From acd8e985d196487884baa90b38ec42633431021c Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Thu, 5 Nov 2026 14:41:02 +0100
Subject: [PATCH 1/5] =?UTF-8?q?mesh-delivery-sdk=20kept:=20the=20version?=
 =?UTF-8?q?=20check,=20CheckName=20and=20IsHex64=20are=20mesh-sdk=20keys'?=
 =?UTF-8?q?=20now;=20kept=20keeps=20Decode=20and=20CheckDigest=20(ruling?=
 =?UTF-8?q?=202,=20ADR=200634=20=C2=A71;=20issue=201966)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Claude-Session: https://claude.ai/code/session_01NcbgfFSnn24M3GcqttoU7i
---
 .../meshdeliverycheckerclient/client.go       |  6 +--
 .../mesh-delivery-builder/builds/builds.go    |  8 +--
 .../builds/builds_test.go                     |  5 +-
 modules/mesh-delivery-builder/builds/log.go   |  3 +-
 .../takein/taken_test.go                      |  3 +-
 modules/mesh-delivery-view/viewstate/reach.go |  2 +-
 sdk/kept/kept.go                              | 49 ++-----------------
 sdk/kept/kept_test.go                         | 11 +----
 8 files changed, 19 insertions(+), 68 deletions(-)

diff --git a/contracts/go/clients/meshdeliverycheckerclient/client.go b/contracts/go/clients/meshdeliverycheckerclient/client.go
index c97e6ac3..80915d61 100644
--- a/contracts/go/clients/meshdeliverycheckerclient/client.go
+++ b/contracts/go/clients/meshdeliverycheckerclient/client.go
@@ -9,7 +9,7 @@ import (
 	"strings"
 
 	checker "git.novox.be/novox/mesh-delivery/contracts/go/seats/meshdeliverychecker"
-	"git.novox.be/novox/mesh-delivery/sdk/kept"
+	"git.novox.be/novox/mesh-sdk/go/keys"
 )
 
 // The states of a verdict, the levels of a check and the compositions' states.
@@ -44,10 +44,10 @@ func CheckRepository(repository string) error {
 	if !ok || strings.Contains(name, "/") {
 		return fmt.Errorf("meshdeliverycheckerclient: the repository %q is not <owner>/<name>, with exactly one slash", repository)
 	}
-	if err := kept.CheckName("repository owner", owner); err != nil {
+	if err := keys.CheckName("repository owner", owner); err != nil {
 		return fmt.Errorf("meshdeliverycheckerclient: the repository %q: %w", repository, err)
 	}
-	if err := kept.CheckName("repository name", name); err != nil {
+	if err := keys.CheckName("repository name", name); err != nil {
 		return fmt.Errorf("meshdeliverycheckerclient: the repository %q: %w", repository, err)
 	}
 	return nil
diff --git a/modules/mesh-delivery-builder/builds/builds.go b/modules/mesh-delivery-builder/builds/builds.go
index 04bd7751..26e0973c 100644
--- a/modules/mesh-delivery-builder/builds/builds.go
+++ b/modules/mesh-delivery-builder/builds/builds.go
@@ -65,7 +65,7 @@ const (
 // being the fingerprint's key part (fingerprint.KeyPart), since a bus key may not hold ':'. A module holding a dot or a
 // character a key refuses, and a fingerprint not of the new form, are refused, naming them.
 func BuilderBuildKey(module, fp string) (string, error) {
-	if err := kept.CheckName("module", module); err != nil {
+	if err := keys.CheckName("module", module); err != nil {
 		return "", err
 	}
 	part, err := fingerprint.KeyPart(fp)
@@ -81,7 +81,7 @@ func ParseBuilderBuildKey(key string) (module, fp string, err error) {
 	if !ok {
 		return "", "", fmt.Errorf("builds: %q is not a builder build key, <module>.<fingerprint hex>", key)
 	}
-	if err := kept.CheckName("module", module); err != nil {
+	if err := keys.CheckName("module", module); err != nil {
 		return "", "", fmt.Errorf("builds: %q is not a builder build key: %w", key, err)
 	}
 	if fp, err = fingerprint.ParseKeyPart(part); err != nil {
@@ -265,7 +265,7 @@ func (b BuilderBuild) check() error {
 		return fmt.Errorf("builds: the build state %q is not queued, building, done or failed", b.State)
 	}
 	if b.Manifest != "" {
-		if !kept.IsHex64(b.Manifest) {
+		if !keys.IsHex64(b.Manifest) {
 			return fmt.Errorf("builds: %q is not a manifest digest, 64 lowercase hex digits", b.Manifest)
 		}
 	}
@@ -355,7 +355,7 @@ func EncodeBuilderBuild(b BuilderBuild) ([]byte, error) {
 	return json.Marshal(b)
 }
 
-// DecodeBuilderBuild reads a builder build value; it refuses an unknown version (kept.ErrUnknownVersion) and what
+// DecodeBuilderBuild reads a builder build value; it refuses an unknown version (keys.ErrUnknownVersion) and what
 // EncodeBuilderBuild refuses.
 func DecodeBuilderBuild(data []byte) (BuilderBuild, error) {
 	var b BuilderBuild
diff --git a/modules/mesh-delivery-builder/builds/builds_test.go b/modules/mesh-delivery-builder/builds/builds_test.go
index e49c966e..8e272b67 100644
--- a/modules/mesh-delivery-builder/builds/builds_test.go
+++ b/modules/mesh-delivery-builder/builds/builds_test.go
@@ -9,7 +9,6 @@ import (
 	"testing"
 
 	"git.novox.be/novox/mesh-delivery/sdk/buildrecord"
-	"git.novox.be/novox/mesh-delivery/sdk/kept"
 	"git.novox.be/novox/mesh-sdk/go/keys"
 )
 
@@ -177,10 +176,10 @@ func TestBuilderBuildNamesItsToolchains(t *testing.T) {
 	}
 }
 
-// 1358/AC5: a value of another version, or none, is refused with kept.ErrUnknownVersion.
+// 1358/AC5: a value of another version, or none, is refused with keys.ErrUnknownVersion.
 func TestBuilderBuildVersion(t *testing.T) {
 	for _, in := range []string{`{"v":2,"state":"queued"}`, `{"state":"queued"}`} {
-		if _, err := DecodeBuilderBuild([]byte(in)); !errors.Is(err, kept.ErrUnknownVersion) {
+		if _, err := DecodeBuilderBuild([]byte(in)); !errors.Is(err, keys.ErrUnknownVersion) {
 			t.Errorf("DecodeBuilderBuild(%s) = %v", in, err)
 		}
 	}
diff --git a/modules/mesh-delivery-builder/builds/log.go b/modules/mesh-delivery-builder/builds/log.go
index d7344eee..8bdc55e8 100644
--- a/modules/mesh-delivery-builder/builds/log.go
+++ b/modules/mesh-delivery-builder/builds/log.go
@@ -6,7 +6,6 @@ import (
 	"sort"
 	"time"
 
-	"git.novox.be/novox/mesh-delivery/sdk/kept"
 	"git.novox.be/novox/mesh-delivery/sdk/trunk"
 	"git.novox.be/novox/mesh-sdk/go/keys"
 )
@@ -36,7 +35,7 @@ const (
 // BuildLogKey is the key of a module's entries in the builder's log: the module's name, refused when a log key could not
 // hold it.
 func BuildLogKey(module string) (string, error) {
-	if err := kept.CheckName("module", module); err != nil {
+	if err := keys.CheckName("module", module); err != nil {
 		return "", err
 	}
 	return module, nil
diff --git a/modules/mesh-delivery-indexer/takein/taken_test.go b/modules/mesh-delivery-indexer/takein/taken_test.go
index 7a0aca61..9e30603e 100644
--- a/modules/mesh-delivery-indexer/takein/taken_test.go
+++ b/modules/mesh-delivery-indexer/takein/taken_test.go
@@ -6,7 +6,6 @@ import (
 	"testing"
 	"time"
 
-	"git.novox.be/novox/mesh-delivery/sdk/kept"
 	"git.novox.be/novox/mesh-sdk/go/keys"
 )
 
@@ -26,7 +25,7 @@ func TestATakenValueRoundTripsAndRefusesWhatLacksARepositoryOrAMerge(t *testing.
 		t.Errorf("taken without merge: %v", err)
 	}
 	for _, in := range []string{`{"v":2,"repository":"a/b","merge":"c"}`, `{"repository":"a/b","merge":"c"}`} {
-		if _, err := DecodeTaken([]byte(in)); !errors.Is(err, kept.ErrUnknownVersion) {
+		if _, err := DecodeTaken([]byte(in)); !errors.Is(err, keys.ErrUnknownVersion) {
 			t.Errorf("decode of %s = %v, want ErrUnknownVersion", in, err)
 		}
 	}
diff --git a/modules/mesh-delivery-view/viewstate/reach.go b/modules/mesh-delivery-view/viewstate/reach.go
index 4cad0487..51574736 100644
--- a/modules/mesh-delivery-view/viewstate/reach.go
+++ b/modules/mesh-delivery-view/viewstate/reach.go
@@ -168,7 +168,7 @@ func EncodeViewAnswer(a ViewAnswer) ([]byte, error) {
 	return json.Marshal(a)
 }
 
-// DecodeViewAnswer reads an answer; it refuses an unknown version (kept.ErrUnknownVersion) and what EncodeViewAnswer refuses.
+// DecodeViewAnswer reads an answer; it refuses an unknown version (keys.ErrUnknownVersion) and what EncodeViewAnswer refuses.
 func DecodeViewAnswer(data []byte) (ViewAnswer, error) {
 	var a ViewAnswer
 	if err := kept.Decode(data, &a); err != nil {
diff --git a/sdk/kept/kept.go b/sdk/kept/kept.go
index 1d907361..35fe7e48 100644
--- a/sdk/kept/kept.go
+++ b/sdk/kept/kept.go
@@ -1,59 +1,20 @@
-// Package kept holds what the layouts of the Delivery domain's kept values share: the version check on reading one, the
-// rule a name must keep to be a key part, and the form of a digest. It names no seat and no module (ADR 0634 §2). The
-// version itself (keys.Version) and the escaping of a name (keys.EscapeName) are mesh-sdk's, since more than one domain uses
-// them.
+// Package kept holds what the layouts of the Delivery domain's kept values share: the reading of one at its version and the form
+// of a digest. It names no seat and no module (ADR 0634 §2). The version (keys.Version, keys.CheckVersion), the rule a name
+// must keep to be a key part (keys.CheckName), keys.IsHex64 and the escaping of a name (keys.EscapeName) are mesh-sdk's,
+// since more than one domain uses them.
 package kept
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
 	"regexp"
 
 	"git.novox.be/novox/mesh-sdk/go/keys"
 )
 
-// ErrUnknownVersion is what Decode returns for a value whose version is missing or not keys.Version. Test it with errors.Is.
-var ErrUnknownVersion = errors.New("kept: unknown value version")
-
-var nameOK = regexp.MustCompile(`^[-/_=a-zA-Z0-9]+$`)
-
-// CheckName refuses a name that is empty or holds a dot, a wildcard, whitespace or a character a bus key refuses.
-func CheckName(kind, name string) error {
-	if name == "" {
-		return fmt.Errorf("kept: the %s name is empty", kind)
-	}
-	if !nameOK.MatchString(name) {
-		return fmt.Errorf("kept: the %s name %q holds a dot, a wildcard, whitespace or a character a key refuses", kind, name)
-	}
-	return nil
-}
-
-var hex64 = regexp.MustCompile(`^[0-9a-f]{64}$`)
-
-// IsHex64 says whether s is 64 lowercase hex digits.
-func IsHex64(s string) bool { return hex64.MatchString(s) }
-
-// CheckVersion refuses a value with no version or one this reader does not read.
-func CheckVersion(data []byte) error {
-	var probe struct {
-		V *int `json:"v"`
-	}
-	if err := json.Unmarshal(data, &probe); err != nil {
-		return fmt.Errorf("kept: value is not JSON: %w", err)
-	}
-	if probe.V == nil {
-		return fmt.Errorf("%w: no version in the value, this reader reads %d", ErrUnknownVersion, keys.Version)
-	}
-	if *probe.V != keys.Version {
-		return fmt.Errorf("%w: the value is version %d, this reader reads %d", ErrUnknownVersion, *probe.V, keys.Version)
-	}
-	return nil
-}
-
 // Decode reads data into into after CheckVersion.
 func Decode(data []byte, into any) error {
-	if err := CheckVersion(data); err != nil {
+	if err := keys.CheckVersion(data); err != nil {
 		return err
 	}
 	if err := json.Unmarshal(data, into); err != nil {
diff --git a/sdk/kept/kept_test.go b/sdk/kept/kept_test.go
index aeff9ec0..870c6cf4 100644
--- a/sdk/kept/kept_test.go
+++ b/sdk/kept/kept_test.go
@@ -2,6 +2,7 @@ package kept
 
 import (
 	"errors"
+	"git.novox.be/novox/mesh-sdk/go/keys"
 	"strings"
 	"testing"
 )
@@ -10,21 +11,13 @@ func TestAKeptValueIsReadOnlyAtItsVersionAndAKeyPartOnlyOfKeyCharacters(t *testi
 	var v struct{ V int }
 	for data, ok := range map[string]bool{`{"v":1}`: true, `{"v":2}`: false, `{}`: false} {
 		err := Decode([]byte(data), &v)
-		if (err == nil) != ok || (!ok && !errors.Is(err, ErrUnknownVersion)) {
+		if (err == nil) != ok || (!ok && !errors.Is(err, keys.ErrUnknownVersion)) {
 			t.Errorf("Decode(%s) = %v", data, err)
 		}
 	}
 	if Decode([]byte(`nope`), &v) == nil {
 		t.Error("a value that is no JSON is read")
 	}
-	for name, ok := range map[string]bool{"a-b_c/d=": true, "": false, "a.b": false, "a b": false, "a*": false} {
-		if (CheckName("module", name) == nil) != ok {
-			t.Errorf("CheckName(%q) = %v", name, CheckName("module", name))
-		}
-	}
-	if !IsHex64(strings.Repeat("a", 64)) || IsHex64(strings.Repeat("A", 64)) || IsHex64("a") {
-		t.Error("IsHex64 reads a wrong form")
-	}
 	if CheckDigest("sha256:"+strings.Repeat("0", 64), "x") != nil || CheckDigest("sha256:0", "x") == nil {
 		t.Error("CheckDigest reads a wrong form")
 	}

From dcd1f3c22b6f0c1700419155f4adf6212af07e3e Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Thu, 5 Nov 2026 14:44:23 +0100
Subject: [PATCH 2/5] =?UTF-8?q?mesh-delivery-contracts:=20the=20artifact?=
 =?UTF-8?q?=20reference=20forms=20move=20to=20the=20registry=20seats'=20cl?=
 =?UTF-8?q?ient=20and=20the=20fingerprint=20key=20part=20to=20a=20new=20cl?=
 =?UTF-8?q?ient=20of=20mesh-catalog;=20mesh-delivery-sdk=20serves=20Delive?=
 =?UTF-8?q?ry=20modules=20only=20(ruling=203,=20ADR=200634=20=C2=A71,=20?=
 =?UTF-8?q?=C2=A72;=20issue=201966)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Claude-Session: https://claude.ai/code/session_01NcbgfFSnn24M3GcqttoU7i
---
 .../reference/reference.go                    |  4 ++--
 .../reference/reference_test.go               |  0
 .../clients/meshcatalogclient}/fingerprint.go | 19 +++++++++----------
 .../meshcatalogclient}/fingerprint_test.go    |  2 +-
 contracts/go/clients/meshcatalogclient/go.mod | 14 ++++++++++++++
 contracts/go/clients/meshcatalogclient/go.sum | 18 ++++++++++++++++++
 contracts/module.json                         |  9 +++++++++
 .../mesh-delivery-builder/builds/builds.go    | 10 +++++-----
 modules/mesh-delivery-builder/builds/go.mod   |  2 ++
 9 files changed, 60 insertions(+), 18 deletions(-)
 rename {sdk => contracts/go/clients/containerimageregistryclient}/reference/reference.go (95%)
 rename {sdk => contracts/go/clients/containerimageregistryclient}/reference/reference_test.go (100%)
 rename {sdk/fingerprint => contracts/go/clients/meshcatalogclient}/fingerprint.go (66%)
 rename {sdk/fingerprint => contracts/go/clients/meshcatalogclient}/fingerprint_test.go (97%)
 create mode 100644 contracts/go/clients/meshcatalogclient/go.mod
 create mode 100644 contracts/go/clients/meshcatalogclient/go.sum

diff --git a/sdk/reference/reference.go b/contracts/go/clients/containerimageregistryclient/reference/reference.go
similarity index 95%
rename from sdk/reference/reference.go
rename to contracts/go/clients/containerimageregistryclient/reference/reference.go
index d451689b..80cdaf46 100644
--- a/sdk/reference/reference.go
+++ b/contracts/go/clients/containerimageregistryclient/reference/reference.go
@@ -1,6 +1,6 @@
 // Package reference holds the form of an artifact's reference once a registry seat published it: `<seat>/<module>/<artifact>@<digest>`
-// (novox/hq ADR 0605 §9), and the older `artifact-store://<path>` form read beside it. It is the Delivery domain's rule over
-// the names of the two registry seats that front the artifact store; it names no seat itself (ADR 0634 §4, ADR 0635 §4): the
+// (novox/hq ADR 0605 §9), and the older `artifact-store://<path>` form read beside it. It is the rule the holders and callers of the two
+// registry seats that front the artifact store share (the seats' client, novox/hq ADR 0625 §4, ADR 0634 §2); it names no seat itself (ADR 0634 §4, ADR 0635 §4): the
 // caller gives the seats' names from their contracts (Seats), so a package here cannot drift from a contract.
 package reference
 
diff --git a/sdk/reference/reference_test.go b/contracts/go/clients/containerimageregistryclient/reference/reference_test.go
similarity index 100%
rename from sdk/reference/reference_test.go
rename to contracts/go/clients/containerimageregistryclient/reference/reference_test.go
diff --git a/sdk/fingerprint/fingerprint.go b/contracts/go/clients/meshcatalogclient/fingerprint.go
similarity index 66%
rename from sdk/fingerprint/fingerprint.go
rename to contracts/go/clients/meshcatalogclient/fingerprint.go
index 34b60bec..0565fdb5 100644
--- a/sdk/fingerprint/fingerprint.go
+++ b/contracts/go/clients/meshcatalogclient/fingerprint.go
@@ -1,11 +1,14 @@
-// Package fingerprint holds the form of a module's source fingerprint, `src2:` and 64 lowercase hex digits (novox/hq ADR 0593
-// §2): the indexer computes it alone, in its own package; every part that keys a state by it reads this form. It is the
-// Delivery domain's rule, over the `fp2` field of mesh-catalog's `modules` value (ADR 0634 §1).
-package fingerprint
+// Package meshcatalogclient holds the logic the holders and callers of the seat mesh-catalog share over its contract (novox/hq
+// ADR 0625 §4, ADR 0634 §2): the form of a module's source fingerprint, `src2:` and 64 lowercase hex digits (ADR 0593 §2),
+// over the `fp2` field of the seat's `modules` value. The indexer computes a fingerprint alone, in its own package; every part
+// that keys a state by it, the node-engine among them, reads this form here.
+package meshcatalogclient
 
 import (
 	"fmt"
 	"strings"
+
+	"git.novox.be/novox/mesh-sdk/go/keys"
 )
 
 // SourcePrefix2 opens every source fingerprint of the form.
@@ -23,7 +26,7 @@ type Toolchain2 struct {
 // refuses a value that is not `src2:` and 64 lowercase hex digits, a src1 fingerprint included, naming it.
 func KeyPart(fp string) (string, error) {
 	part, ok := strings.CutPrefix(fp, SourcePrefix2)
-	if !ok || !isHex64(part) {
+	if !ok || !keys.IsHex64(part) {
 		return "", fmt.Errorf("fingerprint: %q is not a fingerprint of the form, %s and 64 lowercase hex digits", fp, SourcePrefix2)
 	}
 	return part, nil
@@ -31,12 +34,8 @@ func KeyPart(fp string) (string, error) {
 
 // ParseKeyPart is the inverse of KeyPart. It refuses a part that is not 64 lowercase hex digits, naming it.
 func ParseKeyPart(part string) (string, error) {
-	if !isHex64(part) {
+	if !keys.IsHex64(part) {
 		return "", fmt.Errorf("fingerprint: %q is not the key part of a fingerprint, 64 lowercase hex digits", part)
 	}
 	return SourcePrefix2 + part, nil
 }
-
-func isHex64(s string) bool {
-	return len(s) == 64 && strings.Trim(s, "0123456789abcdef") == ""
-}
diff --git a/sdk/fingerprint/fingerprint_test.go b/contracts/go/clients/meshcatalogclient/fingerprint_test.go
similarity index 97%
rename from sdk/fingerprint/fingerprint_test.go
rename to contracts/go/clients/meshcatalogclient/fingerprint_test.go
index 11efe273..ec575e0a 100644
--- a/sdk/fingerprint/fingerprint_test.go
+++ b/contracts/go/clients/meshcatalogclient/fingerprint_test.go
@@ -1,4 +1,4 @@
-package fingerprint
+package meshcatalogclient
 
 import (
 	"strings"
diff --git a/contracts/go/clients/meshcatalogclient/go.mod b/contracts/go/clients/meshcatalogclient/go.mod
new file mode 100644
index 00000000..12ac8e36
--- /dev/null
+++ b/contracts/go/clients/meshcatalogclient/go.mod
@@ -0,0 +1,14 @@
+module git.novox.be/novox/mesh-delivery/contracts/go/clients/meshcatalogclient
+
+go 1.26.0
+
+require git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261104174118-f94abb95aaef
+
+require (
+	github.com/klauspost/compress v1.20.1 // indirect
+	github.com/nats-io/nats.go v1.54.0 // indirect
+	github.com/nats-io/nkeys v0.4.16 // indirect
+	github.com/nats-io/nuid v1.0.1 // indirect
+	golang.org/x/crypto v0.57.0 // indirect
+	golang.org/x/sys v0.48.0 // indirect
+)
diff --git a/contracts/go/clients/meshcatalogclient/go.sum b/contracts/go/clients/meshcatalogclient/go.sum
new file mode 100644
index 00000000..c811fda7
--- /dev/null
+++ b/contracts/go/clients/meshcatalogclient/go.sum
@@ -0,0 +1,18 @@
+git.novox.be/novox/mesh-contracts/go v0.0.0-20261104172218-347a3053580a h1:E9ERPqR4uZXypudHGxv2/wNIOYcder9torVqJwJq/DI=
+git.novox.be/novox/mesh-contracts/go v0.0.0-20261104172218-347a3053580a/go.mod h1:0dD1XEJBJ0G5UYDQxSZI84nuujb6m3tOpJl4C8rQVvg=
+git.novox.be/novox/mesh-delivery/contracts/go/seats/containerimageregistry v0.0.0-20261105000000-000000000000 h1:BTqpa7dCCTQH9m08Jle8KVFwyIHiHPSUbwWxuqSg2yA=
+git.novox.be/novox/mesh-delivery/contracts/go/seats/containerimageregistry v0.0.0-20261105000000-000000000000/go.mod h1:pPxwhTMb3hIk7UUrBicJnGQCqfTEoBGJvNFspEK2U18=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261104174118-f94abb95aaef h1:/Jic5ho0xz32Z9DH2NSUqVxCF1KyfIOWuRTrX1aLjus=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261104174118-f94abb95aaef/go.mod h1:2wHG7ntLCG8Tpm/SCfgp524a5emUJm1gAC4KrRYsU9s=
+github.com/klauspost/compress v1.20.1 h1:T7kKElXUMXrUJ2E9QhQhxFtcK5rPyLdsGZvdbLMPdiQ=
+github.com/klauspost/compress v1.20.1/go.mod h1:LUdAzn7YLVvxLpc7y3V1m40wESHTgc1422pwwBSKYuI=
+github.com/nats-io/nats.go v1.54.0 h1:vsXoOxjHp/GmPUN+EcI7uOf/uB+iAP+kEsAFNQN0yzA=
+github.com/nats-io/nats.go v1.54.0/go.mod h1:y+DZoD1oBOYfZTU681eTUiUjI0vbqYGixNVFHcjHJ0k=
+github.com/nats-io/nkeys v0.4.16 h1:rd5oAuLOb8mnAycB0xleuEBNS1pVVnN0fv/FF34Eypg=
+github.com/nats-io/nkeys v0.4.16/go.mod h1:llLgWoI0o4z/Q57q2R1kHfmocyhGV6VG/U18Glg1Afs=
+github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
+github.com/nats-io/nuid v1.0.1/go.mod h1:19wcPz3Ph3q0Jbyiqsd0kePYG7A95tJPxeL+1OSON2c=
+golang.org/x/crypto v0.57.0 h1:3ZVCjf8Ggz7zneR/EHRVx68Ctf+2pmIMP2UFhh9cC6M=
+golang.org/x/crypto v0.57.0/go.mod h1:Fdz0i5U6CoizGwLda9DttjSk6qlZo25zYNtR+ycvuZA=
+golang.org/x/sys v0.48.0 h1:bbX/i/6MgT9BVLM9RT1thmxL04yeTAhbEz4SyadbXoo=
+golang.org/x/sys v0.48.0/go.mod h1:hNLxWAXmnKAxqDtdwIYC4bM9oQPEecfsnNMuSxOs3og=
diff --git a/contracts/module.json b/contracts/module.json
index 4e537386..a239ea00 100644
--- a/contracts/module.json
+++ b/contracts/module.json
@@ -112,6 +112,15 @@
         ],
         "series": "0.1"
       },
+      {
+        "name": "go-meshcatalogclient",
+        "kind": "package",
+        "language": "go",
+        "paths": [
+          "go/clients/meshcatalogclient"
+        ],
+        "series": "0.1"
+      },
       {
         "name": "go-meshdeliverycheckerclient",
         "kind": "package",
diff --git a/modules/mesh-delivery-builder/builds/builds.go b/modules/mesh-delivery-builder/builds/builds.go
index 26e0973c..b52b676d 100644
--- a/modules/mesh-delivery-builder/builds/builds.go
+++ b/modules/mesh-delivery-builder/builds/builds.go
@@ -11,12 +11,12 @@ import (
 	"slices"
 	"strings"
 
