heygen_create_avatar_video

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

No annotations are provided, so the description carries full responsibility for behavioral disclosure. It mentions creation and returning a video_id for polling, which implies async behavior, but does not explicitly state that the operation is asynchronous, that quota is consumed (except the test parameter hint), or what happens in error cases. Significant behavioral details are missing.

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 extremely concise: two sentences that front-load the purpose and outcome. No extraneous information. Every sentence adds value.

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?

Given the tool's complexity (10 parameters, no output schema, no annotations), the description is insufficiently complete. It does not explain the async nature, quota implications, required parameter relationships (e.g., avatar_id from list tool), or process for obtaining the final video. The description leaves a knowledgeable agent with unanswered questions.

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?

The input schema provides descriptions for all 10 parameters (100% coverage). The description adds minimal extra context beyond the schema, such as connecting script and voice to avatar actions. With full schema coverage, the baseline is 3, and the description does not degrade or significantly enhance 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 identifies the tool's purpose: creating an AI avatar video with HeyGen. It specifies the key actions (avatar speaks script using selected voice) and the return value (video_id for polling). The tool is well-differentiated from sibling tools like heygen_list_avatars, heygen_list_voices, and heygen_get_video_status.

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?

Usage guidance is implied rather than explicit. The description mentions using a selected voice and avatar, which hints at prerequisites, but does not explicitly state when to use this tool versus alternatives or provide conditions for use. No 'when not to use' or alternative tool references are given.

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