face_swap_video

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

With no annotations provided, the description carries full burden for behavioral disclosure. It mentions the asynchronous nature ('Returns the project ID to check status'), which is valuable. However, it doesn't address critical aspects like processing time, file format requirements, size limits, authentication needs, rate limits, or what happens if the face detection fails.

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 efficiently structured in two sentences: the first states the core functionality, the second explains the return value and status checking. Every sentence serves a clear purpose with no wasted words, though it could be slightly more front-loaded with key behavioral 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 complex video processing tool with 5 parameters, no annotations, and no output schema, the description is insufficient. It doesn't explain what the tool actually produces (a modified video file? a processing job?), doesn't mention error handling, and provides minimal guidance on parameter usage despite the schema doing the technical documentation.

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 the schema fully documents all 5 parameters. The description adds minimal value beyond the schema - it mentions 'source video' and 'face image' which map to the two required parameters, but doesn't provide additional context about parameter interactions, defaults, or practical usage examples.

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 specific action ('Swap a face onto a video') and identifies the key resources involved ('source video' and 'face image'). It distinguishes this tool from siblings like 'face_swap_photo' (photo vs video) and 'face_swap_video_individual' (individual vs unspecified scope) by focusing on the basic video face-swapping operation.

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 provides no guidance on when to use this tool versus alternatives like 'face_swap_video_individual' or 'face_swap_video_youtube'. It mentions the return value ('project ID to check status') but doesn't explain prerequisites, error conditions, or when other tools might be more appropriate.

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