SaladDay · Sep 28, 2026 · Sep 28, 2026 · Sep 28, 2026
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -3816,3 +3816,13 @@ bounds/catalog details. Preserve Project/key rune limits and node byte limits
 separately. Keep sandbox validation metadata through its existing store wrapper
 without changing transaction or provider authority. Public Session provider
 validation remains byte-compatible; cover it with handler-level golden responses.
+
+Root Session/Turn diagnostics are Core-key reads from one committed database
+snapshot, reusing public status projection and precedence. Keep their finite
+failure catalog separate from private outcome text. Persist safe provisioning
+details in the existing failure transaction; never reconstruct historical details
+from reason strings. Item settlement belongs to the existing Session lock and
+terminal transaction: event/input receipt for normal terminal projections, one
+post-lock database wall-clock sample for forced incomplete Items. Preserve
+historical terminal nulls and public native completion times. See the
+[diagnostics contract](contracts/agents-api/session-diagnostics.md).
diff --git a/apps/docs/content/docs/api-reference/core/sessions.mdx b/apps/docs/content/docs/api-reference/core/sessions.mdx
@@ -22,8 +22,11 @@ _openapi:
           Core key only. Reuses the public resource projection and operation
           rules; the Project ID selects the target space and does not
           authenticate.
+      - content: >-
+          Core key only. Safe failure categories from one committed snapshot; no
+          native text or historical inference.
 ---
 
 {/* This file was generated by Fumadocs. Do not edit this file directly. Any changes should be made by running the generation command again. */}
 
-<APIPage document={"core-api"} operations={[{"path":"/core/v1/projects/{project_id}/sessions","method":"get"},{"path":"/core/v1/projects/{project_id}/sessions/{session_id}","method":"get"},{"path":"/core/v1/projects/{project_id}/sessions/{session_id}","method":"delete"}]} webhooks={[]} hasHead={true} />
+<APIPage document={"core-api"} operations={[{"path":"/core/v1/projects/{project_id}/sessions","method":"get"},{"path":"/core/v1/projects/{project_id}/sessions/{session_id}","method":"get"},{"path":"/core/v1/projects/{project_id}/sessions/{session_id}","method":"delete"},{"path":"/core/v1/projects/{project_id}/sessions/{session_id}/diagnostics","method":"get"}]} webhooks={[]} hasHead={true} />
diff --git a/apps/docs/content/docs/api-reference/core/turns.mdx b/apps/docs/content/docs/api-reference/core/turns.mdx
@@ -18,8 +18,11 @@ _openapi:
           Core key only. Reuses the public resource projection and operation
           rules; the Project ID selects the target space and does not
           authenticate.
+      - content: >-
+          Core key only. At most 1000 root Item receipt timings in public Item
+          order. Receipt intervals are not native execution durations.
 ---
 
 {/* This file was generated by Fumadocs. Do not edit this file directly. Any changes should be made by running the generation command again. */}
 
-<APIPage document={"core-api"} operations={[{"path":"/core/v1/projects/{project_id}/sessions/{session_id}/turns","method":"get"},{"path":"/core/v1/projects/{project_id}/sessions/{session_id}/turns/{turn_id}","method":"get"}]} webhooks={[]} hasHead={true} />
+<APIPage document={"core-api"} operations={[{"path":"/core/v1/projects/{project_id}/sessions/{session_id}/turns","method":"get"},{"path":"/core/v1/projects/{project_id}/sessions/{session_id}/turns/{turn_id}","method":"get"},{"path":"/core/v1/projects/{project_id}/sessions/{session_id}/turns/{turn_id}/diagnostics","method":"get"}]} webhooks={[]} hasHead={true} />
diff --git a/apps/docs/content/docs/public-api.mdx b/apps/docs/content/docs/public-api.mdx
@@ -48,6 +48,7 @@ with the Core key.
 | `projects`, `projects/{project_id}[/archive]`, `projects/{project_id}/keys[/{key_id}]` | Projects and their API keys | [Administrator contract](https://github.com/MiniMax-AI/parsar-core/blob/f36ac3592bfe9f77a2172680aa52b14c6f525062/contracts/agents-api/admin-api.md) |
 | `projects/{project_id}/{agents,environment-templates,skills,files,vaults,sessions}/**` | Resource reads and deletion, Session history, artifacts and archive | [Administrator contract](https://github.com/MiniMax-AI/parsar-core/blob/f36ac3592bfe9f77a2172680aa52b14c6f525062/contracts/agents-api/admin-api.md) |
 | `projects/{project_id}/sessions/{session_id}/execution-configuration` | Committed harness and model selection | [Execution configuration](https://github.com/MiniMax-AI/parsar-core/blob/f36ac3592bfe9f77a2172680aa52b14c6f525062/contracts/agents-api/execution-configuration.md) |
+| `projects/{project_id}/sessions/{session_id}/diagnostics`, `projects/{project_id}/sessions/{session_id}/turns/{turn_id}/diagnostics` | Root failure categories and Item receipt timing | [Session diagnostics](https://github.com/MiniMax-AI/parsar-core/blob/f36ac3592bfe9f77a2172680aa52b14c6f525062/contracts/agents-api/session-diagnostics.md) |
 | `projects/{project_id}/sessions/{session_id}/runtime-observation`, `sandbox/runtime-observations` | Current Runtime observations | [Runtime observations](/observability) |
 | `projects/{project_id}/sessions/{session_id}/runtime-history` | Stored Runtime history | [Runtime history](https://github.com/MiniMax-AI/parsar-core/blob/f36ac3592bfe9f77a2172680aa52b14c6f525062/contracts/agents-api/runtime-history-api.md) |
 | `projects/{project_id}/{resource-owners,write-operations}`, `audit-log`, `summary` | Provenance, write history, administrator audit and usage summary | [Write audit](https://github.com/MiniMax-AI/parsar-core/blob/f36ac3592bfe9f77a2172680aa52b14c6f525062/contracts/agents-api/write-audit.md), [administrator contract](https://github.com/MiniMax-AI/parsar-core/blob/f36ac3592bfe9f77a2172680aa52b14c6f525062/contracts/agents-api/admin-api.md) |

