whoami

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

Annotations already declare readOnlyHint=true; the description adds real context beyond them — that the call is offline, takes no arguments, and never exposes the stored key, with the key file path named. It stops short of describing return values in detail, but an output schema exists to carry that.

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 sentences, front-loaded with the primary instruction, with the parenthetical about key storage kept short. Dense but every clause carries information an agent needs.

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 bootstrap tool with an output schema, this covers everything: when to call it, that it is offline and argument-free, what it returns, and how peers consume the result. Nothing needed to invoke it correctly is missing.

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?

With zero parameters there is nothing to disambiguate, and the description confirms no arguments are required. That matches the baseline for a parameterless tool without adding anything further.

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?

States a specific outcome — learning your own identity as a public key and passport URL — and explicitly positions itself as the first tool to call, which separates it from check_agent (which verifies others) and issue_receipt.

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?

"Use first" gives explicit ordering guidance, and the final clause names the downstream action: share the pubkey so peers can check_agent you and sign receipts naming you. There is no competing tool for this purpose, so no exclusions are needed.

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