diff --git a/contracts/parts/build-step.json b/contracts/parts/build-step.json
index b92efdb3..872d1435 100644
--- a/contracts/parts/build-step.json
+++ b/contracts/parts/build-step.json
@@ -42,7 +42,10 @@
     {
       "name": "drop",
       "description": "End an ask this node holds for a caller that no longer waits for it: a step not yet running is ended dropped when the bus gives it, one running is cancelled; both end the step dropped, naming who dropped it and why. Writes dropped.<id> in the pauses state; the build module removes the key when it has acted.",
-      "callers": "the build seats' asker (the builder and the checker)",
+      "callers": [
+        "seat:mesh-pipeline-runner",
+        "seat:mesh-builds"
+      ],
       "input": {
         "type": "object",
         "properties": {
@@ -67,7 +70,153 @@
       "answer": {
         "type": "object",
         "description": "whether the ask was held here"
-      }
+      },
+      "class": "act"
+    },
+    {
+      "name": "kept-artifact",
+      "description": "The one build this node keeps instead of storing it through the seat oci-artifact-registry: the new build of that seat's holder, when the running holder refused or did not answer the store (design 47 *The artifact store's holder takes its own new build even when its seat is the one broken*). Answers where the bytes are, as an object by their digest on the bus (the old objects form, ADR 0619 \u00a72), never in the answer; the node-engine checks what it fetched against the digest and applies nothing that differs. A module that claims no oci-artifact-registry is refused by name, so a store outage never becomes a delivery from build nodes; so is a build this node no longer keeps, or keeps under another digest.",
+      "input": {
+        "type": "object",
+        "properties": {
+          "module": {
+            "type": "string",
+            "description": "the module, the holder of oci-artifact-registry",
+            "minLength": 1
+          },
+          "fp": {
+            "type": "string",
+            "description": "its build's fingerprint",
+            "minLength": 1
+          },
+          "digest": {
+            "type": "string",
+            "description": "the artifact's sha256, 64 lowercase hex digits, as the builder's done key names it",
+            "pattern": "^[0-9a-f]{64}$"
+          }
+        },
+        "required": [
+          "module",
+          "fp",
+          "digest"
+        ]
+      },
+      "answer": {
+        "type": "object",
+        "properties": {
+          "module": {
+            "type": "string",
+            "description": "the module asked"
+          },
+          "fp": {
+            "type": "string",
+            "description": "the fingerprint asked"
+          },
+          "digest": {
+            "type": "string",
+            "description": "the digest of the bytes kept",
+            "pattern": "^[0-9a-f]{64}$"
+          },
+          "size": {
+            "type": "integer",
+            "description": "bytes"
+          },
+          "store": {
+            "type": "string",
+            "description": "the object store the bytes are in, the build module's kept builds, as its manifest's objects names it on the bus"
+          },
+          "object": {
+            "type": "string",
+            "description": "the object's name in it: the digest"
+          },
+          "refused": {
+            "type": "string",
+            "enum": [
+              "claims no oci-artifact-registry",
+              "not kept",
+              "digest differs"
+            ],
+            "description": "why nothing is answered: the module claims no oci-artifact-registry, this node keeps no build of it at that fingerprint (never kept, or swept), or keeps it under another digest"
+          },
+          "words": {
+            "type": "string",
+            "description": "the refusal in words, naming the module"
+          },
+          "error": {
+            "type": "string",
+            "description": "why it could not answer"
+          }
+        },
+        "required": [
+          "module",
+          "fp"
+        ]
+      },
+      "callers": [
+        "seat:node-engine"
+      ],
+      "class": "read"
+    },
+    {
+      "name": "steps",
+      "description": "Which pipeline steps an artifact can run, found by its language's convention (design 47 *Pipeline steps and the policy*): lint always, unit and integration tests where its packages hold them. Kept by the artifact's fingerprint; again finds them anew.",
+      "callers": [
+        "seat:mesh-pipeline-runner",
+        "seat:mesh-catalog"
+      ],
+      "input": {
+        "type": "object",
+        "properties": {
+          "module": {
+            "type": "string"
+          },
+          "artifact": {
+            "type": "string",
+            "description": "the artifact reference, <module>:<artifact>"
+          },
+          "fingerprint": {
+            "type": "string"
+          },
+          "fetch": {
+            "$ref": "#/defs/Fetch"
+          },
+          "again": {
+            "type": "boolean",
