From 245143d948ea9d28c67dc6e6b4b0fa5de990d39d Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Mon, 26 Oct 2026 19:55:31 +0100
Subject: [PATCH 1/2] Build modules run at most as many steps as their node's
 build CPU gives, and say a check's phases

Each of mesh-build-go, -node and -image declares cores-per-step (6, 2, 2) and hands it to the
SDK puller, which bounds the configured capacity by floor(slice quota cores / cores-per-step),
read live; thread limits and the status tools follow the effective capacity (issue 1806's
follow-up: three Go checks on shanks' 12-core slice starved past the 30-minute step bound).
mesh-build-go says its lint and test phases with the ask id (issue 1890).
---
 modules/mesh-build-go/cmd/mesh-build-go/asks.go  |  6 +++++-
 .../mesh-build-go/cmd/mesh-build-go/asks_test.go | 16 +++++++++++++---
 modules/mesh-build-go/cmd/mesh-build-go/cpu.go   |  8 +++++++-
 modules/mesh-build-go/cmd/mesh-build-go/lint.go  |  4 ++++
 modules/mesh-build-go/files/settings.json        |  3 ++-
 modules/mesh-build-go/go.mod                     |  2 +-
 modules/mesh-build-go/go.sum                     |  4 ++--
 modules/mesh-build-go/module.json                |  8 +++++++-
 .../cmd/mesh-build-image/asks.go                 |  6 +++++-
 .../mesh-build-image/cmd/mesh-build-image/cpu.go |  8 +++++++-
 modules/mesh-build-image/files/settings.json     |  3 ++-
 modules/mesh-build-image/go.mod                  |  2 +-
 modules/mesh-build-image/go.sum                  |  4 ++--
 modules/mesh-build-image/module.json             |  8 +++++++-
 .../mesh-build-node/cmd/mesh-build-node/asks.go  |  6 +++++-
 .../cmd/mesh-build-node/asks_test.go             | 16 +++++++++++++---
 .../mesh-build-node/cmd/mesh-build-node/cpu.go   |  8 +++++++-
 modules/mesh-build-node/files/settings.json      |  3 ++-
 modules/mesh-build-node/go.mod                   |  2 +-
 modules/mesh-build-node/go.sum                   |  4 ++--
 modules/mesh-build-node/module.json              |  8 +++++++-
 21 files changed, 102 insertions(+), 27 deletions(-)

diff --git a/modules/mesh-build-go/cmd/mesh-build-go/asks.go b/modules/mesh-build-go/cmd/mesh-build-go/asks.go
index f514673c..722d5b48 100644
--- a/modules/mesh-build-go/cmd/mesh-build-go/asks.go
+++ b/modules/mesh-build-go/cmd/mesh-build-go/asks.go
@@ -84,9 +84,13 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 	// The capacity's own change wakes the puller (issue 1887): the runtime's watch of the config value as mesh-config
 	// resolved it; the settings file is read only when that watch cannot start. A test's Capacity is its own.
 	var watch func(string, func(stdio.ProvisionChange) error) error
+	// And the CPU bounds it (issue 1806's follow-up): the configured capacity is an upper bound, the node's build slice
+	// gives floor(its quota's cores / the module's cores-per-step) at once, read live; a test judges by its own Capacity.
+	var cores func() float64
 	if capacity == nil {
 		capacity = buildstep.NodeCapacity(m.Settings, buildstep.DefaultCapacities, m.Node, m.Say)
 		watch = buildstep.WatchConfigServed
+		cores = buildstep.NodeCoresPerStep(m.Settings, buildstep.DefaultCoresPerStep[delivery.AskGo], m.Say)
 	}
 	ask := m.askSteps(steps)
 	var load func(string) ([]byte, error)
@@ -97,7 +101,7 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 		}
 	}
 	return &buildstep.Puller{Source: source, Language: delivery.AskGo, Node: m.Node, Put: m.Steps, PausePut: m.Pauses, Load: load,
-		Capacity: capacity, WatchConfig: watch, Logf: m.Say, Has: m.Has,
+		Capacity: capacity, WatchConfig: watch, CoresPerStep: cores, Logf: m.Say, Has: m.Has,
 		Run: func(ctx context.Context, a delivery.StepAsk) (any, error) {
 			if err := m.Check(ctx); err != nil {
 				return nil, err
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/asks_test.go b/modules/mesh-build-go/cmd/mesh-build-go/asks_test.go
index 91783730..02f18241 100644
--- a/modules/mesh-build-go/cmd/mesh-build-go/asks_test.go
+++ b/modules/mesh-build-go/cmd/mesh-build-go/asks_test.go
@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"os"
 	"slices"
 	"strings"
@@ -125,12 +126,21 @@ func TestManifestClaimsTheGoBuildSeatAndReadsItsCapacity(t *testing.T) {
 	raw, _ := os.ReadFile(moduleDir + "/module.json")
 	var doc struct {
 		Config map[string]struct {
-			Default string `json:"default"`
+			Default json.RawMessage `json:"default"`
 		} `json:"config"`
 	}
 	_ = json.Unmarshal(raw, &doc)
-	if doc.Config[buildstep.CapacitySetting].Default != buildstep.DefaultCapacities {
-		t.Errorf("the capacity's default = %q, want %q", doc.Config[buildstep.CapacitySetting].Default, buildstep.DefaultCapacities)
+	// Issue 1806's follow-up: the cores a step needs is a setting of its own, in the settings file, with the SDK's default.