+	"git.novox.be/novox/mesh-delivery/contracts/go/clients/containerimageregistryclient/reference"
+	"git.novox.be/novox/mesh-delivery/contracts/go/clients/meshcatalogclient"
 	"git.novox.be/novox/mesh-delivery/contracts/go/seats/containerimageregistry"
 	"git.novox.be/novox/mesh-delivery/contracts/go/seats/ociartifactregistry"
 	"git.novox.be/novox/mesh-delivery/sdk/buildstep"
-	"git.novox.be/novox/mesh-delivery/sdk/fingerprint"
 	"git.novox.be/novox/mesh-delivery/sdk/kept"
-	"git.novox.be/novox/mesh-delivery/sdk/reference"
 	"git.novox.be/novox/mesh-delivery/sdk/trunk"
 	"git.novox.be/novox/mesh-sdk/go/keys"
 )
@@ -62,13 +62,13 @@ const (
 )
 
 // BuilderBuildKey is the key, in BuilderBuildsBucket, of a module's build at a fingerprint: `<module>.<hex>`, the hex
-// being the fingerprint's key part (fingerprint.KeyPart), since a bus key may not hold ':'. A module holding a dot or a
+// being the fingerprint's key part (meshcatalogclient.KeyPart), since a bus key may not hold ':'. A module holding a dot or a
 // character a key refuses, and a fingerprint not of the new form, are refused, naming them.
 func BuilderBuildKey(module, fp string) (string, error) {
 	if err := keys.CheckName("module", module); err != nil {
 		return "", err
 	}
-	part, err := fingerprint.KeyPart(fp)
+	part, err := meshcatalogclient.KeyPart(fp)
 	if err != nil {
 		return "", err
 	}
@@ -84,7 +84,7 @@ func ParseBuilderBuildKey(key string) (module, fp string, err error) {
 	if err := keys.CheckName("module", module); err != nil {
 		return "", "", fmt.Errorf("builds: %q is not a builder build key: %w", key, err)
 	}
-	if fp, err = fingerprint.ParseKeyPart(part); err != nil {
+	if fp, err = meshcatalogclient.ParseKeyPart(part); err != nil {
 		return "", "", fmt.Errorf("builds: %q is not a builder build key: %w", key, err)
 	}
 	return module, fp, nil
diff --git a/modules/mesh-delivery-builder/builds/go.mod b/modules/mesh-delivery-builder/builds/go.mod
index 8fc38072..4eb84be8 100644
--- a/modules/mesh-delivery-builder/builds/go.mod
+++ b/modules/mesh-delivery-builder/builds/go.mod
@@ -3,6 +3,8 @@ module git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/builds
 go 1.26.0
 
 require (
+	git.novox.be/novox/mesh-delivery/contracts/go/clients/containerimageregistryclient v0.0.0
+	git.novox.be/novox/mesh-delivery/contracts/go/clients/meshcatalogclient v0.0.0
 	git.novox.be/novox/mesh-delivery/contracts/go/seats/containerimageregistry v0.0.0
 	git.novox.be/novox/mesh-delivery/contracts/go/seats/ociartifactregistry v0.0.0
 	git.novox.be/novox/mesh-delivery/sdk v0.0.0

From ccef33ef317c988bac75a4cea6ca1690e7590426 Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Thu, 5 Nov 2026 14:47:16 +0100
Subject: [PATCH 3/5] =?UTF-8?q?mesh-delivery-contracts:=20the=20client=20o?=
 =?UTF-8?q?f=20mesh-delivery=20(heads=20hash,=20merge=20ask=20key,=20ask?=
 =?UTF-8?q?=20id,=20owed=20acts=20and=20keys,=20owed=20values)=20and=20the?=
 =?UTF-8?q?=20checker=20client's=20preview=20rules=20(D-27,=20ADR=200625?=
 =?UTF-8?q?=20=C2=A74,=20ADR=200635=20=C2=A75;=20issue=201966)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Claude-Session: https://claude.ai/code/session_01NcbgfFSnn24M3GcqttoU7i
---
 .../meshdeliverycheckerclient/client.go       |  58 ++++
 .../meshdeliverycheckerclient/client_test.go  |  46 +++
 .../go/clients/meshdeliveryclient/client.go   | 323 ++++++++++++++++++
 .../clients/meshdeliveryclient/client_test.go |  91 +++++
 .../go/clients/meshdeliveryclient/go.mod      |  17 +
 .../go/clients/meshdeliveryclient/go.sum      |  18 +
 contracts/module.json                         |   9 +
 7 files changed, 562 insertions(+)
 create mode 100644 contracts/go/clients/meshdeliveryclient/client.go
 create mode 100644 contracts/go/clients/meshdeliveryclient/client_test.go
 create mode 100644 contracts/go/clients/meshdeliveryclient/go.mod
 create mode 100644 contracts/go/clients/meshdeliveryclient/go.sum

diff --git a/contracts/go/clients/meshdeliverycheckerclient/client.go b/contracts/go/clients/meshdeliverycheckerclient/client.go
index 80915d61..c7d75a2e 100644
--- a/contracts/go/clients/meshdeliverycheckerclient/client.go
+++ b/contracts/go/clients/meshdeliverycheckerclient/client.go
@@ -6,6 +6,7 @@ package meshdeliverycheckerclient
 
 import (
 	"fmt"
+	pathpkg "path"
 	"strings"
 
 	checker "git.novox.be/novox/mesh-delivery/contracts/go/seats/meshdeliverychecker"
@@ -220,3 +221,60 @@ func CheckKept(k checker.KeptByLevelDigestValue) error {
 	}
 	return nil
 }
+
+// CheckPreview refuses a preview a reader could not place (the checker writes it, the indexer reads it for the candidates'
+// fingerprints): a repository, head or trunk commit that does not key, a head in conflict that names no file or has a merge
+// commit or modules, a head that merged and names no merge commit, and a module with no directory, no tree, a manifest
+// digest that is not 64 lowercase hex digits, a lock without path or hash, or a named path that is not clean and inside the
+// module's directory or names no git object.
+func CheckPreview(p checker.PreviewsByRepositoryHeadTrunkValue) error {
+	const who = "meshdeliverycheckerclient: "
+	if err := CheckRepository(p.Repository); err != nil {
+		return err
+	}
+	if err := keys.CheckName("head", p.Head); err != nil {
+		return fmt.Errorf(who+"the preview: %w", err)
+	}
+	if err := keys.CheckName("trunk commit", p.Trunk); err != nil {
+		return fmt.Errorf(who+"the preview: %w", err)
+	}
+	for _, f := range p.Conflicts {
+		if f == "" {
+			return fmt.Errorf(who + "a preview names a conflicting file with an empty path")
+		}
+	}
+	if len(p.Conflicts) > 0 {
+		if p.Merge != "" || len(p.Modules) > 0 {
+			return fmt.Errorf(who + "a preview of a head in conflict has no merge commit and no modules")
+		}
+		return nil
+	}
+	if p.Merge == "" {
+		return fmt.Errorf(who + "a preview names no merge commit")
+	}
+	for dir, m := range p.Modules {
+		if dir == "" {
+			return fmt.Errorf(who + "a preview names a module with an empty directory")
+		}
+		if m.Tree == "" {
+			return fmt.Errorf(who+"the preview's module %q has no tree", dir)
+		}
+		if !keys.IsHex64(m.Manifest) {
+			return fmt.Errorf(who+"the preview's module %q: %q is not a manifest digest, 64 lowercase hex digits", dir, m.Manifest)
+		}
+		for path, hash := range m.Locks {
+			if path == "" || hash == "" {
+				return fmt.Errorf(who+"the lock %q of the preview's module %q has an empty path or hash", path, dir)
+			}
+		}
+		for p, object := range m.Paths {
+			if p == "" || p != pathpkg.Clean(p) || strings.HasPrefix(p, "/") || p == ".." || strings.HasPrefix(p, "../") {
+				return fmt.Errorf(who+"the preview's module %q: the named path %q is not a clean path inside the module's directory", dir, p)
+			}
+			if object == "" {
+				return fmt.Errorf(who+"the preview's module %q: the named path %q names no git object", dir, p)
+			}
+		}
+	}
+	return nil
+}
diff --git a/contracts/go/clients/meshdeliverycheckerclient/client_test.go b/contracts/go/clients/meshdeliverycheckerclient/client_test.go
index 062efc25..04191ae5 100644
--- a/contracts/go/clients/meshdeliverycheckerclient/client_test.go
+++ b/contracts/go/clients/meshdeliverycheckerclient/client_test.go
@@ -59,6 +59,7 @@ func TestAVerdictIsRefusedForWhatAReaderCouldNotPlace(t *testing.T) {
 }
 