+            "description": "find them anew, not from the kept answer"
+          }
+        },
+        "required": [
+          "module",
+          "artifact",
+          "fetch"
+        ]
+      },
+      "answer": {
+        "type": "object",
+        "properties": {
+          "artifact": {
+            "type": "string"
+          },
+          "fingerprint": {
+            "type": "string"
+          },
+          "steps": {
+            "type": "array",
+            "items": {
+              "$ref": "#/defs/DetectedStep"
+            }
+          },
+          "kept": {
+            "type": "boolean",
+            "description": "answered from the kept answer"
+          }
+        },
+        "required": [
+          "artifact",
+          "steps"
+        ]
+      },
+      "class": "act"
     }
   ],
   "defs": {
@@ -83,7 +232,7 @@
         },
         "kind": {
           "type": "string",
-          "description": "build, check or compose"
+          "description": "build, check, compose or step"
         },
         "language": {
           "type": "string",
@@ -220,6 +369,10 @@
             "type": "string"
           },
           "description": "package to the tagged version a build pins"
+        },
+        "step": {
+          "$ref": "#/defs/StepRun",
+          "description": "a pipeline step: lint, unit tests or integration tests of one artifact at one commit, sent by the runner as the accepted kind step (design 47 *The steps and who serves them*)"
         }
       },
       "required": [
@@ -253,6 +406,10 @@
           "items": {
             "type": "string"
           }
+        },
+        "kept": {
+          "type": "string",
+          "description": "the digest of the artifact this node kept for the artifact store's holder instead of storing it through the seat oci-artifact-registry (the verb kept-artifact serves it); the keeping node is the step's own; absent when every artifact was stored"
         }
       },
       "required": [
@@ -665,11 +822,21 @@
           "type": "object",
           "description": "the TypeScript module's group package: the group's tagged version of the SDK ({name, version}), placed from the registry in each member whatever its lock names, or the group's package member ({repository, commit, ref}), packed by the fetch and served to the members in place of the registry's",
           "properties": {
-            "name": { "type": "string" },
-            "version": { "type": "string" },
-            "repository": { "type": "string" },
-            "commit": { "type": "string" },
-            "ref": { "type": "string" }
+            "name": {
+              "type": "string"
+            },
+            "version": {
+              "type": "string"
+            },
+            "repository": {
+              "type": "string"
+            },
+            "commit": {
+              "type": "string"
+            },
+            "ref": {
+              "type": "string"
+            }
           }
         },
         "beside": {
@@ -872,7 +1039,7 @@
     },
     "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 run's built, key, exit, output and said; a declined ask's declined, needs and lacks. The fields of the kinds do not meet, so one layout holds the five",
+      "description": "what a step answered, by the kind of ask: a build's artifacts, toolchain, imports, out-of-step modules and the artifact it kept; a check's fetch and levels; a compose's built, key and verdict; a run's built, key, exit, output and said; a declined ask's declined, needs and lacks. The fields of the kinds do not meet, so one layout holds the five",
       "properties": {
         "artifacts": {
           "type": "array",
@@ -895,6 +1062,10 @@
             "type": "string"
           }
         },
+        "kept": {
+          "type": "string",
+          "description": "the digest of the artifact this node kept for the artifact store's holder instead of storing it through the seat oci-artifact-registry (the verb kept-artifact serves it); the keeping node is the step's own; absent when every artifact was stored"
+        },
         "fetch": {
           "$ref": "#/defs/FetchAnswer"
         },
@@ -1148,6 +1319,301 @@
         "commit",
         "modules"
       ]
+    },
+    "StepNames": {
+      "type": "object",
+      "description": "the names the registrations hold, which the lint step refuses fixed in code logic (ADR 0666 section 5, seams ruling M7): carried in the ask, never read by the build module from another part",
+      "properties": {
+        "modules": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "minItems": 1,
+          "description": "every module the registrations name"
+        },
+        "repositories": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "minItems": 1,
+          "description": "every repository a registration's git origin names, as <owner>/<name>"
+        },
+        "branches": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "minItems": 1,
+          "description": "every watched branch a registration names"
+        }
+      },
+      "required": [
+        "modules",