+	if cores := string(doc.Config[buildstep.CoresPerStepSetting].Default); cores != fmt.Sprint(buildstep.DefaultCoresPerStep[delivery.AskGo]) {
+		t.Errorf("the cores-per-step default = %s, want %g", cores, buildstep.DefaultCoresPerStep[delivery.AskGo])
+	}
+	if got := buildstep.NodeCoresPerStep(moduleDir+"/files/settings.json", 0, nil)(); got != buildstep.DefaultCoresPerStep[delivery.AskGo] {
+		t.Errorf("the settings template holds cores-per-step %g", got)
+	}
+	var capacity string
+	_ = json.Unmarshal(doc.Config[buildstep.CapacitySetting].Default, &capacity)
+	if capacity != buildstep.DefaultCapacities {
+		t.Errorf("the capacity's default = %q, want %q", capacity, buildstep.DefaultCapacities)
 	}
 	settings := resource(t, m, "settings")
 	if settings["path"] != "${dir:state}/settings.json" {
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/cpu.go b/modules/mesh-build-go/cmd/mesh-build-go/cpu.go
index 24457cb4..c1c00903 100644
--- a/modules/mesh-build-go/cmd/mesh-build-go/cpu.go
+++ b/modules/mesh-build-go/cmd/mesh-build-go/cpu.go
@@ -15,6 +15,8 @@ import (
 func (m *Module) cpuLimits() buildcpu.Limits {
 	slots := 1
 	switch {
+	case m.Held != nil:
+		slots = m.Held.CapacityNow() // the capacity the puller judges by, bounded by the node's build slice
 	case m.Capacity != nil:
 		slots = m.Capacity()
 	case m.Settings != "":
@@ -32,5 +34,9 @@ func (m *Module) threadEnv() []string {
 // cpuStatus is what the status tool says of it: the limits a step is given, and what the kernel holds this runtime
 // to (its unit and its slice), read from its cgroup rather than assumed.
 func (m *Module) cpuStatus() map[string]any {
-	return map[string]any{"limits": m.cpuLimits(), "in-force": buildcpu.ReadInForce()}
+	out := map[string]any{"limits": m.cpuLimits(), "in-force": buildcpu.ReadInForce()}
+	if m.Held != nil {
+		out["capacity"] = m.Held.CapacityDetail() // the capacity judged by and why (issue 1806's follow-up)
+	}
+	return out
 }
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/lint.go b/modules/mesh-build-go/cmd/mesh-build-go/lint.go
index 7fb41f5f..23527db1 100644
--- a/modules/mesh-build-go/cmd/mesh-build-go/lint.go
+++ b/modules/mesh-build-go/cmd/mesh-build-go/lint.go
@@ -14,6 +14,7 @@ import (
 	"strings"
 	"sync"
 
+	"git.novox.be/novox/mesh-sdk/go/buildstep"
 	"git.novox.be/novox/mesh-sdk/go/forgekey"
 )
 
@@ -132,6 +133,9 @@ func (m *Module) lint(ctx context.Context, run forgekey.Runner, tree, d string,
 // lintAll lints each directory, up to m.parallel() at once like the level's tests; the failures join in directory order
 // and the error is the first directory's, so the answer does not depend on which ended first (issue 1930).
 func (m *Module) lintAll(ctx context.Context, run forgekey.Runner, tree string, dirs []string, env func(d string) []string) ([]Failure, error) {
+	// The ask's phases say it (issue 1890): lint of the directories, then their tests.
+	buildstep.Phase(ctx, fmt.Sprintf("unit: lint of %d directories", len(dirs)))
+	defer buildstep.Phase(ctx, fmt.Sprintf("unit: tests of %d directories", len(dirs)))
 	type answer struct {
 		failed []Failure
 		err    error
diff --git a/modules/mesh-build-go/files/settings.json b/modules/mesh-build-go/files/settings.json
index 3175fe39..054af9a2 100644
--- a/modules/mesh-build-go/files/settings.json
+++ b/modules/mesh-build-go/files/settings.json
@@ -1,3 +1,4 @@
 {
-  "capacity": "shanks=3,ace=2,g14=0,novox=0"
+  "capacity": "shanks=3,ace=2,g14=0,novox=0",
+  "cores-per-step": 6
 }
diff --git a/modules/mesh-build-go/go.mod b/modules/mesh-build-go/go.mod
index 868b22d2..5e2a7a39 100644
--- a/modules/mesh-build-go/go.mod
+++ b/modules/mesh-build-go/go.mod
@@ -3,7 +3,7 @@ module meshbuildgo
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026142629-ff81bdf8cc8f
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642
 	github.com/distribution/distribution/v3 v3.1.2
 	github.com/nats-io/nats-server/v2 v2.11.17
 	github.com/nats-io/nats.go v1.54.0
diff --git a/modules/mesh-build-go/go.sum b/modules/mesh-build-go/go.sum
index c86aa01f..b4a5f723 100644
--- a/modules/mesh-build-go/go.sum
+++ b/modules/mesh-build-go/go.sum
@@ -1,5 +1,5 @@
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026142629-ff81bdf8cc8f h1:GYLCvz2x+JNUOTbXzyh2QwzX0sTzvRlXR7lGocWjk3A=
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026142629-ff81bdf8cc8f/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642 h1:mSBxF9KgIJyNL0gOKYq5naWewUj2yazU/tGOh12Tze0=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 github.com/alicebob/miniredis/v2 v2.35.0 h1:QwLphYqCEAo1eu1TqPRN2jgVMPBweeQcR21jeqDCONI=
 github.com/alicebob/miniredis/v2 v2.35.0/go.mod h1:TcL7YfarKPGDAthEtl5NBeHZfeUQj6OXMm/+iu5cLMM=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
diff --git a/modules/mesh-build-go/module.json b/modules/mesh-build-go/module.json
index 2f566cbf..9530f128 100644
--- a/modules/mesh-build-go/module.json
+++ b/modules/mesh-build-go/module.json
@@ -29,6 +29,12 @@
       "description": "How many asks of the Go build seat this module runs at once on each node, as node=asks pairs separated by commas, such as shanks=3,ace=2 (novox/hq ADR 0525 §5); a node set to 0 pulls nothing, a node not named runs one at a time. The control-node and the laptop build nothing.",
       "pattern": "|[a-z0-9_-]+=[0-9]+(,[a-z0-9_-]+=[0-9]+)*",
       "default": "shanks=3,ace=2,g14=0,novox=0"
+    },
+    "cores-per-step": {
+      "type": "number",
+      "description": "How many processors one Go step of this module needs (a full check of a large repository takes what it is given: three at about 4 cores each ran past the 30-minute step bound on 2026-10-26). The capacity above is an upper bound: on each node the module runs at most floor(the cores of its build slice's CPU quota / this) steps at once, the quota read live from its cgroup (issue 1806), so a lowered build CPU share never starves its steps. Above 0.",
+      "minimum": 0.1,
+      "default": 6
     }
   },
   "tools": [
@@ -107,7 +113,7 @@
       "path": "${dir:state}/settings.json",
       "mode": "0600",
       "owner": "mesh-build-go",
-      "takes-config": ["capacity"],
+      "takes-config": ["capacity", "cores-per-step"],
       "merge": "json",
       "template": "files/settings.json"
     },
diff --git a/modules/mesh-build-image/cmd/mesh-build-image/asks.go b/modules/mesh-build-image/cmd/mesh-build-image/asks.go
index 45e03207..3775fc7b 100644
--- a/modules/mesh-build-image/cmd/mesh-build-image/asks.go
+++ b/modules/mesh-build-image/cmd/mesh-build-image/asks.go
@@ -40,9 +40,13 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 	// The capacity's own change wakes the puller (issue 1887): the runtime's watch of the config value as mesh-config
 	// resolved it; the settings file is read only when that watch cannot start. A test's Capacity is its own.
 	var watch func(string, func(stdio.ProvisionChange) error) error
+	// And the CPU bounds it (issue 1806's follow-up): the configured capacity is an upper bound, the node's build slice
+	// gives floor(its quota's cores / the module's cores-per-step) at once, read live; a test judges by its own Capacity.
