstream.ErrBucketNotFound):
-		logger.Printf("the bucket %s does not exist yet: the line says nothing of the builds until the checker starts again", delivery.BuilderBuildsBucket)
-	case err != nil:
-		return fmt.Errorf("the bucket %s: %w", delivery.BuilderBuildsBucket, err)
-	default:
+	if kv := optionalBucket(ctx, js, delivery.BuilderBuildsBucket, "the line says nothing of the builds until the checker starts again", logger.Printf); kv != nil {
 		builds = buildReader{kvStore{kv}}
 	}
 	// The assigner's compositions (ADR 0528 clause 5, issue 1297): their bucket is looked up at each check until it is
@@ -290,47 +280,38 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	// the assigner's own presence says whether a composition is being made (compositionWatch, ADR 0537 §4). A check is no
 	// longer held for a node: its asks wait in the build seats' streams, which redeliver a lost node's ask (ADR 0525 §6,
 	// issue 1912), so the node-engine's have is not watched here.
-	switch kv, err := js.KeyValue(ctx, delivery.PresenceBucket); {
-	case errors.Is(err, jetstream.ErrBucketNotFound):
-		logger.Printf("the bucket %s does not exist yet: no node counts as online until the checker starts again", delivery.PresenceBucket)
-	case err != nil:
-		return fmt.Errorf("the bucket %s: %w", delivery.PresenceBucket, err)
-	default:
-		pw, err := settle(ctx, kv, func(e jetstream.KeyValueEntry) { presence.Put(e.Key(), e.Value(), !opOf(e)) })
-		if err != nil {
-			return err
+	if kv := optionalBucket(ctx, js, delivery.PresenceBucket, "no node counts as online until the checker starts again", logger.Printf); kv != nil {
+		if pw, err := settle(ctx, kv, func(e jetstream.KeyValueEntry) { presence.Put(e.Key(), e.Value(), !opOf(e)) }); err != nil {
+			logger.Printf("the bucket %s cannot be watched (%v): no node counts as online until the checker starts again", delivery.PresenceBucket, err)
+		} else {
+			go func() {
+				errs <- follow(ctx, pw, func(e jetstream.KeyValueEntry) {
+					if presence.Put(e.Key(), e.Value(), !opOf(e)) {
+						ch.NodesChanged(ctx) // a node came online or went: a check whose forge was not heard may now be heard
+					}
+				})
+			}()
 		}
-		go func() {
-			errs <- follow(ctx, pw, func(e jetstream.KeyValueEntry) {
-				if presence.Put(e.Key(), e.Value(), !opOf(e)) {
-					ch.NodesChanged(ctx) // a node came online or went: a check whose forge was not heard may now be heard
-				}
-			})
-		}()
 	}
 	// The gate's source says the trunk head of each repository, which a pull request is merged onto. Where it is not there
 	// yet no trunk is known, so nothing is checked.
-	switch kv, err := js.KeyValue(ctx, delivery.SourceBucket); {
-	case errors.Is(err, jetstream.ErrBucketNotFound):
-		logger.Printf("the bucket %s does not exist yet: no trunk is known until the checker starts again", delivery.SourceBucket)
-	case err != nil:
-		return fmt.Errorf("the bucket %s: %w", delivery.SourceBucket, err)
-	default:
+	if kv := optionalBucket(ctx, js, delivery.SourceBucket, "no trunk is known, so nothing is checked until the checker starts again", logger.Printf); kv != nil {
 		sw, err := settle(ctx, kv, func(e jetstream.KeyValueEntry) {
 			if e.Key() == delivery.SourceMainKey {
 				trunks.Put(e.Value(), !opOf(e))
 			}
 		})
 		if err != nil {
-			return err
+			logger.Printf("the bucket %s cannot be watched (%v): no trunk is known, so nothing is checked until the checker starts again", delivery.SourceBucket, err)
+		} else {
+			go func() {
+				errs <- follow(ctx, sw, func(e jetstream.KeyValueEntry) {
+					if e.Key() == delivery.SourceMainKey && trunks.Put(e.Value(), !opOf(e)) {
+						ch.TrunkMoved(ctx) // the trunk moved: its statuses go pending, and a verdict for the old trunk is judged again
+					}
+				})
+			}()
 		}
-		go func() {
-			errs <- follow(ctx, sw, func(e jetstream.KeyValueEntry) {
-				if e.Key() == delivery.SourceMainKey && trunks.Put(e.Value(), !opOf(e)) {
-					ch.TrunkMoved(ctx) // the trunk moved: its statuses go pending, and a verdict for the old trunk is judged again
-				}
-			})
-		}()
 	}
 	// The modules say which repository holds a TypeScript module, so the Node build module judges it too.
 	mw, err := settle(ctx, buckets[delivery.ModulesBucket], func(e jetstream.KeyValueEntry) { repos.Put(ctx, e.Key(), e.Value(), !opOf(e)) })
diff --git a/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/optional.go b/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/optional.go
new file mode 100644
index 0000000..466cdd0
--- /dev/null
+++ b/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/optional.go
@@ -0,0 +1,41 @@
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// **A part does not stop for a bucket it can work without** (novox/hq issue 1945, met twice on 2026-10-25: the builder of
+// mesh-delivery #48 exited on a refused read of the gate's source, and its new reasks bucket would have done the same). A
+// grant reaches the bus with a delivery, so a bucket the bus refuses, or times out on, at start is often only not granted
+// yet: exiting for it stops the part until a person's hand. A bucket the checker cannot do its job at all without still stops
+// the start, naming the grant to look at; every other is said and left. (The same two functions are in each delivery part;
+// they belong in mesh-sdk.)
+
+// essentialBucket opens a bucket the checker cannot work without; its error names the bucket and the grant.
+func essentialBucket(ctx context.Context, js bucketOpener, name, does string) (jetstream.KeyValue, error) {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		return nil, essentialErr(name, does, err)
+	}
+	return kv, nil
+}
+
+// essentialErr is the error of a bucket the part cannot work without: it names the bucket and the grant.
+func essentialErr(name, does string, err error) error {
+	return fmt.Errorf("the bucket %s cannot be read (%v): the checker cannot %s without it, so it stops; where the bus "+
+		"refused it or did not answer, this module's grant of %s (its manifest's reads or state, issued with its credential) "+
+		"has not reached the bus yet", name, err, does, name)
+}
+
+// optionalBucket opens a bucket the checker works without: any error is said with what is not heard, and nil answered.
+func optionalBucket(ctx context.Context, js bucketOpener, name, without string, logf func(string, ...any)) jetstream.KeyValue {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		logf("the bucket %s cannot be read (%v): %s", name, err, without)
+		return nil
+	}
+	return kv
+}
diff --git a/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/standing.go b/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/standing.go
index 3d6decf..9a06cec 100644
--- a/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/standing.go
+++ b/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/standing.go
@@ -193,7 +193,9 @@ func watchAssignments(ctx context.Context, js bucketOpener, gate *toolchainGate,
 	each := func(e jetstream.KeyValueEntry) { gate.Assignment(e.Key(), e.Value(), !opOf(e), e.Created()) }
 	w, err := settle(ctx, kv, each)
 	if err != nil {
-		return nil, fmt.Errorf("the bucket %s: %w", provider.AssignmentsBucket, err)
+		// Not fatal either (issue 1945): a watch the bus refuses is the same missing grant as a refused read.
+		logger.Printf("the bucket %s cannot be watched, so every node's toolchain report counts, an unassigned build node's too (issue 1940): %v", provider.AssignmentsBucket, err)
+		return errs, nil
 	}
 	if gate.Settled() {
 		changed(ctx)
diff --git a/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/standing_test.go b/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/standing_test.go
index 28fccc4..c759d3a 100644
--- a/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/standing_test.go
+++ b/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/standing_test.go
@@ -3,11 +3,17 @@ package main
 // The same in mesh-delivery-indexer, mesh-delivery-builder and mesh-delivery-checker, as standing.go is (issue 1940).
 