+        "repositories",
+        "branches"
+      ]
+    },
+    "KeptResult": {
+      "type": "object",
+      "description": "a package's passing result the runner keeps, by the digest of what its tests read (ADR 0666 section 8): the step runs no package whose digest and level it names",
+      "properties": {
+        "package": {
+          "type": "string"
+        },
+        "digest": {
+          "type": "string",
+          "description": "sha256:<hex> of what the package's tests read"
+        },
+        "level": {
+          "type": "string",
+          "description": "unit or integration"
+        },
+        "toolchain": {
+          "$ref": "#/defs/ToolchainUsed"
+        },
+        "pipeline": {
+          "type": "string",
+          "description": "the pipeline whose step kept it"
+        }
+      },
+      "required": [
+        "package",
+        "digest",
+        "level"
+      ]
+    },
+    "TestCounts": {
+      "type": "object",
+      "description": "how many tests a step ran and carried, per level (ADR 0666 section 8: the pipeline's end names any repository or catalog module over the test budget)",
+      "properties": {
+        "unit": {
+          "type": "integer"
+        },
+        "integration": {
+          "type": "integer"
+        }
+      }
+    },
+    "StepRun": {
+      "type": "object",
+      "description": "one pipeline step of one artifact at one commit (ADR 0666 sections 7, 8, 17): the step a build seat runs in its sandbox from the change's own heads, the names the lint step needs and the kept results it may skip",
+      "properties": {
+        "pipeline": {
+          "type": "string",
+          "description": "the runner's pipeline key, <branch>.<revision>.<module>, a branch escaped as a key's name is"
+        },
+        "step": {
+          "type": "string",
+          "enum": [
+            "lint",
+            "unit",
+            "integration"
+          ],
+          "description": "the pipeline step"
+        },
+        "module": {
+          "type": "string"
+        },
+        "artifact": {
+          "type": "string",
+          "description": "the artifact reference, <module>:<artifact>"
+        },
+        "branch": {
+          "type": "string",
+          "description": "the watched branch, or the branch of a run on request"
+        },
+        "commit": {
+          "type": "string",
+          "description": "the commit the step runs at"
+        },
+        "revision": {
+          "type": "integer",
+          "description": "the source revision of the watched branch the pipeline runs for; absent for a run on request"
+        },
+        "fingerprint": {
+          "type": "string",
+          "description": "the artifact's build-input fingerprint at the commit"
+        },
+        "fetch": {
+          "$ref": "#/defs/Fetch",
+          "description": "where the step reads the change's heads"
+        },
+        "toolchain": {
+          "$ref": "#/defs/ToolchainUsed"
+        },
+        "names": {
+          "$ref": "#/defs/StepNames"
+        },
+        "kept": {
+          "type": "array",
+          "items": {
+            "$ref": "#/defs/KeptResult"
+          },
+          "description": "the kept results of the artifact's packages, by digest and level (design 47 *Carried, not run*)"
+        },
+        "rerun": {
+          "type": "boolean",
+          "description": "the step is asked again by the runner's rerun"
+        },
+        "by": {
+          "type": "string",
+          "description": "for a rerun, the caller the runtime proved"
+        }
+      },
+      "required": [
+        "pipeline",
+        "step",
+        "module",
+        "artifact",
+        "commit",
+        "fingerprint",
+        "fetch",
+        "names"
+      ]
+    },
+    "StepEnded": {
+      "type": "object",
+      "description": "a pipeline step's end, said by the build seat's holder on the node that ran it (ADR 0666 sections 7, 21): the runner takes it only from that holder's account, naming the ask, the commit and the fingerprint it was asked at",
+      "properties": {
+        "v": {
+          "type": "integer",
+          "description": "the layout version"
+        },
+        "id": {
+          "type": "string",
+          "description": "the ask's id"
+        },
+        "pipeline": {
+          "type": "string"
+        },
+        "step": {
+          "type": "string",
+          "enum": [
+            "lint",
+            "unit",
+            "integration"
+          ]
+        },
+        "module": {
+          "type": "string"
+        },
+        "artifact": {
+          "type": "string"
+        },
+        "commit": {
+          "type": "string"
+        },
+        "fingerprint": {
+          "type": "string"
+        },
+        "node": {
+          "type": "string",
+          "description": "the node that ran it, as in the subject"
+        },
+        "outcome": {
+          "type": "string",
+          "enum": [
+            "passed",
+            "failed",
+            "nothing to run",
+            "could not run"
+          ],
