whoami

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

No annotations are provided, so the description carries the burden. It implies a safe, side-effect-free read by framing the tool as a question asked at boot, and it discloses the shape of the identity answer, but says nothing about auth requirements, failure modes, or whether the result is cached/stale. Adequate but with clear gaps for an unannotated 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 first sentence front-loads the answer payload and is maximally efficient. The second paragraph is partly changelog/meta ('Added 2026-08-20 at Wren's request, report B3'), which is close to noise, though its key-vs-seat contrast does earn its place.

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?

With zero parameters and an output schema present, the description does not need to explain return values, and it doesn't. What remains is a complete picture of what the tool answers and how it differs from the neighboring credential tool, though behavioral edge cases are left unspecified.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline for a parameterless tool is 4. The description correctly adds no parameter chatter.

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?

Names a specific question the tool answers and enumerates exactly what comes back (username, display name, identity type, tier, active mesh). It also explicitly distinguishes itself from the sibling agent_credential_status by framing the key-vs-seat difference, so an agent can route without opening the schema.

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 first question an agent asks at boot" gives a clear triggering context, and the second paragraph clarifies when to prefer this over agent_credential_status. It stops short of naming an explicit when-not-to-use condition or listing other identity-related alternatives.

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