diff --git a/apps/docs/content/guide-sources.json b/apps/docs/content/guide-sources.json
@@ -8,7 +8,7 @@
     "docs/configuration.md": "e911757a03fbce4b803a284c8bb40bdb7000ca2f70e27938706dcdcd74bc7f9a",
     "docs/web/core-connection.md": "46f86520e70bf41079708e2c398655aa9087ad9488c8e661d9a73035d11098c4",
     "docs/getting-started/quickstart.md": "5effeffcfb343f7939910f0c1758e1492d49e7bd66c409b1819cefe67af592d7",
-    "docs/api/README.md": "3c590ca05a07b2bea5ab88ab67719741f8a73a28056ec7d943a5912eb5f9052f",
+    "docs/api/README.md": "592fc2aef474e36eb760be0dd1b2269b6766c0d984f826eaf6f47711ea139387",
     "contracts/agents-api/execution-tools.md": "e0b61f6c0c236c362186c5f6d0ad69a16dd8a8d9afabe1329a1fe22e5f4a71e9",
     "docs/api/public-agent-api.md": "18829b366bd2e49fe5beb76dc8a709bc1aa8e35d4fbfd2484a0c52b46cf75417",
     "contracts/agents-api/environments.md": "89ffc903ee44d00ee87c16950202a3ca4c8345160780dcdd4ed2a71b25b1c2dc",
@@ -36,7 +36,7 @@
     "content/docs/bootstrap-projects-keys.zh.mdx": "509b4dcea4c865d6834bcaef78baa681180d48274931230f958a39e46011c88f",
     "content/docs/quickstart.mdx": "4ebc8ac16df66042e816ff51cf6672d8a85f44e119211efba584025666dce845",
     "content/docs/quickstart.zh.mdx": "c5f119b100b102918a45763834d0ed7fd436479fb411e16a62a408411dbcb3e1",
-    "content/docs/public-api.mdx": "da6aa71753cc84081fba9ae03491717042369a12ea94037fc532f5f1f69d2319",
+    "content/docs/public-api.mdx": "12d4fdbe6291c7d74af591369ac1edd2eca2940b93d156612497cc52b933740d",
     "content/docs/public-api.zh.mdx": "fb0efb9be2fba3f4a3dc71bf053d2c7eddffbfe010f59fa5a1ae60a3f068545b",
     "content/docs/agents-and-tools.mdx": "b8cc50792e579cbf66bcc597685b745d8721266970b75e928d8edee2ce11b08b",
     "content/docs/agents-and-tools.zh.mdx": "cc8d4e0ef0ea894f068f3bbd143d5ee70c6346bf98f425b1d5fe07ec3931f128",