+          "description": "never passed for a step that ran nothing"
+        },
+        "tests": {
+          "$ref": "#/defs/TestCounts"
+        },
+        "carried": {
+          "type": "array",
+          "items": {
+            "$ref": "#/defs/KeptResult"
+          },
+          "description": "the packages not run because the ask's kept results held them"
+        },
+        "kept": {
+          "type": "array",
+          "items": {
+            "$ref": "#/defs/KeptResult"
+          },
+          "description": "the packages that passed at their digest, for the runner to keep"
+        },
+        "said": {
+          "type": "string",
+          "description": "why it failed or could not run, naming the part not heard"
+        },
+        "output": {
+          "type": "string",
+          "description": "the step's output when it fits the message"
+        },
+        "output-object": {
+          "type": "string",
+          "description": "the output's object in the sender's sent store, when over the per-message limit (ADR 0666 section 16)"
+        },
+        "rerun": {
+          "type": "boolean"
+        },
+        "by": {
+          "type": "string",
+          "description": "for a rerun, the caller the runtime proved"
+        },
+        "started": {
+          "type": "string",
+          "format": "date-time"
+        },
+        "ended": {
+          "type": "string",
+          "format": "date-time"
+        }
+      },
+      "required": [
+        "id",
+        "pipeline",
+        "step",
+        "module",
+        "artifact",
+        "commit",
+        "fingerprint",
+        "node",
+        "outcome"
+      ]
+    },
+    "DetectedStep": {
+      "type": "object",
+      "properties": {
+        "step": {
+          "type": "string",
+          "enum": [
+            "lint",
+            "unit",
+            "integration"
+          ]
+        },
+        "packages": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "description": "the packages the step runs, by the language's convention"
+        }
+      },
+      "required": [
+        "step"
+      ]
     }
-  }
+  },
+  "events": [
+    {
+      "name": "step-ended",
+      "subject": "step-ended.<node>",
+      "body": {
+        "$ref": "#/defs/StepEnded"
+      },
+      "keep": {
+        "max-age-days": 90,
+        "max-mib": 128
+      }
+    }
+  ]
 }
diff --git a/contracts/seats/node-build-go/fixtures/events.json b/contracts/seats/node-build-go/fixtures/events.json
new file mode 100644
index 00000000..06ad58d6
--- /dev/null
+++ b/contracts/seats/node-build-go/fixtures/events.json
@@ -0,0 +1,57 @@
+[
+  {
+    "name": "a unit step ended passed on its node, with its counts and what it carried",
+    "of": "event:step-ended",
+    "subject": "mesh.seat.node-build-go.event.step-ended.ace",
+    "given": {
+      "v": 1,
+      "id": "m2kx9a1b3c4d5e",
+      "pipeline": "main.12.nats",
+      "step": "unit",
+      "module": "nats",
+      "artifact": "nats:program",
+      "commit": "0123456789abcdef0123456789abcdef01234567",
+      "fingerprint": "fp-0123",
+      "node": "ace",
+      "outcome": "passed",
+      "tests": {
+        "unit": 14
+      },
+      "carried": [
+        {
+          "package": "./modules/nats/a",
+          "digest": "sha256:bbbb",
+          "level": "unit"
+        }
+      ],
+      "kept": [
+        {
+          "package": "./modules/nats/b",
+          "digest": "sha256:cccc",
+          "level": "unit"
+        }
+      ],
+      "started": "2026-11-10T10:00:00Z",
+      "ended": "2026-11-10T10:02:00Z"
+    }
+  },
+  {
+    "name": "an integration step that could not run, naming the part not heard",
+    "of": "event:step-ended",
+    "subject": "mesh.seat.node-build-go.event.step-ended.g14",
+    "given": {
+      "v": 1,
+      "id": "m2kx9a1b3c4d5f",
+      "pipeline": "main.12.nats",
+      "step": "integration",
+      "module": "nats",
+      "artifact": "nats:program",
+      "commit": "0123456789abcdef0123456789abcdef01234567",
+      "fingerprint": "fp-0123",
+      "node": "g14",
+      "outcome": "could not run",
+      "said": "the sandbox could not fetch novox/mesh-sdk",
+      "output-object": "mesh-build-go_sent-objects/m2kx9a1b3c4d5f"
+    }
+  }
+]
diff --git a/contracts/seats/node-build-go/fixtures/states.json b/contracts/seats/node-build-go/fixtures/states.json
index 9af3c52c..b14fffbb 100644
--- a/contracts/seats/node-build-go/fixtures/states.json
+++ b/contracts/seats/node-build-go/fixtures/states.json
@@ -134,6 +134,37 @@
       }
     }
   },
+  {
+    "name": "a finished build step that kept its artifact on its node",
+    "of": "state:steps/<node>.<id>",
+    "given": {
+      "v": 1,
+      "id": "a1b3",
+      "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"
+        ],
+        "kept": "sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+      }
+    }
+  },
   {
     "name": "a finished check step with its levels",
     "of": "state:steps/<node>.<id>",
@@ -339,5 +370,53 @@
       "why": "a newer fingerprint supersedes it",
       "at": "2026-11-05T10:00:00Z"
     }
+  },
+  {
