C1c-1: the three build seats' verb output answers a run's answer in chunks

The part build-step gains the verb `output` (the ask and the call in, the ask and the chunk count out, marked chunks, read by the
askers of a run), and the fields output and output-object of step-ended name the run's answer inline or as an object the holder
keeps. The three seats' fixtures carry the verb; the generated Go and TypeScript follow.

Builds: design 47 G A-254, A-139, §712, §354

Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h

modules/mesh-delivery-contracts/go/seats/nodebuildgo/contract.go

@@ -21,6 +21,7 @@ const (
 	VerbDrop         = "drop"
 	VerbKeptArtifact = "kept-artifact"
 	VerbSteps        = "steps"
+	VerbOutput       = "output"
 )
 
 const (
@@ -41,7 +42,7 @@ const (
 
 // Verbs is every verb the seat serves, in its definition's order: a new copy each call.
 func Verbs() []string {
-	return []string{VerbCurrent, VerbPause, VerbResume, VerbDrop, VerbKeptArtifact, VerbSteps}
+	return []string{VerbCurrent, VerbPause, VerbResume, VerbDrop, VerbKeptArtifact, VerbSteps, VerbOutput}
 }
 
 // Events is every event published on the seat's subject: a new copy each call.
@@ -804,9 +805,9 @@ type StepEnded struct {
 	Node string `json:"node"`
 	// never passed for a step that ran nothing
 	Outcome string `json:"outcome"`
-	// the step's output when it fits the message
+	// the run's answer (its program's standard output's last line) when it fits the event (design 47 G A-254)
 	Output string `json:"output,omitempty"`
-	// the output's object in the sender's sent store, when over the per-message limit (ADR 0666 section 16)
+	// the name of the object that holds the run's answer, kept by the build seat's holder, when the answer is over what the event carries (design 47 G A-254); read through the verb output
 	OutputObject string `json:"output-object,omitempty"`
 	Pipeline     string `json:"pipeline,omitempty"`
 	Rerun        bool   `json:"rerun,omitempty"`
@@ -1064,6 +1065,22 @@ type StepsAnswer struct {
 	Steps []DetectedStep `json:"steps,omitempty"`
 }
 
+// OutputInput is what output takes.
+type OutputInput struct {
+	// the ask's id, the `output-object` of its step-ended naming it
+	Ask string `json:"ask"`
+	// 128 random bits the caller chooses: the subject token of this send's chunks and acknowledgements
+	Call string `json:"call"`
+}
+
+// OutputAnswer is what output answers.
+type OutputAnswer struct {
+	// the ask's id
+	Ask string `json:"ask"`
+	// how many chunks are sent; 0 when this node keeps no answer of that ask
+	Chunks int64 `json:"chunks"`
+}
+
 // DeliveryAccept is the body of delivery.
 type DeliveryAccept = StepAsk
 

modules/mesh-delivery-contracts/go/seats/nodebuildgo/contract_test.go

@@ -121,6 +121,10 @@ func TestFixtures(t *testing.T) {
 			decode: func(b []byte) (any, error) { var v StepsAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
 		{name: "steps answers a drop that the hand-act log refused", subject: "", given: "{\"error\":\"the hand-act log refused: nothing was deleted\"}", wire: "{\"error\":\"the hand-act log refused: nothing was deleted\"}",
 			decode: func(b []byte) (any, error) { var v StepsAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
+		{name: "output asks a run's answer by its ask", subject: "", given: "{\"ask\":\"m2kx9a1b3c4d5f\",\"call\":\"0123456789abcdef0123456789abcdef\"}", wire: "{\"ask\":\"m2kx9a1b3c4d5f\",\"call\":\"0123456789abcdef0123456789abcdef\"}",
+			decode: func(b []byte) (any, error) { var v OutputInput; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
+		{name: "output answers how many chunks carry the answer", subject: "", given: "{\"ask\":\"m2kx9a1b3c4d5f\",\"chunks\":3}", wire: "{\"ask\":\"m2kx9a1b3c4d5f\",\"chunks\":3}",
+			decode: func(b []byte) (any, error) { var v OutputAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
 	}
 	for _, c := range cases {
 		v, err := c.decode([]byte(c.given))

modules/mesh-delivery-contracts/go/seats/nodebuildimage/contract.go

@@ -21,6 +21,7 @@ const (
 	VerbDrop         = "drop"
 	VerbKeptArtifact = "kept-artifact"
 	VerbSteps        = "steps"
+	VerbOutput       = "output"
 )
 
 const (
@@ -40,7 +41,7 @@ const (
 
 // Verbs is every verb the seat serves, in its definition's order: a new copy each call.
 func Verbs() []string {
-	return []string{VerbCurrent, VerbPause, VerbResume, VerbDrop, VerbKeptArtifact, VerbSteps}
+	return []string{VerbCurrent, VerbPause, VerbResume, VerbDrop, VerbKeptArtifact, VerbSteps, VerbOutput}
 }
 