+	var cores func() float64
 	if capacity == nil {
 		capacity = buildstep.NodeCapacity(m.Settings, buildstep.DefaultCapacities, m.Node, m.Say)
 		watch = buildstep.WatchConfigServed
+		cores = buildstep.NodeCoresPerStep(m.Settings, buildstep.DefaultCoresPerStep[delivery.AskImage], m.Say)
 	}
 	ask := m.askSteps(steps)
 	var load func(string) ([]byte, error)
@@ -50,7 +54,7 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 		load = func(key string) ([]byte, error) { return m.ReadPauses.Get(key) }
 	}
 	return &buildstep.Puller{Source: source, Language: delivery.AskImage, Node: m.Node, Put: m.Steps, PausePut: m.Pauses, Load: load,
-		Capacity: capacity, WatchConfig: watch, Logf: m.Say,
+		Capacity: capacity, WatchConfig: watch, CoresPerStep: cores, Logf: m.Say,
 		Run: func(ctx context.Context, a delivery.StepAsk) (any, error) {
 			if err := m.Check(ctx); err != nil {
 				return nil, err
diff --git a/modules/mesh-build-image/cmd/mesh-build-image/cpu.go b/modules/mesh-build-image/cmd/mesh-build-image/cpu.go
index 126b319d..91f1d314 100644
--- a/modules/mesh-build-image/cmd/mesh-build-image/cpu.go
+++ b/modules/mesh-build-image/cmd/mesh-build-image/cpu.go
@@ -15,6 +15,8 @@ import (
 func (m *Module) cpuLimits() buildcpu.Limits {
 	slots := 1
 	switch {
+	case m.Held != nil:
+		slots = m.Held.CapacityNow() // the capacity the puller judges by, bounded by the node's build slice
 	case m.Capacity != nil:
 		slots = m.Capacity()
 	case m.Settings != "":
@@ -32,5 +34,9 @@ func (m *Module) threadEnv() []string {
 // cpuStatus is what the status tool says of it: the limits a step is given, and what the kernel holds this runtime
 // to (its unit and its slice), read from its cgroup rather than assumed.
 func (m *Module) cpuStatus() map[string]any {
-	return map[string]any{"limits": m.cpuLimits(), "in-force": buildcpu.ReadInForce()}
+	out := map[string]any{"limits": m.cpuLimits(), "in-force": buildcpu.ReadInForce()}
+	if m.Held != nil {
+		out["capacity"] = m.Held.CapacityDetail() // the capacity judged by and why (issue 1806's follow-up)
+	}
+	return out
 }
diff --git a/modules/mesh-build-image/files/settings.json b/modules/mesh-build-image/files/settings.json
index 3175fe39..9acf4e20 100644
--- a/modules/mesh-build-image/files/settings.json
+++ b/modules/mesh-build-image/files/settings.json
@@ -1,3 +1,4 @@
 {
-  "capacity": "shanks=3,ace=2,g14=0,novox=0"
+  "capacity": "shanks=3,ace=2,g14=0,novox=0",
+  "cores-per-step": 2
 }
diff --git a/modules/mesh-build-image/go.mod b/modules/mesh-build-image/go.mod
index 52658707..0e530690 100644
--- a/modules/mesh-build-image/go.mod
+++ b/modules/mesh-build-image/go.mod
@@ -3,7 +3,7 @@ module meshbuildimage
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026142629-ff81bdf8cc8f
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642
 	github.com/nats-io/nats-server/v2 v2.11.17
 	github.com/nats-io/nats.go v1.54.0
 )
diff --git a/modules/mesh-build-image/go.sum b/modules/mesh-build-image/go.sum
index ba65afa3..9e114f39 100644
--- a/modules/mesh-build-image/go.sum
+++ b/modules/mesh-build-image/go.sum
@@ -1,5 +1,5 @@
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026142629-ff81bdf8cc8f h1:GYLCvz2x+JNUOTbXzyh2QwzX0sTzvRlXR7lGocWjk3A=
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026142629-ff81bdf8cc8f/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642 h1:mSBxF9KgIJyNL0gOKYq5naWewUj2yazU/tGOh12Tze0=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 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/google/go-tpm v0.9.8 h1:slArAR9Ft+1ybZu0lBwpSmpwhRXaa85hWtMinMyRAWo=
diff --git a/modules/mesh-build-image/module.json b/modules/mesh-build-image/module.json
index ae9c5162..3fe1377f 100644
--- a/modules/mesh-build-image/module.json
+++ b/modules/mesh-build-image/module.json
@@ -24,6 +24,12 @@
       "description": "How many asks of the image build seat this module runs at once on each node, as node=asks pairs separated by commas, such as shanks=3,ace=2 (novox/hq ADR 0525 §5); a node set to 0 pulls nothing, a node not named runs one at a time. The control-node and the laptop build nothing.",
       "pattern": "|[a-z0-9_-]+=[0-9]+(,[a-z0-9_-]+=[0-9]+)*",
       "default": "shanks=3,ace=2,g14=0,novox=0"
+    },
+    "cores-per-step": {
+      "type": "number",
+      "description": "How many processors one image step of this module needs (buildah, whose RUN lines are mostly fetches). The capacity above is an upper bound: on each node the module runs at most floor(the cores of its build slice's CPU quota / this) steps at once, the quota read live from its cgroup (issue 1806), so a lowered build CPU share never starves its steps. Above 0.",
+      "minimum": 0.1,
+      "default": 2
     }
   },
   "tools": [
@@ -78,7 +84,7 @@
       "path": "${dir:state}/settings.json",
       "mode": "0600",
       "owner": "mesh-build-image",
-      "takes-config": ["capacity"],
+      "takes-config": ["capacity", "cores-per-step"],
       "merge": "json",
       "template": "files/settings.json"
     },
diff --git a/modules/mesh-build-node/cmd/mesh-build-node/asks.go b/modules/mesh-build-node/cmd/mesh-build-node/asks.go
index 0e1b845d..25bff14f 100644
--- a/modules/mesh-build-node/cmd/mesh-build-node/asks.go
+++ b/modules/mesh-build-node/cmd/mesh-build-node/asks.go
@@ -48,9 +48,13 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 	// The capacity's own change wakes the puller (issue 1887): the runtime's watch of the config value as mesh-config
 	// resolved it; the settings file is read only when that watch cannot start. A test's Capacity is its own.