 import (
+	"bytes"
+	"context"
+	"errors"
 	"fmt"
+	"log"
 	"strings"
 	"testing"
 	"time"
 
+	"github.com/nats-io/nats.go/jetstream"
+
 	"git.novox.be/novox/mesh-sdk/go/delivery"
 	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 )
@@ -89,6 +95,51 @@ func TestAnUnassignedBuildNodesReportIsNoBuilder(t *testing.T) {
 	if n := len(set.Entries("typescript")); n != 2 {
 		t.Fatalf("novox and shanks are left; got %d entries", n)
 	}
+
+	// 1945 (a part exits at start for a bucket it works without): a bus that refuses the assignments' watch, or every
+	// toolchains bucket, leaves the watches unstarted and the part running, said; a refused bucket it cannot work without
+	// is an error naming the bucket and its grant.
+	var logs bytes.Buffer
+	logger := log.New(&logs, "", 0)
+	refused := refusingBus{err: errors.New("nats: permissions violation for publish to $JS.API.CONSUMER.CREATE.KV_mesh-controller_assignments")}
+	if _, err := watchAssignments(context.Background(), refused, newToolchainGate(nil, set.Put, t.Logf), func(context.Context) {}, logger); err != nil {
+		t.Errorf("a refused watch of the assignments stopped the start: %v", err)
+	}
+	if err := newToolchainWatch(context.Background(), refusingBus{refuseOpen: true, err: refused.err}, set, func(context.Context) {}, logger).start(); err != nil {
+		t.Errorf("a refused toolchains bucket stopped the start: %v", err)
+	}
+	if !strings.Contains(logs.String(), "cannot be watched") || !strings.Contains(logs.String(), "cannot be read") {
+		t.Errorf("the refusals were not said: %q", logs.String())
+	}
+	if _, err := essentialBucket(context.Background(), refusingBus{refuseOpen: true, err: refused.err}, "mesh-delivery-indexer_modules", "work"); err == nil ||
+		!strings.Contains(err.Error(), "grant of mesh-delivery-indexer_modules") {
+		t.Errorf("a refused bucket the part needs: %v, want an error naming its grant", err)
+	}
+}
+
+// refusingBus is a bus that refuses: every open (refuseOpen), or every watch of a bucket it opens, with err.
+type refusingBus struct {
+	refuseOpen bool
+	err        error
+}
+
+func (r refusingBus) KeyValue(context.Context, string) (jetstream.KeyValue, error) {
+	if r.refuseOpen {
+		return nil, r.err
+	}
+	return refusedWatch{err: r.err}, nil
+}
+
+type refusedWatch struct {
+	jetstream.KeyValue
+	err error
+}
+
+func (r refusedWatch) WatchAll(context.Context, ...jetstream.WatchOpt) (jetstream.KeyWatcher, error) {
+	return nil, r.err
+}
+func (r refusedWatch) Watch(context.Context, string, ...jetstream.WatchOpt) (jetstream.KeyWatcher, error) {
+	return nil, r.err
 }
 
