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.

Input Schema

TableJSON 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

TableJSON 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.

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

A4.5/5.0

Behavior5/5

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

Goes well beyond the annotations (destructiveHint, idempotentHint) by defining the blast radius: it stops pending work but does not delete the project or undo completed work, and terminal runs are untouched. That is exactly the destructive-scope context an agent needs before invoking.

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

Conciseness5/5

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

Three tight sentences, front-loaded with the action and its scope, then the negative constraints, then the acknowledgment payload. Every sentence earns its place with no repetition of the title.

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

Completeness5/5

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

Given a single required parameter, an output schema that defines return fields, and annotations covering the safety profile, the description supplies everything missing: scope limits, terminal-run behavior, and the follow-up status tool.

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% with a single well-documented workflowRunId, so the schema carries the parameter burden. The description only mentions workflowRunId in the return list and adds no format or sourcing detail beyond the schema.

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 ('Request cancellation') and a scoped resource ('API-started workflow and its related generation, remix, and export tasks'). The word 'Request' correctly signals asynchronous behavior, distinguishing it from get_workflow_run and list_workflow_runs among siblings.

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?

Gives clear context: use it to stop pending work, terminal runs are unchanged, and it points to get_workflow_run for status afterward. It does not explicitly contrast with cancel_tool_execution or state prerequisites/permissions, so it stops short of full when/when-not guidance.

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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