 // Events is every event published on the seat's subject: a new copy each call.
@@ -802,9 +803,9 @@ type StepEnded struct {
 	Node string `json:"node"`
 	// never passed for a step that ran nothing
 	Outcome string `json:"outcome"`
-	// the step's output when it fits the message
+	// the run's answer (its program's standard output's last line) when it fits the event (design 47 G A-254)
 	Output string `json:"output,omitempty"`
-	// the output's object in the sender's sent store, when over the per-message limit (ADR 0666 section 16)
+	// the name of the object that holds the run's answer, kept by the build seat's holder, when the answer is over what the event carries (design 47 G A-254); read through the verb output
 	OutputObject string `json:"output-object,omitempty"`
 	Pipeline     string `json:"pipeline,omitempty"`
 	Rerun        bool   `json:"rerun,omitempty"`
@@ -1062,6 +1063,22 @@ type StepsAnswer struct {
 	Steps []DetectedStep `json:"steps,omitempty"`
 }
 
+// OutputInput is what output takes.
+type OutputInput struct {
+	// the ask's id, the `output-object` of its step-ended naming it
+	Ask string `json:"ask"`
+	// 128 random bits the caller chooses: the subject token of this send's chunks and acknowledgements
+	Call string `json:"call"`
+}
+
+// OutputAnswer is what output answers.
+type OutputAnswer struct {
+	// the ask's id
+	Ask string `json:"ask"`
+	// how many chunks are sent; 0 when this node keeps no answer of that ask
+	Chunks int64 `json:"chunks"`
+}
+
 // DeliveryAccept is the body of delivery.
 type DeliveryAccept = StepAsk
 

modules/mesh-delivery-contracts/go/seats/nodebuildimage/contract_test.go

@@ -103,6 +103,10 @@ func TestFixtures(t *testing.T) {
 			decode: func(b []byte) (any, error) { var v StepsAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
 		{name: "steps answers a drop that the hand-act log refused", subject: "", given: "{\"error\":\"the hand-act log refused: nothing was deleted\"}", wire: "{\"error\":\"the hand-act log refused: nothing was deleted\"}",
 			decode: func(b []byte) (any, error) { var v StepsAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
+		{name: "output asks a run's answer by its ask", subject: "", given: "{\"ask\":\"m2kx9a1b3c4d5f\",\"call\":\"0123456789abcdef0123456789abcdef\"}", wire: "{\"ask\":\"m2kx9a1b3c4d5f\",\"call\":\"0123456789abcdef0123456789abcdef\"}",
+			decode: func(b []byte) (any, error) { var v OutputInput; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
+		{name: "output answers how many chunks carry the answer", subject: "", given: "{\"ask\":\"m2kx9a1b3c4d5f\",\"chunks\":3}", wire: "{\"ask\":\"m2kx9a1b3c4d5f\",\"chunks\":3}",
+			decode: func(b []byte) (any, error) { var v OutputAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
 	}
 	for _, c := range cases {
 		v, err := c.decode([]byte(c.given))

modules/mesh-delivery-contracts/go/seats/nodebuildnode/contract.go

@@ -21,6 +21,7 @@ const (
 	VerbDrop         = "drop"
 	VerbKeptArtifact = "kept-artifact"
 	VerbSteps        = "steps"
+	VerbOutput       = "output"
 )
 
 const (
@@ -40,7 +41,7 @@ const (
 
 // Verbs is every verb the seat serves, in its definition's order: a new copy each call.
 func Verbs() []string {
-	return []string{VerbCurrent, VerbPause, VerbResume, VerbDrop, VerbKeptArtifact, VerbSteps}
+	return []string{VerbCurrent, VerbPause, VerbResume, VerbDrop, VerbKeptArtifact, VerbSteps, VerbOutput}
 }
 
