bokelley · Oct 27, 2026 · Oct 28, 2026 · aao-secretariat · Oct 28, 2026 · aao-secretariat
diff --git a/.changeset/response-adcp-version-echo.md b/.changeset/response-adcp-version-echo.md
@@ -0,0 +1,5 @@
+---
+"adcontextprotocol": patch
+---
+
+Every task response schema now accepts and declares the `adcp_version` echo that `versioning.mdx` requires on every response (#8518). Closed responses that rejected it now declare `adcp_version` as a `$ref` to `core/version-envelope.json#/properties/adcp_version`: `control_media_buy`, `decline_proposals`, `get_media_buy_issue`, `report_media_buy_issue`, `list_collections`, `list_proposals`, and `media-buy-commitment-response.json`, which covers `buy_products` and `accept_proposal`. Open status payloads that tolerated it without declaring it now compose `core/version-envelope.json` via root `allOf`: `core/compact-task-working.json`, `core/compact-task-input-required.json`, and the non-compact `*-async-response-{submitted,working,input-required}` payloads. The `list_products` echo drops its `x-added-in: 3.3.0` marker because the echo is backported to 3.2.x. A conforming seller already emits the echo, so no seller becomes non-conformant; a malformed echo (for example `"3.3.0"`) now fails validation where these schemas declare it. `tests/response-version-echo.test.cjs` enumerates every tool's response and async status schemas from the tool registry and fails when one rejects the echo, leaves it undeclared, or declares it with a different shape.
diff --git a/package.json b/package.json
@@ -121,7 +121,7 @@
     "test:storyboard-doc-parity": "node --test --test-force-exit --test-timeout=30000 tests/lint-universal-storyboard-doc-parity.test.cjs",
     "test:v4-compatibility-registry": "node --test --test-force-exit --test-timeout=30000 tests/lint-v4-compatibility-registry.test.cjs",
     "test:pagination-invariant": "node --test --test-force-exit --test-timeout=30000 tests/lint-pagination-invariant.test.cjs",
-    "test:version-envelope": "node --test --test-force-exit --test-timeout=30000 tests/lint-version-envelope.test.cjs tests/compact-version-envelope.test.cjs",
+    "test:version-envelope": "node --test --test-force-exit --test-timeout=30000 tests/lint-version-envelope.test.cjs tests/compact-version-envelope.test.cjs tests/response-version-echo.test.cjs",
     "test:test-dynamic-imports": "node --test --test-force-exit --test-timeout=30000 tests/lint-test-dynamic-imports.test.cjs",
     "test:sdk-shims": "node --test --test-force-exit --test-timeout=30000 tests/lint-sdk-shims.test.cjs tests/sdk-runtime-compat.test.cjs",
     "test:tenant-routing": "vitest run --config server/vitest.config.ts server/src/training-agent/tenants/tenant-smoke.test.ts",

diff --git a/static/schemas/source/core/compact-task-input-required.json b/static/schemas/source/core/compact-task-input-required.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/core/compact-task-input-required.json",
   "title": "Compact Task Input Required",
   "description": "Bounded payload for a compact lifecycle task paused for buyer input or approval.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "reason": { "type": "string", "minLength": 1, "maxLength": 200 },

diff --git a/static/schemas/source/core/compact-task-working.json b/static/schemas/source/core/compact-task-working.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/core/compact-task-working.json",
   "title": "Compact Task Working",
   "description": "Bounded progress payload shared by the compact lifecycle tools.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "percentage": { "type": "number", "minimum": 0, "maximum": 100 },

diff --git a/static/schemas/source/creative/get-creative-features-async-response-submitted.json b/static/schemas/source/creative/get-creative-features-async-response-submitted.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/creative/get-creative-features-async-response-submitted.json",
   "title": "Get Creative Features - Submitted",
   "description": "Async acknowledgement returned after get_creative_features accepts a provider evaluation but cannot complete it within the response window. Exact keyed request replays return this original acknowledgement with replayed: true and the same task_id. In AdCP 3.x providers SHOULD also return evaluation_id; it becomes required in AdCP 4.0. When present, exact replays and terminal results preserve it. The caller polls get_task_status using task_id.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "status": {

diff --git a/static/schemas/source/creative/sync-creatives-async-response-input-required.json b/static/schemas/source/creative/sync-creatives-async-response-input-required.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/creative/sync-creatives-async-response-input-required.json",
   "title": "Sync Creatives - Input Required",
   "description": "Payload when sync_creatives task is paused waiting for buyer clarification or approval.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "reason": {

