画像を生成する

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

With no annotations, the description carries the burden and does disclose a key behavior: returns path rather than base64, and explicitly saves to file. It does not discuss permissions, error cases, or rate limits, which would be expected for a generation tool without 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?

The description is only two sentences: the first states core behavior concisely, the second offers domain-specific advice. No redundant content, and key facts are front-loaded.

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, combined with a high-coverage schema and no output schema, appropriately covers behavior and a key use case. It doesn't describe errors or environmental dependencies, but for a generation tool this is sufficient.

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?

Although schema coverage is 100%, the description adds meaningful guidance for the prompt parameter, recommending solid background, no shadows/gradients, and face-forward for avatar use. This enriches the schema's minimal parameter description.

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 generates an image from a prompt, saves it to a file, and returns the path, explicitly noting it does not return base64. This distinguishes it from sibling tools like edit_image and make_mask by emphasizing creation and file output.

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?

It provides a specific use case for avatar base generation with prompt styling tips, which gives context on when this tool is appropriate. However, it does not explicitly name alternatives or state when not to use it, so it falls short of full 5.

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