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

With no annotations provided, the description carries the full behavioral-disclosure burden. It adds useful cost information ('Billing per call: Credits: metered') but does not describe permissions, rate limits, output format, or what happens on error. For a generation tool with no annotations, this leaves major behavioral 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 three short fragments with no wasted words. The purpose is front-loaded, followed by grouping and billing details. It is appropriately sized for a single-parameter tool.

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 one body parameter and no output schema, the description should ideally explain what is returned, such as audio data or a URL, but it does not. The billing note is useful, and the schema covers input structure, but the lack of return-value guidance leaves a contextual gap for an agent invoking the tool.

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?

There is one parameter, and the schema description coverage is 100%, with the schema example showing body fields like model, input, and voice. The description only says 'input text' and does not add meaning beyond the schema's existing example. Baseline 3 is appropriate because the schema does the heavy lifting.

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 states a specific verb and resource: 'Generates audio from the input text.' This clearly distinguishes the tool from its siblings like post_chat_completions, post_embeddings, and post_moderations. The 'Group: Audio' label reinforces the domain without ambiguity.

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?

There is no explicit guidance on when to use this tool versus alternatives. The description implies that it is for text-to-speech generation but does not mention conditions, prerequisites, or when a different sibling tool would be preferred. 'Group: Audio' is a categorization, not usage direction.

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