+    "name": "a step ask of the runner with the names and kept results",
+    "of": "accept:step",
+    "subject": "mesh.seat.node-build-go.accept.step",
+    "given": {
+      "v": 1,
+      "id": "m2kx9a1b3c4d5e",
+      "kind": "step",
+      "language": "go",
+      "asker": "mesh-delivery-pipeline",
+      "at": "2026-11-10T10:00:00Z",
+      "step": {
+        "pipeline": "main.12.nats",
+        "step": "unit",
+        "module": "nats",
+        "artifact": "nats:program",
+        "branch": "main",
+        "commit": "0123456789abcdef0123456789abcdef01234567",
+        "revision": 12,
+        "fingerprint": "fp-0123",
+        "fetch": {
+          "repository": "novox/mesh-catalog",
+          "commit": "0123456789abcdef0123456789abcdef01234567"
+        },
+        "names": {
+          "modules": [
+            "nats",
+            "mesh-sdk"
+          ],
+          "repositories": [
+            "novox/mesh-catalog",
+            "novox/mesh-sdk"
+          ],
+          "branches": [
+            "main"
+          ]
+        },
+        "kept": [
+          {
+            "package": "./modules/nats/a",
+            "digest": "sha256:bbbb",
+            "level": "unit",
+            "pipeline": "main.11.nats"
+          }
+        ]
+      }
+    }
   }
 ]
diff --git a/contracts/seats/node-build-go/fixtures/verbs.json b/contracts/seats/node-build-go/fixtures/verbs.json
index 727e95b6..1e4af4dd 100644
--- a/contracts/seats/node-build-go/fixtures/verbs.json
+++ b/contracts/seats/node-build-go/fixtures/verbs.json
@@ -7,5 +7,98 @@
       "by": "mesh-delivery-builder",
       "why": "a newer fingerprint supersedes it"
     }
+  },
+  {
+    "name": "kept-artifact asks",
+    "of": "verb:kept-artifact.input",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "digest": "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
+    }
+  },
+  {
+    "name": "kept-artifact answers where the bytes are",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "digest": "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd",
+      "size": 18874368,
+      "store": "mesh-build-go-kept",
+      "object": "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
+    }
+  },
+  {
+    "name": "kept-artifact refuses a module that is claims no oci-artifact-registry",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "mesh-delivery-gate",
+      "fp": "src2:aaaaaaaa",
+      "refused": "claims no oci-artifact-registry",
+      "words": "mesh-delivery-gate claims no oci-artifact-registry: its build is fetched from the store"
+    }
+  },
+  {
+    "name": "kept-artifact refuses a build it no longer keeps",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "refused": "not kept",
+      "words": "this node keeps no build of artifact-store at src2:1480985e"
+    }
+  },
+  {
+    "name": "kept-artifact refuses a build kept under another digest",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "digest": "eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee",
+      "refused": "digest differs",
+      "words": "artifact-store at src2:1480985e is kept as eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee"
+    }
+  },
+  {
+    "name": "kept-artifact answers an error, never none",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "error": "the kept builds could not be read"
+    }
+  },
+  {
+    "name": "steps asks an artifact's pipeline steps at a commit",
+    "of": "verb:steps.input",
+    "given": {
+      "module": "nats",
+      "artifact": "nats:program",
+      "fingerprint": "fp-0123",
+      "fetch": {
+        "repository": "novox/mesh-catalog",
+        "commit": "0123456789abcdef0123456789abcdef01234567"
+      }
+    }
+  },
+  {
+    "name": "steps answers lint and unit tests",
+    "of": "verb:steps.answer",
+    "given": {
+      "artifact": "nats:program",
+      "fingerprint": "fp-0123",
+      "steps": [
+        {
+          "step": "lint"
+        },
+        {
+          "step": "unit",
+          "packages": [
+            "./modules/nats"
+          ]
+        }
+      ]
+    }
   }
 ]
diff --git a/contracts/seats/node-build-go/seat.json b/contracts/seats/node-build-go/seat.json
index ccdd85cd..6bb7f53a 100644
--- a/contracts/seats/node-build-go/seat.json
+++ b/contracts/seats/node-build-go/seat.json
@@ -7,24 +7,51 @@
   "decision": "novox/hq ADR 0525, ADR 0536, ADR 0553",
   "pulled-by-kind": true,
   "yields": true,
+  "acts": [
+    {
+      "step": "build",
+      "on": "go",
+      "bound": "60m"
+    }
+  ],
   "accepts": [
     {
       "name": "delivery",
       "body": {
         "$ref": "#/defs/StepAsk"
-      }
+      },
+      "callers": [
+        "seat:mesh-builds"
+      ]
     },
     {
       "name": "check",
       "body": {
         "$ref": "#/defs/StepAsk"
-      }
+      },
+      "callers": [
+        "seat:mesh-delivery-checker",
+        "seat:mesh-catalog",
+        "seat:mesh-pipeline-runner"
+      ]
+    },
+    {
+      "name": "step",
+      "body": {
+        "$ref": "#/defs/StepAsk"
+      },
+      "callers": [
+        "seat:mesh-pipeline-runner"
+      ]
     },
     {
       "name": "recheck",
       "body": {
         "$ref": "#/defs/StepAsk"