diff --git a/static/schemas/source/creative/sync-creatives-async-response-submitted.json b/static/schemas/source/creative/sync-creatives-async-response-submitted.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/creative/sync-creatives-async-response-submitted.json",
   "title": "Sync Creatives - Submitted",
   "description": "Async task envelope returned when the whole sync_creatives operation cannot be confirmed before the response is emitted — for example, when the seller batches ingestion or when async review must settle before per-item results can be issued. The buyer invokes get_task_status with task_id or receives a webhook when the task completes; the creatives array lands in the terminal result, not this envelope.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "status": {

diff --git a/static/schemas/source/creative/sync-creatives-async-response-working.json b/static/schemas/source/creative/sync-creatives-async-response-working.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/creative/sync-creatives-async-response-working.json",
   "title": "Sync Creatives - Working",
   "description": "Progress payload for active sync_creatives task.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "percentage": {

diff --git a/static/schemas/source/media-buy/build-creative-async-response-input-required.json b/static/schemas/source/media-buy/build-creative-async-response-input-required.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/build-creative-async-response-input-required.json",
   "title": "Build Creative - Input Required",
   "description": "Payload when build_creative is paused waiting for user input. May occur during generation when the agent needs creative direction, or when brand guidelines require approval.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "reason": {

diff --git a/static/schemas/source/media-buy/build-creative-async-response-submitted.json b/static/schemas/source/media-buy/build-creative-async-response-submitted.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/build-creative-async-response-submitted.json",
   "title": "Build Creative - Submitted",
   "description": "Async task envelope returned when build_creative cannot be confirmed before the response — for example, when a slow generative pipeline or multi-minute LLM workflow is queued. The buyer invokes get_task_status with task_id or receives a webhook when the task completes; the creative_manifest(s) land in the terminal result, not this envelope.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "status": {

diff --git a/static/schemas/source/media-buy/build-creative-async-response-working.json b/static/schemas/source/media-buy/build-creative-async-response-working.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/build-creative-async-response-working.json",
   "title": "Build Creative - Working",
   "description": "Progress payload for active build_creative task. Returned during AI generation, format transformation, or complex library retrieval with macro resolution.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "percentage": {

diff --git a/static/schemas/source/media-buy/control-media-buy-response.json b/static/schemas/source/media-buy/control-media-buy-response.json
@@ -12,6 +12,7 @@
       "title": "Control Applied",
       "type": "object",
       "properties": {
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
         "status": { "type": "string", "const": "completed" },
         "media_buy_id": { "type": "string", "minLength": 1, "x-entity": "media_buy" },
         "revision": { "type": "integer", "minimum": 1 },
@@ -54,6 +55,7 @@
       "title": "Control Error",
       "type": "object",
       "properties": {
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
         "status": { "type": "string", "const": "failed" },
         "errors": { "type": "array", "items": { "$ref": "/schemas/core/error.json" }, "minItems": 1 },
         "context": { "$ref": "/schemas/core/context.json" },
@@ -68,6 +70,7 @@
       "title": "Control Submitted",
       "type": "object",
       "properties": {
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
         "status": { "type": "string", "const": "submitted" },
         "task_id": { "type": "string", "minLength": 1, "x-entity": "task" },
         "message": { "type": "string", "maxLength": 2000 },

diff --git a/static/schemas/source/media-buy/create-media-buy-async-response-input-required.json b/static/schemas/source/media-buy/create-media-buy-async-response-input-required.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/create-media-buy-async-response-input-required.json",
   "title": "Create Media Buy - Input Required",
   "description": "Payload when task is paused waiting for user input or approval.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "reason": {

diff --git a/static/schemas/source/media-buy/create-media-buy-async-response-submitted.json b/static/schemas/source/media-buy/create-media-buy-async-response-submitted.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/create-media-buy-async-response-submitted.json",
   "title": "Create Media Buy - Submitted",
   "description": "Async task envelope returned when create_media_buy cannot be confirmed before the response is emitted. The buyer invokes get_task_status with task_id or receives a webhook when the task completes; the media_buy_id and packages land in the terminal result, not this envelope.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "status": {

diff --git a/static/schemas/source/media-buy/create-media-buy-async-response-working.json b/static/schemas/source/media-buy/create-media-buy-async-response-working.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/create-media-buy-async-response-working.json",
   "title": "Create Media Buy - Working",
   "description": "Progress payload for active create_media_buy task.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "percentage": {

diff --git a/static/schemas/source/media-buy/decline-proposals-response.json b/static/schemas/source/media-buy/decline-proposals-response.json
@@ -19,6 +19,7 @@
     }
   ],
   "properties": {
+    "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
     "results": {
       "type": "array",
       "minItems": 0,

