VideoGen

Cancel workflow run

cancel_workflow_run

DestructiveIdempotent

Request cancellation of an API-started workflow and its related generation, remix, and export tasks. This stops pending work; it does not delete the project or undo completed work. Terminal runs are unchanged. Returns workflowRunId, projectId, projectUrl, and remixActionIds as an acknowledgment; use get_workflow_run for status.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "workflowRunId": "<workflowRunId>"
    },
    "name": "cancel_workflow_run"
  }
}

Input Schema

Name	Required	Description	Default
`workflowRunId`	Yes	Run to inspect or cancel. Use workflowRunId from a workflow start result or list_workflow_runs.

Output Schema

Name	Required	Description
`error`	No	Error details when status is failed; otherwise null.
`status`	No	Job status: pending, running, succeeded, failed, or cancelled.
`exportId`	No	Export id when autoExport succeeded (vg_expo_...).
`projectId`	Yes	Project created for this exact workflow attempt (vg_proj_...). A retry creates a different project.
`projectUrl`	Yes	Deep link to the project created for this exact workflow attempt. Keep it paired with workflowRunId; a retry returns a new URL.
`downloadUrl`	No	Signed MP4 download URL when autoExport succeeded. Give this to the user.
`attemptIndex`	No	Current or latest attempt index.
`exportFileId`	No	File id of the rendered MP4 when autoExport succeeded.
`workflowType`	No	Workflow type (present after polling).
`workflowRunId`	Yes	Workflow run id (vg_work_...). Keep it paired with this response's projectId and projectUrl; a retry returns a new tuple.
`remixActionIds`	No	Remix action ids from the start response (empty when none requested).
`progressPercentage`	No	Completion progress 0-100 (present after polling).
`downloadUrlExpiresAt`	No	Unix expiry for downloadUrl.

Schema Changelog

Changes observed during successful MCP inspections.

Changed9 schema fields changedNov 4, 2026

removedOutput schema / properties / downloadUrl / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / downloadUrl / type
```
Added value: +[
+  "string",
+  "null"
+]
```

removedOutput schema / properties / downloadUrlExpiresAt / anyOf

Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / downloadUrlExpiresAt / type
```
Added value: +[
+  "number",
+  "null"
+]
```

changedOutput schema / properties / error / anyOf

Previous value: -[
-  {
-    "additionalProperties": {},
-    "properties": {
-      "code": {
-        "anyOf": [
-          {
-            "type": "string"
-          },
-          {
-            "type": "null"
-          }
-        ],
-        "description": "Machine-readable error code."
-      },
-      "internalErrorCode": {
-        "anyOf": [
-          {
-            "type": "string"
-          },
-          {
-            "type": "null"
-          }
-        ],
-        "description": "Opaque code for support."
-      },
-      "message": {
-        "description": "Human-readable error description.",
-        "type": "string"
-      },
-      "requirement": {
-        "anyOf": [
-          {
-            "additionalProperties": {},
-            "properties": {
-              "details": {
-                "additionalProperties": {
-                  "type": "string"
-                },
-                "propertyNames": {
-                  "type": "string"
-                },
-                "type": "object"
-              },
-              "type": {
-                "description": "Requirement type (e.g. purchase_add_on).",
-                "type": "string"
-              }
-            },
-            "required": [
-              "type"
-            ],
-            "type": "object"
-          },
-          {
-            "type": "null"
-          }
-        ],
-        "description": "What is needed to resolve the error, when applicable."
-      }
-    },
-    "required": [
-      "message"
-    ],
-    "type": "object"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "additionalProperties": {},
+    "properties": {
+      "code": {
+        "description": "Machine-readable error code.",
+        "type": [
+          "string",
+          "null"
+        ]
+      },
+      "internalErrorCode": {
+        "description": "Opaque code for support.",
+        "type": [
+          "string",
+          "null"
+        ]
+      },
+      "message": {
+        "description": "Human-readable error description.",
+        "type": "string"
+      },
+      "requirement": {
+        "anyOf": [
+          {
+            "additionalProperties": {},
+            "properties": {
+              "details": {
+                "additionalProperties": {
+                  "type": "string"
+                },
+                "propertyNames": {
+                  "type": "string"
+                },
+                "type": "object"
+              },
+              "type": {
+                "description": "Requirement type (e.g. purchase_add_on).",
+                "type": "string"
+              }
+            },
+            "required": [
+              "type"
+            ],
+            "type": "object"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "description": "What is needed to resolve the error, when applicable."
+      }
+    },
+    "required": [
+      "message"
+    ],
+    "type": "object"
+  },
+  {
+    "type": "null"
+  }
+]

removedOutput schema / properties / exportFileId / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / exportFileId / type
```
Added value: +[
+  "string",
+  "null"
+]
```

removedOutput schema / properties / exportId / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]

addedOutput schema / properties / exportId / type
```
Added value: +[
+  "string",
+  "null"
+]
```

Changed1 schema field changedOct 16, 2026

changedInput schema / properties / workflowRunId / description

Previous value: -"Workflow run id (vg_work_...)."New value: +"Run to inspect or cancel. Use workflowRunId from a workflow start result or list_workflow_runs."

First observedOct 9, 2026

TDQS

A4.1/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true and idempotentHint=true; the description adds real nuance by defining what 'destructive' means here — pending work stops, but nothing is deleted and completed work and terminal runs are untouched. That is exactly the context an agent needs before firing a destructive-hinted call. The only gap is that it doesn't say whether cancellation is immediate or asynchronous beyond pointing at get_workflow_run.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Four short sentences, front-loaded with the action and its scope, then the exclusions, then the return acknowledgment. The enumeration of returned fields (workflowRunId, projectId, projectUrl, remixActionIds) is mildly redundant given an output schema exists, but it is one clause and it signals the call is an acknowledgment rather than a status poll.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter destructive mutation with full annotations and an output schema, the description covers action, scope, exclusions, and follow-up. It needn't explain return structure since the output schema does, though the partial field listing edges into that territory. Nothing essential for correct invocation is absent.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the single workflowRunId parameter is already documented with its provenance (a start result or list_workflow_runs). The description adds no format, validation, or edge-case detail about the identifier, so baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ("Request cancellation of an API-started workflow") plus the blast radius (related generation, remix, and export tasks). The scope qualifier "API-started" and the named sibling get_workflow_run let an agent distinguish this from get_workflow_run, list_workflow_runs, and cancel_tool_execution without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly sets boundaries: stops pending work, does not delete the project, does not undo completed work, terminal runs unchanged. It also routes to get_workflow_run for status. What's missing is any guidance on choosing between this and cancel_tool_execution or cancel_billing_order, but the cancellation scope is clear enough that misuse is unlikely.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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