-      }
+      },
+      "callers": [
+        "seat:mesh-delivery-checker"
+      ]
     }
   ],
   "description": "The Go build module on a node: it takes the asks of the builder and the checker, runs them as steps and answers.",
@@ -91,5 +118,9 @@
       "description": "the toolchains the nodes report",
       "history": 1
     }
-  ]
+  ],
+  "family": {
+    "name": "node-build-go.events",
+    "max-age-days": 7
+  }
 }
diff --git a/contracts/seats/node-build-image/fixtures/events.json b/contracts/seats/node-build-image/fixtures/events.json
new file mode 100644
index 00000000..1e20d2ed
--- /dev/null
+++ b/contracts/seats/node-build-image/fixtures/events.json
@@ -0,0 +1,40 @@
+[
+  {
+    "name": "a lint step ended passed on its node",
+    "of": "event:step-ended",
+    "subject": "mesh.seat.node-build-image.event.step-ended.ace",
+    "given": {
+      "v": 1,
+      "id": "m2kx9a1b3c4d5e",
+      "pipeline": "main.12.nats",
+      "step": "lint",
+      "module": "nats",
+      "artifact": "nats:program",
+      "commit": "0123456789abcdef0123456789abcdef01234567",
+      "fingerprint": "fp-0123",
+      "node": "ace",
+      "outcome": "passed",
+      "started": "2026-11-10T10:00:00Z",
+      "ended": "2026-11-10T10:02:00Z"
+    }
+  },
+  {
+    "name": "a lint step that could not run, naming the part not heard",
+    "of": "event:step-ended",
+    "subject": "mesh.seat.node-build-image.event.step-ended.g14",
+    "given": {
+      "v": 1,
+      "id": "m2kx9a1b3c4d5f",
+      "pipeline": "main.12.nats",
+      "step": "lint",
+      "module": "nats",
+      "artifact": "nats:program",
+      "commit": "0123456789abcdef0123456789abcdef01234567",
+      "fingerprint": "fp-0123",
+      "node": "g14",
+      "outcome": "could not run",
+      "said": "the sandbox could not fetch novox/mesh-sdk",
+      "output-object": "mesh-build-go_sent-objects/m2kx9a1b3c4d5f"
+    }
+  }
+]
diff --git a/contracts/seats/node-build-image/fixtures/states.json b/contracts/seats/node-build-image/fixtures/states.json
index 7e3ef453..c993e033 100644
--- a/contracts/seats/node-build-image/fixtures/states.json
+++ b/contracts/seats/node-build-image/fixtures/states.json
@@ -86,5 +86,45 @@
       "why": "a newer fingerprint supersedes it",
       "at": "2026-11-05T10:00:00Z"
     }
+  },
+  {
+    "name": "a lint step ask of the runner with the names",
+    "of": "accept:step",
+    "subject": "mesh.seat.node-build-image.accept.step",
+    "given": {
+      "v": 1,
+      "id": "m2kx9a1b3c4d5e",
+      "kind": "step",
+      "language": "image",
+      "asker": "mesh-delivery-pipeline",
+      "at": "2026-11-10T10:00:00Z",
+      "step": {
+        "pipeline": "main.12.nats",
+        "step": "lint",
+        "module": "nats",
+        "artifact": "nats:program",
+        "branch": "main",
+        "commit": "0123456789abcdef0123456789abcdef01234567",
+        "revision": 12,
+        "fingerprint": "fp-0123",
+        "fetch": {
+          "repository": "novox/mesh-catalog",
+          "commit": "0123456789abcdef0123456789abcdef01234567"
+        },
+        "names": {
+          "modules": [
+            "nats",
+            "mesh-sdk"
+          ],
+          "repositories": [
+            "novox/mesh-catalog",
+            "novox/mesh-sdk"
+          ],
+          "branches": [
+            "main"
+          ]
+        }
+      }
+    }
   }
 ]
diff --git a/contracts/seats/node-build-image/fixtures/verbs.json b/contracts/seats/node-build-image/fixtures/verbs.json
index 727e95b6..1e4af4dd 100644
--- a/contracts/seats/node-build-image/fixtures/verbs.json
+++ b/contracts/seats/node-build-image/fixtures/verbs.json
@@ -7,5 +7,98 @@
       "by": "mesh-delivery-builder",
       "why": "a newer fingerprint supersedes it"
     }
+  },
+  {
+    "name": "kept-artifact asks",
+    "of": "verb:kept-artifact.input",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "digest": "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
+    }
+  },
+  {
+    "name": "kept-artifact answers where the bytes are",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "digest": "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd",
+      "size": 18874368,
+      "store": "mesh-build-go-kept",
+      "object": "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
+    }
+  },
+  {
+    "name": "kept-artifact refuses a module that is claims no oci-artifact-registry",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "mesh-delivery-gate",
+      "fp": "src2:aaaaaaaa",
+      "refused": "claims no oci-artifact-registry",
+      "words": "mesh-delivery-gate claims no oci-artifact-registry: its build is fetched from the store"
+    }
+  },
+  {
+    "name": "kept-artifact refuses a build it no longer keeps",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "refused": "not kept",
+      "words": "this node keeps no build of artifact-store at src2:1480985e"
+    }
+  },
+  {
+    "name": "kept-artifact refuses a build kept under another digest",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "digest": "eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee",