 func TestAKeptVerdictIsAPassOfAPackageAtALevel(t *testing.T) {
+	t.Run("a preview is refused for what a reader of candidates could not place", previewIsRefused)
 	ok := checker.KeptByLevelDigestValue{State: VerdictPass, Repository: "novox/mesh-sdk", Package: "./go/keys", Level: LevelUnit, Toolchain: "1.26.0", At: "2026-11-05T10:00:00Z"}
 	if err := CheckKept(ok); err != nil {
 		t.Fatalf("a kept pass is refused: %v", err)
@@ -79,3 +80,48 @@ func TestAKeptVerdictIsAPassOfAPackageAtALevel(t *testing.T) {
 		}
 	}
 }
+
+// A preview is refused for what a reader of candidates could not place.
+func previewIsRefused(t *testing.T) {
+	good := func() checker.PreviewsByRepositoryHeadTrunkValue {
+		return checker.PreviewsByRepositoryHeadTrunkValue{Repository: "novox/a", Head: "h1", Trunk: "t1", Merge: "m1",
+			Modules: map[string]checker.PreviewsByRepositoryHeadTrunkValueModulesValue{"mod": {Tree: "tr", Manifest: strings.Repeat("a", 64),
+				Locks: map[string]string{"go.sum": "x"}, Paths: map[string]string{"src": "o1"}}}}
+	}
+	if err := CheckPreview(good()); err != nil {
+		t.Fatalf("a good preview is refused: %v", err)
+	}
+	for name, c := range map[string]struct {
+		edit func(*checker.PreviewsByRepositoryHeadTrunkValue)
+		says string
+	}{
+		"a repository with no owner": {func(p *checker.PreviewsByRepositoryHeadTrunkValue) { p.Repository = "a" }, "<owner>/<name>"},
+		"a head with a dot":          {func(p *checker.PreviewsByRepositoryHeadTrunkValue) { p.Head = "h.1" }, "head"},
+		"a conflict with a merge":    {func(p *checker.PreviewsByRepositoryHeadTrunkValue) { p.Conflicts = []string{"f"} }, "in conflict"},
+		"no merge commit":            {func(p *checker.PreviewsByRepositoryHeadTrunkValue) { p.Merge = "" }, "no merge commit"},
+		"a module with no tree": {func(p *checker.PreviewsByRepositoryHeadTrunkValue) {
+			m := p.Modules["mod"]
+			m.Tree = ""
+			p.Modules["mod"] = m
+		}, "no tree"},
+		"a short manifest digest": {func(p *checker.PreviewsByRepositoryHeadTrunkValue) {
+			m := p.Modules["mod"]
+			m.Manifest = "abc"
+			p.Modules["mod"] = m
+		}, "manifest digest"},
+		"a path outside the module": {func(p *checker.PreviewsByRepositoryHeadTrunkValue) {
+			m := p.Modules["mod"]
+			m.Paths = map[string]string{"../x": "o"}
+			p.Modules["mod"] = m
+		}, "clean path"},
+	} {
+		p := good()
+		c.edit(&p)
+		if err := CheckPreview(p); err == nil || !strings.Contains(err.Error(), c.says) {
+			t.Errorf("%s: CheckPreview = %v, want it to say %q", name, err, c.says)
+		}
+	}
+	if err := CheckPreview(checker.PreviewsByRepositoryHeadTrunkValue{Repository: "novox/a", Head: "h", Trunk: "t", Conflicts: []string{"f"}}); err != nil {
+		t.Errorf("a head in conflict is refused: %v", err)
+	}
+}
diff --git a/contracts/go/clients/meshdeliveryclient/client.go b/contracts/go/clients/meshdeliveryclient/client.go
new file mode 100644
index 00000000..5754e183
--- /dev/null
+++ b/contracts/go/clients/meshdeliveryclient/client.go
@@ -0,0 +1,323 @@
+// Package meshdeliveryclient holds the logic the holders and callers of the seat mesh-delivery share over its contract
+// (novox/hq ADR 0625 §4, ADR 0634 §2, ADR 0635 §5): the keys of its states `merges`, `asks` and `owed` and the rules their
+// values keep, the id the teller gives the router for an ask, and the act an ask's options bind. The gate writes them, the
+// forge bridge, the teller and the assigner read them; the contract's decoding is strict by schema only, so these rules are
+// written once here and no caller copies them.
+package meshdeliveryclient
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+
+	seat "git.novox.be/novox/mesh-delivery/contracts/go/seats/meshdelivery"
+	"git.novox.be/novox/mesh-sdk/go/keys"
+)
+
+// AskKindMerge is the kind of the gate's ask for a group's merge, the first part of its key.
+const AskKindMerge = "merge"
+
+// VerbMerge is the act an ask for a group's merge binds in its options, `mesh-delivery.merge` (Approve).
+const VerbMerge = "merge"
+
+// Head is one pull request at one commit: the repository as `<owner>/<name>` and the full sha.
+type Head struct {
+	Repository string `json:"repository"`
+	Number     int    `json:"number"`
+	Head       string `json:"head"`
+}
+
+// HeadsHash is the first 12 hex digits of the sha256 over the lines `<repository>#<number>=<head>`, sorted and joined by a
+// newline: the same for every order of heads, different when any head changes. An empty list is refused.
+func HeadsHash(heads []Head) (string, error) {
+	if len(heads) == 0 {
+		return "", fmt.Errorf("meshdeliveryclient: a heads hash needs at least one pull request")
+	}
+	lines := make([]string, len(heads))
+	for i, h := range heads {
+		lines[i] = fmt.Sprintf("%s#%d=%s", h.Repository, h.Number, h.Head)
+	}
+	sort.Strings(lines)
+	sum := sha256.Sum256([]byte(strings.Join(lines, "\n")))
+	return hex.EncodeToString(sum[:])[:12], nil
+}
+
+var hashOK = regexp.MustCompile(`^[0-9a-f]{12}$`)
+
+func groupKey(group string) (string, error) {
+	if group == "" {
+		return "", fmt.Errorf("meshdeliveryclient: the group name is empty")
+	}
+	return keys.EscapeName(group), nil
+}
+
+// MergesKey is the key, in the state merges, of a group: `<group>`, escaped so a branch such as `fix/1.2` keys.
+func MergesKey(group string) (string, error) { return groupKey(group) }
+
+// MergeAskKey is the key, in the state asks, of the ask for merging a group at these heads: `merge.<group>.<heads hash>`.
+// The teller's answer has the same key.
+func MergeAskKey(group string, heads []Head) (string, error) {
+	part, err := groupKey(group)
+	if err != nil {
+		return "", err
+	}
+	hash, err := HeadsHash(heads)
+	if err != nil {
+		return "", err
+	}
+	return AskKindMerge + "." + part + "." + hash, nil
+}
+
+// ParseAskKey is the inverse of MergeAskKey: the kind, the group and the heads hash.
+func ParseAskKey(key string) (kind, group, hash string, err error) {
+	parts := strings.Split(key, ".")
+	if len(parts) != 3 || parts[0] != AskKindMerge {
+		return "", "", "", fmt.Errorf("meshdeliveryclient: %q is not an ask key, merge.<group>.<heads hash>", key)
+	}
+	if parts[1] == "" {
+		return "", "", "", fmt.Errorf("meshdeliveryclient: %q is not an ask key: the group name is empty", key)
+	}
+	if group, err = keys.UnescapeName(parts[1]); err != nil {
+		return "", "", "", fmt.Errorf("meshdeliveryclient: %q is not an ask key: %w", key, err)
+	}
+	if !hashOK.MatchString(parts[2]) {
+		return "", "", "", fmt.Errorf("meshdeliveryclient: %q is not an ask key: %q is not 12 hex digits", key, parts[2])
+	}
+	return parts[0], group, parts[2], nil
+}
+
+// SettleGroupPrefix begins the group of a settle ask (novox/hq ADR 0556 clause 5): a person's ask to settle deliveries held
+// because their merge reached the trunk without a passing check. It is kept in the asks under MergeAskKey like a merge ask,
+// so the teller carries it unchanged. Git forbids a colon in a branch name, so no pull request's group ever begins with it.
+const SettleGroupPrefix = "settle:"
+
+// SettleGroup is the group of the settle ask of these delivery ids: the prefix and twelve hex digits of the sha256 over the
+// ids, sorted and joined by a newline, so the same deliveries asked again keep one key.
+func SettleGroup(ids []string) string {
+	sorted := append([]string(nil), ids...)
+	sort.Strings(sorted)
+	sum := sha256.Sum256([]byte(strings.Join(sorted, "\n")))
+	return SettleGroupPrefix + hex.EncodeToString(sum[:])[:12]
+}
+
+// AskVerb is the act the options of an ask bind, by its group: a settle ask's `mesh-delivery.settle`, any other
+// `mesh-delivery.merge`. The gate composes the act with it and the teller checks a warrant against it.
+func AskVerb(group string) string {
+	if strings.HasPrefix(group, SettleGroupPrefix) {
+		return seat.Seat + "." + seat.VerbSettle
+	}
+	return seat.Seat + "." + VerbMerge
+}
+
+// AskID is the id the teller gives the router for the ask at askKey. The router's ids refuse dots, so in the readable part a
+// dot becomes `-` and any other byte outside letters, digits, `_` and `-` becomes `_`; that part is cut to fit, and every id
+// ends in `-` and the first 12 hex digits of the sha256 of the whole key, so two keys never give one id. It cannot be read
+// back: the teller keeps the key beside it.
+func AskID(askKey string) string {
+	const most = 64 // the router's bound on an id
+	const tail = 13 // "-" and 12 hex digits
+	readable := []byte(askKey)
+	for i, c := range readable {
+		switch {
+		case c >= 'A' && c <= 'Z', c >= 'a' && c <= 'z', c >= '0' && c <= '9':
+		case c == '.':
+			readable[i] = '-'
+		default: // a slash, an equals sign or any other byte the router's id refuses
+			readable[i] = '_'
+		}
+	}
+	if len(readable) > 0 && (readable[0] == '-' || readable[0] == '_') {
+		readable[0] = 'k' // an id starts with a letter or digit
+	}
+	if len(readable) > most-tail {
+		readable = readable[:most-tail]
+	}
+	sum := sha256.Sum256([]byte(askKey))
+	return string(readable) + "-" + hex.EncodeToString(sum[:])[:12]
+}
+
+// AskingID is the id of the asking-th writing of the ask at askKey. Asking 0 and 1 give AskID(askKey), so the first asking's
+// id is unchanged; asking n of 2 or more gives the AskID form of askKey + "." + n, so each asking has an id of its own and the
+// router, which drops an ask under an id it keeps as a redelivery, takes each as new and an answer to an earlier asking is
+// never taken for a later one.
+func AskingID(askKey string, asking int) string {
+	if asking < 2 {
+		return AskID(askKey)
+	}
+	return AskID(askKey + "." + strconv.Itoa(asking))
+}
+
+// The acts the gate owes the forge, the last part of an owed key.
+const (
+	OwedStatus  = "status"
+	OwedView    = "view"
+	OwedNote    = "note"
+	OwedComment = "comment"
+)
+
+// The status contexts the mesh owes the forge.
+const (
+	StatusContextMergeGate     = "mesh/merge-gate"
+	StatusContextDelivery      = "mesh/delivery"
+	StatusContextDeliveryGroup = "mesh/delivery-group"
+	StatusContextRepoCheck     = "mesh/repo-check"
+	StatusContextCheck         = "mesh/check"
+)
+
+var statusContexts = []string{StatusContextMergeGate, StatusContextDelivery, StatusContextDeliveryGroup, StatusContextRepoCheck, StatusContextCheck}
+
+// StatusContexts is the contexts, in a new slice.
+func StatusContexts() []string { return append([]string(nil), statusContexts...) }
+
+// The states a status the gate owes the forge may carry.
+var statusStates = []string{"pending", "success", "failure", "error", "warning"}
+
+func checkStatusContext(context string) error {
+	for _, c := range statusContexts {
+		if context == c {
+			return nil
+		}
+	}
+	return fmt.Errorf("meshdeliveryclient: the status context %q is not one of %s", context, strings.Join(statusContexts, ", "))
+}
+
+// ParseOwedAct splits an owed act into its kind and, for a status, its context, for a comment its sequence as digits. The act
+// is `status=<context>`, `view`, `note` or `comment.<seq>`.
+func ParseOwedAct(act string) (kind, context string, err error) {
+	kind, context, hasContext := strings.Cut(act, "=")
+	switch kind {
+	case OwedStatus:
+		if !hasContext {
+			return "", "", fmt.Errorf("meshdeliveryclient: the owed act %q is a status without its context, status=<context>", act)
+		}
+		if err := checkStatusContext(context); err != nil {
+			return "", "", err
+		}
+		return kind, context, nil
+	case OwedView, OwedNote:
+		if hasContext {
+			return "", "", fmt.Errorf("meshdeliveryclient: the owed act %q takes no context", act)
+		}
+		return kind, "", nil
+	}
+	if kind, seq, ok := strings.Cut(act, "."); ok && kind == OwedComment {
+		if n, err := strconv.Atoi(seq); err != nil || n < 1 || strconv.Itoa(n) != seq {
+			return "", "", fmt.Errorf("meshdeliveryclient: the owed act %q is a comment without its sequence, comment.<seq> with seq of 1 or more", act)
+		}
+		return OwedComment, seq, nil
+	}
+	return "", "", fmt.Errorf("meshdeliveryclient: the owed act %q is not status=<context>, view, note or comment.<seq>", act)
+}
+
+// OwedCommentAct is the act of the seq-th comment on a head: `comment.<seq>`, seq of 1 or more, so a second comment has a key
+// of its own and does not overwrite the first.
+func OwedCommentAct(seq int) (string, error) {
+	if seq < 1 {
+		return "", fmt.Errorf("meshdeliveryclient: a comment's sequence is 1 or more, not %d", seq)
+	}
+	return OwedComment + "." + strconv.Itoa(seq), nil
+}
+
+func escapeRepository(repository string) (string, error) {
+	owner, name, ok := strings.Cut(repository, "/")
+	if !ok || owner == "" || name == "" || strings.Contains(name, "/") {
+		return "", fmt.Errorf("meshdeliveryclient: the repository %q is not <owner>/<name>, with exactly one slash", repository)
+	}
+	return keys.EscapeName(owner) + "/" + keys.EscapeName(name), nil
+}
+
+func unescapeRepository(part string) (string, error) {
+	owner, name, ok := strings.Cut(part, "/")
+	if !ok || owner == "" || name == "" || strings.Contains(name, "/") {
+		return "", fmt.Errorf("meshdeliveryclient: the repository %q is not <owner>/<name>, with exactly one slash", part)
+	}
+	o, err := keys.UnescapeName(owner)
+	if err != nil {
+		return "", err
+	}
+	n, err := keys.UnescapeName(name)
+	if err != nil {
+		return "", err
+	}
+	return o + "/" + n, nil
+}
+
+// OwedKey is the key, in the state owed, of an act the gate owes the forge on a pull request at a head:
+// `<repository>.<number>.<head>.<act>`. The number is 0 for a commit no pull request names, and never negative.
+func OwedKey(repository string, number int, head, act string) (string, error) {
+	repo, err := escapeRepository(repository)
+	if err != nil {
+		return "", err
+	}
+	if number < 0 {
+		return "", fmt.Errorf("meshdeliveryclient: an owed key's pull request number is 0 (none) or more, not %d", number)
+	}
+	if err := keys.CheckName("head", head); err != nil {
+		return "", err
+	}
+	if _, _, err := ParseOwedAct(act); err != nil {
+		return "", err
+	}
+	return repo + "." + strconv.Itoa(number) + "." + head + "." + act, nil
+}
+
+// ParseOwedKey is the inverse of OwedKey; act is whole, as `status=<context>` for a status.
+func ParseOwedKey(key string) (repository string, number int, head, act string, err error) {
+	parts := strings.SplitN(key, ".", 4) // a comment's act holds a dot
+	if len(parts) != 4 {
+		return "", 0, "", "", fmt.Errorf("meshdeliveryclient: %q is not an owed key, <repository>.<number>.<head>.<act>", key)
+	}
+	number, convErr := strconv.Atoi(parts[1])
+	if convErr != nil {
+		return "", 0, "", "", fmt.Errorf("meshdeliveryclient: %q is not an owed key: %q is not a pull request number", key, parts[1])
+	}
+	if repository, err = unescapeRepository(parts[0]); err != nil {
+		return "", 0, "", "", fmt.Errorf("meshdeliveryclient: %q is not an owed key: %w", key, err)
+	}
+	if _, err := OwedKey(repository, number, parts[2], parts[3]); err != nil {
+		return "", 0, "", "", fmt.Errorf("meshdeliveryclient: %q is not an owed key: %w", key, err)
+	}
+	return repository, number, parts[2], parts[3], nil
+}
+
+// CheckOwed refuses an owed value the forge bridge could not perform: a status needs its context (one the mesh owes), a
+// state of the list and a target; a view and a comment need text; a note needs text and a ref.
+func CheckOwed(o seat.OwedByRepositoryNumberHeadActValue) error {
+	const who = "meshdeliveryclient: "
+	switch o.Act {
+	case OwedStatus:
+		if o.Context == "" {
+			return fmt.Errorf(who + "an owed status has no context")
+		}
+		if err := checkStatusContext(o.Context); err != nil {
+			return err
+		}
+		if o.Target == "" {
+			return fmt.Errorf(who + "an owed status has no target")
+		}
+		for _, s := range statusStates {
+			if o.State == s {
+				return nil
+			}
+		}
+		return fmt.Errorf(who+"the owed status state %q is not %s", o.State, strings.Join(statusStates, ", "))
+	case OwedView, OwedComment:
+		if o.Text == "" {
+			return fmt.Errorf(who+"an owed %s has no text", o.Act)
+		}
+	case OwedNote:
+		if o.Text == "" {
+			return fmt.Errorf(who + "an owed note has no text")
+		}
+		if o.Ref == "" {
+			return fmt.Errorf(who + "an owed note has no ref")
+		}
+	default:
+		return fmt.Errorf(who+"the owed act %q is not status, view, note or comment", o.Act)
+	}
+	return nil
+}
diff --git a/contracts/go/clients/meshdeliveryclient/client_test.go b/contracts/go/clients/meshdeliveryclient/client_test.go
new file mode 100644
index 00000000..71cf9ad1
--- /dev/null
+++ b/contracts/go/clients/meshdeliveryclient/client_test.go
@@ -0,0 +1,91 @@
+package meshdeliveryclient
+
+import (
+	"strings"
+	"testing"
+
+	seat "git.novox.be/novox/mesh-delivery/contracts/go/seats/meshdelivery"
+)
+
+// The keys, ids and acts equal what the gate and the teller have always written (the expected strings are the trunk's own
+// output for the same input), so a value written before is read after.
+func TestTheAsksAndOwedActsKeepTheirFormsAndRules(t *testing.T) {
+	heads := []Head{{Repository: "novox/a", Number: 3, Head: "abc"}, {Repository: "novox/b", Number: 1, Head: "def"}}
+	key, err := MergeAskKey("fix/1.2", heads)
+	if err != nil || key != "merge.fix/1=2e2.d106c7950d28" {
+		t.Fatalf("MergeAskKey = %q, %v", key, err)
+	}
+	if rev, _ := MergeAskKey("fix/1.2", []Head{heads[1], heads[0]}); rev != key {
+		t.Errorf("the heads' order changes the key: %q", rev)
+	}
+	if kind, group, hash, err := ParseAskKey(key); err != nil || kind != "merge" || group != "fix/1.2" || hash != "d106c7950d28" {
+		t.Errorf("ParseAskKey = %q %q %q %v", kind, group, hash, err)
+	}
+	for _, bad := range []string{"merge.g", "settle.g.d106c7950d28", "merge..d106c7950d28", "merge.g.D106C7950D28", "merge.g.d106"} {
+		if _, _, _, err := ParseAskKey(bad); err == nil {
+			t.Errorf("ParseAskKey(%q) reads a wrong key", bad)
+		}
+	}
+	if _, err := MergeAskKey("", heads); err == nil {
+		t.Error("an empty group keys")
+	}
+	if _, err := MergeAskKey("g", nil); err == nil {
+		t.Error("no heads keys")
+	}
+	if id := AskID(key); id != "merge-fix_1_2e2-d106c7950d28-400030402c88" || AskingID(key, 1) != id || AskingID(key, 0) != id {
+		t.Errorf("AskID = %q", id)
+	}
+	if id := AskingID(key, 3); id != "merge-fix_1_2e2-d106c7950d28-3-ea06879e48d8" || len(id) > 64 {
+		t.Errorf("AskingID(3) = %q", id)
+	}
+	if g := SettleGroup([]string{"b", "a"}); g != "settle:7e18f737311b" || g != SettleGroup([]string{"a", "b"}) {
+		t.Errorf("SettleGroup = %q", g)
+	}
+	if AskVerb(SettleGroup([]string{"a"})) != "mesh-delivery.settle" || AskVerb("fix/1") != "mesh-delivery.merge" {
+		t.Error("AskVerb binds the wrong act")
+	}
+
+	for act, want := range map[string]string{"status=mesh/check": "novox/a.3.abc.status=mesh/check", "view": "novox/a.3.abc.view", "comment.2": "novox/a.3.abc.comment.2"} {
+		k, err := OwedKey("novox/a", 3, "abc", act)
+		if err != nil || k != want {
+			t.Errorf("OwedKey(%q) = %q, %v", act, k, err)
+		}
+		if repo, n, head, a, err := ParseOwedKey(k); err != nil || repo != "novox/a" || n != 3 || head != "abc" || a != act {
+			t.Errorf("ParseOwedKey(%q) = %q %d %q %q %v", k, repo, n, head, a, err)
+		}
+	}
+	for _, act := range []string{"status", "status=mesh/other", "view=x", "comment", "comment.0", "comment.01", "other"} {
+		if _, err := OwedKey("novox/a", 3, "abc", act); err == nil {
+			t.Errorf("OwedKey takes the act %q", act)
+		}
+	}
+	if _, err := OwedKey("novox", 0, "abc", "view"); err == nil {
+		t.Error("a repository with no slash keys")
+	}
+	if _, err := OwedKey("novox/a", -1, "abc", "view"); err == nil {
+		t.Error("a negative number keys")
+	}
+	if act, err := OwedCommentAct(2); err != nil || act != "comment.2" {
+		t.Errorf("OwedCommentAct = %q, %v", act, err)
+	}
+
+	type owed = seat.OwedByRepositoryNumberHeadActValue
+	for name, c := range map[string]struct {
+		v    owed
+		says string
+	}{
+		"a good status":        {owed{Act: "status", Context: StatusContextCheck, Target: "http://x", State: "success"}, ""},
+		"a good note":          {owed{Act: "note", Text: "t", Ref: "mesh-plan"}, ""},
+		"a status no target":   {owed{Act: "status", Context: StatusContextCheck, State: "success"}, "no target"},
+		"a status wrong state": {owed{Act: "status", Context: StatusContextCheck, Target: "x", State: "done"}, "state"},
+		"a status no context":  {owed{Act: "status", Target: "x", State: "success"}, "no context"},
+		"a view no text":       {owed{Act: "view"}, "no text"},
+		"a note no ref":        {owed{Act: "note", Text: "t"}, "no ref"},
+		"an unknown act":       {owed{Act: "merge"}, "not status"},
+	} {
+		err := CheckOwed(c.v)
+		if (c.says == "") != (err == nil) || (err != nil && !strings.Contains(err.Error(), c.says)) {
+			t.Errorf("%s: CheckOwed = %v, want %q", name, err, c.says)
+		}
+	}
+}
diff --git a/contracts/go/clients/meshdeliveryclient/go.mod b/contracts/go/clients/meshdeliveryclient/go.mod
new file mode 100644
index 00000000..975c6294
--- /dev/null
+++ b/contracts/go/clients/meshdeliveryclient/go.mod
@@ -0,0 +1,17 @@
+module git.novox.be/novox/mesh-delivery/contracts/go/clients/meshdeliveryclient
+
+go 1.26.0
+
+require (
+	git.novox.be/novox/mesh-delivery/contracts/go/seats/meshdelivery v0.0.0
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261104174118-f94abb95aaef
+)
+
+require (
+	github.com/klauspost/compress v1.20.1 // indirect
+	github.com/nats-io/nats.go v1.54.0 // indirect
+	github.com/nats-io/nkeys v0.4.16 // indirect
+	github.com/nats-io/nuid v1.0.1 // indirect
+	golang.org/x/crypto v0.57.0 // indirect
+	golang.org/x/sys v0.48.0 // indirect
+)
diff --git a/contracts/go/clients/meshdeliveryclient/go.sum b/contracts/go/clients/meshdeliveryclient/go.sum
new file mode 100644
index 00000000..c811fda7
--- /dev/null
+++ b/contracts/go/clients/meshdeliveryclient/go.sum
@@ -0,0 +1,18 @@
+git.novox.be/novox/mesh-contracts/go v0.0.0-20261104172218-347a3053580a h1:E9ERPqR4uZXypudHGxv2/wNIOYcder9torVqJwJq/DI=
+git.novox.be/novox/mesh-contracts/go v0.0.0-20261104172218-347a3053580a/go.mod h1:0dD1XEJBJ0G5UYDQxSZI84nuujb6m3tOpJl4C8rQVvg=
+git.novox.be/novox/mesh-delivery/contracts/go/seats/containerimageregistry v0.0.0-20261105000000-000000000000 h1:BTqpa7dCCTQH9m08Jle8KVFwyIHiHPSUbwWxuqSg2yA=
+git.novox.be/novox/mesh-delivery/contracts/go/seats/containerimageregistry v0.0.0-20261105000000-000000000000/go.mod h1:pPxwhTMb3hIk7UUrBicJnGQCqfTEoBGJvNFspEK2U18=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261104174118-f94abb95aaef h1:/Jic5ho0xz32Z9DH2NSUqVxCF1KyfIOWuRTrX1aLjus=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261104174118-f94abb95aaef/go.mod h1:2wHG7ntLCG8Tpm/SCfgp524a5emUJm1gAC4KrRYsU9s=
+github.com/klauspost/compress v1.20.1 h1:T7kKElXUMXrUJ2E9QhQhxFtcK5rPyLdsGZvdbLMPdiQ=
+github.com/klauspost/compress v1.20.1/go.mod h1:LUdAzn7YLVvxLpc7y3V1m40wESHTgc1422pwwBSKYuI=
+github.com/nats-io/nats.go v1.54.0 h1:vsXoOxjHp/GmPUN+EcI7uOf/uB+iAP+kEsAFNQN0yzA=
+github.com/nats-io/nats.go v1.54.0/go.mod h1:y+DZoD1oBOYfZTU681eTUiUjI0vbqYGixNVFHcjHJ0k=
+github.com/nats-io/nkeys v0.4.16 h1:rd5oAuLOb8mnAycB0xleuEBNS1pVVnN0fv/FF34Eypg=
+github.com/nats-io/nkeys v0.4.16/go.mod h1:llLgWoI0o4z/Q57q2R1kHfmocyhGV6VG/U18Glg1Afs=
+github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
+github.com/nats-io/nuid v1.0.1/go.mod h1:19wcPz3Ph3q0Jbyiqsd0kePYG7A95tJPxeL+1OSON2c=
+golang.org/x/crypto v0.57.0 h1:3ZVCjf8Ggz7zneR/EHRVx68Ctf+2pmIMP2UFhh9cC6M=
+golang.org/x/crypto v0.57.0/go.mod h1:Fdz0i5U6CoizGwLda9DttjSk6qlZo25zYNtR+ycvuZA=
+golang.org/x/sys v0.48.0 h1:bbX/i/6MgT9BVLM9RT1thmxL04yeTAhbEz4SyadbXoo=
+golang.org/x/sys v0.48.0/go.mod h1:hNLxWAXmnKAxqDtdwIYC4bM9oQPEecfsnNMuSxOs3og=
diff --git a/contracts/module.json b/contracts/module.json
index a239ea00..d80c383c 100644
--- a/contracts/module.json
+++ b/contracts/module.json
@@ -121,6 +121,15 @@
         ],
         "series": "0.1"
       },
+      {
+        "name": "go-meshdeliveryclient",
+        "kind": "package",
+        "language": "go",
+        "paths": [
+          "go/clients/meshdeliveryclient"
+        ],
+        "series": "0.1"
+      },
       {
         "name": "go-meshdeliverycheckerclient",
         "kind": "package",

From c183f170cc60a0cc73ee58ea45dfa24e4d9a1542 Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Thu, 5 Nov 2026 14:52:26 +0100
Subject: [PATCH 4/5] =?UTF-8?q?mesh-delivery-assigner:=20the=20asks=20pack?=
 =?UTF-8?q?age=20(the=20keys=20of=20its=20asks=20and=20their=20value)=20is?=
 =?UTF-8?q?=20the=20module's=20own,=20a=20package=20artifact;=20the=20view?=
 =?UTF-8?q?'s=20answer=20key=20and=20fit=20in=20viewstate=20(ADR=200634=20?=
 =?UTF-8?q?=C2=A71,=20=C2=A74,=20ADR=200635=20=C2=A75;=20issue=201966)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Claude-Session: https://claude.ai/code/session_01NcbgfFSnn24M3GcqttoU7i
---
 modules/mesh-delivery-assigner/asks/asks.go   | 257 ++++++++++++++++++
 .../mesh-delivery-assigner/asks/asks_test.go  |  85 ++++++
 modules/mesh-delivery-assigner/asks/go.mod    |  13 +
 modules/mesh-delivery-assigner/module.json    |   9 +
 .../mesh-delivery-view/viewstate/answerkey.go |  48 ++++
 modules/mesh-delivery-view/viewstate/go.mod   |   2 +
 .../viewstate/viewstate_test.go               |  28 ++
 7 files changed, 442 insertions(+)
 create mode 100644 modules/mesh-delivery-assigner/asks/asks.go
 create mode 100644 modules/mesh-delivery-assigner/asks/asks_test.go
 create mode 100644 modules/mesh-delivery-assigner/asks/go.mod
 create mode 100644 modules/mesh-delivery-view/viewstate/answerkey.go