 // Events is every event published on the seat's subject: a new copy each call.
@@ -802,9 +803,9 @@ type StepEnded struct {
 	Node string `json:"node"`
 	// never passed for a step that ran nothing
 	Outcome string `json:"outcome"`
-	// the step's output when it fits the message
+	// the run's answer (its program's standard output's last line) when it fits the event (design 47 G A-254)
 	Output string `json:"output,omitempty"`
-	// the output's object in the sender's sent store, when over the per-message limit (ADR 0666 section 16)
+	// the name of the object that holds the run's answer, kept by the build seat's holder, when the answer is over what the event carries (design 47 G A-254); read through the verb output
 	OutputObject string `json:"output-object,omitempty"`
 	Pipeline     string `json:"pipeline,omitempty"`
 	Rerun        bool   `json:"rerun,omitempty"`
@@ -1062,6 +1063,22 @@ type StepsAnswer struct {
 	Steps []DetectedStep `json:"steps,omitempty"`
 }
 
+// OutputInput is what output takes.
+type OutputInput struct {
+	// the ask's id, the `output-object` of its step-ended naming it
+	Ask string `json:"ask"`
+	// 128 random bits the caller chooses: the subject token of this send's chunks and acknowledgements
+	Call string `json:"call"`
+}
+
+// OutputAnswer is what output answers.
+type OutputAnswer struct {
+	// the ask's id
+	Ask string `json:"ask"`
+	// how many chunks are sent; 0 when this node keeps no answer of that ask
+	Chunks int64 `json:"chunks"`
+}
+
 // DeliveryAccept is the body of delivery.
 type DeliveryAccept = StepAsk
 

modules/mesh-delivery-contracts/go/seats/nodebuildnode/contract_test.go

@@ -107,6 +107,10 @@ func TestFixtures(t *testing.T) {
 			decode: func(b []byte) (any, error) { var v StepsAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
 		{name: "steps answers a drop that the hand-act log refused", subject: "", given: "{\"error\":\"the hand-act log refused: nothing was deleted\"}", wire: "{\"error\":\"the hand-act log refused: nothing was deleted\"}",
 			decode: func(b []byte) (any, error) { var v StepsAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
+		{name: "output asks a run's answer by its ask", subject: "", given: "{\"ask\":\"m2kx9a1b3c4d5f\",\"call\":\"0123456789abcdef0123456789abcdef\"}", wire: "{\"ask\":\"m2kx9a1b3c4d5f\",\"call\":\"0123456789abcdef0123456789abcdef\"}",
+			decode: func(b []byte) (any, error) { var v OutputInput; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
+		{name: "output answers how many chunks carry the answer", subject: "", given: "{\"ask\":\"m2kx9a1b3c4d5f\",\"chunks\":3}", wire: "{\"ask\":\"m2kx9a1b3c4d5f\",\"chunks\":3}",
+			decode: func(b []byte) (any, error) { var v OutputAnswer; err := json.Unmarshal(b, &v); return v, err }, subjectIs: nil},
 	}
 	for _, c := range cases {
 		v, err := c.decode([]byte(c.given))

modules/mesh-delivery-contracts/parts/build-step.json

@@ -233,6 +233,55 @@
         "required": []
       },
       "class": "act"
+    },
+    {
+      "name": "output",
+      "class": "read",
+      "callers": [
+        "seat:mesh-catalog",
+        "seat:mesh-wants",
+        "seat:mesh-delivery-checker",
+        "seat:mesh-pipeline-runner"
+      ],
+      "description": "A run's answer by its ask, when the step-ended of the run names it as `output-object` because the answer is over what the event carries (design 47 G A-254): the answer's bytes in chunks of at most 512 KiB on the chunk subject of the call, each acknowledged by the caller on the ack subject within 30 seconds; the answer is of any size. An answer inline in the event is never asked here.",
+      "input": {
+        "type": "object",
+        "properties": {
+          "ask": {
+            "type": "string",
+            "description": "the ask's id, the `output-object` of its step-ended naming it",
+            "minLength": 1
+          },
+          "call": {
+            "type": "string",
+            "description": "128 random bits the caller chooses: the subject token of this send's chunks and acknowledgements",
+            "minLength": 1
+          }
+        },
+        "required": [
+          "ask",
+          "call"
+        ]
+      },
+      "answer": {
+        "type": "object",
+        "properties": {
+          "ask": {
+            "type": "string",
+            "description": "the ask's id"
+          },
+          "chunks": {
+            "type": "integer",
+            "minimum": 0,
+            "description": "how many chunks are sent; 0 when this node keeps no answer of that ask"
+          }
+        },
+        "required": [
+          "ask",
+          "chunks"
+        ]
+      },
+      "chunks": true
     }
   ],
   "defs": {
@@ -1595,11 +1644,11 @@
         },
         "output": {
           "type": "string",
-          "description": "the step's output when it fits the message"
+          "description": "the run's answer (its program's standard output's last line) when it fits the event (design 47 G A-254)"
         },
         "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)"
+          "description": "the name of the object that holds the run's answer, kept by the build seat's holder, when the answer is over what the event carries (design 47 G A-254); read through the verb output"
         },
         "rerun": {
           "type": "boolean"