 	var watch func(string, func(stdio.ProvisionChange) error) error
+	// And the CPU bounds it (issue 1806's follow-up): the configured capacity is an upper bound, the node's build slice
+	// gives floor(its quota's cores / the module's cores-per-step) at once, read live; a test judges by its own Capacity.
+	var cores func() float64
 	if capacity == nil {
 		capacity = buildstep.NodeCapacity(m.Settings, buildstep.DefaultCapacities, m.Node, m.Say)
 		watch = buildstep.WatchConfigServed
+		cores = buildstep.NodeCoresPerStep(m.Settings, buildstep.DefaultCoresPerStep[delivery.AskNode], m.Say)
 	}
 	ask := m.askSteps(steps)
 	var load func(string) ([]byte, error)
@@ -58,7 +62,7 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 		load = func(key string) ([]byte, error) { return m.ReadPauses.Get(key) }
 	}
 	return &buildstep.Puller{Source: source, Language: delivery.AskNode, Node: m.Node, Put: m.Steps, PausePut: m.Pauses, Load: load,
-		Capacity: capacity, WatchConfig: watch, Logf: m.Say,
+		Capacity: capacity, WatchConfig: watch, CoresPerStep: cores, Logf: m.Say,
 		Run: func(ctx context.Context, a delivery.StepAsk) (any, error) {
 			if err := m.Prepare(ctx); err != nil {
 				return nil, err
diff --git a/modules/mesh-build-node/cmd/mesh-build-node/asks_test.go b/modules/mesh-build-node/cmd/mesh-build-node/asks_test.go
index 1985c863..dcecf188 100644
--- a/modules/mesh-build-node/cmd/mesh-build-node/asks_test.go
+++ b/modules/mesh-build-node/cmd/mesh-build-node/asks_test.go
@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"os"
 	"strings"
 	"testing"
@@ -83,12 +84,21 @@ func TestManifestTakesTheBuildCapacity(t *testing.T) {
 	raw, _ := os.ReadFile(moduleDir + "/module.json")
 	var doc struct {
 		Config map[string]struct {
-			Default string `json:"default"`
+			Default json.RawMessage `json:"default"`
 		} `json:"config"`
 	}
 	_ = json.Unmarshal(raw, &doc)
-	if doc.Config[buildstep.CapacitySetting].Default != buildstep.DefaultCapacities {
-		t.Errorf("the capacity's default = %q", doc.Config[buildstep.CapacitySetting].Default)
+	// Issue 1806's follow-up: the cores a step needs is a setting of its own, in the settings file, with the SDK's default.
+	if cores := string(doc.Config[buildstep.CoresPerStepSetting].Default); cores != fmt.Sprint(buildstep.DefaultCoresPerStep[delivery.AskNode]) {
+		t.Errorf("the cores-per-step default = %s, want %g", cores, buildstep.DefaultCoresPerStep[delivery.AskNode])
+	}
+	if got := buildstep.NodeCoresPerStep(moduleDir+"/files/settings.json", 0, nil)(); got != buildstep.DefaultCoresPerStep[delivery.AskNode] {
+		t.Errorf("the settings template holds cores-per-step %g", got)
+	}
+	var capacity string
+	_ = json.Unmarshal(doc.Config[buildstep.CapacitySetting].Default, &capacity)
+	if capacity != buildstep.DefaultCapacities {
+		t.Errorf("the capacity's default = %q", capacity)
 	}
 	if resource(t, m, "settings")["path"] != "${dir:state}/settings.json" {
 		t.Error("no settings file")
diff --git a/modules/mesh-build-node/cmd/mesh-build-node/cpu.go b/modules/mesh-build-node/cmd/mesh-build-node/cpu.go
index b40ceda4..5936b615 100644
--- a/modules/mesh-build-node/cmd/mesh-build-node/cpu.go
+++ b/modules/mesh-build-node/cmd/mesh-build-node/cpu.go
@@ -15,6 +15,8 @@ import (
 func (m *Module) cpuLimits() buildcpu.Limits {
 	slots := 1
 	switch {
+	case m.Held != nil:
+		slots = m.Held.CapacityNow() // the capacity the puller judges by, bounded by the node's build slice
 	case m.Capacity != nil:
 		slots = m.Capacity()
 	case m.Settings != "":
@@ -32,5 +34,9 @@ func (m *Module) threadEnv() []string {
 // cpuStatus is what the status tool says of it: the limits a step is given, and what the kernel holds this runtime
 // to (its unit and its slice), read from its cgroup rather than assumed.