diff --git a/modules/mesh-delivery-assigner/asks/asks.go b/modules/mesh-delivery-assigner/asks/asks.go
new file mode 100644
index 00000000..d255408b
--- /dev/null
+++ b/modules/mesh-delivery-assigner/asks/asks.go
@@ -0,0 +1,257 @@
+// Package asks holds the layout of the assigner's state `asks`: the keys of the asks the assigner puts to a person and the
+// value it keeps at each, which the assigner writes and the view and the teller read (novox/hq ADR 0634 §1, ADR 0635 §5). It
+// is the assigner's own published package. The gate's merge ask (`merge.<group>.<heads hash>`) needs proof of who answered
+// (ADR 0421 §1), so it is answered on the phone alone until issue 953 closes. The assigner's asks need no such proof, and the
+// view may answer them: the hold of a fingerprint whose health check failed (`hold.<module>.<fingerprint hex>`: release it or
+// keep it held), the restore of a data module set back (`restore.<node>.<module>.<fingerprint hex>`: restore and lose newer
+// writes, or leave it stopped, ADR 0429 §6), a backup that failed before an apply, a move a person must allow for a module of
+// policy record, and the authorising ask of a proposal of placement.
+package asks
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"git.novox.be/novox/mesh-contracts/go/clients/nodeengineclient"
+	"git.novox.be/novox/mesh-contracts/placement/go/clients/meshmoduleassignerclient"
+	"git.novox.be/novox/mesh-delivery/contracts/go/clients/meshcatalogclient"
+	"git.novox.be/novox/mesh-delivery/contracts/go/clients/meshdeliveryclient"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/builds"
+	"git.novox.be/novox/mesh-delivery/sdk/kept"
+	"git.novox.be/novox/mesh-sdk/go/keys"
+)
+
+const (
+	// AskKindHold is the kind of the assigner's ask about a held fingerprint.
+	AskKindHold = "hold"
+	// AskKindRestore is the kind of the assigner's ask about a data module set back.
+	AskKindRestore = "restore"
+	// AskKindBackup is the kind of the assigner's ask about a backup before an apply that failed: back up again, or go on
+	// without one (novox/hq ADR 0539 clause 16).
+	AskKindBackup = "backup"
+	// AskKindRecord is the kind of the assigner's ask about a move a person must allow, for a module of policy record: a
+	// composition judged to recreate a container or move data, or one that cannot be judged (ADR 0539 clause 14).
+	AskKindRecord = "record"
+	// AskKindPlacement is the kind of the authorising ask about a proposal of placement (novox/hq ADR 0567 §5):
+	// `placement.<proposal id>`. The kind needs no proof, as the bus's put does not: its yes is an Approve, which only a
+	// channel proving who answered takes and the view never does (ViewAnswerFits).
+	AskKindPlacement = "placement"
+)
+
+// AskKey is an ask's key read whole: its Kind, and the parts its kind has: a merge's Group and heads Hash, a hold's Module
+// and fingerprint FP, a restore's and a backup's Node, Module and FP, a record's Node, Module and the digest Composed of the
+// composition it would allow, a placement's Proposal.
+type AskKey struct {
+	Proposal string
+	Kind     string
+	Group    string
+	Hash     string
+	Node     string
+	Module   string
+	FP       string
+	Composed string
+}
+
+// AskNeedsProof says whether an ask of this kind must prove who answered it, so the view may not answer it: the merge's
+// Approve does (ADR 0421 §1, issue 953), the assigner's hold and restore do not. An unknown kind is refused.
+func AskNeedsProof(kind string) (bool, error) {
+	switch kind {
+	case meshdeliveryclient.AskKindMerge:
+		return true, nil
+	case AskKindHold, AskKindRestore, AskKindBackup, AskKindRecord, AskKindPlacement:
+		return false, nil
+	}
+	return false, fmt.Errorf("asks: %q is not a kind of ask, %s, %s, %s, %s, %s or %s", kind, meshdeliveryclient.AskKindMerge, AskKindHold,
+		AskKindRestore, AskKindBackup, AskKindRecord, AskKindPlacement)
+}
+
+// HoldAskKey is the key of the ask about a module's held fingerprint: `hold.<module>.<hex>`.
+func HoldAskKey(module, fingerprint string) (string, error) {
+	key, err := builds.BuilderBuildKey(module, fingerprint)
+	if err != nil {
+		return "", err
+	}
+	return AskKindHold + "." + key, nil
+}
+
+// RestoreAskKey is the key of the ask about a data module set back on a node from a fingerprint:
+// `restore.<node>.<module>.<hex>`.
+func RestoreAskKey(node, module, fingerprint string) (string, error) {
+	if err := keys.CheckName("node", node); err != nil {
+		return "", err
+	}
+	key, err := builds.BuilderBuildKey(module, fingerprint)
+	if err != nil {
+		return "", err
+	}
+	return AskKindRestore + "." + node + "." + key, nil
+}
+
+// BackupAskKey is the key of the ask about a module's failed backup on a node before it applies a fingerprint:
+// `backup.<node>.<module>.<hex>`.
+func BackupAskKey(node, module, fingerprint string) (string, error) {
+	part, err := meshcatalogclient.KeyPart(fingerprint)
+	if err != nil {
+		return "", err
+	}
+	key, err := nodeengineclient.ComposedKey(node, module, part)
+	if err != nil {
+		return "", err
+	}
+	return AskKindBackup + "." + key, nil
+}
+
+// PlacementAskKey is the key of the authorising ask about a proposal of placement: `placement.<proposal id>` (ADR 0567 §5).
+func PlacementAskKey(proposal string) (string, error) {
+	if err := meshmoduleassignerclient.CheckProposalID(proposal); err != nil {
+		return "", err
+	}
+	return AskKindPlacement + "." + proposal, nil
+}
+
+// RecordAskKey is the key of the ask about a move of a module on a node to the composition whose digest it names:
+// `record.<node>.<module>.<digest hex>`, so a new revision at the same fingerprint is asked again (ADR 0539 clause 14).
+func RecordAskKey(node, module, composed string) (string, error) {
+	have, err := nodeengineclient.HaveKey(node, module)
+	if err != nil {
+		return "", err
+	}
+	if err := kept.CheckDigest(composed, "a record ask's composition digest"); err != nil {
+		return "", err
+	}
+	return AskKindRecord + "." + have + "." + strings.TrimPrefix(composed, "sha256:"), nil
+}
+
+// ParseAnyAskKey reads an ask key of any kind (a merge, hold, restore, backup, record or placement ask); it refuses an unknown
+// kind and a key whose parts do not fit its kind, naming the key.
+func ParseAnyAskKey(key string) (AskKey, error) {
+	kind, rest, _ := strings.Cut(key, ".")
+	refused := func(err error) (AskKey, error) {
+		return AskKey{}, fmt.Errorf("asks: %q is not an ask key: %w", key, err)
+	}
+	switch kind {
+	case meshdeliveryclient.AskKindMerge:
+		_, group, hash, err := meshdeliveryclient.ParseAskKey(key)
+		if err != nil {
+			return AskKey{}, err
+		}
+		return AskKey{Kind: kind, Group: group, Hash: hash}, nil
+	case AskKindHold:
+		module, fp, err := builds.ParseBuilderBuildKey(rest)
+		if err != nil {
+			return refused(err)
+		}
+		return AskKey{Kind: kind, Module: module, FP: fp}, nil
+	case AskKindRestore:
+		node, build, ok := strings.Cut(rest, ".")
+		if !ok {
+			return refused(fmt.Errorf("a restore ask is restore.<node>.<module>.<fingerprint hex>"))
+		}
+		if err := keys.CheckName("node", node); err != nil {
+			return refused(err)
+		}
+		module, fp, err := builds.ParseBuilderBuildKey(build)
+		if err != nil {
+			return refused(err)
+		}
+		return AskKey{Kind: kind, Node: node, Module: module, FP: fp}, nil
+	case AskKindBackup:
+		node, module, part, isNode, err := nodeengineclient.ParseComposedKey(rest)
+		if err != nil || isNode {
+			return refused(fmt.Errorf("a backup ask is backup.<node>.<module>.<fingerprint hex>"))
+		}
+		fp, err := meshcatalogclient.ParseKeyPart(part)
+		if err != nil {
+			return refused(err)
+		}
+		return AskKey{Kind: kind, Node: node, Module: module, FP: fp}, nil
+	case AskKindPlacement:
+		if err := meshmoduleassignerclient.CheckProposalID(rest); err != nil {
+			return refused(err)
+		}
+		return AskKey{Kind: kind, Proposal: rest}, nil
+	case AskKindRecord:
+		parts := strings.Split(rest, ".")
+		if len(parts) != 3 {
+			return refused(fmt.Errorf("a record ask is record.<node>.<module>.<digest hex>"))
+		}
+		node, module, isNode, err := nodeengineclient.ParseHaveKey(parts[0] + "." + parts[1])
+		if err != nil || isNode {
+			return refused(fmt.Errorf("a record ask is record.<node>.<module>.<digest hex>"))
+		}
+		composed := "sha256:" + parts[2]
+		if err := kept.CheckDigest(composed, "a record ask's composition digest"); err != nil {
+			return refused(err)
+		}
+		return AskKey{Kind: kind, Node: node, Module: module, Composed: composed}, nil
+	}
+	_, err := AskNeedsProof(kind)
+	return refused(err)
+}
+
+// Ask is the value of a key in the assigner's state asks: the router's ask whole, as the assigner composes it, so the teller
+// publishes it unchanged. Asking counts the times the assigner wrote the ask at this key, as the gate's ask does: 0 or 1 for
+// the first, n for the n-th, and the ask's id is meshdeliveryclient.AskingID(key, Asking), so each asking has its own id and
+// an answer to an earlier asking is never taken for a later one. The ask is the operator-channel seat's as its JSON: its id,
+// its options and its digest are checked by the assigner and the teller through operator-channel's client (novox/hq ADR
+// 0627 §4).
+type Ask struct {
+	V      int             `json:"v"`
+	Ask    json.RawMessage `json:"ask"`
+	Asking int             `json:"asking,omitempty"`
+}
+
+func (a Ask) check(key string) error {
+	ask, err := ParseAnyAskKey(key)
+	if err != nil {
+		return err
+	}
+	if proof, _ := AskNeedsProof(ask.Kind); proof {
+		return fmt.Errorf("asks: the assigner asks no %s ask: it needs proof of who answered", ask.Kind)
+	}
+	if a.Asking < 0 {
+		return fmt.Errorf("asks: the ask's asking %d is negative", a.Asking)
+	}
+	var fields map[string]json.RawMessage
+	if len(bytes.TrimSpace(a.Ask)) == 0 || json.Unmarshal(a.Ask, &fields) != nil || fields == nil {
+		return fmt.Errorf("asks: the value carries no router's ask")
+	}
+	return nil
+}
+
+// EncodeAsk is a, the ask at key, as JSON at keys.Version; it refuses a key of a kind that needs proof or of no kind, a
+// negative asking, and a value carrying no router's ask.
+func EncodeAsk(key string, a Ask) ([]byte, error) {
+	if err := a.check(key); err != nil {
+		return nil, err
+	}
+	a.V = keys.Version
+	return json.Marshal(a)
+}
+
+// DecodeAsk reads the ask at key; it refuses an unknown version (keys.ErrUnknownVersion) and what EncodeAsk refuses.
+func DecodeAsk(key string, data []byte) (Ask, error) {
+	var a Ask
+	if err := kept.Decode(data, &a); err != nil {
+		return Ask{}, err
+	}
+	if err := a.check(key); err != nil {
+		return Ask{}, err
+	}
+	return a, nil
+}
+
+// SameAsk says whether two asks are the same value: the same version, asking and router's ask, its JSON compared compacted.
+func SameAsk(a, b Ask) bool {
+	return a.V == b.V && a.Asking == b.Asking && bytes.Equal(compacted(a.Ask), compacted(b.Ask))
+}
+
+func compacted(raw json.RawMessage) []byte {
+	var b bytes.Buffer
+	if json.Compact(&b, raw) != nil {
+		return raw
+	}
+	return b.Bytes()
+}
diff --git a/modules/mesh-delivery-assigner/asks/asks_test.go b/modules/mesh-delivery-assigner/asks/asks_test.go
new file mode 100644
index 00000000..bfa79231
--- /dev/null
+++ b/modules/mesh-delivery-assigner/asks/asks_test.go
@@ -0,0 +1,85 @@
+package asks
+
+import (
+	"errors"
+	"strings"
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/keys"
+)
+
+// The keys equal what the assigner has always written (the expected strings are the trunk's own output for the same input),
+// and each reads back to its parts.
+func TestTheAssignersAskKeysKeepTheirFormsAndTheValueItsRules(t *testing.T) {
+	fp := "src2:" + strings.Repeat("ab", 32)
+	hex := strings.Repeat("ab", 32)
+	digest := "sha256:" + strings.Repeat("cd", 32)
+	hold, _ := HoldAskKey("gitea", fp)
+	restore, _ := RestoreAskKey("n1", "gitea", fp)
+	backup, _ := BackupAskKey("n1", "novox.be", fp)
+	placement, _ := PlacementAskKey("p-20261028t183000-1a2b3c")
+	record, _ := RecordAskKey("n1", "gitea", digest)
+	for key, want := range map[string]struct {
+		got  string
+		back AskKey
+	}{
+		"hold":      {hold, AskKey{Kind: "hold", Module: "gitea", FP: fp}},
+		"restore":   {restore, AskKey{Kind: "restore", Node: "n1", Module: "gitea", FP: fp}},
+		"backup":    {backup, AskKey{Kind: "backup", Node: "n1", Module: "novox.be", FP: fp}},
+		"placement": {placement, AskKey{Kind: "placement", Proposal: "p-20261028t183000-1a2b3c"}},
+		"record":    {record, AskKey{Kind: "record", Node: "n1", Module: "gitea", Composed: digest}},
+	} {
+		back, err := ParseAnyAskKey(want.got)
+		if err != nil || back != want.back {
+			t.Errorf("%s: ParseAnyAskKey(%q) = %+v, %v; want %+v", key, want.got, back, err, want.back)
+		}
+	}
+	for got, want := range map[string]string{hold: "hold.gitea." + hex, restore: "restore.n1.gitea." + hex, backup: "backup.n1.novox=2ebe." + hex,
+		placement: "placement.p-20261028t183000-1a2b3c", record: "record.n1.gitea." + strings.Repeat("cd", 32)} {
+		if got != want {
+			t.Errorf("key %q, want %q", got, want)
+		}
+	}
+	merge, err := ParseAnyAskKey("merge.fix/1=2e2.d106c7950d28")
+	if err != nil || merge.Kind != "merge" || merge.Group != "fix/1.2" || merge.Hash != "d106c7950d28" {
+		t.Errorf("a merge ask key: %+v, %v", merge, err)
+	}
+	for _, bad := range []string{"", "other.x", "hold.gitea", "hold.gitea.src2:" + hex, "restore.n1", "backup.n1.node", "backup.n1.gitea." + hex[:60],
+		"placement.AB", "record.n1.gitea." + hex[:10], "record.n1.node." + hex, "merge.g"} {
+		if _, err := ParseAnyAskKey(bad); err == nil {
+			t.Errorf("ParseAnyAskKey(%q) reads a wrong key", bad)
+		}
+	}
+	if proof, err := AskNeedsProof("merge"); err != nil || !proof {
+		t.Error("a merge ask needs proof")
+	}
+	if proof, err := AskNeedsProof("hold"); err != nil || proof {
+		t.Error("a hold ask needs no proof")
+	}
+	if _, err := AskNeedsProof("view"); err == nil {
+		t.Error("an unknown kind of ask is taken")
+	}
+
+	// The value: the router's ask whole; an ask of a kind that needs proof, a negative asking and no ask are refused.
+	good := Ask{Ask: []byte(`{"id":"x"}`), Asking: 2}
+	data, err := EncodeAsk(hold, good)
+	if err != nil {
+		t.Fatalf("EncodeAsk: %v", err)
+	}
+	back, err := DecodeAsk(hold, data)
+	if err != nil || !SameAsk(back, Ask{V: keys.Version, Ask: []byte(` {"id": "x"} `), Asking: 2}) {
+		t.Errorf("DecodeAsk = %+v, %v", back, err)
+	}
+	for name, c := range map[string]struct {
+		key string
+		a   Ask
+	}{"a merge ask": {"merge.g.d106c7950d28", good}, "a negative asking": {hold, Ask{Ask: good.Ask, Asking: -1}}, "no ask": {hold, Ask{}},
+		"a null ask": {hold, Ask{Ask: []byte("null")}}, "an unknown kind": {"other.x", good}} {
+		if _, err := EncodeAsk(c.key, c.a); err == nil {
+			t.Errorf("EncodeAsk takes %s", name)
+		}
+	}
+	if _, err := DecodeAsk(hold, []byte(`{"v":2,"ask":{}}`)); !errors.Is(err, keys.ErrUnknownVersion) {
+		t.Errorf("DecodeAsk of another version = %v", err)
+	}
+}
diff --git a/modules/mesh-delivery-assigner/asks/go.mod b/modules/mesh-delivery-assigner/asks/go.mod
new file mode 100644
index 00000000..fbda6c1d
--- /dev/null
+++ b/modules/mesh-delivery-assigner/asks/go.mod
@@ -0,0 +1,13 @@
+module git.novox.be/novox/mesh-delivery/modules/mesh-delivery-assigner/asks
+
+go 1.26.0
+
+require (
+	git.novox.be/novox/mesh-contracts/go/clients/nodeengineclient v0.0.0
+	git.novox.be/novox/mesh-contracts/placement/go/clients/meshmoduleassignerclient v0.0.0
+	git.novox.be/novox/mesh-delivery/contracts/go/clients/meshcatalogclient v0.0.0
+	git.novox.be/novox/mesh-delivery/contracts/go/clients/meshdeliveryclient v0.0.0
+	git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/builds v0.0.0
+	git.novox.be/novox/mesh-delivery/sdk v0.0.0
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261104174359-05b3e2e1b94f
+)
diff --git a/modules/mesh-delivery-assigner/module.json b/modules/mesh-delivery-assigner/module.json
index 423a565a..97a163ae 100644
--- a/modules/mesh-delivery-assigner/module.json
+++ b/modules/mesh-delivery-assigner/module.json
@@ -158,6 +158,15 @@
           "MESH_VIEW_CALLERS_SEAT_HOLDERS": "node-tools",
           "MESH_VIEW_CALLERS_WANTS": "mesh-grants"
         }
+      },
+      {
+        "name": "asks",
+        "kind": "package",
+        "language": "go",
+        "paths": [
+          "asks"
+        ],
+        "series": "0.1"
       }
     ]
   }
diff --git a/modules/mesh-delivery-view/viewstate/answerkey.go b/modules/mesh-delivery-view/viewstate/answerkey.go
new file mode 100644
index 00000000..7d7d8a09
--- /dev/null
+++ b/modules/mesh-delivery-view/viewstate/answerkey.go
@@ -0,0 +1,48 @@
+package viewstate
+
+import (
+	"fmt"
+	"strings"
+
+	"git.novox.be/novox/mesh-delivery/contracts/go/clients/meshdeliveryclient"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-assigner/asks"
+)
+
+const viewWord = "view"
+
+// ViewAnswerKey is the key, in the state answers, of the view's answer to the ask at askKey: `<ask key>.view`. An ask that needs
+// proof of who answered is refused with its reason: it is answered on the phone (issue 953).
+func ViewAnswerKey(askKey string) (string, error) {
+	ask, err := asks.ParseAnyAskKey(askKey)
+	if err != nil {
+		return "", err
+	}
+	if proof, _ := asks.AskNeedsProof(ask.Kind); proof {
+		return "", fmt.Errorf("viewstate: the ask %s needs proof of who answered: answer it on the phone (issue 953)", askKey)
+	}
+	return askKey + "." + viewWord, nil
+}
+
+// ParseViewAnswerKey is the inverse of ViewAnswerKey: the ask's key. It refuses a key without `.view`, an ask key of a kind that
+// needs proof, and a key of another state, naming it.
+func ParseViewAnswerKey(key string) (askKey string, err error) {
+	askKey, ok := strings.CutSuffix(key, "."+viewWord)
+	if !ok {
+		return "", fmt.Errorf("viewstate: %q is not a view answer key, <ask key>.view", key)
+	}
+	if _, err := ViewAnswerKey(askKey); err != nil {
+		return "", fmt.Errorf("viewstate: %q is not a view answer key: %w", key, err)
+	}
+	return askKey, nil
+}
+
+// ViewAnswerFits says whether the view's answer a answers the ask at key as it stands now: it refuses an answer to another
+// asking of the ask (a stale answer to an earlier writing of the same key), naming both. Whether the ask offers the option
+// chosen, and at the level acknowledge only (an option that authorises is answered on a channel that proves who answered,
+// never in the view, which proves nobody), the teller reads from the ask through operator-channel's client.
+func ViewAnswerFits(a ViewAnswer, key string, ask asks.Ask) error {
+	if want := meshdeliveryclient.AskingID(key, ask.Asking); a.Asking != want {
+		return fmt.Errorf("viewstate: the view's answer is to the asking %s, and the ask stands at the asking %s", a.Asking, want)
+	}
+	return nil
+}
diff --git a/modules/mesh-delivery-view/viewstate/go.mod b/modules/mesh-delivery-view/viewstate/go.mod
index 5a17cb64..9c9477e4 100644
--- a/modules/mesh-delivery-view/viewstate/go.mod
+++ b/modules/mesh-delivery-view/viewstate/go.mod
@@ -3,6 +3,8 @@ module git.novox.be/novox/mesh-delivery/modules/mesh-delivery-view/viewstate
 go 1.26.0
 
 require (
+	git.novox.be/novox/mesh-delivery/contracts/go/clients/meshdeliveryclient v0.0.0
+	git.novox.be/novox/mesh-delivery/modules/mesh-delivery-assigner/asks v0.0.0
 	git.novox.be/novox/mesh-delivery/sdk v0.0.0
 	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261104174359-05b3e2e1b94f
 )
diff --git a/modules/mesh-delivery-view/viewstate/viewstate_test.go b/modules/mesh-delivery-view/viewstate/viewstate_test.go
index c35726bb..9863ec8d 100644
--- a/modules/mesh-delivery-view/viewstate/viewstate_test.go
+++ b/modules/mesh-delivery-view/viewstate/viewstate_test.go
@@ -4,6 +4,8 @@ import (
 	"strings"
 	"testing"
 
+	"git.novox.be/novox/mesh-delivery/contracts/go/clients/meshdeliveryclient"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-assigner/asks"
 	"git.novox.be/novox/mesh-sdk/go/keys"
 )
 
@@ -72,6 +74,32 @@ func TestReachValuesDifferingInAnyPartAreNotTheSame(t *testing.T) {
 }
 
 func TestViewAnswerRoundTrip(t *testing.T) {
+	t.Run("the key and the asking", func(t *testing.T) {
+		fp := "src2:" + strings.Repeat("ab", 32)
+		hold, _ := asks.HoldAskKey("gitea", fp)
+		key, err := ViewAnswerKey(hold)
+		if err != nil || key != hold+".view" {
+			t.Fatalf("ViewAnswerKey = %q, %v", key, err)
+		}
+		if back, err := ParseViewAnswerKey(key); err != nil || back != hold {
+			t.Errorf("ParseViewAnswerKey = %q, %v", back, err)
+		}
+		for _, bad := range []string{hold, "merge.g.d106c7950d28.view", "other.x.view"} {
+			if _, err := ParseViewAnswerKey(bad); err == nil {
+				t.Errorf("ParseViewAnswerKey(%q) reads a wrong key", bad)
+			}
+		}
+		if _, err := ViewAnswerKey("merge.g.d106c7950d28"); err == nil || !strings.Contains(err.Error(), "proof") {
+			t.Errorf("a merge ask is answered by the view: %v", err)
+		}
+		first := ViewAnswer{Asking: meshdeliveryclient.AskingID(hold, 0), Option: "release"}
+		if err := ViewAnswerFits(first, hold, asks.Ask{}); err != nil {
+			t.Errorf("an answer to the first asking is refused: %v", err)
+		}
+		if err := ViewAnswerFits(first, hold, asks.Ask{Asking: 2}); err == nil {
+			t.Error("an answer to an earlier asking is taken for the later one")
+		}
+	})
 	a := ViewAnswer{Asking: "hold-mesh-mail-aaaa-0123456789ab", Option: "release", Words: "fixed by #12"}
 	data, err := EncodeViewAnswer(a)
 	if err != nil {

From f2c61815f8653d37cda43bb7a006998be4dff1a0 Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Thu, 5 Nov 2026 14:55:35 +0100
Subject: [PATCH 5/5] =?UTF-8?q?mesh-delivery-contracts:=20the=20build=20se?=
 =?UTF-8?q?ats'=20part=20types=20Fetch,=20the=20toolchain,=20the=20artifac?=
 =?UTF-8?q?ts,=20the=20check's=20levels=20and=20a=20step's=20result,=20and?=
 =?UTF-8?q?=20marks=20the=20times=20date-time;=20fixtures=20for=20a=20chec?=
 =?UTF-8?q?k=20ask=20and=20the=20three=20kinds=20of=20result=20(ADR=200634?=
 =?UTF-8?q?=20=C2=A76;=20issue=201966)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Claude-Session: https://claude.ai/code/session_01NcbgfFSnn24M3GcqttoU7i
---
 .../reference/reference_test.go               |   8 +-
 contracts/go/seats/nodebuildgo/contract.go    | 226 ++++----
 .../go/seats/nodebuildgo/contract_test.go     |   8 +
 contracts/go/seats/nodebuildimage/contract.go | 226 ++++----
 contracts/go/seats/nodebuildnode/contract.go  | 226 ++++----
 contracts/parts/build-step.json               | 513 +++++++++++-------
 .../seats/node-build-go/fixtures/states.json  | 140 +++++
 contracts/ts/seats/nodebuildgo/src/index.ts   |  22 +-
 .../seats/nodebuildgo/src/parts/build-step.ts | 190 ++++---
 .../ts/seats/nodebuildimage/src/index.ts      |  22 +-
 .../nodebuildimage/src/parts/build-step.ts    | 190 ++++---
 contracts/ts/seats/nodebuildnode/src/index.ts |  22 +-
 .../nodebuildnode/src/parts/build-step.ts     | 190 ++++---
 13 files changed, 1243 insertions(+), 740 deletions(-)

diff --git a/contracts/go/clients/containerimageregistryclient/reference/reference_test.go b/contracts/go/clients/containerimageregistryclient/reference/reference_test.go
index d707c9e4..60823b7d 100644
--- a/contracts/go/clients/containerimageregistryclient/reference/reference_test.go
+++ b/contracts/go/clients/containerimageregistryclient/reference/reference_test.go
@@ -7,7 +7,7 @@ import (
 
 var digest = "sha256:" + strings.Repeat("d", 64)
 
-var seats = Seats{Image: "container-image-registry", Object: "oci-artifact-registry"}
+var seats = Seats{Image: "container-image-registry", Object: "object-registry"}
 
 func TestAReferenceIsRecordedWithoutTheStoresAddress(t *testing.T) {
 	cases := map[string]string{
@@ -21,7 +21,7 @@ func TestAReferenceIsRecordedWithoutTheStoresAddress(t *testing.T) {
 		"https://registry.example/v2/gitea/config/blobs/" + digest: "https://registry.example/v2/gitea/config/blobs/" + digest,
 		// The form a registry seat answers is recorded as it is (ADR 0605 §9).
 		"container-image-registry/gitea/server@" + digest: "container-image-registry/gitea/server@" + digest,
-		"oci-artifact-registry/gitea/config@" + digest:    "oci-artifact-registry/gitea/config@" + digest,
+		"object-registry/gitea/config@" + digest:    "object-registry/gitea/config@" + digest,
 	}
 	for announced, want := range cases {
 		if got := seats.Recorded(announced); got != want {
@@ -33,7 +33,7 @@ func TestAReferenceIsRecordedWithoutTheStoresAddress(t *testing.T) {
 		ArtifactStoreScheme + "gitea/server@" + digest:       "10.0.0.1:5000/gitea/server@" + digest,
 		"container-image-registry/gitea/server@" + digest:    "10.0.0.1:5000/gitea/server@" + digest,
 		ArtifactStoreScheme + "gitea/config/blobs/" + digest: "http://10.0.0.1:5000/v2/gitea/config/blobs/" + digest,
-		"oci-artifact-registry/gitea/config@" + digest:       "http://10.0.0.1:5000/v2/gitea/config/blobs/" + digest,
+		"object-registry/gitea/config@" + digest:       "http://10.0.0.1:5000/v2/gitea/config/blobs/" + digest,
 		"registry.example/gitea/server@" + digest:            "registry.example/gitea/server@" + digest,
 		"mesh-artifact-store/gitea/server@" + digest:         "mesh-artifact-store/gitea/server@" + digest,
 		// An upstream copy under the holder's own naming, in both forms.
@@ -54,7 +54,7 @@ func TestAReferenceIsRecordedWithoutTheStoresAddress(t *testing.T) {
 	// The holder's naming of an upstream copy reads through the image seat only, and InUpstream reads its host and path.
 	for reference, want := range map[string]bool{
 		"container-image-registry/upstream/quay.io:443/org/app@" + digest: true,
-		"oci-artifact-registry/upstream/quay.io:443/org/app@" + digest:    false,
+		"object-registry/upstream/quay.io:443/org/app@" + digest:    false,
 		"container-image-registry/upstream/org/app@" + digest:             false,
 		"container-image-registry/upstream/quay.io/app":                   false,
 	} {
diff --git a/contracts/go/seats/nodebuildgo/contract.go b/contracts/go/seats/nodebuildgo/contract.go
index 59b72a28..a734103f 100644
--- a/contracts/go/seats/nodebuildgo/contract.go
+++ b/contracts/go/seats/nodebuildgo/contract.go
@@ -187,26 +187,27 @@ func DecodeToolchainsByNodeLanguageValue(raw []byte) (ToolchainsByNodeLanguageVa
 	return v, nil
 }
 
-// BuildAnswerArtifactsItem is a type of the contract.
-type BuildAnswerArtifactsItem struct {
-	Artifact  string `json:"artifact"`
-	Digest    string `json:"digest"`
-	Reference string `json:"reference,omitempty"`
-}
-
-// BuildAnswerToolchain is a type of the contract.
-type BuildAnswerToolchain struct {
-	Language string `json:"language"`
-	Recipe   string `json:"recipe"`
-	Version  string `json:"version"`
+// AskArtifact is one artifact of a build ask: built from the fetched tree, or copied from an upstream pin.
+type AskArtifact struct {
+	Artifact string `json:"artifact"`
+	From     string `json:"from,omitempty"`
+	Seat     string `json:"seat,omitempty"`
+	Version  string `json:"version,omitempty"`
 }
 
 // BuildAnswer is a type of the contract.
 type BuildAnswer struct {
-	Artifacts []BuildAnswerArtifactsItem `json:"artifacts"`
-	Imports   []string                   `json:"imports,omitempty"`
-	OutOfStep []string                   `json:"out-of-step,omitempty"`
-	Toolchain *BuildAnswerToolchain      `json:"toolchain,omitempty"`
+	Artifacts []BuiltArtifact `json:"artifacts"`
+	Imports   []string        `json:"imports,omitempty"`
+	OutOfStep []string        `json:"out-of-step,omitempty"`
+	Toolchain *ToolchainUsed  `json:"toolchain,omitempty"`
+}
+
+// BuiltArtifact is one artifact a build made: its digest and the reference it was published under.
+type BuiltArtifact struct {
+	Artifact  string `json:"artifact"`
+	Digest    string `json:"digest"`
+	Reference string `json:"reference,omitempty"`
 }
 