 // A build node's report counts from the first one it writes since its assignment: a newly assigned node that has not
diff --git a/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/toolchains.go b/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/toolchains.go
index bc848ca..0fe2f41 100644
--- a/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/toolchains.go
+++ b/modules/mesh-delivery-checker/cmd/mesh-delivery-checker/toolchains.go
@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"errors"
-	"fmt"
 	"log"
 	"strings"
 	"sync"
@@ -63,11 +62,14 @@ func (w *toolchainWatch) ensure(module string) error {
 		w.logger.Printf("the bucket %s does not exist yet: it is watched when %s reports a toolchain", name, module)
 		return nil
 	case err != nil:
-		return fmt.Errorf("the bucket %s: %w", name, err)
+		// Refused or not answered (its grant not on the bus yet, issue 1945): said, and opened again at the module's next report.
+		w.logger.Printf("the bucket %s cannot be read (%v): %s's toolchains are not heard until its next report", name, err, module)
+		return nil
 	}
 	watcher, err := settle(w.ctx, kv, func(e jetstream.KeyValueEntry) { w.put(module, e.Key(), e.Value(), !opOf(e)) })
 	if err != nil {
-		return err
+		w.logger.Printf("the bucket %s cannot be watched (%v): %s's toolchains are not heard until its next report", name, err, module)
+		return nil
 	}
 	w.watched[module] = true
 	go func() {
diff --git a/modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/main.go b/modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/main.go
index a11a3b2..383bedc 100644
--- a/modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/main.go
+++ b/modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/main.go
@@ -188,18 +188,18 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	call := callerOn(conn, cred.User)
 	// No forge event is heard while the open pull requests are read and said (ADR 0443 §5): events and syncs take turns.
 	var turn sync.Mutex
-	kv, err := js.KeyValue(ctx, headsBucket)
+	kv, err := essentialBucket(ctx, js, headsBucket, "keep the heads it wrote on the forge stream")
 	if err != nil {
-		return fmt.Errorf("the bucket %s: %w", headsBucket, err)
+		return err
 	}
 	heads := kvHeads{kv}
 	// Everything written on FORGE, an event's and a sync's, keeps the head in the bucket.
 	rec := &recorder{pub: js, heads: heads, logger: logger}
 	said := func(ctx context.Context) error { return syncOpen(ctx, call, rec, heads, &turn, logger) }
 	// What the gate asks of the forge (ADR 0437 §8): its owed acts and its merges, each performed once per revision.
-	performedKV, err := js.KeyValue(ctx, performedBucket)
+	performedKV, err := essentialBucket(ctx, js, performedBucket, "perform an act of the gate only once")
 	if err != nil {
-		return fmt.Errorf("the bucket %s: %w", performedBucket, err)
+		return err
 	}
 	perf := &performer{call: call, pub: rec, done: kvRevisions{performedKV}, logger: logger}
 	watching := make(chan error, 3)
@@ -207,16 +207,12 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 		bucket string
 		react  func(ctx context.Context, key string, rev uint64, value []byte)
 	}{{delivery.OwedBucket, perf.owed}, {delivery.MergesBucket, perf.merges}} {
-		kv, err := js.KeyValue(ctx, w.bucket)
-		if errors.Is(err, jetstream.ErrBucketNotFound) {
-			// The gate's buckets come with the gate; the bridge does not wait for them (no timer), and is started again
-			// by its delivery when the gate arrives.
-			logger.Printf("the bucket %s does not exist yet: nothing of it is performed until the bridge starts again", w.bucket)
+		// The gate's buckets come with the gate and its grant; the bridge does not wait for them (no timer), and is started
+		// again by its delivery when the gate arrives. A bucket refused or not answered is the same (issue 1945).
+		kv := optionalBucket(ctx, js, w.bucket, "nothing of it is performed until the bridge starts again", logger.Printf)
+		if kv == nil {
 			continue
 		}
-		if err != nil {
-			return fmt.Errorf("the bucket %s: %w", w.bucket, err)
-		}
 		go func() {
 			watching <- watch(ctx, kv, func(key string, rev uint64, value []byte) {
 				hctx, cancel := context.WithTimeout(ctx, syncDeadline)
@@ -231,7 +227,8 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	go onReconnect(ctx, again, said, logger)
 	cons, err := js.Consumer(ctx, eventsStream, cred.Node+"_"+cred.Module)
 	if err != nil {
-		return fmt.Errorf("the consumer %s_%s on %s: %w", cred.Node, cred.Module, eventsStream, err)
+		// Essential: the forge's events are what the bridge carries.
+		return fmt.Errorf("the consumer %s_%s on %s cannot be read (%v): the bridge hears no forge event without it, so it stops; where the bus refused it or did not answer, this module's consumes (made by the controller with its grant) have not reached the bus yet", cred.Node, cred.Module, eventsStream, err)
 	}
 	cc, err := cons.Consume(func(m jetstream.Msg) {
 		hear(&turn, func() {
diff --git a/modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/main_test.go b/modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/main_test.go
index c4ab010..0f9cc32 100644
--- a/modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/main_test.go
+++ b/modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/main_test.go
@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"log"
 	"slices"
 	"strings"
@@ -66,6 +67,16 @@ func body(m map[string]any) []byte {
 }
 