modules/mesh-delivery-contracts/seats/node-build-go/fixtures/verbs.json

@@ -124,5 +124,21 @@
     "given": {
       "error": "the hand-act log refused: nothing was deleted"
     }
+  },
+  {
+    "name": "output asks a run's answer by its ask",
+    "of": "verb:output.input",
+    "given": {
+      "ask": "m2kx9a1b3c4d5f",
+      "call": "0123456789abcdef0123456789abcdef"
+    }
+  },
+  {
+    "name": "output answers how many chunks carry the answer",
+    "of": "verb:output.answer",
+    "given": {
+      "ask": "m2kx9a1b3c4d5f",
+      "chunks": 3
+    }
   }
 ]

modules/mesh-delivery-contracts/seats/node-build-image/fixtures/verbs.json

@@ -124,5 +124,21 @@
     "given": {
       "error": "the hand-act log refused: nothing was deleted"
     }
+  },
+  {
+    "name": "output asks a run's answer by its ask",
+    "of": "verb:output.input",
+    "given": {
+      "ask": "m2kx9a1b3c4d5f",
+      "call": "0123456789abcdef0123456789abcdef"
+    }
+  },
+  {
+    "name": "output answers how many chunks carry the answer",
+    "of": "verb:output.answer",
+    "given": {
+      "ask": "m2kx9a1b3c4d5f",
+      "chunks": 3
+    }
   }
 ]

modules/mesh-delivery-contracts/seats/node-build-node/fixtures/verbs.json

@@ -124,5 +124,21 @@
     "given": {
       "error": "the hand-act log refused: nothing was deleted"
     }
+  },
+  {
+    "name": "output asks a run's answer by its ask",
+    "of": "verb:output.input",
+    "given": {
+      "ask": "m2kx9a1b3c4d5f",
+      "call": "0123456789abcdef0123456789abcdef"
+    }
+  },
+  {
+    "name": "output answers how many chunks carry the answer",
+    "of": "verb:output.answer",
+    "given": {
+      "ask": "m2kx9a1b3c4d5f",
+      "chunks": 3
+    }
   }
 ]

modules/mesh-delivery-contracts/ts/seats/nodebuildgo/index.d.ts

@@ -13,6 +13,7 @@ export declare const verbs: {
   readonly drop: "drop";
   readonly keptArtifact: "kept-artifact";
   readonly steps: "steps";
+  readonly output: "output";
 };
 
 export declare const accepts: {
@@ -146,6 +147,8 @@ export type LevelAnswerDigestPackagesItem = buildStep.LevelAnswerDigestPackagesI
 export type LevelAnswerKeptItem = buildStep.LevelAnswerKeptItem;
 export type LevelAnswerUnmetItem = buildStep.LevelAnswerUnmetItem;
 export type ModuleTree = buildStep.ModuleTree;
+export type OutputAnswer = buildStep.OutputAnswer;
+export type OutputInput = buildStep.OutputInput;
 export type Pause = buildStep.Pause;
 export type PauseAnswer = buildStep.PauseAnswer;
 export type PauseInput = buildStep.PauseInput;

modules/mesh-delivery-contracts/ts/seats/nodebuildgo/index.js

@@ -11,6 +11,7 @@ export const verbs = {
   drop: "drop",
   keptArtifact: "kept-artifact",
   steps: "steps",
+  output: "output",
 };
 
