whoami

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

With no annotations, the description carries the full burden and does reasonably well: it discloses cost ("cheap"), safety ("safe to call any time"), and the exact return content including the `commons-ok` sentinel. It does not state whether the call requires a valid key or what happens on an unauthenticated call.

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?

Two short sentences, front-loaded with the operation type, no filler. Every clause conveys information (purpose, return values, cost, safety).

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?

For a trivial, side-effect-free tool with no output schema, the description substitutes well by naming the returned fields and flagging cost/safety. The remaining gap is the two undocumented input parameters, which neither the schema nor the prose explains.

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 description coverage is 0% for the two parameters (`agent`, `api_key`), and the description only obliquely implies a key exists via "which agent this key belongs to." It never explains what `agent` is for or whether either parameter is meant to be supplied by the caller.

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 function (connection/identity check) and enumerates the return payload: which agent the key belongs to, the server version, and the `commons-ok` marker. It never differentiates from the near-identical sibling `who`, so an agent must infer the distinction.

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?

"Cheap; safe to call any time" gives a general usage signal and the "Connection check" framing implies the use case, but there is no explicit when-to-use condition and no mention of alternatives such as `who` or `credentials`, which likely overlap.

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