+      "refused": "digest differs",
+      "words": "artifact-store at src2:1480985e is kept as eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee"
+    }
+  },
+  {
+    "name": "kept-artifact answers an error, never none",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "error": "the kept builds could not be read"
+    }
+  },
+  {
+    "name": "steps asks an artifact's pipeline steps at a commit",
+    "of": "verb:steps.input",
+    "given": {
+      "module": "nats",
+      "artifact": "nats:program",
+      "fingerprint": "fp-0123",
+      "fetch": {
+        "repository": "novox/mesh-catalog",
+        "commit": "0123456789abcdef0123456789abcdef01234567"
+      }
+    }
+  },
+  {
+    "name": "steps answers lint and unit tests",
+    "of": "verb:steps.answer",
+    "given": {
+      "artifact": "nats:program",
+      "fingerprint": "fp-0123",
+      "steps": [
+        {
+          "step": "lint"
+        },
+        {
+          "step": "unit",
+          "packages": [
+            "./modules/nats"
+          ]
+        }
+      ]
+    }
   }
 ]
diff --git a/contracts/seats/node-build-image/seat.json b/contracts/seats/node-build-image/seat.json
index 60295d98..d2329e72 100644
--- a/contracts/seats/node-build-image/seat.json
+++ b/contracts/seats/node-build-image/seat.json
@@ -12,19 +12,37 @@
       "name": "delivery",
       "body": {
         "$ref": "#/defs/StepAsk"
-      }
+      },
+      "callers": [
+        "seat:mesh-builds"
+      ]
     },
     {
       "name": "check",
       "body": {
         "$ref": "#/defs/StepAsk"
-      }
+      },
+      "callers": [
+        "seat:mesh-delivery-checker"
+      ]
+    },
+    {
+      "name": "step",
+      "body": {
+        "$ref": "#/defs/StepAsk"
+      },
+      "callers": [
+        "seat:mesh-pipeline-runner"
+      ]
     },
     {
       "name": "recheck",
       "body": {
         "$ref": "#/defs/StepAsk"
-      }
+      },
+      "callers": [
+        "seat:mesh-delivery-checker"
+      ]
     }
   ],
   "description": "The image build module on a node: it takes the asks of the builder and the checker, runs them as steps and answers.",
@@ -91,5 +109,9 @@
       "description": "the toolchains the nodes report",
       "history": 1
     }
-  ]
+  ],
+  "family": {
+    "name": "node-build-image.events",
+    "max-age-days": 7
+  }
 }
diff --git a/contracts/seats/node-build-node/fixtures/events.json b/contracts/seats/node-build-node/fixtures/events.json
new file mode 100644
index 00000000..0fb1ac2d
--- /dev/null
+++ b/contracts/seats/node-build-node/fixtures/events.json
@@ -0,0 +1,57 @@
+[
+  {
+    "name": "a unit step ended passed on its node, with its counts and what it carried",
+    "of": "event:step-ended",
+    "subject": "mesh.seat.node-build-node.event.step-ended.ace",
+    "given": {
+      "v": 1,
+      "id": "m2kx9a1b3c4d5e",
+      "pipeline": "main.12.nats",
+      "step": "unit",
+      "module": "nats",
+      "artifact": "nats:program",
+      "commit": "0123456789abcdef0123456789abcdef01234567",
+      "fingerprint": "fp-0123",
+      "node": "ace",
+      "outcome": "passed",
+      "tests": {
+        "unit": 14
+      },
+      "carried": [
+        {
+          "package": "./modules/nats/a",
+          "digest": "sha256:bbbb",
+          "level": "unit"
+        }
+      ],
+      "kept": [
+        {
+          "package": "./modules/nats/b",
+          "digest": "sha256:cccc",
+          "level": "unit"
+        }
+      ],
+      "started": "2026-11-10T10:00:00Z",
+      "ended": "2026-11-10T10:02:00Z"
+    }
+  },
+  {
+    "name": "an integration step that could not run, naming the part not heard",
+    "of": "event:step-ended",
+    "subject": "mesh.seat.node-build-node.event.step-ended.g14",
+    "given": {
+      "v": 1,
+      "id": "m2kx9a1b3c4d5f",
+      "pipeline": "main.12.nats",
+      "step": "integration",
+      "module": "nats",
+      "artifact": "nats:program",
+      "commit": "0123456789abcdef0123456789abcdef01234567",
+      "fingerprint": "fp-0123",
+      "node": "g14",
+      "outcome": "could not run",
+      "said": "the sandbox could not fetch novox/mesh-sdk",
+      "output-object": "mesh-build-go_sent-objects/m2kx9a1b3c4d5f"
+    }
+  }
+]
diff --git a/contracts/seats/node-build-node/fixtures/states.json b/contracts/seats/node-build-node/fixtures/states.json
index d8e5ea20..e2cd93a4 100644
--- a/contracts/seats/node-build-node/fixtures/states.json
+++ b/contracts/seats/node-build-node/fixtures/states.json
@@ -158,5 +158,53 @@
       "why": "a newer fingerprint supersedes it",
       "at": "2026-11-05T10:00:00Z"
     }
+  },
+  {
+    "name": "a step ask of the runner with the names and kept results",
+    "of": "accept:step",
+    "subject": "mesh.seat.node-build-node.accept.step",
+    "given": {
+      "v": 1,
+      "id": "m2kx9a1b3c4d5e",
+      "kind": "step",
+      "language": "typescript",
+      "asker": "mesh-delivery-pipeline",
+      "at": "2026-11-10T10:00:00Z",
+      "step": {
+        "pipeline": "main.12.nats",
+        "step": "unit",
+        "module": "nats",
+        "artifact": "nats:program",
+        "branch": "main",