 func TestReadableEventIsWrittenOnForgeAndAcked(t *testing.T) { // 1235/AC2 (unit part; the bus is the integration test)
+	t.Run("1945: a refused bucket is said, or stops the start naming its grant", func(t *testing.T) {
+		refusal := errors.New("nats: permissions violation for publish to $JS.API.STREAM.INFO.KV_x")
+		var said []string
+		if kv := optionalBucket(context.Background(), refusingBus{refusal}, "x", "x is not heard", func(f string, a ...any) { said = append(said, fmt.Sprintf(f, a...)) }); kv != nil || len(said) != 1 || !strings.Contains(said[0], "permissions violation") {
+			t.Errorf("an optional bucket refused: %v, said %v", kv, said)
+		}
+		if _, err := essentialBucket(context.Background(), refusingBus{refusal}, "x", "work"); err == nil || !strings.Contains(err.Error(), "grant of x") {
+			t.Errorf("an essential bucket refused: %v, want its grant named", err)
+		}
+	})
 	var logs bytes.Buffer
 	m, pub := &fakeMsg{subject: "mesh.mod.gitea.event.pull.updated", data: body(nil)}, &fakePub{}
 	handle(context.Background(), m, pub, nil, someFiles, log.New(&logs, "", 0))
@@ -230,3 +241,8 @@ func someFiles(_, _, path, _ string) ([]byte, error) {
 	}
 	return nil, bridge.ErrNotFound
 }
+
+// refusingBus refuses every bucket with err (issue 1945).
+type refusingBus struct{ err error }
+
+func (r refusingBus) KeyValue(context.Context, string) (jetstream.KeyValue, error) { return nil, r.err }
diff --git a/modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/optional.go b/modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/optional.go
new file mode 100644
index 0000000..68df917
--- /dev/null
+++ b/modules/mesh-delivery-forge-bridge/cmd/mesh-delivery-forge-bridge/optional.go
@@ -0,0 +1,46 @@
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// **A part does not stop for a bucket it can work without** (novox/hq issue 1945, met twice on 2026-10-25: the builder of
+// mesh-delivery #48 exited on a refused read of the gate's source, and its new reasks bucket would have done the same). A
+// grant reaches the bus with a delivery, so a bucket the bus refuses, or times out on, at start is often only not granted
+// yet: exiting for it stops the part until a person's hand. A bucket the bridge cannot do its job at all without still stops
+// the start, naming the grant to look at; every other is said and left. (The same two functions are in each delivery part;
+// they belong in mesh-sdk.)
+
+// bucketOpener is the part of the bus a start opens buckets with.
+type bucketOpener interface {
+	KeyValue(ctx context.Context, bucket string) (jetstream.KeyValue, error)
+}
+
+// essentialBucket opens a bucket the bridge cannot work without; its error names the bucket and the grant.
+func essentialBucket(ctx context.Context, js bucketOpener, name, does string) (jetstream.KeyValue, error) {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		return nil, essentialErr(name, does, err)
+	}
+	return kv, nil
+}
+
+// essentialErr is the error of a bucket the part cannot work without: it names the bucket and the grant.
+func essentialErr(name, does string, err error) error {
+	return fmt.Errorf("the bucket %s cannot be read (%v): the bridge cannot %s without it, so it stops; where the bus "+
+		"refused it or did not answer, this module's grant of %s (its manifest's reads or state, issued with its credential) "+
+		"has not reached the bus yet", name, err, does, name)
+}
+
+// optionalBucket opens a bucket the bridge works without: any error is said with what is not heard, and nil answered.
+func optionalBucket(ctx context.Context, js bucketOpener, name, without string, logf func(string, ...any)) jetstream.KeyValue {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		logf("the bucket %s cannot be read (%v): %s", name, err, without)
+		return nil
+	}
+	return kv
+}
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go
index fbf6ff3..0e32028 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go
@@ -240,29 +240,21 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	if err != nil {
 		return err
 	}
-	bucket := func(name string) (jetstream.KeyValue, error) {
-		kv, err := js.KeyValue(ctx, name)
-		if err != nil {
-			return nil, fmt.Errorf("the bucket %s: %w", name, err)
-		}
-		return kv, nil
-	}
-	candidates, err := bucket(delivery.CandidatesBucket)
+	candidates, err := essentialBucket(ctx, js, delivery.CandidatesBucket, "write a candidate's fingerprints")
 	if err != nil {
 		return err
 	}
-	modules, err := bucket(delivery.ModulesBucket)
+	modules, err := essentialBucket(ctx, js, delivery.ModulesBucket, "write a module's fingerprint")
 	if err != nil {
 		return err
 	}
-	manifests, err := bucket(delivery.ManifestsBucket)
-	if err != nil {
-		return err
-	}
-	builds, err := bucket(delivery.BuildsBucket)
+	manifests, err := essentialBucket(ctx, js, delivery.ManifestsBucket, "keep a module's manifest")
 	if err != nil {
 		return err
 	}
+	// The controller's build records only name the directory of a module whose key names none (fillPaths): without them
+	// such a module waits for its path, every other is indexed (issue 1945).
+	builds := optionalBucket(ctx, js, delivery.BuildsBucket, "a module whose key names no directory is not given one from the controller's build records until the indexer starts again", logger.Printf)
 	known := index.NewBuilds()
 	// The controller's build records name the directory of a module whose key names none (fillPaths); no build of any
 	// module moves a fingerprint since no fingerprint takes the builder (ADR 0530 §1).
@@ -273,12 +265,14 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 			known.Delete(e.Key())
 		}
 	}
-	w, err := settle(ctx, builds, each)
-	if err != nil {
-		return err
-	}
 	errs := make(chan error, 1)
-	go func() { errs <- follow(ctx, w, each) }()
+	if builds != nil {
+		if w, err := settle(ctx, builds, each); err != nil {
+			logger.Printf("the bucket %s cannot be watched (%v): a module whose key names no directory is not given one until the indexer starts again", delivery.BuildsBucket, err)
+		} else {
+			go func() { errs <- follow(ctx, w, each) }()
+		}
+	}
 
