create_avatar

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 details free vs paid modes, the two-step generation workflow with confirmed flick, face-checking, constraints (single person, facing camera, head-and-shoulders), and the return format. It does not mention idempotency or error behavior, but for a creation tool these are acceptable gaps.

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 front-loaded with the core purpose, then details usage modes, constraints, and return value. It is somewhat lengthy but every sentence adds necessary context. Minor improvement could split into shorter paragraphs.

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 6 parameters (1 required), no output schema, the description covers the creation workflow, parameter choices, cost implications, constraints, and integration with sibling tools (generate_talking_avatar, face_swap_video, list_avatars). It is fully self-contained and actionable for an AI agent.

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 baseline is 3. The description adds significant value: explains the two-step process for portrait_prompt, typical token cost, that image_url accepts avots file UUIDs, and that voice is used automatically by downstream tools. This goes beyond schema explanations.

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 saves an 'AVATAR (face identity)' for reuse in talking-avatar and face-swap videos, and distinguishes it from sibling tools like list_avatars (listing created avatars) and generate_talking_avatar (using an avatar). The verb 'save' and specific resource 'avatar' are precise.

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 explains when to use image_url (ready photo, free) vs portrait_prompt (generate, costs tokens, two-step) and mentions the 20-avatar account limit. It does not explicitly exclude cases where the tool should not be used, but provides sufficient context for proper selection among alternatives.

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