 func (m *Module) cpuStatus() map[string]any {
-	return map[string]any{"limits": m.cpuLimits(), "in-force": buildcpu.ReadInForce()}
+	out := map[string]any{"limits": m.cpuLimits(), "in-force": buildcpu.ReadInForce()}
+	if m.Held != nil {
+		out["capacity"] = m.Held.CapacityDetail() // the capacity judged by and why (issue 1806's follow-up)
+	}
+	return out
 }
diff --git a/modules/mesh-build-node/files/settings.json b/modules/mesh-build-node/files/settings.json
index 3175fe39..9acf4e20 100644
--- a/modules/mesh-build-node/files/settings.json
+++ b/modules/mesh-build-node/files/settings.json
@@ -1,3 +1,4 @@
 {
-  "capacity": "shanks=3,ace=2,g14=0,novox=0"
+  "capacity": "shanks=3,ace=2,g14=0,novox=0",
+  "cores-per-step": 2
 }
diff --git a/modules/mesh-build-node/go.mod b/modules/mesh-build-node/go.mod
index e79f663b..4f5fd29a 100644
--- a/modules/mesh-build-node/go.mod
+++ b/modules/mesh-build-node/go.mod
@@ -3,7 +3,7 @@ module meshbuildnode
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026142629-ff81bdf8cc8f
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642
 	github.com/distribution/distribution/v3 v3.1.2
 	github.com/nats-io/nats.go v1.54.0
 )
diff --git a/modules/mesh-build-node/go.sum b/modules/mesh-build-node/go.sum
index 28122ac9..8b19ae3a 100644
--- a/modules/mesh-build-node/go.sum
+++ b/modules/mesh-build-node/go.sum
@@ -1,5 +1,5 @@
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026142629-ff81bdf8cc8f h1:GYLCvz2x+JNUOTbXzyh2QwzX0sTzvRlXR7lGocWjk3A=
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026142629-ff81bdf8cc8f/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642 h1:mSBxF9KgIJyNL0gOKYq5naWewUj2yazU/tGOh12Tze0=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 github.com/alicebob/miniredis/v2 v2.35.0 h1:QwLphYqCEAo1eu1TqPRN2jgVMPBweeQcR21jeqDCONI=
 github.com/alicebob/miniredis/v2 v2.35.0/go.mod h1:TcL7YfarKPGDAthEtl5NBeHZfeUQj6OXMm/+iu5cLMM=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
diff --git a/modules/mesh-build-node/module.json b/modules/mesh-build-node/module.json
index 701419b2..970cd694 100644
--- a/modules/mesh-build-node/module.json
+++ b/modules/mesh-build-node/module.json
@@ -25,6 +25,12 @@
       "description": "How many asks of the Node build seat this module runs at once on each node, as node=asks pairs separated by commas, such as shanks=3,ace=2 (novox/hq ADR 0525 §5); a node set to 0 pulls nothing, a node not named runs one at a time. The control-node and the laptop build nothing.",
       "pattern": "|[a-z0-9_-]+=[0-9]+(,[a-z0-9_-]+=[0-9]+)*",
       "default": "shanks=3,ace=2,g14=0,novox=0"
+    },
+    "cores-per-step": {
+      "type": "number",
+      "description": "How many processors one Node step of this module needs (tsc, esbuild and a test runner; a median step takes 15 s). The capacity above is an upper bound: on each node the module runs at most floor(the cores of its build slice's CPU quota / this) steps at once, the quota read live from its cgroup (issue 1806), so a lowered build CPU share never starves its steps. Above 0.",
+      "minimum": 0.1,
+      "default": 2
     }
   },
   "tools": [
@@ -100,7 +106,7 @@
       "path": "${dir:state}/settings.json",
       "mode": "0600",
       "owner": "mesh-build-node",
-      "takes-config": ["capacity"],
+      "takes-config": ["capacity", "cores-per-step"],
       "merge": "json",
       "template": "files/settings.json"
     },

From 3f8b0b42480b6eef362f2360ec5d9d0c2e088b7d Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Mon, 26 Oct 2026 21:19:59 +0100
Subject: [PATCH 2/2] Build modules take asks only within their node's build
 hours

mesh-build-go, -node and -image declare build-hours (node=HH:MM-HH:MM in the node's local time,
empty = any hour) and hand it to the SDK puller (the operator, 2026-10-26: g14 builds only from
18:00 to 06:00); their SDK pin moves to mesh-sdk d00dac1, which has it.
---
 modules/mesh-build-go/cmd/mesh-build-go/asks.go          | 6 +++++-
 modules/mesh-build-go/cmd/mesh-build-go/asks_test.go     | 7 +++++++
 modules/mesh-build-go/files/settings.json                | 3 ++-
 modules/mesh-build-go/go.mod                             | 2 +-
 modules/mesh-build-go/go.sum                             | 4 ++--
 modules/mesh-build-go/module.json                        | 8 +++++++-
 modules/mesh-build-image/cmd/mesh-build-image/asks.go    | 6 +++++-
 modules/mesh-build-image/files/settings.json             | 3 ++-
 modules/mesh-build-image/go.mod                          | 2 +-
 modules/mesh-build-image/go.sum                          | 4 ++--
 modules/mesh-build-image/module.json                     | 8 +++++++-
 modules/mesh-build-node/cmd/mesh-build-node/asks.go      | 6 +++++-
 modules/mesh-build-node/cmd/mesh-build-node/asks_test.go | 7 +++++++
 modules/mesh-build-node/files/settings.json              | 3 ++-
 modules/mesh-build-node/go.mod                           | 2 +-
 modules/mesh-build-node/go.sum                           | 4 ++--
 modules/mesh-build-node/module.json                      | 8 +++++++-
 17 files changed, 65 insertions(+), 18 deletions(-)

diff --git a/modules/mesh-build-go/cmd/mesh-build-go/asks.go b/modules/mesh-build-go/cmd/mesh-build-go/asks.go
index 722d5b48..816793b2 100644
--- a/modules/mesh-build-go/cmd/mesh-build-go/asks.go
+++ b/modules/mesh-build-go/cmd/mesh-build-go/asks.go
@@ -86,8 +86,12 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 	var watch func(string, func(stdio.ProvisionChange) error) error
 	// And the CPU bounds it (issue 1806's follow-up): the configured capacity is an upper bound, the node's build slice
 	// gives floor(its quota's cores / the module's cores-per-step) at once, read live; a test judges by its own Capacity.