diff --git a/static/schemas/source/media-buy/get-media-buy-issue-response.json b/static/schemas/source/media-buy/get-media-buy-issue-response.json
@@ -9,6 +9,7 @@
     {
       "type": "object",
       "properties": {
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
         "outcome": {
           "type": "string",
           "const": "found"
@@ -35,6 +36,7 @@
     {
       "type": "object",
       "properties": {
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
         "outcome": {
           "type": "string",
           "const": "failed"

diff --git a/static/schemas/source/media-buy/get-products-async-response-input-required.json b/static/schemas/source/media-buy/get-products-async-response-input-required.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/get-products-async-response-input-required.json",
   "title": "Get Products - Input Required",
   "description": "Payload when search is paused waiting for user clarification.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "reason": {

diff --git a/static/schemas/source/media-buy/get-products-async-response-submitted.json b/static/schemas/source/media-buy/get-products-async-response-submitted.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/get-products-async-response-submitted.json",
   "title": "Get Products - Submitted",
   "description": "Async task envelope returned when get_products cannot be confirmed before the response — for example, when custom or bespoke product curation is queued for processing. This envelope is valid only for `buying_mode: \"brief\"` and `buying_mode: \"refine\"`; `buying_mode: \"wholesale\"` is a synchronous wholesale product feed read and MUST NOT use the Submitted arm. The buyer can always poll `get_task_status` (legacy `tasks/get`) with `task_id`. If the originating request carried `push_notification_config`, the seller also delivers at least the terminal completion/failure notification to that webhook URL; intermediate progress notifications are MAY. The products array lands on the completion artifact, not this envelope.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "status": {

diff --git a/static/schemas/source/media-buy/get-products-async-response-working.json b/static/schemas/source/media-buy/get-products-async-response-working.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/get-products-async-response-working.json",
   "title": "Get Products - Working",
   "description": "Progress payload for active get_products task.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "percentage": {

diff --git a/static/schemas/source/media-buy/get-reporting-status-response.json b/static/schemas/source/media-buy/get-reporting-status-response.json
@@ -153,8 +153,8 @@
       "title": "Unavailable lookup",
       "type": "object",
       "properties": {
-        "adcp_version": { "type": "string" },
-        "adcp_major_version": { "type": "integer" },
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
+        "adcp_major_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_major_version" },
         "status": { "type": "string", "const": "failed" },
         "view": { "enum": ["summary", "periods", "revision"] },
         "failure_kind": { "type": "string", "const": "lookup_unavailable" },
@@ -194,8 +194,8 @@
       "title": "Operational failure",
       "type": "object",
       "properties": {
-        "adcp_version": { "type": "string" },
-        "adcp_major_version": { "type": "integer" },
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
+        "adcp_major_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_major_version" },
         "status": { "type": "string", "const": "failed" },
         "view": { "enum": ["summary", "periods", "revision"] },
         "failure_kind": { "type": "string", "const": "operational" },

diff --git a/static/schemas/source/media-buy/list-collections-response.json b/static/schemas/source/media-buy/list-collections-response.json
@@ -9,6 +9,7 @@
     "propertyName": "outcome"
   },
   "properties": {
+    "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
     "outcome": {
       "type": "string",
       "enum": ["listed", "unchanged"],

diff --git a/static/schemas/source/media-buy/list-products-response.json b/static/schemas/source/media-buy/list-products-response.json
@@ -8,7 +8,7 @@
     "propertyName": "outcome"
   },
   "properties": {
-    "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version", "x-added-in": "3.3.0" },
+    "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
     "outcome": {
       "type": "string",
       "enum": ["listed", "unchanged"],

diff --git a/static/schemas/source/media-buy/list-proposals-response.json b/static/schemas/source/media-buy/list-proposals-response.json
@@ -7,6 +7,7 @@
   "description": "One page of proposals for the requested account with their seller-tracked dispositions, plus the current state of every opportunity those proposals belong to. Each snapshot is returned byte-for-byte as issued, so terms_digest still verifies; lifecycle state lives beside it, never inside it. Experimental (media_buy.open_opportunities).",
   "type": "object",
   "properties": {
+    "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
     "outcome": { "type": "string", "const": "listed" },
     "proposals": {
       "type": "array",

diff --git a/static/schemas/source/media-buy/media-buy-commitment-response.json b/static/schemas/source/media-buy/media-buy-commitment-response.json
@@ -21,6 +21,7 @@
         }
       },
       "properties": {
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
         "status": { "type": "string", "const": "completed" },
         "media_buy_id": {
           "type": "string",
@@ -126,6 +127,7 @@
       "title": "Commitment Error",
       "type": "object",
       "properties": {
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
         "status": { "type": "string", "const": "failed" },
         "errors": {
           "type": "array",
@@ -144,6 +146,7 @@
       "title": "Commitment Submitted",
       "type": "object",
       "properties": {
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
         "status": { "type": "string", "const": "submitted" },
         "task_id": { "type": "string", "minLength": 1, "x-entity": "task" },
         "message": { "type": "string", "maxLength": 2000 },