 	// The indexer asks the forge for the objects of a manifest's named paths as its own account (ADR 0499 clause 3).
 	account, err := process.ReadAccount(path)
@@ -296,22 +290,17 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	// main is the mesh's source revision, which stamps the modules (issue 1344). Where it does not exist yet the indexer does
 	// not wait for it (that needs a timer, ADR 0437 §8): it says so, and is started again with the gate.
 	sourceErrs := make(chan error, 1)
-	switch source, err := js.KeyValue(ctx, delivery.SourceBucket); {
-	case errors.Is(err, jetstream.ErrBucketNotFound):
-		logger.Printf("the bucket %s does not exist yet: no source revision is read until the indexer starts again", delivery.SourceBucket)
-	case err != nil:
-		return fmt.Errorf("the bucket %s: %w", delivery.SourceBucket, err)
-	default:
+	if source := optionalBucket(ctx, js, delivery.SourceBucket, "no source revision is read until the indexer starts again", logger.Printf); source != nil {
 		each := func(e jetstream.KeyValueEntry) {
 			if opOf(e) {
 				applySource(ctx, ix, e.Key(), e.Revision(), e.Value(), logger)
 			}
 		}
-		sw, err := settle(ctx, source, each)
-		if err != nil {
-			return err
+		if sw, err := settle(ctx, source, each); err != nil {
+			logger.Printf("the bucket %s cannot be watched (%v): no source revision is read until the indexer starts again", delivery.SourceBucket, err)
+		} else {
+			go func() { sourceErrs <- follow(ctx, sw, each) }()
 		}
-		go func() { sourceErrs <- follow(ctx, sw, each) }()
 	}
 	// Only the toolchain reports of nodes the build module is assigned to count (issue 1940): the controller's
 	// assignments are settled first, so the toolchains settle through the gate already knowing them.
@@ -381,7 +370,8 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	}
 	cons, err := js.Consumer(ctx, forgeStream, cred.Node+"_"+cred.Module)
 	if err != nil {
-		return fmt.Errorf("the consumer %s_%s on %s: %w", cred.Node, cred.Module, forgeStream, err)
+		// Essential: the forge's merges are what the indexer indexes.
+		return fmt.Errorf("the consumer %s_%s on %s cannot be read (%v): the indexer hears no merge without it, so it stops; where the bus refused it or did not answer, this module's consumes (made by the controller with its grant) have not reached the bus yet", cred.Node, cred.Module, forgeStream, err)
 	}
 	cc, err := cons.Consume(func(m jetstream.Msg) { handle(ctx, m, ix, logger) },
 		jetstream.ConsumeErrHandler(func(_ jetstream.ConsumeContext, err error) { logger.Printf("hearing the bus: %v", err) }))
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/optional.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/optional.go
new file mode 100644
index 0000000..1f1fb5c
--- /dev/null
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/optional.go
@@ -0,0 +1,41 @@
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// **A part does not stop for a bucket it can work without** (novox/hq issue 1945, met twice on 2026-10-25: the builder of
+// mesh-delivery #48 exited on a refused read of the gate's source, and its new reasks bucket would have done the same). A
+// grant reaches the bus with a delivery, so a bucket the bus refuses, or times out on, at start is often only not granted
+// yet: exiting for it stops the part until a person's hand. A bucket the indexer cannot do its job at all without still stops
+// the start, naming the grant to look at; every other is said and left. (The same two functions are in each delivery part;
+// they belong in mesh-sdk.)
+
+// essentialBucket opens a bucket the indexer cannot work without; its error names the bucket and the grant.
+func essentialBucket(ctx context.Context, js bucketOpener, name, does string) (jetstream.KeyValue, error) {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		return nil, essentialErr(name, does, err)
+	}
+	return kv, nil
+}
+
+// essentialErr is the error of a bucket the part cannot work without: it names the bucket and the grant.
+func essentialErr(name, does string, err error) error {
+	return fmt.Errorf("the bucket %s cannot be read (%v): the indexer cannot %s without it, so it stops; where the bus "+
+		"refused it or did not answer, this module's grant of %s (its manifest's reads or state, issued with its credential) "+
+		"has not reached the bus yet", name, err, does, name)
+}
+
+// optionalBucket opens a bucket the indexer works without: any error is said with what is not heard, and nil answered.
+func optionalBucket(ctx context.Context, js bucketOpener, name, without string, logf func(string, ...any)) jetstream.KeyValue {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		logf("the bucket %s cannot be read (%v): %s", name, err, without)
+		return nil
+	}
+	return kv
+}
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/previews.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/previews.go
index c42221c..748182b 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/previews.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/previews.go
@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"errors"
-	"fmt"
 	"log"
 	"strings"
 	"sync"
@@ -55,11 +54,14 @@ func (w *previewWatch) ensure() error {
 		w.logger.Printf("the bucket %s does not exist yet: it is watched when the checker says it wrote a preview", delivery.PreviewsBucket)
 		return nil
 	case err != nil:
-		return fmt.Errorf("the bucket %s: %w", delivery.PreviewsBucket, err)
+		// Refused or not answered (its grant not on the bus yet, issue 1945): said, and opened again at the checker's next preview.
+		w.logger.Printf("the bucket %s cannot be read (%v): it is watched when the checker says it wrote a preview", delivery.PreviewsBucket, err)
+		return nil
 	}
 	watcher, err := settle(w.ctx, kv, func(e jetstream.KeyValueEntry) { w.ix.PutPreview(e.Key(), e.Value(), !opOf(e)) })
 	if err != nil {
-		return err
+		w.logger.Printf("the bucket %s cannot be watched (%v): it is watched when the checker says it wrote a preview", delivery.PreviewsBucket, err)
+		return nil
 	}
 	w.watched = true
 	go func() {
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/standing.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/standing.go
index 3d6decf..9a06cec 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/standing.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/standing.go
@@ -193,7 +193,9 @@ func watchAssignments(ctx context.Context, js bucketOpener, gate *toolchainGate,
 	each := func(e jetstream.KeyValueEntry) { gate.Assignment(e.Key(), e.Value(), !opOf(e), e.Created()) }
 	w, err := settle(ctx, kv, each)
 	if err != nil {
-		return nil, fmt.Errorf("the bucket %s: %w", provider.AssignmentsBucket, err)
+		// Not fatal either (issue 1945): a watch the bus refuses is the same missing grant as a refused read.
+		logger.Printf("the bucket %s cannot be watched, so every node's toolchain report counts, an unassigned build node's too (issue 1940): %v", provider.AssignmentsBucket, err)
+		return errs, nil
 	}
 	if gate.Settled() {
 		changed(ctx)
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/toolchains.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/toolchains.go
index 30892ae..3e4f0cf 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/toolchains.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/toolchains.go
@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"errors"
-	"fmt"
 	"log"
 	"maps"
 	"slices"
@@ -73,11 +72,14 @@ func (w *toolchainWatch) ensure(module string) error {
 			w.logger.Printf("the bucket %s does not exist yet: it is watched when %s reports a toolchain", name, module)
 			return nil
 		case err != nil:
-			return fmt.Errorf("the bucket %s: %w", name, err)
+			// Refused or not answered (its grant not on the bus yet, issue 1945): said, and opened again at the module's next report.
+			w.logger.Printf("the bucket %s cannot be read (%v): %s's toolchains are not heard until its next report", name, err, module)
+			return nil
 		}
 		watcher, err := settle(w.ctx, kv, func(e jetstream.KeyValueEntry) { w.sink.put(module, e.Key(), e.Value(), !opOf(e)) })
 		if err != nil {
-			return err
+			w.logger.Printf("the bucket %s cannot be watched (%v): %s's toolchains are not heard until its next report", name, err, module)
+			return nil
 		}
 		w.watched[module] = true
 		go func() {
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/toolchains_test.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/toolchains_test.go
index e26bf76..7427efb 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/toolchains_test.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/toolchains_test.go
@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"context"
+	"errors"
 	"log"
 	"strings"
 	"sync"
@@ -21,6 +22,7 @@ type laterBuckets struct {
 	mu      sync.Mutex
 	appears map[string]jetstream.KeyValue // buckets that exist now
 	asked   map[string]int
+	refuse  error // answered for a bucket that does not exist, when set: a bus that refuses it (issue 1945)
 }
 
 func (l *laterBuckets) KeyValue(_ context.Context, name string) (jetstream.KeyValue, error) {
@@ -30,6 +32,9 @@ func (l *laterBuckets) KeyValue(_ context.Context, name string) (jetstream.KeyVa
 	if kv, ok := l.appears[name]; ok {
 		return kv, nil
 	}
+	if l.refuse != nil {
+		return nil, l.refuse
+	}
 	return nil, jetstream.ErrBucketNotFound
 }
 
