whoami

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

No annotations are provided, so the description carries the disclosure burden. It does convey that the tool returns the authenticated user's id and validates the session, but it omits potential behavioral details such as error responses on invalid sessions or rate limits. Minimal but acceptable for a simple read-only tool.

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 a single, clear sentence that directly states the tool's action and purpose. Every word earns its place with no redundancy or irrelevant 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?

Given the tool's extreme simplicity (no parameters, no output schema, no annotations), the description fully covers what an agent needs to know: what it returns and why it might be used. There are no missing details that would affect tool selection or invocation.

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?

This tool has zero parameters, and the schema is empty with 100% coverage. The baseline of 4 applies since there is no parameter meaning to add beyond what the schema already shows.

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 a specific verb ('Return') and resource ('the authenticated account's own user id'), which distinguishes it from sibling tools like get_user or get_user_by_id that target other users. It also adds the purpose of confirming session validity, making its function unambiguous.

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 phrase 'confirms the session works' provides clear context for when to use this tool (e.g., to verify authentication or retrieve the current user's id). However, it does not explicitly exclude alternatives or mention when not to use it, so it falls short of full guidance.

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