+        "commit": "0123456789abcdef0123456789abcdef01234567",
+        "revision": 12,
+        "fingerprint": "fp-0123",
+        "fetch": {
+          "repository": "novox/mesh-catalog",
+          "commit": "0123456789abcdef0123456789abcdef01234567"
+        },
+        "names": {
+          "modules": [
+            "nats",
+            "mesh-sdk"
+          ],
+          "repositories": [
+            "novox/mesh-catalog",
+            "novox/mesh-sdk"
+          ],
+          "branches": [
+            "main"
+          ]
+        },
+        "kept": [
+          {
+            "package": "./modules/nats/a",
+            "digest": "sha256:bbbb",
+            "level": "unit",
+            "pipeline": "main.11.nats"
+          }
+        ]
+      }
+    }
   }
 ]
diff --git a/contracts/seats/node-build-node/fixtures/verbs.json b/contracts/seats/node-build-node/fixtures/verbs.json
index 727e95b6..1e4af4dd 100644
--- a/contracts/seats/node-build-node/fixtures/verbs.json
+++ b/contracts/seats/node-build-node/fixtures/verbs.json
@@ -7,5 +7,98 @@
       "by": "mesh-delivery-builder",
       "why": "a newer fingerprint supersedes it"
     }
+  },
+  {
+    "name": "kept-artifact asks",
+    "of": "verb:kept-artifact.input",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "digest": "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
+    }
+  },
+  {
+    "name": "kept-artifact answers where the bytes are",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "digest": "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd",
+      "size": 18874368,
+      "store": "mesh-build-go-kept",
+      "object": "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
+    }
+  },
+  {
+    "name": "kept-artifact refuses a module that is claims no oci-artifact-registry",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "mesh-delivery-gate",
+      "fp": "src2:aaaaaaaa",
+      "refused": "claims no oci-artifact-registry",
+      "words": "mesh-delivery-gate claims no oci-artifact-registry: its build is fetched from the store"
+    }
+  },
+  {
+    "name": "kept-artifact refuses a build it no longer keeps",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "refused": "not kept",
+      "words": "this node keeps no build of artifact-store at src2:1480985e"
+    }
+  },
+  {
+    "name": "kept-artifact refuses a build kept under another digest",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "digest": "eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee",
+      "refused": "digest differs",
+      "words": "artifact-store at src2:1480985e is kept as eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee"
+    }
+  },
+  {
+    "name": "kept-artifact answers an error, never none",
+    "of": "verb:kept-artifact.answer",
+    "given": {
+      "module": "artifact-store",
+      "fp": "src2:1480985e",
+      "error": "the kept builds could not be read"
+    }
+  },
+  {
+    "name": "steps asks an artifact's pipeline steps at a commit",
+    "of": "verb:steps.input",
+    "given": {
+      "module": "nats",
+      "artifact": "nats:program",
+      "fingerprint": "fp-0123",
+      "fetch": {
+        "repository": "novox/mesh-catalog",
+        "commit": "0123456789abcdef0123456789abcdef01234567"
+      }
+    }
+  },
+  {
+    "name": "steps answers lint and unit tests",
+    "of": "verb:steps.answer",
+    "given": {
+      "artifact": "nats:program",
+      "fingerprint": "fp-0123",
+      "steps": [
+        {
+          "step": "lint"
+        },
+        {
+          "step": "unit",
+          "packages": [
+            "./modules/nats"
+          ]
+        }
+      ]
+    }
   }
 ]
diff --git a/contracts/seats/node-build-node/seat.json b/contracts/seats/node-build-node/seat.json
index 74873ba1..d500250e 100644
--- a/contracts/seats/node-build-node/seat.json
+++ b/contracts/seats/node-build-node/seat.json
@@ -7,24 +7,49 @@
   "decision": "novox/hq ADR 0525, ADR 0536, ADR 0553",
   "pulled-by-kind": true,
   "yields": true,
+  "acts": [
+    {
+      "step": "build",
+      "on": "typescript",
+      "bound": "60m"
+    }
+  ],
   "accepts": [
     {
       "name": "delivery",
       "body": {
         "$ref": "#/defs/StepAsk"
-      }
+      },
+      "callers": [
+        "seat:mesh-builds"
+      ]
     },
     {
       "name": "check",
       "body": {
         "$ref": "#/defs/StepAsk"
-      }
+      },
+      "callers": [
+        "seat:mesh-delivery-checker"
+      ]
+    },
+    {
+      "name": "step",
+      "body": {
+        "$ref": "#/defs/StepAsk"
+      },
+      "callers": [
+        "seat:mesh-pipeline-runner"
+      ]
     },
     {
       "name": "recheck",
       "body": {
         "$ref": "#/defs/StepAsk"
-      }
+      },
+      "callers": [
+        "seat:mesh-delivery-checker"
+      ]
     }
   ],
   "description": "The Node build module on a node: it takes the asks of the builder and the checker, runs them as steps and answers.",
@@ -91,5 +116,9 @@
       "description": "the toolchains the nodes report",
       "history": 1
     }
-  ]
+  ],
+  "family": {
+    "name": "node-build-node.events",
+    "max-age-days": 7
+  }
 }