 // Capacity is how many steps the node runs at once.
@@ -229,56 +230,10 @@ type Capacity struct {
 	Why string `json:"why"`
 }
 
-// CheckAnswerLevelsItemDigestNeedsItem is a type of the contract.
-type CheckAnswerLevelsItemDigestNeedsItem struct {
-	Needs   []string `json:"needs,omitempty"`
-	Package string   `json:"package,omitempty"`
-}
-
-// CheckAnswerLevelsItemDigestPackagesItem is a type of the contract.
-type CheckAnswerLevelsItemDigestPackagesItem struct {
-	Digest  string `json:"digest"`
-	Package string `json:"package"`
-}
-
-// CheckAnswerLevelsItemDigest is a type of the contract.
-type CheckAnswerLevelsItemDigest struct {
-	Beside       []string                                  `json:"beside,omitempty"`
-	JudgedBy     string                                    `json:"judged_by,omitempty"`
-	Level        string                                    `json:"level,omitempty"`
-	Needs        []CheckAnswerLevelsItemDigestNeedsItem    `json:"needs,omitempty"`
-	Packages     []CheckAnswerLevelsItemDigestPackagesItem `json:"packages,omitempty"`
-	WithoutTests []string                                  `json:"without_tests,omitempty"`
-}
-
-// CheckAnswerLevelsItemKeptItem is a type of the contract.
-type CheckAnswerLevelsItemKeptItem struct {
-	Digest  string `json:"digest,omitempty"`
-	Package string `json:"package,omitempty"`
-	Tests   int64  `json:"tests,omitempty"`
-}
-
-// CheckAnswerLevelsItemUnmetItem is a type of the contract.
-type CheckAnswerLevelsItemUnmetItem struct {
-	Needs   []string `json:"needs,omitempty"`
-	Package string   `json:"package,omitempty"`
-}
-
-// CheckAnswerLevelsItem is a type of the contract.
-type CheckAnswerLevelsItem struct {
-	Digest *CheckAnswerLevelsItemDigest     `json:"digest,omitempty"`
-	Judged string                           `json:"judged,omitempty"`
-	Kept   []CheckAnswerLevelsItemKeptItem  `json:"kept,omitempty"`
-	Level  string                           `json:"level"`
-	Tests  []any                            `json:"tests,omitempty"`
-	Unmet  []CheckAnswerLevelsItemUnmetItem `json:"unmet,omitempty"`
-}
-
 // CheckAnswer is a type of the contract.
 type CheckAnswer struct {
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch  any                     `json:"fetch"`
-	Levels []CheckAnswerLevelsItem `json:"levels,omitempty"`
+	Fetch  Fetch         `json:"fetch"`
+	Levels []LevelAnswer `json:"levels,omitempty"`
 }
 
 // ComposeAnswer is a type of the contract.
@@ -289,6 +244,77 @@ type ComposeAnswer struct {
 	Verdict any `json:"verdict,omitempty"`
 }
 
+// FetchBesideItem is a type of the contract.
+type FetchBesideItem struct {
+	Commit     string `json:"commit"`
+	Repository string `json:"repository"`
+}
+
+// Fetch is what a build module's fetch tool is asked: the repository and the full commit, the pull request's ref when only its head carries the commit, the trunk commit to merge onto for a merge preview, the module's directory and named paths, the mesh packages to build against, and the sibling repositories placed beside.
+type Fetch struct {
+	// the trunk commit a merge preview merges onto
+	Base string `json:"base,omitempty"`
+	// the sibling repositories placed beside the fetched tree
+	Beside []FetchBesideItem `json:"beside,omitempty"`
+	// the full commit
+	Commit string `json:"commit"`
+	// the module's directory in the repository ("." for its root), with paths
+	Dir string `json:"dir,omitempty"`
+	// the version (a full commit) of each mesh package to build against, by its module path
+	Packages map[string]string `json:"packages,omitempty"`
+	// the paths the module names, relative to dir
+	Paths []string `json:"paths,omitempty"`
+	// the pull request's ref, when only its head carries the commit
+	Ref string `json:"ref,omitempty"`
+	// <owner>/<name>
+	Repository string `json:"repository"`
+}
+
+// LevelAnswerDigestNeedsItem is a type of the contract.
+type LevelAnswerDigestNeedsItem struct {
+	Needs   []string `json:"needs,omitempty"`
+	Package string   `json:"package,omitempty"`
+}
+
+// LevelAnswerDigestPackagesItem is a type of the contract.
+type LevelAnswerDigestPackagesItem struct {
+	Digest  string `json:"digest"`
+	Package string `json:"package"`
+}
+
+// LevelAnswerDigest is a type of the contract.
+type LevelAnswerDigest struct {
+	Beside       []string                        `json:"beside,omitempty"`
+	JudgedBy     string                          `json:"judged_by,omitempty"`
+	Level        string                          `json:"level,omitempty"`
+	Needs        []LevelAnswerDigestNeedsItem    `json:"needs,omitempty"`
+	Packages     []LevelAnswerDigestPackagesItem `json:"packages,omitempty"`
+	WithoutTests []string                        `json:"without_tests,omitempty"`
+}
+
+// LevelAnswerKeptItem is a type of the contract.
+type LevelAnswerKeptItem struct {
+	Digest  string `json:"digest,omitempty"`
+	Package string `json:"package,omitempty"`
+	Tests   int64  `json:"tests,omitempty"`
+}
+
+// LevelAnswerUnmetItem is a type of the contract.
+type LevelAnswerUnmetItem struct {
+	Needs   []string `json:"needs,omitempty"`
+	Package string   `json:"package,omitempty"`
+}
+
+// LevelAnswer is one level of a check ask: the digest's answer, the kept verdicts taken, one test result per test step run, and the packages the node could not test.
+type LevelAnswer struct {
+	Digest *LevelAnswerDigest     `json:"digest,omitempty"`
+	Judged string                 `json:"judged,omitempty"`
+	Kept   []LevelAnswerKeptItem  `json:"kept,omitempty"`
+	Level  string                 `json:"level"`
+	Tests  []any                  `json:"tests,omitempty"`
+	Unmet  []LevelAnswerUnmetItem `json:"unmet,omitempty"`
+}
+
 // Pause is whether the node takes no new ask.
 type Pause struct {
 	// when (RFC 3339 time)
@@ -308,10 +334,9 @@ type Step struct {
 	Owner string `json:"owner,omitempty"`
 	Phase string `json:"phase,omitempty"`
 	// when (RFC 3339 time)
-	PhaseAt string `json:"phase-at,omitempty"`
-	Reason  string `json:"reason,omitempty"`
-	// what the step answered
-	Result any `json:"result,omitempty"`
+	PhaseAt string      `json:"phase-at,omitempty"`
+	Reason  string      `json:"reason,omitempty"`
+	Result  *StepResult `json:"result,omitempty"`
 	// when (RFC 3339 time)
 	Started string `json:"started"`
 	// running, passed, failed or refused
@@ -322,37 +347,20 @@ type Step struct {
 	What string `json:"what,omitempty"`
 }
 
-// StepAskBuildArtifactsItem is a type of the contract.
-type StepAskBuildArtifactsItem struct {
-	Artifact string `json:"artifact"`
-	From     string `json:"from,omitempty"`
-	Seat     string `json:"seat,omitempty"`
-	Version  string `json:"version,omitempty"`
-}
-
-// StepAskBuildToolchain is a type of the contract.
-type StepAskBuildToolchain struct {
-	Language string `json:"language"`
-	Recipe   string `json:"recipe"`
-	Version  string `json:"version"`
-}
-
 // StepAskBuild is a type of the contract.
 type StepAskBuild struct {
-	Artifacts []StepAskBuildArtifactsItem `json:"artifacts"`
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch     any                    `json:"fetch,omitempty"`
-	Fp        string                 `json:"fp,omitempty"`
-	Module    string                 `json:"module"`
-	Path      string                 `json:"path,omitempty"`
-	Publish   bool                   `json:"publish,omitempty"`
-	Toolchain *StepAskBuildToolchain `json:"toolchain,omitempty"`
+	Artifacts []AskArtifact  `json:"artifacts"`
+	Fetch     *Fetch         `json:"fetch,omitempty"`
+	Fp        string         `json:"fp,omitempty"`
+	Module    string         `json:"module"`
+	Path      string         `json:"path,omitempty"`
+	Publish   bool           `json:"publish,omitempty"`
+	Toolchain *ToolchainUsed `json:"toolchain,omitempty"`
 }
 
 // StepAskCheck is a type of the contract.
 type StepAskCheck struct {
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch      any      `json:"fetch"`
+	Fetch      Fetch    `json:"fetch"`
 	Kept       bool     `json:"kept,omitempty"`
 	Levels     []string `json:"levels"`
 	Packages   []string `json:"packages,omitempty"`
@@ -363,9 +371,8 @@ type StepAskCheck struct {
 
 // StepAskCompose is a type of the contract.
 type StepAskCompose struct {
-	Dir string `json:"dir"`
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch   any    `json:"fetch"`
+	Dir     string `json:"dir"`
+	Fetch   Fetch  `json:"fetch"`
 	Package string `json:"package"`
 	Reader  string `json:"reader,omitempty"`
 	// the compose-candidate request
@@ -392,6 +399,26 @@ type StepAsk struct {
 	V int64 `json:"v,omitempty"`
 }
 
+// StepResult is what a step answered, by the kind of ask: a build's artifacts, toolchain, imports and out-of-step modules; a check's fetch and levels; a compose's built, key and verdict; a declined ask's declined, needs and lacks. The fields of the kinds do not meet, so one layout holds the four.
+type StepResult struct {
+	Artifacts []BuiltArtifact `json:"artifacts,omitempty"`
+	Built     bool            `json:"built,omitempty"`
+	// the holder declined the ask: its node lacks what the ask needs
+	Declined bool     `json:"declined,omitempty"`
+	Fetch    *Fetch   `json:"fetch,omitempty"`
+	Imports  []string `json:"imports,omitempty"`
+	Key      string   `json:"key,omitempty"`
+	// what the holder's node lacks of it
+	Lacks  []string      `json:"lacks,omitempty"`
+	Levels []LevelAnswer `json:"levels,omitempty"`
+	// what the declined ask needs
+	Needs     []string       `json:"needs,omitempty"`
+	OutOfStep []string       `json:"out-of-step,omitempty"`
+	Toolchain *ToolchainUsed `json:"toolchain,omitempty"`
+	// the compose-candidate verdict (the composer's own layout)
+	Verdict any `json:"verdict,omitempty"`
+}
+
 // Toolchain is the toolchain a node reports.
 type Toolchain struct {
 	// when (RFC 3339 time)
@@ -404,6 +431,13 @@ type Toolchain struct {
 	Version string `json:"version"`
 }
 
+// ToolchainUsed is the toolchain a build was made with: the language, the installed version and the build module's recipe.
+type ToolchainUsed struct {
+	Language string `json:"language"`
+	Recipe   string `json:"recipe"`
+	Version  string `json:"version"`
+}
+
 // CurrentInput is what current takes.
 type CurrentInput struct {
 }
diff --git a/contracts/go/seats/nodebuildgo/contract_test.go b/contracts/go/seats/nodebuildgo/contract_test.go
index e7dd00cc..4aabcc73 100644
--- a/contracts/go/seats/nodebuildgo/contract_test.go
+++ b/contracts/go/seats/nodebuildgo/contract_test.go
@@ -39,6 +39,14 @@ func TestFixtures(t *testing.T) {
 			}, subjectIs: nil},
 		{name: "a build ask", subject: "mesh.seat.node-build-go.accept.delivery", given: "{\"asker\":\"mesh-delivery-builder\",\"build\":{\"artifacts\":[{\"artifact\":\"go\"}],\"module\":\"nats\"},\"id\":\"a1b2\",\"kind\":\"build\",\"language\":\"go\"}", wire: "{\"asker\":\"mesh-delivery-builder\",\"build\":{\"artifacts\":[{\"artifact\":\"go\"}],\"module\":\"nats\"},\"id\":\"a1b2\",\"kind\":\"build\",\"language\":\"go\"}",
 			decode: func(b []byte) (any, error) { var v DeliveryAccept; err := json.Unmarshal(b, &v); return v, err }, subjectIs: regexp.MustCompile("^mesh\\.seat\\.node-build-go\\.accept\\.delivery$")},
+		{name: "a check ask with its fetch, siblings and levels", subject: "mesh.seat.node-build-go.accept.check", given: "{\"asker\":\"mesh-delivery-checker\",\"at\":\"2026-11-05T10:00:00Z\",\"check\":{\"fetch\":{\"base\":\"89abcdef0123456789abcdef0123456789abcdef\",\"beside\":[{\"commit\":\"fedcba9876543210fedcba9876543210fedcba98\",\"repository\":\"novox/mesh-sdk\"}],\"commit\":\"0123456789abcdef0123456789abcdef01234567\",\"packages\":{\"git.novox.be/novox/mesh-sdk/go\":\"fedcba9876543210fedcba9876543210fedcba98\"},\"ref\":\"refs/pull/7/head\",\"repository\":\"novox/mesh-catalog\"},\"kept\":true,\"levels\":[\"unit\",\"integration\"]},\"id\":\"c3d4\",\"kind\":\"check\",\"language\":\"go\",\"v\":1}", wire: "{\"asker\":\"mesh-delivery-checker\",\"at\":\"2026-11-05T10:00:00Z\",\"check\":{\"fetch\":{\"base\":\"89abcdef0123456789abcdef0123456789abcdef\",\"beside\":[{\"commit\":\"fedcba9876543210fedcba9876543210fedcba98\",\"repository\":\"novox/mesh-sdk\"}],\"commit\":\"0123456789abcdef0123456789abcdef01234567\",\"packages\":{\"git.novox.be/novox/mesh-sdk/go\":\"fedcba9876543210fedcba9876543210fedcba98\"},\"ref\":\"refs/pull/7/head\",\"repository\":\"novox/mesh-catalog\"},\"kept\":true,\"levels\":[\"unit\",\"integration\"]},\"id\":\"c3d4\",\"kind\":\"check\",\"language\":\"go\",\"v\":1}",
+			decode: func(b []byte) (any, error) { var v CheckAccept; err := json.Unmarshal(b, &v); return v, err }, subjectIs: regexp.MustCompile("^mesh\\.seat\\.node-build-go\\.accept\\.check$")},
+		{name: "a finished build step with its artifacts", subject: "", given: "{\"ended\":\"2026-11-05T10:03:00Z\",\"id\":\"a1b2\",\"node\":\"ace\",\"result\":{\"artifacts\":[{\"artifact\":\"go\",\"digest\":\"sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\",\"reference\":\"container-image-registry/nats/go@sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\"}],\"imports\":[\"git.novox.be/novox/mesh-sdk/go\"],\"toolchain\":{\"language\":\"go\",\"recipe\":\"1\",\"version\":\"1.26.0\"}},\"started\":\"2026-11-05T10:00:00Z\",\"state\":\"passed\",\"tool\":\"build\",\"v\":1}", wire: "{\"ended\":\"2026-11-05T10:03:00Z\",\"id\":\"a1b2\",\"node\":\"ace\",\"result\":{\"artifacts\":[{\"artifact\":\"go\",\"digest\":\"sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\",\"reference\":\"container-image-registry/nats/go@sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\"}],\"imports\":[\"git.novox.be/novox/mesh-sdk/go\"],\"toolchain\":{\"language\":\"go\",\"recipe\":\"1\",\"version\":\"1.26.0\"}},\"started\":\"2026-11-05T10:00:00Z\",\"state\":\"passed\",\"tool\":\"build\",\"v\":1}",
+			decode: func(b []byte) (any, error) { var v StepsByNodeIDValue; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
+		{name: "a finished check step with its levels", subject: "", given: "{\"ended\":\"2026-11-05T10:06:00Z\",\"id\":\"c3d4\",\"node\":\"ace\",\"result\":{\"fetch\":{\"commit\":\"0123456789abcdef0123456789abcdef01234567\",\"repository\":\"novox/mesh-catalog\"},\"levels\":[{\"digest\":{\"level\":\"unit\",\"packages\":[{\"digest\":\"sha256:bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\",\"package\":\"./modules/a\"}]},\"kept\":[{\"digest\":\"sha256:bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\",\"package\":\"./modules/a\",\"tests\":12}],\"level\":\"unit\",\"tests\":[{\"package\":\"./modules/b\",\"pass\":true}],\"unmet\":[{\"needs\":[\"docker\"],\"package\":\"./modules/c\"}]}]},\"started\":\"2026-11-05T10:00:00Z\",\"state\":\"passed\",\"tool\":\"check\",\"v\":1}", wire: "{\"ended\":\"2026-11-05T10:06:00Z\",\"id\":\"c3d4\",\"node\":\"ace\",\"result\":{\"fetch\":{\"commit\":\"0123456789abcdef0123456789abcdef01234567\",\"repository\":\"novox/mesh-catalog\"},\"levels\":[{\"digest\":{\"level\":\"unit\",\"packages\":[{\"digest\":\"sha256:bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\",\"package\":\"./modules/a\"}]},\"kept\":[{\"digest\":\"sha256:bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\",\"package\":\"./modules/a\",\"tests\":12}],\"level\":\"unit\",\"tests\":[{\"package\":\"./modules/b\",\"pass\":true}],\"unmet\":[{\"needs\":[\"docker\"],\"package\":\"./modules/c\"}]}]},\"started\":\"2026-11-05T10:00:00Z\",\"state\":\"passed\",\"tool\":\"check\",\"v\":1}",
+			decode: func(b []byte) (any, error) { var v StepsByNodeIDValue; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
+		{name: "a declined step", subject: "", given: "{\"id\":\"c3d5\",\"node\":\"ace\",\"result\":{\"declined\":true,\"lacks\":[\"docker\"],\"needs\":[\"docker\"]},\"started\":\"2026-11-05T10:00:00Z\",\"state\":\"refused\",\"tool\":\"check\",\"v\":1}", wire: "{\"id\":\"c3d5\",\"node\":\"ace\",\"result\":{\"declined\":true,\"lacks\":[\"docker\"],\"needs\":[\"docker\"]},\"started\":\"2026-11-05T10:00:00Z\",\"state\":\"refused\",\"tool\":\"check\",\"v\":1}",
+			decode: func(b []byte) (any, error) { var v StepsByNodeIDValue; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
 	}
 	for _, c := range cases {
 		v, err := c.decode([]byte(c.given))
diff --git a/contracts/go/seats/nodebuildimage/contract.go b/contracts/go/seats/nodebuildimage/contract.go
index 843c04ae..db640ee3 100644
--- a/contracts/go/seats/nodebuildimage/contract.go
+++ b/contracts/go/seats/nodebuildimage/contract.go
@@ -187,26 +187,27 @@ func DecodeToolchainsByNodeLanguageValue(raw []byte) (ToolchainsByNodeLanguageVa
 	return v, nil
 }
 
-// BuildAnswerArtifactsItem is a type of the contract.
-type BuildAnswerArtifactsItem struct {
-	Artifact  string `json:"artifact"`
-	Digest    string `json:"digest"`
-	Reference string `json:"reference,omitempty"`
-}
-
-// BuildAnswerToolchain is a type of the contract.
-type BuildAnswerToolchain struct {
-	Language string `json:"language"`
-	Recipe   string `json:"recipe"`
-	Version  string `json:"version"`
+// AskArtifact is one artifact of a build ask: built from the fetched tree, or copied from an upstream pin.
+type AskArtifact struct {
+	Artifact string `json:"artifact"`
+	From     string `json:"from,omitempty"`
+	Seat     string `json:"seat,omitempty"`
+	Version  string `json:"version,omitempty"`
 }
 
 // BuildAnswer is a type of the contract.
 type BuildAnswer struct {
-	Artifacts []BuildAnswerArtifactsItem `json:"artifacts"`
-	Imports   []string                   `json:"imports,omitempty"`
-	OutOfStep []string                   `json:"out-of-step,omitempty"`
-	Toolchain *BuildAnswerToolchain      `json:"toolchain,omitempty"`
+	Artifacts []BuiltArtifact `json:"artifacts"`
+	Imports   []string        `json:"imports,omitempty"`
+	OutOfStep []string        `json:"out-of-step,omitempty"`
+	Toolchain *ToolchainUsed  `json:"toolchain,omitempty"`
+}
+
+// BuiltArtifact is one artifact a build made: its digest and the reference it was published under.
+type BuiltArtifact struct {
+	Artifact  string `json:"artifact"`
+	Digest    string `json:"digest"`
+	Reference string `json:"reference,omitempty"`
 }
 
 // Capacity is how many steps the node runs at once.
@@ -229,56 +230,10 @@ type Capacity struct {
 	Why string `json:"why"`
 }
 
-// CheckAnswerLevelsItemDigestNeedsItem is a type of the contract.
-type CheckAnswerLevelsItemDigestNeedsItem struct {
-	Needs   []string `json:"needs,omitempty"`
-	Package string   `json:"package,omitempty"`
-}
-
-// CheckAnswerLevelsItemDigestPackagesItem is a type of the contract.
-type CheckAnswerLevelsItemDigestPackagesItem struct {
-	Digest  string `json:"digest"`
-	Package string `json:"package"`
-}
-
-// CheckAnswerLevelsItemDigest is a type of the contract.
-type CheckAnswerLevelsItemDigest struct {
-	Beside       []string                                  `json:"beside,omitempty"`
-	JudgedBy     string                                    `json:"judged_by,omitempty"`
-	Level        string                                    `json:"level,omitempty"`
-	Needs        []CheckAnswerLevelsItemDigestNeedsItem    `json:"needs,omitempty"`
-	Packages     []CheckAnswerLevelsItemDigestPackagesItem `json:"packages,omitempty"`
-	WithoutTests []string                                  `json:"without_tests,omitempty"`
-}
-
-// CheckAnswerLevelsItemKeptItem is a type of the contract.
-type CheckAnswerLevelsItemKeptItem struct {
-	Digest  string `json:"digest,omitempty"`
-	Package string `json:"package,omitempty"`
-	Tests   int64  `json:"tests,omitempty"`
-}
-
-// CheckAnswerLevelsItemUnmetItem is a type of the contract.
-type CheckAnswerLevelsItemUnmetItem struct {
-	Needs   []string `json:"needs,omitempty"`
-	Package string   `json:"package,omitempty"`
-}
-
-// CheckAnswerLevelsItem is a type of the contract.
-type CheckAnswerLevelsItem struct {
-	Digest *CheckAnswerLevelsItemDigest     `json:"digest,omitempty"`
-	Judged string                           `json:"judged,omitempty"`
-	Kept   []CheckAnswerLevelsItemKeptItem  `json:"kept,omitempty"`
-	Level  string                           `json:"level"`
-	Tests  []any                            `json:"tests,omitempty"`
-	Unmet  []CheckAnswerLevelsItemUnmetItem `json:"unmet,omitempty"`
-}
-
 // CheckAnswer is a type of the contract.
 type CheckAnswer struct {
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch  any                     `json:"fetch"`
-	Levels []CheckAnswerLevelsItem `json:"levels,omitempty"`
+	Fetch  Fetch         `json:"fetch"`
+	Levels []LevelAnswer `json:"levels,omitempty"`
 }
 
 // ComposeAnswer is a type of the contract.
@@ -289,6 +244,77 @@ type ComposeAnswer struct {
 	Verdict any `json:"verdict,omitempty"`
 }
 