 export const accepts = {

modules/mesh-delivery-contracts/ts/seats/nodebuildgo/parts/build-step.d.ts

@@ -9,6 +9,7 @@ export declare const verbs: {
   readonly drop: "drop";
   readonly keptArtifact: "kept-artifact";
   readonly steps: "steps";
+  readonly output: "output";
 };
 
 export declare const events: {
@@ -432,9 +433,9 @@ export interface StepEnded {
   "node": string;
   /** never passed for a step that ran nothing */
   "outcome": "passed" | "failed" | "nothing to run" | "could not run";
-  /** the step's output when it fits the message */
+  /** the run's answer (its program's standard output's last line) when it fits the event (design 47 G A-254) */
   "output"?: string;
-  /** the output's object in the sender's sent store, when over the per-message limit (ADR 0666 section 16) */
+  /** the name of the object that holds the run's answer, kept by the build seat's holder, when the answer is over what the event carries (design 47 G A-254); read through the verb output */
   "output-object"?: string;
   "pipeline"?: string;
   "rerun"?: boolean;
@@ -655,6 +656,22 @@ export interface StepsAnswer {
   "steps"?: DetectedStep[];
 }
 
+/** is what output takes. */
+export interface OutputInput {
+  /** the ask's id, the `output-object` of its step-ended naming it */
+  "ask": string;
+  /** 128 random bits the caller chooses: the subject token of this send's chunks and acknowledgements */
+  "call": string;
+}
+
+/** is what output answers. */
+export interface OutputAnswer {
+  /** the ask's id */
+  "ask": string;
+  /** how many chunks are sent; 0 when this node keeps no answer of that ask */
+  "chunks": number;
+}
+
 /** is the body of the event step-ended. */
 export type StepEndedEvent = StepEnded;
 

modules/mesh-delivery-contracts/ts/seats/nodebuildgo/parts/build-step.js

@@ -9,6 +9,7 @@ export const verbs = {
   drop: "drop",
   keptArtifact: "kept-artifact",
   steps: "steps",
+  output: "output",
 };
 
 export const events = {

modules/mesh-delivery-contracts/ts/seats/nodebuildimage/index.d.ts

@@ -13,6 +13,7 @@ export declare const verbs: {
   readonly drop: "drop";
   readonly keptArtifact: "kept-artifact";
   readonly steps: "steps";
+  readonly output: "output";
 };
 
 export declare const accepts: {
@@ -143,6 +144,8 @@ export type LevelAnswerDigestPackagesItem = buildStep.LevelAnswerDigestPackagesI
 export type LevelAnswerKeptItem = buildStep.LevelAnswerKeptItem;
 export type LevelAnswerUnmetItem = buildStep.LevelAnswerUnmetItem;
 export type ModuleTree = buildStep.ModuleTree;
+export type OutputAnswer = buildStep.OutputAnswer;
+export type OutputInput = buildStep.OutputInput;
 export type Pause = buildStep.Pause;
 export type PauseAnswer = buildStep.PauseAnswer;
 export type PauseInput = buildStep.PauseInput;

modules/mesh-delivery-contracts/ts/seats/nodebuildimage/index.js

@@ -11,6 +11,7 @@ export const verbs = {
   drop: "drop",
   keptArtifact: "kept-artifact",
   steps: "steps",
+  output: "output",
 };
 
 export const accepts = {

modules/mesh-delivery-contracts/ts/seats/nodebuildimage/parts/build-step.d.ts

@@ -9,6 +9,7 @@ export declare const verbs: {
   readonly drop: "drop";
   readonly keptArtifact: "kept-artifact";
   readonly steps: "steps";
+  readonly output: "output";
 };
 
 export declare const events: {
@@ -432,9 +433,9 @@ export interface StepEnded {
   "node": string;
   /** never passed for a step that ran nothing */
   "outcome": "passed" | "failed" | "nothing to run" | "could not run";
-  /** the step's output when it fits the message */
+  /** the run's answer (its program's standard output's last line) when it fits the event (design 47 G A-254) */
   "output"?: string;
-  /** the output's object in the sender's sent store, when over the per-message limit (ADR 0666 section 16) */
+  /** the name of the object that holds the run's answer, kept by the build seat's holder, when the answer is over what the event carries (design 47 G A-254); read through the verb output */
   "output-object"?: string;
   "pipeline"?: string;
   "rerun"?: boolean;
@@ -655,6 +656,22 @@ export interface StepsAnswer {
   "steps"?: DetectedStep[];
 }
 
