diff --git a/contracts/go/seats/meshbuilds/contract.go b/contracts/go/seats/meshbuilds/contract.go
index 298fe378..bbf20ee0 100644
--- a/contracts/go/seats/meshbuilds/contract.go
+++ b/contracts/go/seats/meshbuilds/contract.go
@@ -45,14 +45,14 @@ const StreamToolchainAgreed = "SEAT_mesh-builds_toolchain-agreed"
 // SubjectToolchainAgreed is where toolchain-agreed is published.
 const SubjectToolchainAgreed = "mesh.seat.mesh-builds.event.toolchain-agreed"
 
-// Dependency is a dependency the build resolved, named by the build module in its step key and carried by the builder (design 47 G section 374).
+// Dependency is a dependency the build resolved: one item of kind 1 for each resolved package and one of kind 3 for the toolchain, named by the build module in its step key and carried by the builder (design 47 G 374, 673).
 type Dependency struct {
-	// the dependency's artifact reference, <module>:<artifact>
-	Artifact string `json:"artifact"`
 	// the digest of the part, as the build used it
 	Digest string `json:"digest"`
 	// 1 an imported package, 3 the build toolchain (design 47 G section 374)
 	Kind int64 `json:"kind"`
+	// the dependency's part: for kind 1 the package's artifact reference, <module>:<artifact>; for kind 3 the agreed toolchain's part (design 47 G 466, 673)
+	Part string `json:"part"`
 	// the version of the dependency the build resolved
 	Version string `json:"version"`
 }
diff --git a/contracts/go/seats/meshbuilds/contract_test.go b/contracts/go/seats/meshbuilds/contract_test.go
index 16da9fcc..1edf441c 100644
--- a/contracts/go/seats/meshbuilds/contract_test.go
+++ b/contracts/go/seats/meshbuilds/contract_test.go
@@ -17,7 +17,7 @@ func TestFixtures(t *testing.T) {
 		decode                     func([]byte) (any, error)
 		subjectIs                  *regexp.Regexp
 	}{
-		{name: "a package published with the dependencies the build resolved", subject: "mesh.seat.mesh-builds.event.package-published", given: "{\"artifact\":\"mesh-sdk:go\",\"at\":\"2026-11-10T10:00:00Z\",\"branch\":\"main\",\"dependencies\":[{\"artifact\":\"mesh-contracts:go-nodeengine\",\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"kind\":1,\"version\":\"0.1.4\"},{\"artifact\":\"mesh-build-go:toolchain\",\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"kind\":3,\"version\":\"1.26.0\"}],\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"module\":\"mesh-sdk\",\"source\":3589,\"v\":1,\"version\":\"0.1.15\"}", wire: "{\"artifact\":\"mesh-sdk:go\",\"at\":\"2026-11-10T10:00:00Z\",\"branch\":\"main\",\"dependencies\":[{\"artifact\":\"mesh-contracts:go-nodeengine\",\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"kind\":1,\"version\":\"0.1.4\"},{\"artifact\":\"mesh-build-go:toolchain\",\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"kind\":3,\"version\":\"1.26.0\"}],\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"module\":\"mesh-sdk\",\"source\":3589,\"v\":1,\"version\":\"0.1.15\"}",
+		{name: "a package published with the dependencies the build resolved", subject: "mesh.seat.mesh-builds.event.package-published", given: "{\"artifact\":\"mesh-sdk:go\",\"at\":\"2026-11-10T10:00:00Z\",\"branch\":\"main\",\"dependencies\":[{\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"kind\":1,\"part\":\"mesh-contracts:go-nodeengine\",\"version\":\"0.1.4\"},{\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"kind\":3,\"part\":\"mesh-build-go:toolchain\",\"version\":\"1.26.0\"}],\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"module\":\"mesh-sdk\",\"source\":3589,\"v\":1,\"version\":\"0.1.15\"}", wire: "{\"artifact\":\"mesh-sdk:go\",\"at\":\"2026-11-10T10:00:00Z\",\"branch\":\"main\",\"dependencies\":[{\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"kind\":1,\"part\":\"mesh-contracts:go-nodeengine\",\"version\":\"0.1.4\"},{\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"kind\":3,\"part\":\"mesh-build-go:toolchain\",\"version\":\"1.26.0\"}],\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"module\":\"mesh-sdk\",\"source\":3589,\"v\":1,\"version\":\"0.1.15\"}",
 			decode: func(b []byte) (any, error) { var v PackagePublishedEvent; err := json.Unmarshal(b, &v); return v, err }, subjectIs: regexp.MustCompile("^mesh\\.seat\\.mesh-builds\\.event\\.package-published$")},