@@ -100,6 +105,12 @@ func TestABuildModulesBucketThatAppearsLaterIsWatchedWhenItsEventArrives(t *test
 		recompute: func(context.Context) error { mu.Lock(); recomputes++; mu.Unlock(); return nil },
 	}
 	var logs bytes.Buffer
+	// 1945: a bus that refuses both buckets, or does not answer, leaves them unwatched, said, and the indexer running.
+	refusing := &laterBuckets{appears: map[string]jetstream.KeyValue{}, asked: map[string]int{}, refuse: errors.New("context deadline exceeded")}
+	if err := newToolchainWatch(ctx, refusing, sink, log.New(&logs, "", 0)).start(); err != nil || !strings.Contains(logs.String(), "cannot be read") {
+		t.Fatalf("a refused toolchains bucket: start %v, log %q; want it said and the start going on", err, logs.String())
+	}
+	logs.Reset()
 	w := newToolchainWatch(ctx, buckets, sink, log.New(&logs, "", 0))
 	if err := w.start(); err != nil { // neither bucket exists: nothing is watched, nothing is written, nobody waits
 		t.Fatal(err)
diff --git a/modules/mesh-delivery-teller/cmd/mesh-delivery-teller/main.go b/modules/mesh-delivery-teller/cmd/mesh-delivery-teller/main.go
index f9b9142..8ed2b7b 100644
--- a/modules/mesh-delivery-teller/cmd/mesh-delivery-teller/main.go
+++ b/modules/mesh-delivery-teller/cmd/mesh-delivery-teller/main.go
@@ -119,12 +119,14 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 		return nil
 	}
 	if err != nil {
-		return fmt.Errorf("the bucket %s: %w", delivery.AsksBucket, err)
+		// Essential: the gate's asks are what the teller tells (issue 1945: the error names the grant).
+		return essentialErr(delivery.AsksBucket, "tell any of the gate's asks", err)
 	}
+	// The answers it writes and what it asked: its own work, so each stops the start, naming its grant.
 	var kvs [2]jetstream.KeyValue
 	for i, name := range []string{delivery.AnswersBucket, askedBucket} {
-		if kvs[i], err = js.KeyValue(ctx, name); err != nil {
-			return fmt.Errorf("the bucket %s: %w", name, err)
+		if kvs[i], err = essentialBucket(ctx, js, name, "write an answer or remember what it asked"); err != nil {
+			return err
 		}
 	}
 	state := kvStore{ctx: ctx, kv: kvs[1]}
@@ -140,7 +142,7 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	// The view's answers to the assigner's asks (issue 1297 B10): both buckets are the controller's to create, and a bucket not
 	// there is said and leaves the teller without that path rather than without the gate's asks (a wait for it needs a timer).
 	failed := make(chan error, 2)
-	assignerKV, viewKV := optionalBucket(ctx, js, delivery.AssignerAsksBucket, logger), optionalBucket(ctx, js, delivery.ViewAnswersBucket, logger)
+	assignerKV, viewKV := optionalBucket(ctx, js, delivery.AssignerAsksBucket, teller, logger.Printf), optionalBucket(ctx, js, delivery.ViewAnswersBucket, teller, logger.Printf)
 	// The assigner's asks are raised on the operator channel whether or not the view's answers can be read (issue 1906).
 	if viewKV != nil {
 		t.View = kvGate{ctx: ctx, kv: viewKV}
@@ -172,15 +174,8 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	}
 }
 
-// optionalBucket is a bucket the teller reads when it exists, and nil, said once, when it does not.
-func optionalBucket(ctx context.Context, js jetstream.JetStream, name string, logger *log.Logger) jetstream.KeyValue {
-	kv, err := js.KeyValue(ctx, name)
-	if err != nil {
-		logger.Printf("the bucket %s cannot be read (%v): the asks and answers it holds are not carried until the teller is started again with it", name, err)
-		return nil
-	}
-	return kv
-}
+// teller is what an optional bucket of the teller leaves out.
+const teller = "the asks and answers it holds are not carried until the teller is started again with it"
 
 // askedBucket is the teller's state bucket asked, `<module>_<name>`: what it asked of the router and which condition it
 // raised (manifest state entry asked, novox/hq ADR 0437 §4).
diff --git a/modules/mesh-delivery-teller/cmd/mesh-delivery-teller/optional.go b/modules/mesh-delivery-teller/cmd/mesh-delivery-teller/optional.go
new file mode 100644
index 0000000..9f8f3bc
--- /dev/null
+++ b/modules/mesh-delivery-teller/cmd/mesh-delivery-teller/optional.go
@@ -0,0 +1,46 @@
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// **A part does not stop for a bucket it can work without** (novox/hq issue 1945, met twice on 2026-10-25: the builder of
+// mesh-delivery #48 exited on a refused read of the gate's source, and its new reasks bucket would have done the same). A
+// grant reaches the bus with a delivery, so a bucket the bus refuses, or times out on, at start is often only not granted
+// yet: exiting for it stops the part until a person's hand. A bucket the teller cannot do its job at all without still stops
+// the start, naming the grant to look at; every other is said and left. (The same two functions are in each delivery part;
+// they belong in mesh-sdk.)
+
+// bucketOpener is the part of the bus a start opens buckets with.
+type bucketOpener interface {
+	KeyValue(ctx context.Context, bucket string) (jetstream.KeyValue, error)
+}
+
+// essentialBucket opens a bucket the teller cannot work without; its error names the bucket and the grant.
+func essentialBucket(ctx context.Context, js bucketOpener, name, does string) (jetstream.KeyValue, error) {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		return nil, essentialErr(name, does, err)
+	}
+	return kv, nil
+}
+
+// essentialErr is the error of a bucket the part cannot work without: it names the bucket and the grant.
+func essentialErr(name, does string, err error) error {
+	return fmt.Errorf("the bucket %s cannot be read (%v): the teller cannot %s without it, so it stops; where the bus "+
+		"refused it or did not answer, this module's grant of %s (its manifest's reads or state, issued with its credential) "+
+		"has not reached the bus yet", name, err, does, name)
+}
+
+// optionalBucket opens a bucket the teller works without: any error is said with what is not heard, and nil answered.
+func optionalBucket(ctx context.Context, js bucketOpener, name, without string, logf func(string, ...any)) jetstream.KeyValue {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		logf("the bucket %s cannot be read (%v): %s", name, err, without)
+		return nil
+	}
+	return kv
+}
diff --git a/modules/mesh-delivery-teller/cmd/mesh-delivery-teller/teller_test.go b/modules/mesh-delivery-teller/cmd/mesh-delivery-teller/teller_test.go
index 8986842..ce2cf62 100644
--- a/modules/mesh-delivery-teller/cmd/mesh-delivery-teller/teller_test.go
+++ b/modules/mesh-delivery-teller/cmd/mesh-delivery-teller/teller_test.go
@@ -1,8 +1,11 @@
 package main
 
