comfyui_generate_video

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

With no annotations, the description carries the behavioral disclosure burden. It explicitly discloses the async/slow behavior, default immediate return, the need to poll comfyui_job_status, and that empty arguments preserve workflow defaults. It does not cover failure modes or exact return payload, but the most operationally critical behaviors are transparent.

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

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

The description is front-loaded with the core action and every sentence earns its place: input formats, duration/length semantics, async behavior, defaults, extra overrides, and workflow swapping. There is no filler or repetition of schema information.

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

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

For a 16-parameter tool with no annotations and no output schema, the description covers the essential operational facts: how to provide images, how to choose duration vs length, how to override defaults, and how to handle the slow async lifecycle. It does not spell out wait/timeout behavior in detail, but the provided guidance is sufficient for correct invocation and follow-up.

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

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

Schema description coverage is 0%, so the description must compensate. It successfully explains the ambiguous parameters: image/image2 input formats, duration vs length mapping, extra raw overrides, and workflow preset substitution. The remaining parameters (fps, seed, width, height, prompt, etc.) are reasonably self-explanatory from their titles, so the gap is mostly covered.

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

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

The description opens with a specific action and resource: 'Generate a video with the default video workflow (preset "video")'. This clearly distinguishes it from sibling generation tools like comfyui_generate_image and comfyui_generate_audio, and the workflow-swap note further clarifies its scope.

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

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

The description gives clear usage context: use it to generate video, and it instructs the agent to poll comfyui_job_status because the video is slow and returns immediately by default. It does not explicitly list when-not-to-use or name alternatives, but the video-generation scope is unambiguous enough for selection.

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