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

Annotations only declare openWorldHint=true, so the description carries most of the burden. It correctly discloses the asynchronous pattern: a request ID is returned and fetch-video must be used to retrieve results. It omits details on the webhook parameter's interplay with polling, cost, or timing, but the key async contract is disclosed.

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?

Three short sentences, front-loaded with what the tool does, then input, then the return contract. No filler, though the leading whitespace/trailing structure is slightly loose.

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 an 11-parameter async generation tool with no output schema, the description covers the essential return contract (request ID + fetch-video). It leaves out how webhook interacts with polling, model discovery via list-models, and any notion of latency or cost, leaving the agent to infer the full workflow.

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 100%, so all 11 parameters are already documented in the schema, establishing a baseline of 3. The description adds no parameter-level detail (e.g., model_id selection or duration constraints) beyond what the schema already provides.

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?

States a specific verb and resource: animate static images into videos, and clarifies the input is image(s) with a prompt. This implicitly separates it from text-to-video and video-to-video, though it never names those siblings explicitly.

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 retrieval path is spelled out (use fetch-video with the returned request ID), which is genuinely useful workflow guidance. However, there is no guidance on when to choose this over sibling tools like image-to-image, video-to-video, or motion-control.

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