 import (
+	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"github.com/nats-io/nats.go/jetstream"
 	"strings"
 	"testing"
 	"time"
@@ -236,6 +239,16 @@ func (b *bed) askedOf(subject string) []published {
 }
 
 func TestAnAsksKeyBecomesOneRouterAskAndDeletingItCancelsIt(t *testing.T) { // 1343/AC1
+	t.Run("1945: a refused bucket is said, or stops the start naming its grant", func(t *testing.T) {
+		refusal := errors.New("nats: permissions violation for publish to $JS.API.STREAM.INFO.KV_x")
+		var said []string
+		if kv := optionalBucket(context.Background(), refusingBus{refusal}, "x", "x is not heard", func(f string, a ...any) { said = append(said, fmt.Sprintf(f, a...)) }); kv != nil || len(said) != 1 || !strings.Contains(said[0], "permissions violation") {
+			t.Errorf("an optional bucket refused: %v, said %v", kv, said)
+		}
+		if _, err := essentialBucket(context.Background(), refusingBus{refusal}, "x", "work"); err == nil || !strings.Contains(err.Error(), "grant of x") {
+			t.Errorf("an essential bucket refused: %v, want its grant named", err)
+		}
+	})
 	b := newBed(t)
 	key, value, ga := gateAsk(t, twoHeads(), twoHeads())
 	b.gate[key] = value
@@ -518,3 +531,8 @@ func TestAnAnswerToAnEarlierAskingDoesNotBlockTheNextAsking(t *testing.T) { // R
 		t.Errorf("writes %d asks %d dropped %v", b.answers.writes, len(b.askedOf(asks.AskSubject(delivery.TellerModule))), b.dropped)
 	}
 }
+
+// refusingBus refuses every bucket with err (issue 1945).
+type refusingBus struct{ err error }
+
+func (r refusingBus) KeyValue(context.Context, string) (jetstream.KeyValue, error) { return nil, r.err }
diff --git a/modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/main.go b/modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/main.go
index f619da4..e59d27f 100644
--- a/modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/main.go
+++ b/modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/main.go
@@ -222,23 +222,23 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	if err != nil {
 		return err
 	}
-	bucket := func(name string) (jetstream.KeyValue, error) {
-		kv, err := js.KeyValue(ctx, name)
-		if err != nil {
-			return nil, fmt.Errorf("the bucket %s: %w", name, err)
-		}
-		return kv, nil
-	}
+	// Its own presence, pulses and stuck rows are what it keeps: each stops the start, naming its grant. The assigner's wants
+	// and the node-engine's haves only make the pulses of a move: without one the watchman watches presence and the build
+	// seats' steps, and says that moves are not watched (issue 1945).
 	var kvs struct{ presence, pulse, stuck, wants, haves jetstream.KeyValue }
 	for _, b := range []struct {
 		name string
 		into *jetstream.KeyValue
-	}{{delivery.PresenceBucket, &kvs.presence}, {delivery.PulseBucket, &kvs.pulse}, {delivery.StuckBucket, &kvs.stuck},
-		{delivery.AssignerWantsBucket, &kvs.wants}, {delivery.HaveBucket, &kvs.haves}} {
-		if *b.into, err = bucket(b.name); err != nil {
+	}{{delivery.PresenceBucket, &kvs.presence}, {delivery.PulseBucket, &kvs.pulse}, {delivery.StuckBucket, &kvs.stuck}} {
+		if *b.into, err = essentialBucket(ctx, js, b.name, "say who is online or what stopped moving"); err != nil {
 			return err
 		}
 	}
+	kvs.wants = optionalBucket(ctx, js, delivery.AssignerWantsBucket, "a want makes no pulse, so a move that stops is not seen, until the watchman starts again", logger.Printf)
+	kvs.haves = optionalBucket(ctx, js, delivery.HaveBucket, "a want makes no pulse, so a move that stops is not seen, until the watchman starts again", logger.Printf)
+	if kvs.wants == nil || kvs.haves == nil {
+		kvs.wants, kvs.haves = nil, nil // a want is a pulse only against the have that ends it
+	}
 