+// FetchBesideItem is a type of the contract.
+type FetchBesideItem struct {
+	Commit     string `json:"commit"`
+	Repository string `json:"repository"`
+}
+
+// Fetch is what a build module's fetch tool is asked: the repository and the full commit, the pull request's ref when only its head carries the commit, the trunk commit to merge onto for a merge preview, the module's directory and named paths, the mesh packages to build against, and the sibling repositories placed beside.
+type Fetch struct {
+	// the trunk commit a merge preview merges onto
+	Base string `json:"base,omitempty"`
+	// the sibling repositories placed beside the fetched tree
+	Beside []FetchBesideItem `json:"beside,omitempty"`
+	// the full commit
+	Commit string `json:"commit"`
+	// the module's directory in the repository ("." for its root), with paths
+	Dir string `json:"dir,omitempty"`
+	// the version (a full commit) of each mesh package to build against, by its module path
+	Packages map[string]string `json:"packages,omitempty"`
+	// the paths the module names, relative to dir
+	Paths []string `json:"paths,omitempty"`
+	// the pull request's ref, when only its head carries the commit
+	Ref string `json:"ref,omitempty"`
+	// <owner>/<name>
+	Repository string `json:"repository"`
+}
+
+// LevelAnswerDigestNeedsItem is a type of the contract.
+type LevelAnswerDigestNeedsItem struct {
+	Needs   []string `json:"needs,omitempty"`
+	Package string   `json:"package,omitempty"`
+}
+
+// LevelAnswerDigestPackagesItem is a type of the contract.
+type LevelAnswerDigestPackagesItem struct {
+	Digest  string `json:"digest"`
+	Package string `json:"package"`
+}
+
+// LevelAnswerDigest is a type of the contract.
+type LevelAnswerDigest struct {
+	Beside       []string                        `json:"beside,omitempty"`
+	JudgedBy     string                          `json:"judged_by,omitempty"`
+	Level        string                          `json:"level,omitempty"`
+	Needs        []LevelAnswerDigestNeedsItem    `json:"needs,omitempty"`
+	Packages     []LevelAnswerDigestPackagesItem `json:"packages,omitempty"`
+	WithoutTests []string                        `json:"without_tests,omitempty"`
+}
+
+// LevelAnswerKeptItem is a type of the contract.
+type LevelAnswerKeptItem struct {
+	Digest  string `json:"digest,omitempty"`
+	Package string `json:"package,omitempty"`
+	Tests   int64  `json:"tests,omitempty"`
+}
+
+// LevelAnswerUnmetItem is a type of the contract.
+type LevelAnswerUnmetItem struct {
+	Needs   []string `json:"needs,omitempty"`
+	Package string   `json:"package,omitempty"`
+}
+
+// LevelAnswer is one level of a check ask: the digest's answer, the kept verdicts taken, one test result per test step run, and the packages the node could not test.
+type LevelAnswer struct {
+	Digest *LevelAnswerDigest     `json:"digest,omitempty"`
+	Judged string                 `json:"judged,omitempty"`
+	Kept   []LevelAnswerKeptItem  `json:"kept,omitempty"`
+	Level  string                 `json:"level"`
+	Tests  []any                  `json:"tests,omitempty"`
+	Unmet  []LevelAnswerUnmetItem `json:"unmet,omitempty"`
+}
+
 // Pause is whether the node takes no new ask.
 type Pause struct {
 	// when (RFC 3339 time)
@@ -308,10 +334,9 @@ type Step struct {
 	Owner string `json:"owner,omitempty"`
 	Phase string `json:"phase,omitempty"`
 	// when (RFC 3339 time)
-	PhaseAt string `json:"phase-at,omitempty"`
-	Reason  string `json:"reason,omitempty"`
-	// what the step answered
-	Result any `json:"result,omitempty"`
+	PhaseAt string      `json:"phase-at,omitempty"`
+	Reason  string      `json:"reason,omitempty"`
+	Result  *StepResult `json:"result,omitempty"`
 	// when (RFC 3339 time)
 	Started string `json:"started"`
 	// running, passed, failed or refused
@@ -322,37 +347,20 @@ type Step struct {
 	What string `json:"what,omitempty"`
 }
 
-// StepAskBuildArtifactsItem is a type of the contract.
-type StepAskBuildArtifactsItem struct {
-	Artifact string `json:"artifact"`
-	From     string `json:"from,omitempty"`
-	Seat     string `json:"seat,omitempty"`
-	Version  string `json:"version,omitempty"`
-}
-
-// StepAskBuildToolchain is a type of the contract.
-type StepAskBuildToolchain struct {
-	Language string `json:"language"`
-	Recipe   string `json:"recipe"`
-	Version  string `json:"version"`
-}
-
 // StepAskBuild is a type of the contract.
 type StepAskBuild struct {
-	Artifacts []StepAskBuildArtifactsItem `json:"artifacts"`
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch     any                    `json:"fetch,omitempty"`
-	Fp        string                 `json:"fp,omitempty"`
-	Module    string                 `json:"module"`
-	Path      string                 `json:"path,omitempty"`
-	Publish   bool                   `json:"publish,omitempty"`
-	Toolchain *StepAskBuildToolchain `json:"toolchain,omitempty"`
+	Artifacts []AskArtifact  `json:"artifacts"`
+	Fetch     *Fetch         `json:"fetch,omitempty"`
+	Fp        string         `json:"fp,omitempty"`
+	Module    string         `json:"module"`
+	Path      string         `json:"path,omitempty"`
+	Publish   bool           `json:"publish,omitempty"`
+	Toolchain *ToolchainUsed `json:"toolchain,omitempty"`
 }
 
 // StepAskCheck is a type of the contract.
 type StepAskCheck struct {
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch      any      `json:"fetch"`
+	Fetch      Fetch    `json:"fetch"`
 	Kept       bool     `json:"kept,omitempty"`
 	Levels     []string `json:"levels"`
 	Packages   []string `json:"packages,omitempty"`
@@ -363,9 +371,8 @@ type StepAskCheck struct {
 
 // StepAskCompose is a type of the contract.
 type StepAskCompose struct {
-	Dir string `json:"dir"`
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch   any    `json:"fetch"`
+	Dir     string `json:"dir"`
+	Fetch   Fetch  `json:"fetch"`
 	Package string `json:"package"`
 	Reader  string `json:"reader,omitempty"`
 	// the compose-candidate request
@@ -392,6 +399,26 @@ type StepAsk struct {
 	V int64 `json:"v,omitempty"`
 }
 
+// StepResult is what a step answered, by the kind of ask: a build's artifacts, toolchain, imports and out-of-step modules; a check's fetch and levels; a compose's built, key and verdict; a declined ask's declined, needs and lacks. The fields of the kinds do not meet, so one layout holds the four.
+type StepResult struct {
+	Artifacts []BuiltArtifact `json:"artifacts,omitempty"`
+	Built     bool            `json:"built,omitempty"`
+	// the holder declined the ask: its node lacks what the ask needs
+	Declined bool     `json:"declined,omitempty"`
+	Fetch    *Fetch   `json:"fetch,omitempty"`
+	Imports  []string `json:"imports,omitempty"`
+	Key      string   `json:"key,omitempty"`
+	// what the holder's node lacks of it
+	Lacks  []string      `json:"lacks,omitempty"`
+	Levels []LevelAnswer `json:"levels,omitempty"`
+	// what the declined ask needs
+	Needs     []string       `json:"needs,omitempty"`
+	OutOfStep []string       `json:"out-of-step,omitempty"`
+	Toolchain *ToolchainUsed `json:"toolchain,omitempty"`
+	// the compose-candidate verdict (the composer's own layout)
+	Verdict any `json:"verdict,omitempty"`
+}
+
 // Toolchain is the toolchain a node reports.
 type Toolchain struct {
 	// when (RFC 3339 time)
@@ -404,6 +431,13 @@ type Toolchain struct {
 	Version string `json:"version"`
 }
 
+// ToolchainUsed is the toolchain a build was made with: the language, the installed version and the build module's recipe.
+type ToolchainUsed struct {
+	Language string `json:"language"`
+	Recipe   string `json:"recipe"`
+	Version  string `json:"version"`
+}
+
 // CurrentInput is what current takes.
 type CurrentInput struct {
 }
diff --git a/contracts/go/seats/nodebuildnode/contract.go b/contracts/go/seats/nodebuildnode/contract.go
index 8e3e0448..9b0c7ff8 100644
--- a/contracts/go/seats/nodebuildnode/contract.go
+++ b/contracts/go/seats/nodebuildnode/contract.go
@@ -187,26 +187,27 @@ func DecodeToolchainsByNodeLanguageValue(raw []byte) (ToolchainsByNodeLanguageVa
 	return v, nil
 }
 
-// BuildAnswerArtifactsItem is a type of the contract.
-type BuildAnswerArtifactsItem struct {
-	Artifact  string `json:"artifact"`
-	Digest    string `json:"digest"`
-	Reference string `json:"reference,omitempty"`
-}
-
-// BuildAnswerToolchain is a type of the contract.
-type BuildAnswerToolchain struct {
-	Language string `json:"language"`
-	Recipe   string `json:"recipe"`
-	Version  string `json:"version"`
+// AskArtifact is one artifact of a build ask: built from the fetched tree, or copied from an upstream pin.
+type AskArtifact struct {
+	Artifact string `json:"artifact"`
+	From     string `json:"from,omitempty"`
+	Seat     string `json:"seat,omitempty"`
+	Version  string `json:"version,omitempty"`
 }
 
 // BuildAnswer is a type of the contract.
 type BuildAnswer struct {
-	Artifacts []BuildAnswerArtifactsItem `json:"artifacts"`
-	Imports   []string                   `json:"imports,omitempty"`
-	OutOfStep []string                   `json:"out-of-step,omitempty"`
-	Toolchain *BuildAnswerToolchain      `json:"toolchain,omitempty"`
+	Artifacts []BuiltArtifact `json:"artifacts"`
+	Imports   []string        `json:"imports,omitempty"`
+	OutOfStep []string        `json:"out-of-step,omitempty"`
+	Toolchain *ToolchainUsed  `json:"toolchain,omitempty"`
+}
+
+// BuiltArtifact is one artifact a build made: its digest and the reference it was published under.
+type BuiltArtifact struct {
+	Artifact  string `json:"artifact"`
+	Digest    string `json:"digest"`
+	Reference string `json:"reference,omitempty"`
 }
 
 // Capacity is how many steps the node runs at once.
@@ -229,56 +230,10 @@ type Capacity struct {
 	Why string `json:"why"`
 }
 
-// CheckAnswerLevelsItemDigestNeedsItem is a type of the contract.
-type CheckAnswerLevelsItemDigestNeedsItem struct {
-	Needs   []string `json:"needs,omitempty"`
-	Package string   `json:"package,omitempty"`
-}
-
-// CheckAnswerLevelsItemDigestPackagesItem is a type of the contract.
-type CheckAnswerLevelsItemDigestPackagesItem struct {
-	Digest  string `json:"digest"`
-	Package string `json:"package"`
-}
-
-// CheckAnswerLevelsItemDigest is a type of the contract.
-type CheckAnswerLevelsItemDigest struct {
-	Beside       []string                                  `json:"beside,omitempty"`
-	JudgedBy     string                                    `json:"judged_by,omitempty"`
-	Level        string                                    `json:"level,omitempty"`
-	Needs        []CheckAnswerLevelsItemDigestNeedsItem    `json:"needs,omitempty"`
-	Packages     []CheckAnswerLevelsItemDigestPackagesItem `json:"packages,omitempty"`
-	WithoutTests []string                                  `json:"without_tests,omitempty"`
-}
-
-// CheckAnswerLevelsItemKeptItem is a type of the contract.
-type CheckAnswerLevelsItemKeptItem struct {
-	Digest  string `json:"digest,omitempty"`
-	Package string `json:"package,omitempty"`
-	Tests   int64  `json:"tests,omitempty"`
-}
-
-// CheckAnswerLevelsItemUnmetItem is a type of the contract.
-type CheckAnswerLevelsItemUnmetItem struct {
-	Needs   []string `json:"needs,omitempty"`
-	Package string   `json:"package,omitempty"`
-}
-
-// CheckAnswerLevelsItem is a type of the contract.
-type CheckAnswerLevelsItem struct {
-	Digest *CheckAnswerLevelsItemDigest     `json:"digest,omitempty"`
-	Judged string                           `json:"judged,omitempty"`
-	Kept   []CheckAnswerLevelsItemKeptItem  `json:"kept,omitempty"`
-	Level  string                           `json:"level"`
-	Tests  []any                            `json:"tests,omitempty"`
-	Unmet  []CheckAnswerLevelsItemUnmetItem `json:"unmet,omitempty"`
-}
-
 // CheckAnswer is a type of the contract.
 type CheckAnswer struct {
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch  any                     `json:"fetch"`
-	Levels []CheckAnswerLevelsItem `json:"levels,omitempty"`
+	Fetch  Fetch         `json:"fetch"`
+	Levels []LevelAnswer `json:"levels,omitempty"`
 }
 
 // ComposeAnswer is a type of the contract.
@@ -289,6 +244,77 @@ type ComposeAnswer struct {
 	Verdict any `json:"verdict,omitempty"`
 }
 
+// FetchBesideItem is a type of the contract.
+type FetchBesideItem struct {
+	Commit     string `json:"commit"`
+	Repository string `json:"repository"`
+}
+
+// Fetch is what a build module's fetch tool is asked: the repository and the full commit, the pull request's ref when only its head carries the commit, the trunk commit to merge onto for a merge preview, the module's directory and named paths, the mesh packages to build against, and the sibling repositories placed beside.
+type Fetch struct {
+	// the trunk commit a merge preview merges onto
+	Base string `json:"base,omitempty"`
+	// the sibling repositories placed beside the fetched tree
+	Beside []FetchBesideItem `json:"beside,omitempty"`
+	// the full commit
+	Commit string `json:"commit"`
+	// the module's directory in the repository ("." for its root), with paths
+	Dir string `json:"dir,omitempty"`
+	// the version (a full commit) of each mesh package to build against, by its module path
+	Packages map[string]string `json:"packages,omitempty"`
+	// the paths the module names, relative to dir
+	Paths []string `json:"paths,omitempty"`
+	// the pull request's ref, when only its head carries the commit
+	Ref string `json:"ref,omitempty"`
+	// <owner>/<name>
+	Repository string `json:"repository"`
+}
+
+// LevelAnswerDigestNeedsItem is a type of the contract.
+type LevelAnswerDigestNeedsItem struct {
+	Needs   []string `json:"needs,omitempty"`
+	Package string   `json:"package,omitempty"`
+}
+
+// LevelAnswerDigestPackagesItem is a type of the contract.
+type LevelAnswerDigestPackagesItem struct {
+	Digest  string `json:"digest"`
+	Package string `json:"package"`
+}
+
+// LevelAnswerDigest is a type of the contract.
+type LevelAnswerDigest struct {
+	Beside       []string                        `json:"beside,omitempty"`
+	JudgedBy     string                          `json:"judged_by,omitempty"`
+	Level        string                          `json:"level,omitempty"`
+	Needs        []LevelAnswerDigestNeedsItem    `json:"needs,omitempty"`
+	Packages     []LevelAnswerDigestPackagesItem `json:"packages,omitempty"`
+	WithoutTests []string                        `json:"without_tests,omitempty"`
+}
+
+// LevelAnswerKeptItem is a type of the contract.
+type LevelAnswerKeptItem struct {
+	Digest  string `json:"digest,omitempty"`
+	Package string `json:"package,omitempty"`
+	Tests   int64  `json:"tests,omitempty"`
+}
+
+// LevelAnswerUnmetItem is a type of the contract.
+type LevelAnswerUnmetItem struct {
+	Needs   []string `json:"needs,omitempty"`
+	Package string   `json:"package,omitempty"`
+}
+
+// LevelAnswer is one level of a check ask: the digest's answer, the kept verdicts taken, one test result per test step run, and the packages the node could not test.
+type LevelAnswer struct {
+	Digest *LevelAnswerDigest     `json:"digest,omitempty"`
+	Judged string                 `json:"judged,omitempty"`
+	Kept   []LevelAnswerKeptItem  `json:"kept,omitempty"`
+	Level  string                 `json:"level"`
+	Tests  []any                  `json:"tests,omitempty"`
+	Unmet  []LevelAnswerUnmetItem `json:"unmet,omitempty"`
+}
+
 // Pause is whether the node takes no new ask.
 type Pause struct {
 	// when (RFC 3339 time)
@@ -308,10 +334,9 @@ type Step struct {
 	Owner string `json:"owner,omitempty"`
 	Phase string `json:"phase,omitempty"`
 	// when (RFC 3339 time)
-	PhaseAt string `json:"phase-at,omitempty"`
-	Reason  string `json:"reason,omitempty"`
-	// what the step answered
-	Result any `json:"result,omitempty"`
+	PhaseAt string      `json:"phase-at,omitempty"`
+	Reason  string      `json:"reason,omitempty"`
+	Result  *StepResult `json:"result,omitempty"`
 	// when (RFC 3339 time)
 	Started string `json:"started"`
 	// running, passed, failed or refused
@@ -322,37 +347,20 @@ type Step struct {
 	What string `json:"what,omitempty"`
 }
 
-// StepAskBuildArtifactsItem is a type of the contract.
-type StepAskBuildArtifactsItem struct {
-	Artifact string `json:"artifact"`
-	From     string `json:"from,omitempty"`
-	Seat     string `json:"seat,omitempty"`
-	Version  string `json:"version,omitempty"`
-}
-
-// StepAskBuildToolchain is a type of the contract.
-type StepAskBuildToolchain struct {
-	Language string `json:"language"`
-	Recipe   string `json:"recipe"`
-	Version  string `json:"version"`
-}
-
 // StepAskBuild is a type of the contract.
 type StepAskBuild struct {
-	Artifacts []StepAskBuildArtifactsItem `json:"artifacts"`
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch     any                    `json:"fetch,omitempty"`
-	Fp        string                 `json:"fp,omitempty"`
-	Module    string                 `json:"module"`
-	Path      string                 `json:"path,omitempty"`
-	Publish   bool                   `json:"publish,omitempty"`
-	Toolchain *StepAskBuildToolchain `json:"toolchain,omitempty"`
+	Artifacts []AskArtifact  `json:"artifacts"`
+	Fetch     *Fetch         `json:"fetch,omitempty"`
+	Fp        string         `json:"fp,omitempty"`
+	Module    string         `json:"module"`
+	Path      string         `json:"path,omitempty"`
+	Publish   bool           `json:"publish,omitempty"`
+	Toolchain *ToolchainUsed `json:"toolchain,omitempty"`
 }
 
 // StepAskCheck is a type of the contract.
 type StepAskCheck struct {
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch      any      `json:"fetch"`
+	Fetch      Fetch    `json:"fetch"`
 	Kept       bool     `json:"kept,omitempty"`
 	Levels     []string `json:"levels"`
 	Packages   []string `json:"packages,omitempty"`
@@ -363,9 +371,8 @@ type StepAskCheck struct {
 
 // StepAskCompose is a type of the contract.
 type StepAskCompose struct {
-	Dir string `json:"dir"`
-	// what the build module fetches: the repository, commit and directory, as the indexer states it
-	Fetch   any    `json:"fetch"`
+	Dir     string `json:"dir"`
+	Fetch   Fetch  `json:"fetch"`
 	Package string `json:"package"`
 	Reader  string `json:"reader,omitempty"`
 	// the compose-candidate request
@@ -392,6 +399,26 @@ type StepAsk struct {
 	V int64 `json:"v,omitempty"`
 }
 
+// StepResult is what a step answered, by the kind of ask: a build's artifacts, toolchain, imports and out-of-step modules; a check's fetch and levels; a compose's built, key and verdict; a declined ask's declined, needs and lacks. The fields of the kinds do not meet, so one layout holds the four.
+type StepResult struct {
+	Artifacts []BuiltArtifact `json:"artifacts,omitempty"`
+	Built     bool            `json:"built,omitempty"`
+	// the holder declined the ask: its node lacks what the ask needs
+	Declined bool     `json:"declined,omitempty"`
+	Fetch    *Fetch   `json:"fetch,omitempty"`
+	Imports  []string `json:"imports,omitempty"`
+	Key      string   `json:"key,omitempty"`
+	// what the holder's node lacks of it
+	Lacks  []string      `json:"lacks,omitempty"`
+	Levels []LevelAnswer `json:"levels,omitempty"`
+	// what the declined ask needs
+	Needs     []string       `json:"needs,omitempty"`
+	OutOfStep []string       `json:"out-of-step,omitempty"`
+	Toolchain *ToolchainUsed `json:"toolchain,omitempty"`
+	// the compose-candidate verdict (the composer's own layout)
+	Verdict any `json:"verdict,omitempty"`
+}
+
 // Toolchain is the toolchain a node reports.
 type Toolchain struct {
 	// when (RFC 3339 time)
@@ -404,6 +431,13 @@ type Toolchain struct {
 	Version string `json:"version"`
 }
 
