Create a video clip from a look

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

Beyond the annotations, the description discloses important behavioral traits: it costs credits, generation runs in the background, it returns a clip id and status, and it requires polling. It also explains the practical downside of lip-sync from still images, which helps set expectations. No contradiction with annotations exists.

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 dense but every sentence earns its place: purpose, cost, prompt guidance, input constraint, return value, and follow-up polling. The most important operational facts are front-loaded, and no filler or redundancy is present.

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?

With no output schema, the description still explains the return value ('Returns the clip id and status') and the full post-call workflow through get_video and download_video. It covers prerequisites, cost, input requirements, and background behavior, making it sufficiently complete for correct invocation.

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 coverage is 100%, so the baseline is already strong. The description adds meaningfully beyond the schema: exact credit costs, the constraint to provide exactly one of image/photo, the scene-staged distinction, and prompt guidance for natural-looking video. This significantly improves parameter understanding.

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 clearly states the tool's function: 'Animate a character look (or your own photo) into a short video clip.' This is a specific verb and resource, and the title reinforces it. However, it does not explicitly distinguish this from the sibling create_motion_clip, leaving some potential ambiguity about which video-creation tool to choose.

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 strong practical context: check get_credits first, provide exactly one of image or photo, prefer silent reaction prompts for realistic results, poll get_video, then call download_video. It does not explicitly state when not to use this tool versus alternatives like create_motion_clip, so it stops short of a full when/when-not set of exclusions.

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