+	// And the node's build hours (the operator, 2026-10-26: g14 builds only from 18:00 to 06:00): outside them it takes
+	// nothing new.
 	var cores func() float64
+	var hours func() (*buildstep.BuildWindow, string)
 	if capacity == nil {
+		hours = buildstep.NodeBuildHours(m.Settings, m.Node, m.Say)
 		capacity = buildstep.NodeCapacity(m.Settings, buildstep.DefaultCapacities, m.Node, m.Say)
 		watch = buildstep.WatchConfigServed
 		cores = buildstep.NodeCoresPerStep(m.Settings, buildstep.DefaultCoresPerStep[delivery.AskGo], m.Say)
@@ -101,7 +105,7 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 		}
 	}
 	return &buildstep.Puller{Source: source, Language: delivery.AskGo, Node: m.Node, Put: m.Steps, PausePut: m.Pauses, Load: load,
-		Capacity: capacity, WatchConfig: watch, CoresPerStep: cores, Logf: m.Say, Has: m.Has,
+		Capacity: capacity, WatchConfig: watch, CoresPerStep: cores, BuildHours: hours, Logf: m.Say, Has: m.Has,
 		Run: func(ctx context.Context, a delivery.StepAsk) (any, error) {
 			if err := m.Check(ctx); err != nil {
 				return nil, err
diff --git a/modules/mesh-build-go/cmd/mesh-build-go/asks_test.go b/modules/mesh-build-go/cmd/mesh-build-go/asks_test.go
index 02f18241..20f6d788 100644
--- a/modules/mesh-build-go/cmd/mesh-build-go/asks_test.go
+++ b/modules/mesh-build-go/cmd/mesh-build-go/asks_test.go
@@ -137,6 +137,13 @@ func TestManifestClaimsTheGoBuildSeatAndReadsItsCapacity(t *testing.T) {
 	if got := buildstep.NodeCoresPerStep(moduleDir+"/files/settings.json", 0, nil)(); got != buildstep.DefaultCoresPerStep[delivery.AskGo] {
 		t.Errorf("the settings template holds cores-per-step %g", got)
 	}
+	// And the build hours (the operator, 2026-10-26): a setting of their own, empty by default (any hour), in the template.
+	if hours := string(doc.Config[buildstep.BuildHoursSetting].Default); hours != `""` {
+		t.Errorf("the build-hours default = %s, want empty", hours)
+	}
+	if w, fault := buildstep.NodeBuildHours(moduleDir+"/files/settings.json", "g14", t.Errorf)(); w != nil || fault != "" {
+		t.Errorf("the settings template holds build hours %v (%s)", w, fault)
+	}
 	var capacity string
 	_ = json.Unmarshal(doc.Config[buildstep.CapacitySetting].Default, &capacity)
 	if capacity != buildstep.DefaultCapacities {
diff --git a/modules/mesh-build-go/files/settings.json b/modules/mesh-build-go/files/settings.json
index 054af9a2..56bb28d4 100644
--- a/modules/mesh-build-go/files/settings.json
+++ b/modules/mesh-build-go/files/settings.json
@@ -1,4 +1,5 @@
 {
   "capacity": "shanks=3,ace=2,g14=0,novox=0",
-  "cores-per-step": 6
+  "cores-per-step": 6,
+  "build-hours": ""
 }
diff --git a/modules/mesh-build-go/go.mod b/modules/mesh-build-go/go.mod
index 5e2a7a39..24e99464 100644
--- a/modules/mesh-build-go/go.mod
+++ b/modules/mesh-build-go/go.mod
@@ -3,7 +3,7 @@ module meshbuildgo
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026202137-d00dac140b03
 	github.com/distribution/distribution/v3 v3.1.2
 	github.com/nats-io/nats-server/v2 v2.11.17
 	github.com/nats-io/nats.go v1.54.0
diff --git a/modules/mesh-build-go/go.sum b/modules/mesh-build-go/go.sum
index b4a5f723..4fd3d8a8 100644
--- a/modules/mesh-build-go/go.sum
+++ b/modules/mesh-build-go/go.sum
@@ -1,5 +1,5 @@
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642 h1:mSBxF9KgIJyNL0gOKYq5naWewUj2yazU/tGOh12Tze0=
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026202137-d00dac140b03 h1:QIcGyV96AHZ6t/4AgBDlUOcs5tq40PppC7pwEpmzZco=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026202137-d00dac140b03/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 github.com/alicebob/miniredis/v2 v2.35.0 h1:QwLphYqCEAo1eu1TqPRN2jgVMPBweeQcR21jeqDCONI=
 github.com/alicebob/miniredis/v2 v2.35.0/go.mod h1:TcL7YfarKPGDAthEtl5NBeHZfeUQj6OXMm/+iu5cLMM=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
diff --git a/modules/mesh-build-go/module.json b/modules/mesh-build-go/module.json
index 9530f128..7526d1a0 100644
--- a/modules/mesh-build-go/module.json
+++ b/modules/mesh-build-go/module.json
@@ -30,6 +30,12 @@
       "pattern": "|[a-z0-9_-]+=[0-9]+(,[a-z0-9_-]+=[0-9]+)*",
       "default": "shanks=3,ace=2,g14=0,novox=0"
     },
+    "build-hours": {
+      "type": "string",
+      "description": "When each node may take this module's build asks, as node=HH:MM-HH:MM pairs in the node's local time, separated by commas, such as g14=18:00-06:00 (an end before its start crosses midnight). Outside its window a node takes no new step and finishes the ones it runs; a node not named, or an empty value, builds at any hour. The operator, 2026-10-26: g14 builds only outside office hours.",
+      "pattern": "|[a-z0-9_-]+=([01][0-9]|2[0-3]):[0-5][0-9]-([01][0-9]|2[0-3]):[0-5][0-9](,[a-z0-9_-]+=([01][0-9]|2[0-3]):[0-5][0-9]-([01][0-9]|2[0-3]):[0-5][0-9])*",
+      "default": ""
+    },
     "cores-per-step": {
       "type": "number",
       "description": "How many processors one Go step of this module needs (a full check of a large repository takes what it is given: three at about 4 cores each ran past the 30-minute step bound on 2026-10-26). The capacity above is an upper bound: on each node the module runs at most floor(the cores of its build slice's CPU quota / this) steps at once, the quota read live from its cgroup (issue 1806), so a lowered build CPU share never starves its steps. Above 0.",
@@ -113,7 +119,7 @@
       "path": "${dir:state}/settings.json",
       "mode": "0600",
       "owner": "mesh-build-go",
-      "takes-config": ["capacity", "cores-per-step"],
+      "takes-config": ["capacity", "cores-per-step", "build-hours"],
       "merge": "json",
       "template": "files/settings.json"
     },
diff --git a/modules/mesh-build-image/cmd/mesh-build-image/asks.go b/modules/mesh-build-image/cmd/mesh-build-image/asks.go
index 3775fc7b..ad9899bf 100644
--- a/modules/mesh-build-image/cmd/mesh-build-image/asks.go
+++ b/modules/mesh-build-image/cmd/mesh-build-image/asks.go
@@ -42,8 +42,12 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 	var watch func(string, func(stdio.ProvisionChange) error) error
 	// And the CPU bounds it (issue 1806's follow-up): the configured capacity is an upper bound, the node's build slice
 	// gives floor(its quota's cores / the module's cores-per-step) at once, read live; a test judges by its own Capacity.