+// ToolchainUsed is the toolchain a build was made with: the language, the installed version and the build module's recipe.
+type ToolchainUsed struct {
+	Language string `json:"language"`
+	Recipe   string `json:"recipe"`
+	Version  string `json:"version"`
+}
+
 // CurrentInput is what current takes.
 type CurrentInput struct {
 }
diff --git a/contracts/parts/build-step.json b/contracts/parts/build-step.json
index dfc809f6..55920376 100644
--- a/contracts/parts/build-step.json
+++ b/contracts/parts/build-step.json
@@ -64,7 +64,8 @@
         },
         "at": {
           "type": "string",
-          "description": "when (RFC 3339 time)"
+          "description": "when (RFC 3339 time)",
+          "format": "date-time"
         },
         "build": {
           "type": "object",
@@ -79,52 +80,19 @@
               "type": "string"
             },
             "fetch": {
-              "description": "what the build module fetches: the repository, commit and directory, as the indexer states it"
+              "$ref": "#/defs/Fetch"
             },
             "artifacts": {
               "type": "array",
               "items": {
-                "type": "object",
-                "properties": {
-                  "artifact": {
-                    "type": "string"
-                  },
-                  "from": {
-                    "type": "string"
-                  },
-                  "seat": {
-                    "type": "string"
-                  },
-                  "version": {
-                    "type": "string"
-                  }
-                },
-                "required": [
-                  "artifact"
-                ]
+                "$ref": "#/defs/AskArtifact"
               }
             },
             "publish": {
               "type": "boolean"
             },
             "toolchain": {
-              "type": "object",
-              "properties": {
-                "language": {
-                  "type": "string"
-                },
-                "version": {
-                  "type": "string"
-                },
-                "recipe": {
-                  "type": "string"
-                }
-              },
-              "required": [
-                "language",
-                "version",
-                "recipe"
-              ]
+              "$ref": "#/defs/ToolchainUsed"
             }
           },
           "required": [
@@ -136,7 +104,7 @@
           "type": "object",
           "properties": {
             "fetch": {
-              "description": "what the build module fetches: the repository, commit and directory, as the indexer states it"
+              "$ref": "#/defs/Fetch"
             },
             "levels": {
               "type": "array",
@@ -173,7 +141,7 @@
           "type": "object",
           "properties": {
             "fetch": {
-              "description": "what the build module fetches: the repository, commit and directory, as the indexer states it"
+              "$ref": "#/defs/Fetch"
             },
             "dir": {
               "type": "string"
@@ -223,42 +191,11 @@
         "artifacts": {
           "type": "array",
           "items": {
-            "type": "object",
-            "properties": {
-              "artifact": {
-                "type": "string"
-              },
-              "digest": {
-                "type": "string"
-              },
-              "reference": {
-                "type": "string"
-              }
-            },
-            "required": [
-              "artifact",
-              "digest"
-            ]
+            "$ref": "#/defs/BuiltArtifact"
           }
         },
         "toolchain": {
-          "type": "object",
-          "properties": {
-            "language": {
-              "type": "string"
-            },
-            "version": {
-              "type": "string"
-            },
-            "recipe": {
-              "type": "string"
-            }
-          },
-          "required": [
-            "language",
-            "version",
-            "recipe"
-          ]
+          "$ref": "#/defs/ToolchainUsed"
         },
         "imports": {
           "type": "array",
@@ -281,121 +218,12 @@
       "type": "object",
       "properties": {
         "fetch": {
-          "description": "what the build module fetches: the repository, commit and directory, as the indexer states it"
+          "$ref": "#/defs/Fetch"
         },
         "levels": {
           "type": "array",
           "items": {
-            "type": "object",
-            "properties": {
-              "level": {
-                "type": "string"
-              },
-              "judged": {
-                "type": "string"
-              },
-              "digest": {
-                "type": "object",
-                "properties": {
-                  "level": {
-                    "type": "string"
-                  },
-                  "packages": {
-                    "type": "array",
-                    "items": {
-                      "type": "object",
-                      "properties": {
-                        "package": {
-                          "type": "string"
-                        },
-                        "digest": {
-                          "type": "string"
-                        }
-                      },
-                      "required": [
-                        "package",
-                        "digest"
-                      ]
-                    }
-                  },
-                  "beside": {
-                    "type": "array",
-                    "items": {
-                      "type": "string"
-                    }
-                  },
-                  "without_tests": {
-                    "type": "array",
-                    "items": {
-                      "type": "string"
-                    }
-                  },
-                  "judged_by": {
-                    "type": "string"
-                  },
-                  "needs": {
-                    "type": "array",
-                    "items": {
-                      "type": "object",
-                      "properties": {
-                        "package": {
-                          "type": "string"
-                        },
-                        "needs": {
-                          "type": "array",
-                          "items": {
-                            "type": "string"
-                          }
-                        }
-                      }
-                    }
-                  }
-                }
-              },
-              "kept": {
-                "type": "array",
-                "items": {
-                  "type": "object",
-                  "properties": {
-                    "package": {
-                      "type": "string"
-                    },
-                    "digest": {
-                      "type": "string"
-                    },
-                    "tests": {
-                      "type": "integer"
-                    }
-                  }
-                }
-              },
-              "tests": {
-                "type": "array",
-                "items": {
-                  "description": "one test's result"
-                }
-              },
-              "unmet": {
-                "type": "array",
-                "items": {
-                  "type": "object",
-                  "properties": {
-                    "package": {
-                      "type": "string"
-                    },
-                    "needs": {
-                      "type": "array",
-                      "items": {
-                        "type": "string"
-                      }
-                    }
-                  }
-                }
-              }
-            },
-            "required": [
-              "level"
-            ]
+            "$ref": "#/defs/LevelAnswer"
           }
         }
       },
@@ -442,17 +270,19 @@
         },
         "started": {
           "type": "string",
-          "description": "when (RFC 3339 time)"
+          "description": "when (RFC 3339 time)",
+          "format": "date-time"
         },
         "ended": {
           "type": "string",
-          "description": "when (RFC 3339 time)"
+          "description": "when (RFC 3339 time)",
+          "format": "date-time"
         },
         "reason": {
           "type": "string"
         },
         "result": {
-          "description": "what the step answered"
+          "$ref": "#/defs/StepResult"
         },
         "what": {
           "type": "string"
@@ -462,7 +292,8 @@
         },
         "phase-at": {
           "type": "string",
-          "description": "when (RFC 3339 time)"
+          "description": "when (RFC 3339 time)",
+          "format": "date-time"
         },
         "owner": {
           "type": "string"
@@ -496,7 +327,8 @@
         },
         "at": {
           "type": "string",
-          "description": "when (RFC 3339 time)"
+          "description": "when (RFC 3339 time)",
+          "format": "date-time"
         }
       },
       "required": [
@@ -521,7 +353,8 @@
         },
         "at": {
           "type": "string",
-          "description": "when (RFC 3339 time)"
+          "description": "when (RFC 3339 time)",
+          "format": "date-time"
         }
       },
       "required": [
@@ -574,7 +407,8 @@
         },
         "at": {
           "type": "string",
-          "description": "when (RFC 3339 time)"
+          "description": "when (RFC 3339 time)",
+          "format": "date-time"
         }
       },
       "required": [
@@ -583,6 +417,305 @@
         "why"
       ],
       "description": "how many steps the node runs at once"
+    },
+    "Fetch": {
+      "type": "object",
+      "description": "what a build module's fetch tool is asked: the repository and the full commit, the pull request's ref when only its head carries the commit, the trunk commit to merge onto for a merge preview, the module's directory and named paths, the mesh packages to build against, and the sibling repositories placed beside",
+      "properties": {
+        "repository": {
+          "type": "string",
+          "description": "<owner>/<name>"
+        },
+        "commit": {
+          "type": "string",
+          "description": "the full commit"
+        },
+        "ref": {
+          "type": "string",
+          "description": "the pull request's ref, when only its head carries the commit"
+        },
+        "base": {
+          "type": "string",
+          "description": "the trunk commit a merge preview merges onto"
+        },
+        "dir": {
+          "type": "string",
+          "description": "the module's directory in the repository (\".\" for its root), with paths"
+        },
+        "paths": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "description": "the paths the module names, relative to dir"
+        },
+        "packages": {
+          "type": "object",
+          "additionalProperties": {
+            "type": "string"
+          },
+          "description": "the version (a full commit) of each mesh package to build against, by its module path"
+        },
+        "beside": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "properties": {
+              "repository": {
+                "type": "string"
+              },
+              "commit": {
+                "type": "string"
+              }
+            },
+            "required": [
+              "repository",
+              "commit"
+            ]
+          },
+          "description": "the sibling repositories placed beside the fetched tree"
+        }
+      },
+      "required": [
+        "repository",
+        "commit"
+      ]
+    },
+    "ToolchainUsed": {
+      "type": "object",
+      "properties": {
+        "language": {
+          "type": "string"
+        },
+        "version": {
+          "type": "string"
+        },
+        "recipe": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "language",
+        "version",
+        "recipe"
+      ],
+      "description": "the toolchain a build was made with: the language, the installed version and the build module's recipe"
+    },
+    "AskArtifact": {
+      "type": "object",
+      "properties": {
+        "artifact": {
+          "type": "string"
+        },
+        "from": {
+          "type": "string"
+        },
+        "seat": {
+          "type": "string"
+        },
+        "version": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "artifact"
+      ],
+      "description": "one artifact of a build ask: built from the fetched tree, or copied from an upstream pin"
+    },
+    "BuiltArtifact": {
+      "type": "object",
+      "properties": {
+        "artifact": {
+          "type": "string"
+        },
+        "digest": {
+          "type": "string"
+        },
+        "reference": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "artifact",
+        "digest"
+      ],
+      "description": "one artifact a build made: its digest and the reference it was published under"
+    },
+    "LevelAnswer": {
+      "type": "object",
+      "properties": {
+        "level": {
+          "type": "string"
+        },
+        "judged": {
+          "type": "string"
+        },
+        "digest": {
+          "type": "object",
+          "properties": {
+            "level": {
+              "type": "string"
+            },
+            "packages": {
+              "type": "array",
+              "items": {
+                "type": "object",
+                "properties": {
+                  "package": {
+                    "type": "string"
+                  },
+                  "digest": {
+                    "type": "string"
+                  }
+                },
+                "required": [
+                  "package",
+                  "digest"
+                ]
+              }
+            },
+            "beside": {
+              "type": "array",
+              "items": {
+                "type": "string"
+              }
+            },
+            "without_tests": {
+              "type": "array",
+              "items": {
+                "type": "string"
+              }
+            },
+            "judged_by": {
+              "type": "string"
+            },
+            "needs": {
+              "type": "array",
+              "items": {
+                "type": "object",
+                "properties": {
+                  "package": {
+                    "type": "string"
+                  },
+                  "needs": {
+                    "type": "array",
+                    "items": {
+                      "type": "string"
+                    }
+                  }
+                }
+              }
+            }
+          }
+        },
+        "kept": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "properties": {
+              "package": {
+                "type": "string"
+              },
+              "digest": {
+                "type": "string"
+              },
+              "tests": {
+                "type": "integer"
+              }
+            }
+          }
+        },
+        "tests": {
+          "type": "array",
+          "items": {
+            "description": "one test's result"
+          }
+        },
+        "unmet": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "properties": {
+              "package": {
+                "type": "string"
+              },
+              "needs": {
+                "type": "array",
+                "items": {
+                  "type": "string"
+                }
+              }
+            }
+          }
+        }
+      },
+      "required": [
+        "level"
+      ],
+      "description": "one level of a check ask: the digest's answer, the kept verdicts taken, one test result per test step run, and the packages the node could not test"
+    },
+    "StepResult": {
+      "type": "object",
+      "description": "what a step answered, by the kind of ask: a build's artifacts, toolchain, imports and out-of-step modules; a check's fetch and levels; a compose's built, key and verdict; a declined ask's declined, needs and lacks. The fields of the kinds do not meet, so one layout holds the four",
+      "properties": {
+        "artifacts": {
+          "type": "array",
+          "items": {
+            "$ref": "#/defs/BuiltArtifact"
+          }
+        },
+        "toolchain": {
+          "$ref": "#/defs/ToolchainUsed"
+        },
+        "imports": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "out-of-step": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "fetch": {
+          "$ref": "#/defs/Fetch"
+        },
+        "levels": {
+          "type": "array",
+          "items": {
+            "$ref": "#/defs/LevelAnswer"
+          }
+        },
+        "built": {
+          "type": "boolean"
+        },
+        "key": {
+          "type": "string"
+        },
+        "verdict": {
+          "description": "the compose-candidate verdict (the composer's own layout)"
+        },
+        "declined": {
+          "type": "boolean",
+          "description": "the holder declined the ask: its node lacks what the ask needs"
+        },
+        "needs": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "description": "what the declined ask needs"
+        },
+        "lacks": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "description": "what the holder's node lacks of it"
+        }
+      }
     }
   }
 }
diff --git a/contracts/seats/node-build-go/fixtures/states.json b/contracts/seats/node-build-go/fixtures/states.json
index 1988c3d4..5193a6af 100644
--- a/contracts/seats/node-build-go/fixtures/states.json
+++ b/contracts/seats/node-build-go/fixtures/states.json
@@ -59,5 +59,145 @@
         ]
       }
     }
+  },
+  {
+    "name": "a check ask with its fetch, siblings and levels",
+    "of": "accept:check",
+    "subject": "mesh.seat.node-build-go.accept.check",
+    "given": {
+      "v": 1,
+      "id": "c3d4",
+      "kind": "check",
+      "language": "go",
+      "asker": "mesh-delivery-checker",
+      "at": "2026-11-05T10:00:00Z",
+      "check": {
+        "fetch": {
+          "repository": "novox/mesh-catalog",
+          "commit": "0123456789abcdef0123456789abcdef01234567",
+          "ref": "refs/pull/7/head",
+          "base": "89abcdef0123456789abcdef0123456789abcdef",
+          "beside": [
+            {
+              "repository": "novox/mesh-sdk",
+              "commit": "fedcba9876543210fedcba9876543210fedcba98"
+            }
+          ],
+          "packages": {
+            "git.novox.be/novox/mesh-sdk/go": "fedcba9876543210fedcba9876543210fedcba98"
+          }
+        },
+        "levels": [
+          "unit",
+          "integration"
+        ],
+        "kept": true
+      }
+    }
+  },
+  {
+    "name": "a finished build step with its artifacts",
+    "of": "state:steps/<node>.<id>",
+    "given": {
+      "v": 1,
+      "id": "a1b2",
+      "tool": "build",
+      "node": "ace",
+      "state": "passed",
+      "started": "2026-11-05T10:00:00Z",
+      "ended": "2026-11-05T10:03:00Z",
+      "result": {
+        "artifacts": [
+          {
+            "artifact": "go",
+            "digest": "sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+            "reference": "container-image-registry/nats/go@sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+          }
+        ],
+        "toolchain": {
+          "language": "go",
+          "version": "1.26.0",
+          "recipe": "1"
+        },
+        "imports": [
+          "git.novox.be/novox/mesh-sdk/go"
+        ]
+      }
+    }
+  },
+  {
+    "name": "a finished check step with its levels",
+    "of": "state:steps/<node>.<id>",
+    "given": {
+      "v": 1,
+      "id": "c3d4",
+      "tool": "check",
+      "node": "ace",
+      "state": "passed",
+      "started": "2026-11-05T10:00:00Z",
+      "ended": "2026-11-05T10:06:00Z",
+      "result": {
+        "fetch": {
+          "repository": "novox/mesh-catalog",
+          "commit": "0123456789abcdef0123456789abcdef01234567"
+        },
+        "levels": [
+          {
+            "level": "unit",
+            "digest": {
+              "level": "unit",
+              "packages": [
+                {
+                  "package": "./modules/a",
+                  "digest": "sha256:bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"
+                }
+              ]
+            },
+            "kept": [
+              {
+                "package": "./modules/a",
+                "digest": "sha256:bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
+                "tests": 12
+              }
+            ],
+            "tests": [
+              {
+                "package": "./modules/b",
+                "pass": true
+              }
+            ],
+            "unmet": [
+              {
+                "package": "./modules/c",
+                "needs": [
+                  "docker"
+                ]
+              }
+            ]
+          }
+        ]
+      }
+    }
+  },
+  {
+    "name": "a declined step",
+    "of": "state:steps/<node>.<id>",
+    "given": {
+      "v": 1,
+      "id": "c3d5",
+      "tool": "check",
+      "node": "ace",
+      "state": "refused",
+      "started": "2026-11-05T10:00:00Z",
+      "result": {
+        "declined": true,
+        "needs": [
+          "docker"
+        ],
+        "lacks": [
+          "docker"
+        ]
+      }
+    }
   }
 ]
diff --git a/contracts/ts/seats/nodebuildgo/src/index.ts b/contracts/ts/seats/nodebuildgo/src/index.ts
index 24fa95b4..48102965 100644
--- a/contracts/ts/seats/nodebuildgo/src/index.ts
+++ b/contracts/ts/seats/nodebuildgo/src/index.ts
@@ -102,20 +102,22 @@ export function parseToolchainsByNodeLanguageKey(key: string): { node: string; l
   return { node, language };
 }
 
+export type AskArtifact = buildStep.AskArtifact;
 export type BuildAnswer = buildStep.BuildAnswer;
-export type BuildAnswerArtifactsItem = buildStep.BuildAnswerArtifactsItem;
-export type BuildAnswerToolchain = buildStep.BuildAnswerToolchain;
+export type BuiltArtifact = buildStep.BuiltArtifact;
 export type Capacity = buildStep.Capacity;
 export type CheckAnswer = buildStep.CheckAnswer;
-export type CheckAnswerLevelsItem = buildStep.CheckAnswerLevelsItem;
-export type CheckAnswerLevelsItemDigest = buildStep.CheckAnswerLevelsItemDigest;
-export type CheckAnswerLevelsItemDigestNeedsItem = buildStep.CheckAnswerLevelsItemDigestNeedsItem;
-export type CheckAnswerLevelsItemDigestPackagesItem = buildStep.CheckAnswerLevelsItemDigestPackagesItem;
-export type CheckAnswerLevelsItemKeptItem = buildStep.CheckAnswerLevelsItemKeptItem;
-export type CheckAnswerLevelsItemUnmetItem = buildStep.CheckAnswerLevelsItemUnmetItem;
 export type ComposeAnswer = buildStep.ComposeAnswer;
 export type CurrentAnswer = buildStep.CurrentAnswer;
 export type CurrentInput = buildStep.CurrentInput;
+export type Fetch = buildStep.Fetch;
+export type FetchBesideItem = buildStep.FetchBesideItem;
+export type LevelAnswer = buildStep.LevelAnswer;
+export type LevelAnswerDigest = buildStep.LevelAnswerDigest;
+export type LevelAnswerDigestNeedsItem = buildStep.LevelAnswerDigestNeedsItem;
+export type LevelAnswerDigestPackagesItem = buildStep.LevelAnswerDigestPackagesItem;
+export type LevelAnswerKeptItem = buildStep.LevelAnswerKeptItem;
+export type LevelAnswerUnmetItem = buildStep.LevelAnswerUnmetItem;
 export type Pause = buildStep.Pause;
 export type PauseAnswer = buildStep.PauseAnswer;
 export type PauseInput = buildStep.PauseInput;
@@ -124,11 +126,11 @@ export type ResumeInput = buildStep.ResumeInput;
 export type Step = buildStep.Step;
 export type StepAsk = buildStep.StepAsk;
 export type StepAskBuild = buildStep.StepAskBuild;
-export type StepAskBuildArtifactsItem = buildStep.StepAskBuildArtifactsItem;
-export type StepAskBuildToolchain = buildStep.StepAskBuildToolchain;
 export type StepAskCheck = buildStep.StepAskCheck;
 export type StepAskCompose = buildStep.StepAskCompose;
+export type StepResult = buildStep.StepResult;
 export type Toolchain = buildStep.Toolchain;
+export type ToolchainUsed = buildStep.ToolchainUsed;
 
 /** is the body of delivery. */
 export type DeliveryAccept = StepAsk;
diff --git a/contracts/ts/seats/nodebuildgo/src/parts/build-step.ts b/contracts/ts/seats/nodebuildgo/src/parts/build-step.ts
index fa5146dc..4ca1eb95 100644
--- a/contracts/ts/seats/nodebuildgo/src/parts/build-step.ts
+++ b/contracts/ts/seats/nodebuildgo/src/parts/build-step.ts
@@ -8,23 +8,26 @@ export const verbs = {
   resume: "resume",
 } as const;
 
-export interface BuildAnswerArtifactsItem {
+/** one artifact of a build ask: built from the fetched tree, or copied from an upstream pin */
+export interface AskArtifact {
   "artifact": string;
-  "digest": string;
-  "reference"?: string;
-}
-
-export interface BuildAnswerToolchain {
-  "language": string;
-  "recipe": string;
-  "version": string;
+  "from"?: string;
+  "seat"?: string;
+  "version"?: string;
 }
 
 export interface BuildAnswer {
-  "artifacts": BuildAnswerArtifactsItem[];
+  "artifacts": BuiltArtifact[];
   "imports"?: string[];
   "out-of-step"?: string[];
-  "toolchain"?: BuildAnswerToolchain;
+  "toolchain"?: ToolchainUsed;
+}
+
+/** one artifact a build made: its digest and the reference it was published under */
+export interface BuiltArtifact {
+  "artifact": string;
+  "digest": string;
+  "reference"?: string;
 }
 
 /** how many steps the node runs at once */
@@ -47,49 +50,9 @@ export interface Capacity {
   "why": string;
 }
 
-export interface CheckAnswerLevelsItemDigestNeedsItem {
-  "needs"?: string[];
-  "package"?: string;
-}
-
-export interface CheckAnswerLevelsItemDigestPackagesItem {
-  "digest": string;
-  "package": string;
-}
-
-export interface CheckAnswerLevelsItemDigest {
-  "beside"?: string[];
-  "judged_by"?: string;
-  "level"?: string;
-  "needs"?: CheckAnswerLevelsItemDigestNeedsItem[];
-  "packages"?: CheckAnswerLevelsItemDigestPackagesItem[];
-  "without_tests"?: string[];
-}
-
-export interface CheckAnswerLevelsItemKeptItem {
-  "digest"?: string;
-  "package"?: string;
-  "tests"?: number;
-}
-
-export interface CheckAnswerLevelsItemUnmetItem {
-  "needs"?: string[];
-  "package"?: string;
-}
-
-export interface CheckAnswerLevelsItem {
-  "digest"?: CheckAnswerLevelsItemDigest;
-  "judged"?: string;
-  "kept"?: CheckAnswerLevelsItemKeptItem[];
-  "level": string;
-  "tests"?: unknown[];
-  "unmet"?: CheckAnswerLevelsItemUnmetItem[];
-}
-
 export interface CheckAnswer {
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch": unknown;
-  "levels"?: CheckAnswerLevelsItem[];
+  "fetch": Fetch;
+  "levels"?: LevelAnswer[];
 }
 
 export interface ComposeAnswer {
@@ -99,6 +62,71 @@ export interface ComposeAnswer {
   "verdict"?: unknown;
 }
 
+export interface FetchBesideItem {
+  "commit": string;
+  "repository": string;
+}
+
+/** what a build module's fetch tool is asked: the repository and the full commit, the pull request's ref when only its head carries the commit, the trunk commit to merge onto for a merge preview, the module's directory and named paths, the mesh packages to build against, and the sibling repositories placed beside */
+export interface Fetch {
+  /** the trunk commit a merge preview merges onto */
+  "base"?: string;
+  /** the sibling repositories placed beside the fetched tree */
+  "beside"?: FetchBesideItem[];
+  /** the full commit */
+  "commit": string;
+  /** the module's directory in the repository ("." for its root), with paths */
+  "dir"?: string;
+  /** the version (a full commit) of each mesh package to build against, by its module path */
+  "packages"?: Record<string, string>;
+  /** the paths the module names, relative to dir */
+  "paths"?: string[];
+  /** the pull request's ref, when only its head carries the commit */
+  "ref"?: string;
+  /** <owner>/<name> */
+  "repository": string;
+}
+
+export interface LevelAnswerDigestNeedsItem {
+  "needs"?: string[];
+  "package"?: string;
+}
+
+export interface LevelAnswerDigestPackagesItem {
+  "digest": string;
+  "package": string;
+}
+
+export interface LevelAnswerDigest {
+  "beside"?: string[];
+  "judged_by"?: string;
+  "level"?: string;
+  "needs"?: LevelAnswerDigestNeedsItem[];
+  "packages"?: LevelAnswerDigestPackagesItem[];
+  "without_tests"?: string[];
+}
+
+export interface LevelAnswerKeptItem {
+  "digest"?: string;
+  "package"?: string;
+  "tests"?: number;
+}
+
+export interface LevelAnswerUnmetItem {
+  "needs"?: string[];
+  "package"?: string;
+}
+
+/** one level of a check ask: the digest's answer, the kept verdicts taken, one test result per test step run, and the packages the node could not test */
+export interface LevelAnswer {
+  "digest"?: LevelAnswerDigest;
+  "judged"?: string;
+  "kept"?: LevelAnswerKeptItem[];
+  "level": string;
+  "tests"?: unknown[];
+  "unmet"?: LevelAnswerUnmetItem[];
+}
+
 /** whether the node takes no new ask */
 export interface Pause {
   /** when (RFC 3339 time) */
@@ -120,8 +148,7 @@ export interface Step {
   /** when (RFC 3339 time) */
   "phase-at"?: string;
   "reason"?: string;
-  /** what the step answered */
-  "result"?: unknown;
+  "result"?: StepResult;
   /** when (RFC 3339 time) */
   "started": string;
   /** running, passed, failed or refused */
@@ -132,33 +159,18 @@ export interface Step {
   "what"?: string;
 }
 
-export interface StepAskBuildArtifactsItem {
-  "artifact": string;
-  "from"?: string;
-  "seat"?: string;
-  "version"?: string;
-}
-
-export interface StepAskBuildToolchain {
-  "language": string;
-  "recipe": string;
-  "version": string;
-}
-
 export interface StepAskBuild {
-  "artifacts": StepAskBuildArtifactsItem[];
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch"?: unknown;
+  "artifacts": AskArtifact[];
+  "fetch"?: Fetch;
   "fp"?: string;
   "module": string;
   "path"?: string;
   "publish"?: boolean;
-  "toolchain"?: StepAskBuildToolchain;
+  "toolchain"?: ToolchainUsed;
 }
 
 export interface StepAskCheck {
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch": unknown;
+  "fetch": Fetch;
   "kept"?: boolean;
   "levels": string[];
   "packages"?: string[];
@@ -169,8 +181,7 @@ export interface StepAskCheck {
 
 export interface StepAskCompose {
   "dir": string;
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch": unknown;
+  "fetch": Fetch;
   "package": string;
   "reader"?: string;
   /** the compose-candidate request */
@@ -197,6 +208,26 @@ export interface StepAsk {
   "v"?: number;
 }
 
+/** what a step answered, by the kind of ask: a build's artifacts, toolchain, imports and out-of-step modules; a check's fetch and levels; a compose's built, key and verdict; a declined ask's declined, needs and lacks. The fields of the kinds do not meet, so one layout holds the four */
+export interface StepResult {
+  "artifacts"?: BuiltArtifact[];
+  "built"?: boolean;
+  /** the holder declined the ask: its node lacks what the ask needs */
+  "declined"?: boolean;
+  "fetch"?: Fetch;
+  "imports"?: string[];
+  "key"?: string;
+  /** what the holder's node lacks of it */
+  "lacks"?: string[];
+  "levels"?: LevelAnswer[];
+  /** what the declined ask needs */
+  "needs"?: string[];
+  "out-of-step"?: string[];
+  "toolchain"?: ToolchainUsed;
+  /** the compose-candidate verdict (the composer's own layout) */
+  "verdict"?: unknown;
+}
+
 /** the toolchain a node reports */
 export interface Toolchain {
   /** when (RFC 3339 time) */
@@ -209,6 +240,13 @@ export interface Toolchain {
   "version": string;
 }
 