diff --git a/apps/docs/openapi/core-api.yaml b/apps/docs/openapi/core-api.yaml
@@ -2046,6 +2046,64 @@ paths:
       summary: Download immutable artifact bytes in a Project
       tags:
         - Artifacts
+  /core/v1/projects/{project_id}/sessions/{session_id}/diagnostics:
+    get:
+      description: Core key only. Safe failure categories from one committed snapshot; no native text or historical inference.
+      parameters:
+        - schema:
+            type: string
+          description: Project ID
+          in: path
+          name: project_id
+          required: true
+        - schema:
+            type: string
+          description: Session ID
+          in: path
+          name: session_id
+          required: true
+      responses:
+        '200':
+          description: OK
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.SessionDiagnostics'
+        '400':
+          description: Bad Request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.CoreErrorResponse'
+        '401':
+          description: Unauthorized
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.CoreErrorResponse'
+        '404':
+          description: Not Found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.CoreErrorResponse'
+        '500':
+          description: Internal Server Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.CoreErrorResponse'
+        '503':
+          description: Service Unavailable
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.CoreErrorResponse'
+      security:
+        - DeploymentAdminAuth: []
+      summary: Retrieve root Session diagnostics
+      tags:
+        - Sessions
   /core/v1/projects/{project_id}/sessions/{session_id}/execution-configuration:
     get:
       description: Core key only; the Project ID selects the target space and does not authenticate. Returns the committed model, harness and safe provider selection with recorded sources. This read never decrypts credentials, resolves current defaults or probes execution health. Deployment defaults frozen after they moved into Core show their safe view; older deployment selections remain redacted. Historical provenance and missing provider projections are explicitly unknown/unavailable.
@@ -2444,6 +2502,70 @@ paths:
       summary: Retrieve an execution Turn in a Project
       tags:
         - Turns
+  /core/v1/projects/{project_id}/sessions/{session_id}/turns/{turn_id}/diagnostics:
+    get:
+      description: Core key only. At most 1000 root Item receipt timings in public Item order. Receipt intervals are not native execution durations.
+      parameters:
+        - schema:
+            type: string
+          description: Project ID
+          in: path
+          name: project_id
+          required: true
+        - schema:
+            type: string
+          description: Session ID
+          in: path
+          name: session_id
+          required: true
+        - schema:
+            type: string
+          description: Root Turn ID
+          in: path
+          name: turn_id
+          required: true
+      responses:
+        '200':
+          description: OK
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.TurnDiagnostics'
+        '400':
+          description: Bad Request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.CoreErrorResponse'
+        '401':
+          description: Unauthorized
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.CoreErrorResponse'
+        '404':
+          description: Not Found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.CoreErrorResponse'
+        '500':
+          description: Internal Server Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.CoreErrorResponse'
+        '503':
+          description: Service Unavailable
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/api.CoreErrorResponse'
+      security:
+        - DeploymentAdminAuth: []
+      summary: Retrieve root Turn diagnostics
+      tags:
+        - Turns
   /core/v1/projects/{project_id}/skills:
     get:
       description: Core key only. Reuses the public resource projection and operation rules; the Project ID selects the target space and does not authenticate.
@@ -4232,6 +4354,17 @@ components:
         - data
         - object
       type: object
+    api.DiagnosticFailure:
+      properties:
+        code:
+          type: string
+        failed_at:
+          anyOf:
+            - type: string
+            - type: 'null'
+        params:
+          type: object
+      type: object
     api.EnvironmentExecutorCredentialRequest:
       properties:
         key_id:
@@ -4397,6 +4530,21 @@ components:
             - type: 'null'
           description: Applied value; always null for a sensitive setting.
       type: object
+    api.ItemDiagnosticTiming:
+      properties:
+        completed_at:
+          anyOf:
+            - type: string
+            - type: 'null'
+        item_id:
+          type: string
+        observed_duration_ms:
+          anyOf:
+            - type: integer
+            - type: 'null'
+        started_at:
+          type: string
+      type: object
     api.ProjectAPIKeyRequest:
       properties:
         name:
@@ -4516,6 +4664,70 @@ components:
             $ref: '#/components/schemas/store.RuntimeNode'
           type: array
       type: object
+    api.SessionDiagnosticFailure:
+      properties:
+        code:
+          type: string
+        failed_at:
+          anyOf:
+            - type: string
+            - type: 'null'
+        params:
+          type: object
+        source:
+          enum:
+            - turn
+            - environment
+            - environment_input
+          type: string
+        turn_id:
+          type: string
+      type: object
+    api.SessionDiagnostics:
+      properties:
+        failure:
+          anyOf:
+            - allOf:
+                - $ref: '#/components/schemas/api.SessionDiagnosticFailure'
+            - type: 'null'
+        object:
+          enum:
+            - core.session_diagnostics
+          type: string
+        session_id:
+          type: string
+        status:
+          enum:
+            - idle
+            - in_progress
+            - requires_action
+            - failed
+          type: string
+      type: object
+    api.TurnDiagnostics:
+      properties:
+        failure:
+          anyOf:
+            - allOf:
+                - $ref: '#/components/schemas/api.DiagnosticFailure'
+            - type: 'null'
+        items:
+          items:
+            $ref: '#/components/schemas/api.ItemDiagnosticTiming'
+          type: array
+        items_truncated:
+          type: boolean
+        object:
+          enum:
+            - core.turn_diagnostics
+          type: string
+        session_id:
+          type: string
+        status:
+          type: string
+        turn_id:
+          type: string
+      type: object
     coremetrics.Database:
       properties:
         ping_ms:

diff --git a/apps/docs/openapi/sources.json b/apps/docs/openapi/sources.json
@@ -1,7 +1,7 @@
 {
   "sources": {
     "contracts/agents-api/openapi.yaml": "a8896e8b67d78ed0608c7cc5636077ec33f4b4895a04bd6cfb8b038afe941e01",
-    "contracts/agents-api/core.openapi.yaml": "e0bcc1b017c358b543a80cf1d50d33304ea92857015ed15e06f6646fb9213c64",
+    "contracts/agents-api/core.openapi.yaml": "ff8526ba681f7561e49cd8e1818ddb7c6e57ce044021b92d2d69d5b087356900",
     "contracts/agents-api/runtime.openapi.yaml": "23852205d3b45892f2de9ecf3d52518c0dd0808962c0c512f219b565aa7ccef2"
   },
   "outputs": {
@@ -29,18 +29,18 @@
     "content/docs/api-reference/core/executor-credentials.mdx": "352dc9cb02cceab6a7fa4fe13356e9532c329277224e7e01d18ae0c02cad1a3e",
     "content/docs/api-reference/core/files.mdx": "05ce1d2296dbb3fc76cf4cf98d24dff249114c73529335214cee97363229f384",
     "content/docs/api-reference/core/write-audit.mdx": "1298590ab7037077e56f6ab8adb020277763f7a670be796d24142323b2f95411",
-    "content/docs/api-reference/core/sessions.mdx": "e8519b5d3b21296b0ea1edede3160766ad6a49197b92b201ee1a845542d99619",
+    "content/docs/api-reference/core/sessions.mdx": "52db14e7c88cb0521a12a9b3d19b14dd38583b97e716b261a44b2bd6bf05140a",
     "content/docs/api-reference/core/artifacts.mdx": "620fe72cd41d19b9694fe7080eb8935ef44292852400c7be1c03a893613ca89c",
     "content/docs/api-reference/core/execution-configuration.mdx": "f6a9ed4cdb73e87f5f4ce16b4f6fa14b756d07c97f2741bd5cade34a3472c548",
     "content/docs/api-reference/core/items.mdx": "7c7b006536d155d003097a504e9931e3dc4d9fd0426852573244453634729250",
     "content/docs/api-reference/core/runtime-history.mdx": "eec6384c6fd5a2bf223ec7dc7ee19332440936e18fc67f782fe81b96e299f634",
     "content/docs/api-reference/core/runtime-observations.mdx": "db3a238ba77d1fcb887835d51b6f3f8f2b6bdf9cc5e14ac6dd11074a1c75ed48",
-    "content/docs/api-reference/core/turns.mdx": "e6f7a154b3c70e1555417e44a7888295afb8f8bd475621300e1b2bbd2fc94933",
+    "content/docs/api-reference/core/turns.mdx": "53f9472de3e0958c06db7e69d7e8f10119e6540b7f05683915248e08d5284b16",
     "content/docs/api-reference/core/skills.mdx": "ed899ade7b032b1732b3097d81419a8fdbb9ead0594fca9f2107da644b97031f",
     "content/docs/api-reference/core/vaults.mdx": "12d0aac96cd4a3472ef4eaa287f7945f78862017956e79bfc3ed0ef8e772e78a",
     "content/docs/api-reference/core/credentials.mdx": "27d586b9a8fd738b9947802f32c80458195370252886bc26abedccf2125ee981",
     "content/docs/api-reference/core/sandbox-manager.mdx": "6be7c52e057365949f0247c18c710561d680847a955f78f1bbe57825d4d5f549",
-    "openapi/core-api.yaml": "5f40de88d0c39e6083f5c002e2772a03971a266a841726d76c594570f6b9bbcd",
+    "openapi/core-api.yaml": "18e100de2375835350d172e8a472db6966e36f1dd3aaae5e5d8132ba3039fa9c",
     "content/docs/api-reference/core/meta.json": "588b163ed2de2100b0f8376688274f80698a6bf6ac037eef56d17c93fa8a5062",
     "content/docs/api-reference/core/index.mdx": "ddf0a8d87a6c21761beac703a32f2a40486a1c74abb341bd726f40c44a866405",
     "content/docs/api-reference/machine/sandbox-node.mdx": "5b367a08d43cea82686345d2ba1c75cc90627a7b2970fe42a0df9d77fb3e1e80",