+	// And the node's build hours (the operator, 2026-10-26: g14 builds only from 18:00 to 06:00): outside them it takes
+	// nothing new.
 	var cores func() float64
+	var hours func() (*buildstep.BuildWindow, string)
 	if capacity == nil {
+		hours = buildstep.NodeBuildHours(m.Settings, m.Node, m.Say)
 		capacity = buildstep.NodeCapacity(m.Settings, buildstep.DefaultCapacities, m.Node, m.Say)
 		watch = buildstep.WatchConfigServed
 		cores = buildstep.NodeCoresPerStep(m.Settings, buildstep.DefaultCoresPerStep[delivery.AskImage], m.Say)
@@ -54,7 +58,7 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 		load = func(key string) ([]byte, error) { return m.ReadPauses.Get(key) }
 	}
 	return &buildstep.Puller{Source: source, Language: delivery.AskImage, Node: m.Node, Put: m.Steps, PausePut: m.Pauses, Load: load,
-		Capacity: capacity, WatchConfig: watch, CoresPerStep: cores, Logf: m.Say,
+		Capacity: capacity, WatchConfig: watch, CoresPerStep: cores, BuildHours: hours, Logf: m.Say,
 		Run: func(ctx context.Context, a delivery.StepAsk) (any, error) {
 			if err := m.Check(ctx); err != nil {
 				return nil, err
diff --git a/modules/mesh-build-image/files/settings.json b/modules/mesh-build-image/files/settings.json
index 9acf4e20..73ee4fa8 100644
--- a/modules/mesh-build-image/files/settings.json
+++ b/modules/mesh-build-image/files/settings.json
@@ -1,4 +1,5 @@
 {
   "capacity": "shanks=3,ace=2,g14=0,novox=0",
-  "cores-per-step": 2
+  "cores-per-step": 2,
+  "build-hours": ""
 }
diff --git a/modules/mesh-build-image/go.mod b/modules/mesh-build-image/go.mod
index 0e530690..e931caa0 100644
--- a/modules/mesh-build-image/go.mod
+++ b/modules/mesh-build-image/go.mod
@@ -3,7 +3,7 @@ module meshbuildimage
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026202137-d00dac140b03
 	github.com/nats-io/nats-server/v2 v2.11.17
 	github.com/nats-io/nats.go v1.54.0
 )
diff --git a/modules/mesh-build-image/go.sum b/modules/mesh-build-image/go.sum
index 9e114f39..cffc5072 100644
--- a/modules/mesh-build-image/go.sum
+++ b/modules/mesh-build-image/go.sum
@@ -1,5 +1,5 @@
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642 h1:mSBxF9KgIJyNL0gOKYq5naWewUj2yazU/tGOh12Tze0=
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026202137-d00dac140b03 h1:QIcGyV96AHZ6t/4AgBDlUOcs5tq40PppC7pwEpmzZco=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026202137-d00dac140b03/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 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/google/go-tpm v0.9.8 h1:slArAR9Ft+1ybZu0lBwpSmpwhRXaa85hWtMinMyRAWo=
diff --git a/modules/mesh-build-image/module.json b/modules/mesh-build-image/module.json
index 3fe1377f..c83b9d88 100644
--- a/modules/mesh-build-image/module.json
+++ b/modules/mesh-build-image/module.json
@@ -25,6 +25,12 @@
       "pattern": "|[a-z0-9_-]+=[0-9]+(,[a-z0-9_-]+=[0-9]+)*",
       "default": "shanks=3,ace=2,g14=0,novox=0"
     },
+    "build-hours": {
+      "type": "string",
+      "description": "When each node may take this module's build asks, as node=HH:MM-HH:MM pairs in the node's local time, separated by commas, such as g14=18:00-06:00 (an end before its start crosses midnight). Outside its window a node takes no new step and finishes the ones it runs; a node not named, or an empty value, builds at any hour. The operator, 2026-10-26: g14 builds only outside office hours.",
+      "pattern": "|[a-z0-9_-]+=([01][0-9]|2[0-3]):[0-5][0-9]-([01][0-9]|2[0-3]):[0-5][0-9](,[a-z0-9_-]+=([01][0-9]|2[0-3]):[0-5][0-9]-([01][0-9]|2[0-3]):[0-5][0-9])*",
+      "default": ""
+    },
     "cores-per-step": {
       "type": "number",
       "description": "How many processors one image step of this module needs (buildah, whose RUN lines are mostly fetches). The capacity above is an upper bound: on each node the module runs at most floor(the cores of its build slice's CPU quota / this) steps at once, the quota read live from its cgroup (issue 1806), so a lowered build CPU share never starves its steps. Above 0.",
@@ -84,7 +90,7 @@
       "path": "${dir:state}/settings.json",
       "mode": "0600",
       "owner": "mesh-build-image",
-      "takes-config": ["capacity", "cores-per-step"],
+      "takes-config": ["capacity", "cores-per-step", "build-hours"],
       "merge": "json",
       "template": "files/settings.json"
     },
diff --git a/modules/mesh-build-node/cmd/mesh-build-node/asks.go b/modules/mesh-build-node/cmd/mesh-build-node/asks.go
index 25bff14f..f2353133 100644
--- a/modules/mesh-build-node/cmd/mesh-build-node/asks.go
+++ b/modules/mesh-build-node/cmd/mesh-build-node/asks.go
@@ -50,8 +50,12 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 	var watch func(string, func(stdio.ProvisionChange) error) error
 	// And the CPU bounds it (issue 1806's follow-up): the configured capacity is an upper bound, the node's build slice
 	// gives floor(its quota's cores / the module's cores-per-step) at once, read live; a test judges by its own Capacity.