+/** the toolchain a build was made with: the language, the installed version and the build module's recipe */
+export interface ToolchainUsed {
+  "language": string;
+  "recipe": string;
+  "version": string;
+}
+
 /** is what current takes. */
 export interface CurrentInput {
 }
diff --git a/contracts/ts/seats/nodebuildimage/src/index.ts b/contracts/ts/seats/nodebuildimage/src/index.ts
index b289e8f7..f0312a18 100644
--- a/contracts/ts/seats/nodebuildimage/src/index.ts
+++ b/contracts/ts/seats/nodebuildimage/src/index.ts
@@ -102,20 +102,22 @@ export function parseToolchainsByNodeLanguageKey(key: string): { node: string; l
   return { node, language };
 }
 
+export type AskArtifact = buildStep.AskArtifact;
 export type BuildAnswer = buildStep.BuildAnswer;
-export type BuildAnswerArtifactsItem = buildStep.BuildAnswerArtifactsItem;
-export type BuildAnswerToolchain = buildStep.BuildAnswerToolchain;
+export type BuiltArtifact = buildStep.BuiltArtifact;
 export type Capacity = buildStep.Capacity;
 export type CheckAnswer = buildStep.CheckAnswer;
-export type CheckAnswerLevelsItem = buildStep.CheckAnswerLevelsItem;
-export type CheckAnswerLevelsItemDigest = buildStep.CheckAnswerLevelsItemDigest;
-export type CheckAnswerLevelsItemDigestNeedsItem = buildStep.CheckAnswerLevelsItemDigestNeedsItem;
-export type CheckAnswerLevelsItemDigestPackagesItem = buildStep.CheckAnswerLevelsItemDigestPackagesItem;
-export type CheckAnswerLevelsItemKeptItem = buildStep.CheckAnswerLevelsItemKeptItem;
-export type CheckAnswerLevelsItemUnmetItem = buildStep.CheckAnswerLevelsItemUnmetItem;
 export type ComposeAnswer = buildStep.ComposeAnswer;
 export type CurrentAnswer = buildStep.CurrentAnswer;
 export type CurrentInput = buildStep.CurrentInput;
+export type Fetch = buildStep.Fetch;
+export type FetchBesideItem = buildStep.FetchBesideItem;
+export type LevelAnswer = buildStep.LevelAnswer;
+export type LevelAnswerDigest = buildStep.LevelAnswerDigest;
+export type LevelAnswerDigestNeedsItem = buildStep.LevelAnswerDigestNeedsItem;
+export type LevelAnswerDigestPackagesItem = buildStep.LevelAnswerDigestPackagesItem;
+export type LevelAnswerKeptItem = buildStep.LevelAnswerKeptItem;
+export type LevelAnswerUnmetItem = buildStep.LevelAnswerUnmetItem;
 export type Pause = buildStep.Pause;
 export type PauseAnswer = buildStep.PauseAnswer;
 export type PauseInput = buildStep.PauseInput;
@@ -124,11 +126,11 @@ export type ResumeInput = buildStep.ResumeInput;
 export type Step = buildStep.Step;
 export type StepAsk = buildStep.StepAsk;
 export type StepAskBuild = buildStep.StepAskBuild;
-export type StepAskBuildArtifactsItem = buildStep.StepAskBuildArtifactsItem;
-export type StepAskBuildToolchain = buildStep.StepAskBuildToolchain;
 export type StepAskCheck = buildStep.StepAskCheck;
 export type StepAskCompose = buildStep.StepAskCompose;
+export type StepResult = buildStep.StepResult;
 export type Toolchain = buildStep.Toolchain;
+export type ToolchainUsed = buildStep.ToolchainUsed;
 
 /** is the body of delivery. */
 export type DeliveryAccept = StepAsk;
diff --git a/contracts/ts/seats/nodebuildimage/src/parts/build-step.ts b/contracts/ts/seats/nodebuildimage/src/parts/build-step.ts
index fa5146dc..4ca1eb95 100644
--- a/contracts/ts/seats/nodebuildimage/src/parts/build-step.ts
+++ b/contracts/ts/seats/nodebuildimage/src/parts/build-step.ts
@@ -8,23 +8,26 @@ export const verbs = {
   resume: "resume",
 } as const;
 
-export interface BuildAnswerArtifactsItem {
+/** one artifact of a build ask: built from the fetched tree, or copied from an upstream pin */
+export interface AskArtifact {
   "artifact": string;
-  "digest": string;
-  "reference"?: string;
-}
-
-export interface BuildAnswerToolchain {
-  "language": string;
-  "recipe": string;
-  "version": string;
+  "from"?: string;
+  "seat"?: string;
+  "version"?: string;
 }
 
 export interface BuildAnswer {
-  "artifacts": BuildAnswerArtifactsItem[];
+  "artifacts": BuiltArtifact[];
   "imports"?: string[];
   "out-of-step"?: string[];
-  "toolchain"?: BuildAnswerToolchain;
+  "toolchain"?: ToolchainUsed;
+}
+
+/** one artifact a build made: its digest and the reference it was published under */
+export interface BuiltArtifact {
+  "artifact": string;
+  "digest": string;
+  "reference"?: string;
 }
 
 /** how many steps the node runs at once */
@@ -47,49 +50,9 @@ export interface Capacity {
   "why": string;
 }
 
-export interface CheckAnswerLevelsItemDigestNeedsItem {
-  "needs"?: string[];
-  "package"?: string;
-}
-
-export interface CheckAnswerLevelsItemDigestPackagesItem {
-  "digest": string;
-  "package": string;
-}
-
-export interface CheckAnswerLevelsItemDigest {
-  "beside"?: string[];
-  "judged_by"?: string;
-  "level"?: string;
-  "needs"?: CheckAnswerLevelsItemDigestNeedsItem[];
-  "packages"?: CheckAnswerLevelsItemDigestPackagesItem[];
-  "without_tests"?: string[];
-}
-
-export interface CheckAnswerLevelsItemKeptItem {
-  "digest"?: string;
-  "package"?: string;
-  "tests"?: number;
-}
-
-export interface CheckAnswerLevelsItemUnmetItem {
-  "needs"?: string[];
-  "package"?: string;
-}
-
-export interface CheckAnswerLevelsItem {
-  "digest"?: CheckAnswerLevelsItemDigest;
-  "judged"?: string;
-  "kept"?: CheckAnswerLevelsItemKeptItem[];
-  "level": string;
-  "tests"?: unknown[];
-  "unmet"?: CheckAnswerLevelsItemUnmetItem[];
-}
-
 export interface CheckAnswer {
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch": unknown;
-  "levels"?: CheckAnswerLevelsItem[];
+  "fetch": Fetch;
+  "levels"?: LevelAnswer[];
 }
 
 export interface ComposeAnswer {
@@ -99,6 +62,71 @@ export interface ComposeAnswer {
   "verdict"?: unknown;
 }
 
+export interface FetchBesideItem {
+  "commit": string;
+  "repository": string;
+}
+
+/** what a build module's fetch tool is asked: the repository and the full commit, the pull request's ref when only its head carries the commit, the trunk commit to merge onto for a merge preview, the module's directory and named paths, the mesh packages to build against, and the sibling repositories placed beside */
+export interface Fetch {
+  /** the trunk commit a merge preview merges onto */
+  "base"?: string;
+  /** the sibling repositories placed beside the fetched tree */
+  "beside"?: FetchBesideItem[];
+  /** the full commit */
+  "commit": string;
+  /** the module's directory in the repository ("." for its root), with paths */
+  "dir"?: string;
+  /** the version (a full commit) of each mesh package to build against, by its module path */
+  "packages"?: Record<string, string>;
+  /** the paths the module names, relative to dir */
+  "paths"?: string[];
+  /** the pull request's ref, when only its head carries the commit */
+  "ref"?: string;
+  /** <owner>/<name> */
+  "repository": string;
+}
+
+export interface LevelAnswerDigestNeedsItem {
+  "needs"?: string[];
+  "package"?: string;
+}
+
+export interface LevelAnswerDigestPackagesItem {
+  "digest": string;
+  "package": string;
+}
+
+export interface LevelAnswerDigest {
+  "beside"?: string[];
+  "judged_by"?: string;
+  "level"?: string;
+  "needs"?: LevelAnswerDigestNeedsItem[];
+  "packages"?: LevelAnswerDigestPackagesItem[];
+  "without_tests"?: string[];
+}
+
+export interface LevelAnswerKeptItem {
+  "digest"?: string;
+  "package"?: string;
+  "tests"?: number;
+}
+
+export interface LevelAnswerUnmetItem {
+  "needs"?: string[];
+  "package"?: string;
+}
+
+/** one level of a check ask: the digest's answer, the kept verdicts taken, one test result per test step run, and the packages the node could not test */
+export interface LevelAnswer {
+  "digest"?: LevelAnswerDigest;
+  "judged"?: string;
+  "kept"?: LevelAnswerKeptItem[];
+  "level": string;
+  "tests"?: unknown[];
+  "unmet"?: LevelAnswerUnmetItem[];
+}
+
 /** whether the node takes no new ask */
 export interface Pause {
   /** when (RFC 3339 time) */
@@ -120,8 +148,7 @@ export interface Step {
   /** when (RFC 3339 time) */
   "phase-at"?: string;
   "reason"?: string;
-  /** what the step answered */
-  "result"?: unknown;
+  "result"?: StepResult;
   /** when (RFC 3339 time) */
   "started": string;
   /** running, passed, failed or refused */
@@ -132,33 +159,18 @@ export interface Step {
   "what"?: string;
 }
 
-export interface StepAskBuildArtifactsItem {
-  "artifact": string;
-  "from"?: string;
-  "seat"?: string;
-  "version"?: string;
-}
-
-export interface StepAskBuildToolchain {
-  "language": string;
-  "recipe": string;
-  "version": string;
-}
-
 export interface StepAskBuild {
-  "artifacts": StepAskBuildArtifactsItem[];
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch"?: unknown;
+  "artifacts": AskArtifact[];
+  "fetch"?: Fetch;
   "fp"?: string;
   "module": string;
   "path"?: string;
   "publish"?: boolean;
-  "toolchain"?: StepAskBuildToolchain;
+  "toolchain"?: ToolchainUsed;
 }
 
 export interface StepAskCheck {
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch": unknown;
+  "fetch": Fetch;
   "kept"?: boolean;
   "levels": string[];
   "packages"?: string[];
@@ -169,8 +181,7 @@ export interface StepAskCheck {
 
 export interface StepAskCompose {
   "dir": string;
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch": unknown;
+  "fetch": Fetch;
   "package": string;
   "reader"?: string;
   /** the compose-candidate request */
@@ -197,6 +208,26 @@ export interface StepAsk {
   "v"?: number;
 }
 
+/** what a step answered, by the kind of ask: a build's artifacts, toolchain, imports and out-of-step modules; a check's fetch and levels; a compose's built, key and verdict; a declined ask's declined, needs and lacks. The fields of the kinds do not meet, so one layout holds the four */
+export interface StepResult {
+  "artifacts"?: BuiltArtifact[];
+  "built"?: boolean;
+  /** the holder declined the ask: its node lacks what the ask needs */
+  "declined"?: boolean;
+  "fetch"?: Fetch;
+  "imports"?: string[];
+  "key"?: string;
+  /** what the holder's node lacks of it */
+  "lacks"?: string[];
+  "levels"?: LevelAnswer[];
+  /** what the declined ask needs */
+  "needs"?: string[];
+  "out-of-step"?: string[];
+  "toolchain"?: ToolchainUsed;
+  /** the compose-candidate verdict (the composer's own layout) */
+  "verdict"?: unknown;
+}
+
 /** the toolchain a node reports */
 export interface Toolchain {
   /** when (RFC 3339 time) */
@@ -209,6 +240,13 @@ export interface Toolchain {
   "version": string;
 }
 
+/** the toolchain a build was made with: the language, the installed version and the build module's recipe */
+export interface ToolchainUsed {
+  "language": string;
+  "recipe": string;
+  "version": string;
+}
+
 /** is what current takes. */
 export interface CurrentInput {
 }
diff --git a/contracts/ts/seats/nodebuildnode/src/index.ts b/contracts/ts/seats/nodebuildnode/src/index.ts
index d84ca0ae..99f5963c 100644
--- a/contracts/ts/seats/nodebuildnode/src/index.ts
+++ b/contracts/ts/seats/nodebuildnode/src/index.ts
@@ -102,20 +102,22 @@ export function parseToolchainsByNodeLanguageKey(key: string): { node: string; l
   return { node, language };
 }
 
+export type AskArtifact = buildStep.AskArtifact;
 export type BuildAnswer = buildStep.BuildAnswer;
-export type BuildAnswerArtifactsItem = buildStep.BuildAnswerArtifactsItem;
-export type BuildAnswerToolchain = buildStep.BuildAnswerToolchain;
+export type BuiltArtifact = buildStep.BuiltArtifact;
 export type Capacity = buildStep.Capacity;
 export type CheckAnswer = buildStep.CheckAnswer;
-export type CheckAnswerLevelsItem = buildStep.CheckAnswerLevelsItem;
-export type CheckAnswerLevelsItemDigest = buildStep.CheckAnswerLevelsItemDigest;
-export type CheckAnswerLevelsItemDigestNeedsItem = buildStep.CheckAnswerLevelsItemDigestNeedsItem;
-export type CheckAnswerLevelsItemDigestPackagesItem = buildStep.CheckAnswerLevelsItemDigestPackagesItem;
-export type CheckAnswerLevelsItemKeptItem = buildStep.CheckAnswerLevelsItemKeptItem;
-export type CheckAnswerLevelsItemUnmetItem = buildStep.CheckAnswerLevelsItemUnmetItem;
 export type ComposeAnswer = buildStep.ComposeAnswer;
 export type CurrentAnswer = buildStep.CurrentAnswer;
 export type CurrentInput = buildStep.CurrentInput;
+export type Fetch = buildStep.Fetch;
+export type FetchBesideItem = buildStep.FetchBesideItem;
+export type LevelAnswer = buildStep.LevelAnswer;
+export type LevelAnswerDigest = buildStep.LevelAnswerDigest;
+export type LevelAnswerDigestNeedsItem = buildStep.LevelAnswerDigestNeedsItem;
+export type LevelAnswerDigestPackagesItem = buildStep.LevelAnswerDigestPackagesItem;
+export type LevelAnswerKeptItem = buildStep.LevelAnswerKeptItem;
+export type LevelAnswerUnmetItem = buildStep.LevelAnswerUnmetItem;
 export type Pause = buildStep.Pause;
 export type PauseAnswer = buildStep.PauseAnswer;
 export type PauseInput = buildStep.PauseInput;
@@ -124,11 +126,11 @@ export type ResumeInput = buildStep.ResumeInput;
 export type Step = buildStep.Step;
 export type StepAsk = buildStep.StepAsk;
 export type StepAskBuild = buildStep.StepAskBuild;
-export type StepAskBuildArtifactsItem = buildStep.StepAskBuildArtifactsItem;
-export type StepAskBuildToolchain = buildStep.StepAskBuildToolchain;
 export type StepAskCheck = buildStep.StepAskCheck;
 export type StepAskCompose = buildStep.StepAskCompose;
+export type StepResult = buildStep.StepResult;
 export type Toolchain = buildStep.Toolchain;
+export type ToolchainUsed = buildStep.ToolchainUsed;
 
 /** is the body of delivery. */
 export type DeliveryAccept = StepAsk;
diff --git a/contracts/ts/seats/nodebuildnode/src/parts/build-step.ts b/contracts/ts/seats/nodebuildnode/src/parts/build-step.ts
index fa5146dc..4ca1eb95 100644
--- a/contracts/ts/seats/nodebuildnode/src/parts/build-step.ts
+++ b/contracts/ts/seats/nodebuildnode/src/parts/build-step.ts
@@ -8,23 +8,26 @@ export const verbs = {
   resume: "resume",
 } as const;
 
-export interface BuildAnswerArtifactsItem {
+/** one artifact of a build ask: built from the fetched tree, or copied from an upstream pin */
+export interface AskArtifact {
   "artifact": string;
-  "digest": string;
-  "reference"?: string;
-}
-
-export interface BuildAnswerToolchain {
-  "language": string;
-  "recipe": string;
-  "version": string;
+  "from"?: string;
+  "seat"?: string;
+  "version"?: string;
 }
 
 export interface BuildAnswer {
-  "artifacts": BuildAnswerArtifactsItem[];
+  "artifacts": BuiltArtifact[];
   "imports"?: string[];
   "out-of-step"?: string[];
-  "toolchain"?: BuildAnswerToolchain;
+  "toolchain"?: ToolchainUsed;
+}
+
+/** one artifact a build made: its digest and the reference it was published under */
+export interface BuiltArtifact {
+  "artifact": string;
+  "digest": string;
+  "reference"?: string;
 }
 
 /** how many steps the node runs at once */
@@ -47,49 +50,9 @@ export interface Capacity {
   "why": string;
 }
 
-export interface CheckAnswerLevelsItemDigestNeedsItem {
-  "needs"?: string[];
-  "package"?: string;
-}
-
-export interface CheckAnswerLevelsItemDigestPackagesItem {
-  "digest": string;
-  "package": string;
-}
-
-export interface CheckAnswerLevelsItemDigest {
-  "beside"?: string[];
-  "judged_by"?: string;
-  "level"?: string;
-  "needs"?: CheckAnswerLevelsItemDigestNeedsItem[];
-  "packages"?: CheckAnswerLevelsItemDigestPackagesItem[];
-  "without_tests"?: string[];
-}
-
-export interface CheckAnswerLevelsItemKeptItem {
-  "digest"?: string;
-  "package"?: string;
-  "tests"?: number;
-}
-
-export interface CheckAnswerLevelsItemUnmetItem {
-  "needs"?: string[];
-  "package"?: string;
-}
-
-export interface CheckAnswerLevelsItem {
-  "digest"?: CheckAnswerLevelsItemDigest;
-  "judged"?: string;
-  "kept"?: CheckAnswerLevelsItemKeptItem[];
-  "level": string;
-  "tests"?: unknown[];
-  "unmet"?: CheckAnswerLevelsItemUnmetItem[];
-}
-
 export interface CheckAnswer {
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch": unknown;
-  "levels"?: CheckAnswerLevelsItem[];
+  "fetch": Fetch;
+  "levels"?: LevelAnswer[];
 }
 
 export interface ComposeAnswer {
@@ -99,6 +62,71 @@ export interface ComposeAnswer {
   "verdict"?: unknown;
 }
 
+export interface FetchBesideItem {
+  "commit": string;
+  "repository": string;
+}
+
+/** what a build module's fetch tool is asked: the repository and the full commit, the pull request's ref when only its head carries the commit, the trunk commit to merge onto for a merge preview, the module's directory and named paths, the mesh packages to build against, and the sibling repositories placed beside */
+export interface Fetch {
+  /** the trunk commit a merge preview merges onto */
+  "base"?: string;
+  /** the sibling repositories placed beside the fetched tree */
+  "beside"?: FetchBesideItem[];
+  /** the full commit */
+  "commit": string;
+  /** the module's directory in the repository ("." for its root), with paths */
+  "dir"?: string;
+  /** the version (a full commit) of each mesh package to build against, by its module path */
+  "packages"?: Record<string, string>;
+  /** the paths the module names, relative to dir */
+  "paths"?: string[];
+  /** the pull request's ref, when only its head carries the commit */
+  "ref"?: string;
+  /** <owner>/<name> */
+  "repository": string;
+}
+
+export interface LevelAnswerDigestNeedsItem {
+  "needs"?: string[];
+  "package"?: string;
+}
+
+export interface LevelAnswerDigestPackagesItem {
+  "digest": string;
+  "package": string;
+}
+
+export interface LevelAnswerDigest {
+  "beside"?: string[];
+  "judged_by"?: string;
+  "level"?: string;
+  "needs"?: LevelAnswerDigestNeedsItem[];
+  "packages"?: LevelAnswerDigestPackagesItem[];
+  "without_tests"?: string[];
+}
+
+export interface LevelAnswerKeptItem {
+  "digest"?: string;
+  "package"?: string;
+  "tests"?: number;
+}
+
+export interface LevelAnswerUnmetItem {
+  "needs"?: string[];
+  "package"?: string;
+}
+
+/** one level of a check ask: the digest's answer, the kept verdicts taken, one test result per test step run, and the packages the node could not test */
+export interface LevelAnswer {
+  "digest"?: LevelAnswerDigest;
+  "judged"?: string;
+  "kept"?: LevelAnswerKeptItem[];
+  "level": string;
+  "tests"?: unknown[];
+  "unmet"?: LevelAnswerUnmetItem[];
+}
+
 /** whether the node takes no new ask */
 export interface Pause {
   /** when (RFC 3339 time) */
@@ -120,8 +148,7 @@ export interface Step {
   /** when (RFC 3339 time) */
   "phase-at"?: string;
   "reason"?: string;
-  /** what the step answered */
-  "result"?: unknown;
+  "result"?: StepResult;
   /** when (RFC 3339 time) */
   "started": string;
   /** running, passed, failed or refused */
@@ -132,33 +159,18 @@ export interface Step {
   "what"?: string;
 }
 
-export interface StepAskBuildArtifactsItem {
-  "artifact": string;
-  "from"?: string;
-  "seat"?: string;
-  "version"?: string;
-}
-
-export interface StepAskBuildToolchain {
-  "language": string;
-  "recipe": string;
-  "version": string;
-}
-
 export interface StepAskBuild {
-  "artifacts": StepAskBuildArtifactsItem[];
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch"?: unknown;
+  "artifacts": AskArtifact[];
+  "fetch"?: Fetch;
   "fp"?: string;
   "module": string;
   "path"?: string;
   "publish"?: boolean;
-  "toolchain"?: StepAskBuildToolchain;
+  "toolchain"?: ToolchainUsed;
 }
 
 export interface StepAskCheck {
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch": unknown;
+  "fetch": Fetch;
   "kept"?: boolean;
   "levels": string[];
   "packages"?: string[];
@@ -169,8 +181,7 @@ export interface StepAskCheck {
 
 export interface StepAskCompose {
   "dir": string;
-  /** what the build module fetches: the repository, commit and directory, as the indexer states it */
-  "fetch": unknown;
+  "fetch": Fetch;
   "package": string;
   "reader"?: string;
   /** the compose-candidate request */
@@ -197,6 +208,26 @@ export interface StepAsk {
   "v"?: number;
 }
 
+/** what a step answered, by the kind of ask: a build's artifacts, toolchain, imports and out-of-step modules; a check's fetch and levels; a compose's built, key and verdict; a declined ask's declined, needs and lacks. The fields of the kinds do not meet, so one layout holds the four */
+export interface StepResult {
+  "artifacts"?: BuiltArtifact[];
+  "built"?: boolean;
+  /** the holder declined the ask: its node lacks what the ask needs */
+  "declined"?: boolean;
+  "fetch"?: Fetch;
+  "imports"?: string[];
+  "key"?: string;
+  /** what the holder's node lacks of it */
+  "lacks"?: string[];
+  "levels"?: LevelAnswer[];
+  /** what the declined ask needs */
+  "needs"?: string[];
+  "out-of-step"?: string[];
+  "toolchain"?: ToolchainUsed;
+  /** the compose-candidate verdict (the composer's own layout) */
+  "verdict"?: unknown;
+}
+
 /** the toolchain a node reports */
 export interface Toolchain {
   /** when (RFC 3339 time) */
@@ -209,6 +240,13 @@ export interface Toolchain {
   "version": string;
 }
 
+/** the toolchain a build was made with: the language, the installed version and the build module's recipe */
+export interface ToolchainUsed {
+  "language": string;
+  "recipe": string;
+  "version": string;
+}
+
 /** is what current takes. */
 export interface CurrentInput {
 }