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

The description clearly discloses that execution is asynchronous, returns a generation_id, and requires polling get_generation until status becomes 'completed'. It also adds pricing and GIF duration limits. These are meaningful behavioral details beyond the annotations.

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?

Two sentences with no filler. The first sentence gives the core purpose, and the second packs cost, limits, async behavior, and next-step instructions efficiently.

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?

The description covers the essential async flow and how to retrieve the result, which is especially valuable since there is no output schema. It is slightly incomplete because the 'gif' parameter's acceptable input format is left ambiguous, but overall an agent can select and invoke the tool correctly.

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 3. The description adds pricing and max duration context, but it does not clarify the 'gif' parameter's accepted input format or add deeper meaning beyond the schema's minimal 'GIF' label.

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 action ('Swap faces') and the exact resource ('in GIFs'), distinguishing it from image-only face swaps and other video/animation tools. It also mentions the async result, so an agent immediately knows what to expect.

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 implies the tool is for GIF face swapping and gives the follow-up step of calling get_generation, but it does not explicitly state when to choose this tool over siblings like face_swap, multiple_face_swap, or ai_face_swap_video. There is workflow guidance, but no alternative tool-fencing.

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