whoami

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

No annotations. Description implies read-only but doesn't explicitly state side-effects or error conditions (e.g., invalid token). Adequate but could add context like 'requires valid authentication'.

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?

Single sentence, zero waste. Directly conveys the tool's action and result.

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?

No output schema. Description mentions 'authenticated user' and 'abilities' but doesn't specify structure or fields. Could be more complete for complex responses, but acceptable for simple 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?

No parameters, schema coverage 100%. Baseline 3 per guidelines; description adds no parameter info, which is acceptable as there are none.

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?

Clearly states the tool returns authenticated user and granted abilities. Specific verb 'returns' and resource 'authenticated user' and 'abilities'. Distinct from siblings which are CRUD on different resources.

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?

No explicit when-to-use or alternatives, but purpose is self-evident. Could mention it's for checking current identity and permissions, but not necessary given simplicity.

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