+	// And the node's build hours (the operator, 2026-10-26: g14 builds only from 18:00 to 06:00): outside them it takes
+	// nothing new.
 	var cores func() float64
+	var hours func() (*buildstep.BuildWindow, string)
 	if capacity == nil {
+		hours = buildstep.NodeBuildHours(m.Settings, m.Node, m.Say)
 		capacity = buildstep.NodeCapacity(m.Settings, buildstep.DefaultCapacities, m.Node, m.Say)
 		watch = buildstep.WatchConfigServed
 		cores = buildstep.NodeCoresPerStep(m.Settings, buildstep.DefaultCoresPerStep[delivery.AskNode], m.Say)
@@ -62,7 +66,7 @@ func (m *Module) Puller(steps []StepTool, source buildstep.AskSource) *buildstep
 		load = func(key string) ([]byte, error) { return m.ReadPauses.Get(key) }
 	}
 	return &buildstep.Puller{Source: source, Language: delivery.AskNode, Node: m.Node, Put: m.Steps, PausePut: m.Pauses, Load: load,
-		Capacity: capacity, WatchConfig: watch, CoresPerStep: cores, Logf: m.Say,
+		Capacity: capacity, WatchConfig: watch, CoresPerStep: cores, BuildHours: hours, Logf: m.Say,
 		Run: func(ctx context.Context, a delivery.StepAsk) (any, error) {
 			if err := m.Prepare(ctx); err != nil {
 				return nil, err
diff --git a/modules/mesh-build-node/cmd/mesh-build-node/asks_test.go b/modules/mesh-build-node/cmd/mesh-build-node/asks_test.go
index dcecf188..8ae9a43d 100644
--- a/modules/mesh-build-node/cmd/mesh-build-node/asks_test.go
+++ b/modules/mesh-build-node/cmd/mesh-build-node/asks_test.go
@@ -95,6 +95,13 @@ func TestManifestTakesTheBuildCapacity(t *testing.T) {
 	if got := buildstep.NodeCoresPerStep(moduleDir+"/files/settings.json", 0, nil)(); got != buildstep.DefaultCoresPerStep[delivery.AskNode] {
 		t.Errorf("the settings template holds cores-per-step %g", got)
 	}
+	// And the build hours (the operator, 2026-10-26): a setting of their own, empty by default (any hour), in the template.
+	if hours := string(doc.Config[buildstep.BuildHoursSetting].Default); hours != `""` {
+		t.Errorf("the build-hours default = %s, want empty", hours)
+	}
+	if w, fault := buildstep.NodeBuildHours(moduleDir+"/files/settings.json", "g14", t.Errorf)(); w != nil || fault != "" {
+		t.Errorf("the settings template holds build hours %v (%s)", w, fault)
+	}
 	var capacity string
 	_ = json.Unmarshal(doc.Config[buildstep.CapacitySetting].Default, &capacity)
 	if capacity != buildstep.DefaultCapacities {
diff --git a/modules/mesh-build-node/files/settings.json b/modules/mesh-build-node/files/settings.json
index 9acf4e20..73ee4fa8 100644
--- a/modules/mesh-build-node/files/settings.json
+++ b/modules/mesh-build-node/files/settings.json
@@ -1,4 +1,5 @@
 {
   "capacity": "shanks=3,ace=2,g14=0,novox=0",
-  "cores-per-step": 2
+  "cores-per-step": 2,
+  "build-hours": ""
 }
diff --git a/modules/mesh-build-node/go.mod b/modules/mesh-build-node/go.mod
index 4f5fd29a..55492ff6 100644
--- a/modules/mesh-build-node/go.mod
+++ b/modules/mesh-build-node/go.mod
@@ -3,7 +3,7 @@ module meshbuildnode
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026202137-d00dac140b03
 	github.com/distribution/distribution/v3 v3.1.2
 	github.com/nats-io/nats.go v1.54.0
 )
diff --git a/modules/mesh-build-node/go.sum b/modules/mesh-build-node/go.sum
index 8b19ae3a..338460ec 100644
--- a/modules/mesh-build-node/go.sum
+++ b/modules/mesh-build-node/go.sum
@@ -1,5 +1,5 @@
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642 h1:mSBxF9KgIJyNL0gOKYq5naWewUj2yazU/tGOh12Tze0=
-git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026185254-02f50bd9d642/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026202137-d00dac140b03 h1:QIcGyV96AHZ6t/4AgBDlUOcs5tq40PppC7pwEpmzZco=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261026202137-d00dac140b03/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 github.com/alicebob/miniredis/v2 v2.35.0 h1:QwLphYqCEAo1eu1TqPRN2jgVMPBweeQcR21jeqDCONI=
 github.com/alicebob/miniredis/v2 v2.35.0/go.mod h1:TcL7YfarKPGDAthEtl5NBeHZfeUQj6OXMm/+iu5cLMM=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
diff --git a/modules/mesh-build-node/module.json b/modules/mesh-build-node/module.json
index 970cd694..baf8b291 100644
--- a/modules/mesh-build-node/module.json
+++ b/modules/mesh-build-node/module.json
@@ -26,6 +26,12 @@
       "pattern": "|[a-z0-9_-]+=[0-9]+(,[a-z0-9_-]+=[0-9]+)*",
       "default": "shanks=3,ace=2,g14=0,novox=0"
     },
+    "build-hours": {
+      "type": "string",
+      "description": "When each node may take this module's build asks, as node=HH:MM-HH:MM pairs in the node's local time, separated by commas, such as g14=18:00-06:00 (an end before its start crosses midnight). Outside its window a node takes no new step and finishes the ones it runs; a node not named, or an empty value, builds at any hour. The operator, 2026-10-26: g14 builds only outside office hours.",
+      "pattern": "|[a-z0-9_-]+=([01][0-9]|2[0-3]):[0-5][0-9]-([01][0-9]|2[0-3]):[0-5][0-9](,[a-z0-9_-]+=([01][0-9]|2[0-3]):[0-5][0-9]-([01][0-9]|2[0-3]):[0-5][0-9])*",
+      "default": ""
+    },
     "cores-per-step": {
       "type": "number",
       "description": "How many processors one Node step of this module needs (tsc, esbuild and a test runner; a median step takes 15 s). The capacity above is an upper bound: on each node the module runs at most floor(the cores of its build slice's CPU quota / this) steps at once, the quota read live from its cgroup (issue 1806), so a lowered build CPU share never starves its steps. Above 0.",
@@ -106,7 +112,7 @@
       "path": "${dir:state}/settings.json",
       "mode": "0600",
       "owner": "mesh-build-node",
-      "takes-config": ["capacity", "cores-per-step"],
+      "takes-config": ["capacity", "cores-per-step", "build-hours"],
       "merge": "json",
       "template": "files/settings.json"
     },