 	w := watch.New(&kvOut{ctx: ctx, presence: kvs.presence, pulse: kvs.pulse, stuk: kvs.stuck}, time.Now)
 	w.Logf(logger.Printf)
@@ -283,13 +283,15 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	}
 	// What the node agents run, then the assigner's wants (issue 1906, ADR 0539 §19): a want is a pulse owed by its node's agent
 	// until the have names its fingerprint, so the haves are read first and a want already applied makes no pulse.
-	haveSeen, err := settle(ctx, kvs.haves, func(e jetstream.KeyValueEntry) { w.Have(e.Key(), e.Value(), opOf(e)) })
-	if err != nil {
-		return err
-	}
-	wantSeen, err := settle(ctx, kvs.wants, func(e jetstream.KeyValueEntry) { w.Want(e.Key(), e.Value(), opOf(e), e.Created()) })
-	if err != nil {
-		return err
+	var haveSeen, wantSeen jetstream.KeyWatcher
+	if kvs.haves != nil {
+		if haveSeen, err = settle(ctx, kvs.haves, func(e jetstream.KeyValueEntry) { w.Have(e.Key(), e.Value(), opOf(e)) }); err != nil {
+			logger.Printf("the bucket %s cannot be watched (%v): moves are not watched until the watchman starts again", delivery.HaveBucket, err)
+		} else if wantSeen, err = settle(ctx, kvs.wants, func(e jetstream.KeyValueEntry) { w.Want(e.Key(), e.Value(), opOf(e), e.Created()) }); err != nil {
+			logger.Printf("the bucket %s cannot be watched (%v): moves are not watched until the watchman starts again", delivery.AssignerWantsBucket, err)
+			haveSeen.Stop()
+			haveSeen = nil
+		}
 	}
 	// The build seats' steps: a step key `<node>.<ask id>` written is the ask taken (issue 1887 A8b). A seat whose build module
 	// keeps no steps bucket (yet) is said and left; the asks of its stream are mirrored all the same.
@@ -304,7 +306,8 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 		lang := lang
 		sw, err := settle(ctx, kv, func(e jetstream.KeyValueEntry) { stepTaken(w, lang, e) })
 		if err != nil {
-			return err
+			logger.Printf("the steps of %s cannot be watched (%v): its asks are mirrored and never seen taken", module, err)
+			continue
 		}
 		taken[lang] = sw
 	}
@@ -348,12 +351,14 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	go func() {
 		errs <- follow(ctx, pulses, func(e jetstream.KeyValueEntry) { w.Pulse(e.Key(), opOf(e), e.Created()) })
 	}()
-	go func() {
-		errs <- follow(ctx, haveSeen, func(e jetstream.KeyValueEntry) { w.Have(e.Key(), e.Value(), opOf(e)) })
-	}()
-	go func() {
-		errs <- follow(ctx, wantSeen, func(e jetstream.KeyValueEntry) { w.Want(e.Key(), e.Value(), opOf(e), e.Created()) })
-	}()
+	if haveSeen != nil && wantSeen != nil {
+		go func() {
+			errs <- follow(ctx, haveSeen, func(e jetstream.KeyValueEntry) { w.Have(e.Key(), e.Value(), opOf(e)) })
+		}()
+		go func() {
+			errs <- follow(ctx, wantSeen, func(e jetstream.KeyValueEntry) { w.Want(e.Key(), e.Value(), opOf(e), e.Created()) })
+		}()
+	}
 	for lang, sw := range taken {
 		lang, sw := lang, sw
 		go func() { errs <- follow(ctx, sw, func(e jetstream.KeyValueEntry) { stepTaken(w, lang, e) }) }()
diff --git a/modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/main_test.go b/modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/main_test.go
index 6a171c2..bee4b2e 100644
--- a/modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/main_test.go
+++ b/modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/main_test.go
@@ -2,11 +2,15 @@ package main
 
 import (
 	"context"
+	"errors"
+	"fmt"
 	"io"
 	"os"
 	"path/filepath"
 	"strings"
 	"testing"
+
+	"github.com/nats-io/nats.go/jetstream"
 )
 
 func TestCredentialIsTheBrokerFile(t *testing.T) { // 1135/AC6
@@ -27,8 +31,23 @@ func TestCredentialIsTheBrokerFile(t *testing.T) { // 1135/AC6
 }
 
 func TestRunNeedsItsCredential(t *testing.T) { // 1135/AC6
+	t.Run("1945: a refused bucket is said, or stops the start naming its grant", func(t *testing.T) {
+		refusal := errors.New("nats: permissions violation for publish to $JS.API.STREAM.INFO.KV_x")
+		var said []string
+		if kv := optionalBucket(context.Background(), refusingBus{refusal}, "x", "x is not heard", func(f string, a ...any) { said = append(said, fmt.Sprintf(f, a...)) }); kv != nil || len(said) != 1 || !strings.Contains(said[0], "permissions violation") {
+			t.Errorf("an optional bucket refused: %v, said %v", kv, said)
+		}
+		if _, err := essentialBucket(context.Background(), refusingBus{refusal}, "x", "work"); err == nil || !strings.Contains(err.Error(), "grant of x") {
+			t.Errorf("an essential bucket refused: %v, want its grant named", err)
+		}
+	})
 	err := run(context.Background(), func(string) string { return "" }, io.Discard)
 	if err == nil || !strings.Contains(err.Error(), "MESH_BROKER_FILE") {
 		t.Fatalf("run = %v, want a refusal naming MESH_BROKER_FILE", err)
 	}
 }
+
+// refusingBus refuses every bucket with err (issue 1945).
+type refusingBus struct{ err error }
+
+func (r refusingBus) KeyValue(context.Context, string) (jetstream.KeyValue, error) { return nil, r.err }
diff --git a/modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/optional.go b/modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/optional.go
new file mode 100644
index 0000000..4d3e2dc
--- /dev/null
+++ b/modules/mesh-delivery-watchman/cmd/mesh-delivery-watchman/optional.go
@@ -0,0 +1,46 @@
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/nats-io/nats.go/jetstream"
+)
+
+// **A part does not stop for a bucket it can work without** (novox/hq issue 1945, met twice on 2026-10-25: the builder of
+// mesh-delivery #48 exited on a refused read of the gate's source, and its new reasks bucket would have done the same). A
+// grant reaches the bus with a delivery, so a bucket the bus refuses, or times out on, at start is often only not granted
+// yet: exiting for it stops the part until a person's hand. A bucket the watchman cannot do its job at all without still stops
+// the start, naming the grant to look at; every other is said and left. (The same two functions are in each delivery part;
+// they belong in mesh-sdk.)
+
+// bucketOpener is the part of the bus a start opens buckets with.
+type bucketOpener interface {
+	KeyValue(ctx context.Context, bucket string) (jetstream.KeyValue, error)
+}
+
+// essentialBucket opens a bucket the watchman cannot work without; its error names the bucket and the grant.
+func essentialBucket(ctx context.Context, js bucketOpener, name, does string) (jetstream.KeyValue, error) {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		return nil, essentialErr(name, does, err)
+	}
+	return kv, nil
+}
+
+// essentialErr is the error of a bucket the part cannot work without: it names the bucket and the grant.
+func essentialErr(name, does string, err error) error {
+	return fmt.Errorf("the bucket %s cannot be read (%v): the watchman cannot %s without it, so it stops; where the bus "+
+		"refused it or did not answer, this module's grant of %s (its manifest's reads or state, issued with its credential) "+
+		"has not reached the bus yet", name, err, does, name)
+}
+
+// optionalBucket opens a bucket the watchman works without: any error is said with what is not heard, and nil answered.
+func optionalBucket(ctx context.Context, js bucketOpener, name, without string, logf func(string, ...any)) jetstream.KeyValue {
+	kv, err := js.KeyValue(ctx, name)
+	if err != nil {
+		logf("the bucket %s cannot be read (%v): %s", name, err, without)
+		return nil
+	}
+	return kv
+}