diff --git a/static/schemas/source/media-buy/report-media-buy-issue-response.json b/static/schemas/source/media-buy/report-media-buy-issue-response.json
@@ -9,6 +9,7 @@
     {
       "type": "object",
       "properties": {
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
         "outcome": {
           "type": "string",
           "const": "recorded"
@@ -35,6 +36,7 @@
     {
       "type": "object",
       "properties": {
+        "adcp_version": { "$ref": "/schemas/core/version-envelope.json#/properties/adcp_version" },
         "outcome": {
           "type": "string",
           "const": "failed"

diff --git a/static/schemas/source/media-buy/sync-catalogs-async-response-input-required.json b/static/schemas/source/media-buy/sync-catalogs-async-response-input-required.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/sync-catalogs-async-response-input-required.json",
   "title": "Sync Catalogs - Input Required",
   "description": "Payload when sync_catalogs task is paused waiting for buyer clarification or approval.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "reason": {

diff --git a/static/schemas/source/media-buy/sync-catalogs-async-response-submitted.json b/static/schemas/source/media-buy/sync-catalogs-async-response-submitted.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/sync-catalogs-async-response-submitted.json",
   "title": "Sync Catalogs - Submitted",
   "description": "Async task envelope returned when sync_catalogs cannot be confirmed before the response — for example, when catalog ingestion and deduplication are queued for batch processing. The buyer invokes get_task_status with task_id or receives a webhook when the task completes; the per-catalog results land in the terminal result, not this envelope.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "status": {

diff --git a/static/schemas/source/media-buy/sync-catalogs-async-response-working.json b/static/schemas/source/media-buy/sync-catalogs-async-response-working.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/sync-catalogs-async-response-working.json",
   "title": "Sync Catalogs - Working",
   "description": "Progress payload for active sync_catalogs task.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "percentage": {

diff --git a/static/schemas/source/media-buy/update-media-buy-async-response-input-required.json b/static/schemas/source/media-buy/update-media-buy-async-response-input-required.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/update-media-buy-async-response-input-required.json",
   "title": "Update Media Buy - Input Required",
   "description": "Payload when update_media_buy task is paused waiting for user input or approval.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "reason": {

diff --git a/static/schemas/source/media-buy/update-media-buy-async-response-submitted.json b/static/schemas/source/media-buy/update-media-buy-async-response-submitted.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/update-media-buy-async-response-submitted.json",
   "title": "Update Media Buy - Submitted",
   "description": "Async task envelope returned when update_media_buy cannot be confirmed before the response — for example, when operator re-approval is required for mid-flight changes. The buyer invokes get_task_status with task_id or receives a webhook when the task completes; the updated media buy state lands in the terminal result, not this envelope.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "status": {

diff --git a/static/schemas/source/media-buy/update-media-buy-async-response-working.json b/static/schemas/source/media-buy/update-media-buy-async-response-working.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/media-buy/update-media-buy-async-response-working.json",
   "title": "Update Media Buy - Working",
   "description": "Progress payload for active update_media_buy task.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "percentage": {

diff --git a/static/schemas/source/signals/get-signals-async-response-submitted.json b/static/schemas/source/signals/get-signals-async-response-submitted.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/signals/get-signals-async-response-submitted.json",
   "title": "Get Signals - Submitted",
   "description": "Async task envelope returned when get_signals cannot be confirmed before the response — for example, when semantic discovery depends on slow provider queries or review. This envelope is valid only for `discovery_mode: \"brief\"`; `discovery_mode: \"wholesale\"` is a synchronous wholesale signals feed read and MUST NOT use the Submitted arm. The caller can always poll `get_task_status` (legacy `tasks/get`) with `task_id`. If the originating request carried `push_notification_config`, the agent also delivers at least the terminal completion/failure notification to that webhook URL; intermediate progress notifications are MAY. The signals array lands on the completion artifact, not this envelope.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "status": {

diff --git a/static/schemas/source/signals/get-signals-async-response-working.json b/static/schemas/source/signals/get-signals-async-response-working.json
@@ -3,6 +3,9 @@
   "$id": "/schemas/signals/get-signals-async-response-working.json",
   "title": "Get Signals - Working",
   "description": "Progress payload for an active get_signals task after a submitted semantic discovery request has started processing. Valid only for `discovery_mode: \"brief\"`; wholesale signals feed reads report partial completion via `incomplete[]`, not async task progress.",
+  "allOf": [
+    { "$ref": "/schemas/core/version-envelope.json" }
+  ],
   "type": "object",
   "properties": {
     "percentage": {