+/** is what output takes. */
+export interface OutputInput {
+  /** the ask's id, the `output-object` of its step-ended naming it */
+  "ask": string;
+  /** 128 random bits the caller chooses: the subject token of this send's chunks and acknowledgements */
+  "call": string;
+}
+
+/** is what output answers. */
+export interface OutputAnswer {
+  /** the ask's id */
+  "ask": string;
+  /** how many chunks are sent; 0 when this node keeps no answer of that ask */
+  "chunks": number;
+}
+
 /** is the body of the event step-ended. */
 export type StepEndedEvent = StepEnded;
 

modules/mesh-delivery-contracts/ts/seats/nodebuildimage/parts/build-step.js

@@ -9,6 +9,7 @@ export const verbs = {
   drop: "drop",
   keptArtifact: "kept-artifact",
   steps: "steps",
+  output: "output",
 };
 
 export const events = {

modules/mesh-delivery-contracts/ts/seats/nodebuildnode/index.d.ts

@@ -13,6 +13,7 @@ export declare const verbs: {
   readonly drop: "drop";
   readonly keptArtifact: "kept-artifact";
   readonly steps: "steps";
+  readonly output: "output";
 };
 
 export declare const accepts: {
@@ -143,6 +144,8 @@ export type LevelAnswerDigestPackagesItem = buildStep.LevelAnswerDigestPackagesI
 export type LevelAnswerKeptItem = buildStep.LevelAnswerKeptItem;
 export type LevelAnswerUnmetItem = buildStep.LevelAnswerUnmetItem;
 export type ModuleTree = buildStep.ModuleTree;
+export type OutputAnswer = buildStep.OutputAnswer;
+export type OutputInput = buildStep.OutputInput;
 export type Pause = buildStep.Pause;
 export type PauseAnswer = buildStep.PauseAnswer;
 export type PauseInput = buildStep.PauseInput;

modules/mesh-delivery-contracts/ts/seats/nodebuildnode/index.js

@@ -11,6 +11,7 @@ export const verbs = {
   drop: "drop",
   keptArtifact: "kept-artifact",
   steps: "steps",
+  output: "output",
 };
 
 export const accepts = {

modules/mesh-delivery-contracts/ts/seats/nodebuildnode/parts/build-step.d.ts

@@ -9,6 +9,7 @@ export declare const verbs: {
   readonly drop: "drop";
   readonly keptArtifact: "kept-artifact";
   readonly steps: "steps";
+  readonly output: "output";
 };
 
 export declare const events: {
@@ -432,9 +433,9 @@ export interface StepEnded {
   "node": string;
   /** never passed for a step that ran nothing */
   "outcome": "passed" | "failed" | "nothing to run" | "could not run";
-  /** the step's output when it fits the message */
+  /** the run's answer (its program's standard output's last line) when it fits the event (design 47 G A-254) */
   "output"?: string;
-  /** the output's object in the sender's sent store, when over the per-message limit (ADR 0666 section 16) */
+  /** the name of the object that holds the run's answer, kept by the build seat's holder, when the answer is over what the event carries (design 47 G A-254); read through the verb output */
   "output-object"?: string;
   "pipeline"?: string;
   "rerun"?: boolean;
@@ -655,6 +656,22 @@ export interface StepsAnswer {
   "steps"?: DetectedStep[];
 }
 
+/** is what output takes. */
+export interface OutputInput {
+  /** the ask's id, the `output-object` of its step-ended naming it */
+  "ask": string;
+  /** 128 random bits the caller chooses: the subject token of this send's chunks and acknowledgements */
+  "call": string;
+}
+
+/** is what output answers. */
+export interface OutputAnswer {
+  /** the ask's id */
+  "ask": string;
+  /** how many chunks are sent; 0 when this node keeps no answer of that ask */
+  "chunks": number;
+}
+
 /** is the body of the event step-ended. */
 export type StepEndedEvent = StepEnded;
 

modules/mesh-delivery-contracts/ts/seats/nodebuildnode/parts/build-step.js

@@ -9,6 +9,7 @@ export const verbs = {
   drop: "drop",
   keptArtifact: "kept-artifact",
   steps: "steps",
+  output: "output",
 };
 
 export const events = {