 		{name: "a toolchain agreed", subject: "mesh.seat.mesh-builds.event.toolchain-agreed", given: "{\"at\":\"2026-11-10T10:00:00Z\",\"digests\":[{\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"nodes\":[\"ace\",\"g14\"]},{\"digest\":\"sha256:fedcba9876543210fedcba9876543210fedcba9876543210fedcba9876543210\",\"nodes\":[\"novox\"]}],\"language\":\"go\",\"v\":1,\"version\":\"1.26.0\"}", wire: "{\"at\":\"2026-11-10T10:00:00Z\",\"digests\":[{\"digest\":\"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\",\"nodes\":[\"ace\",\"g14\"]},{\"digest\":\"sha256:fedcba9876543210fedcba9876543210fedcba9876543210fedcba9876543210\",\"nodes\":[\"novox\"]}],\"language\":\"go\",\"v\":1,\"version\":\"1.26.0\"}",
 			decode: func(b []byte) (any, error) { var v ToolchainAgreedEvent; err := json.Unmarshal(b, &v); return v, err }, subjectIs: regexp.MustCompile("^mesh\\.seat\\.mesh-builds\\.event\\.toolchain-agreed$")},
diff --git a/contracts/seats/mesh-builds/fixtures/events.json b/contracts/seats/mesh-builds/fixtures/events.json
index 44192577..69f20574 100644
--- a/contracts/seats/mesh-builds/fixtures/events.json
+++ b/contracts/seats/mesh-builds/fixtures/events.json
@@ -13,16 +13,16 @@
       "source": 3589,
       "dependencies": [
         {
-          "artifact": "mesh-contracts:go-nodeengine",
           "kind": 1,
           "version": "0.1.4",
-          "digest": "sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+          "digest": "sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
+          "part": "mesh-contracts:go-nodeengine"
         },
         {
-          "artifact": "mesh-build-go:toolchain",
           "kind": 3,
           "version": "1.26.0",
-          "digest": "sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+          "digest": "sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
+          "part": "mesh-build-go:toolchain"
         }
       ],
       "at": "2026-11-10T10:00:00Z"
diff --git a/contracts/seats/mesh-builds/seat.json b/contracts/seats/mesh-builds/seat.json
index fca0bacf..c984ac2e 100644
--- a/contracts/seats/mesh-builds/seat.json
+++ b/contracts/seats/mesh-builds/seat.json
@@ -108,9 +108,9 @@
     "Dependency": {
       "type": "object",
       "properties": {
-        "artifact": {
+        "part": {
           "type": "string",
-          "description": "the dependency's artifact reference, <module>:<artifact>"
+          "description": "the dependency's part: for kind 1 the package's artifact reference, <module>:<artifact>; for kind 3 the agreed toolchain's part (design 47 G 466, 673)"
         },
         "kind": {
           "type": "integer",
@@ -130,12 +130,12 @@
         }
       },
       "required": [
-        "artifact",
+        "part",
         "kind",
         "version",
         "digest"
       ],
-      "description": "a dependency the build resolved, named by the build module in its step key and carried by the builder (design 47 G section 374)"
+      "description": "a dependency the build resolved: one item of kind 1 for each resolved package and one of kind 3 for the toolchain, named by the build module in its step key and carried by the builder (design 47 G 374, 673)"
     },
     "PackagePublished": {
       "type": "object",
diff --git a/contracts/ts/seats/meshbuilds/index.d.ts b/contracts/ts/seats/meshbuilds/index.d.ts
index f02549ab..426f20d5 100644
--- a/contracts/ts/seats/meshbuilds/index.d.ts
+++ b/contracts/ts/seats/meshbuilds/index.d.ts
@@ -23,14 +23,14 @@ export declare const toolchainAgreedStream: "SEAT_mesh-builds_toolchain-agreed";
 
 export declare const toolchainAgreedSubject: "mesh.seat.mesh-builds.event.toolchain-agreed";
 
-/** a dependency the build resolved, named by the build module in its step key and carried by the builder (design 47 G section 374) */
+/** a dependency the build resolved: one item of kind 1 for each resolved package and one of kind 3 for the toolchain, named by the build module in its step key and carried by the builder (design 47 G 374, 673) */
 export interface Dependency {
-  /** the dependency's artifact reference, <module>:<artifact> */
-  "artifact": string;
   /** the digest of the part, as the build used it */
   "digest": string;
   /** 1 an imported package, 3 the build toolchain (design 47 G section 374) */
   "kind": number;
+  /** the dependency's part: for kind 1 the package's artifact reference, <module>:<artifact>; for kind 3 the agreed toolchain's part (design 47 G 466, 673) */
+  "part": string;
   /** the version of the dependency the build resolved */
   "version": string;
 }