Whoami

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

With no annotations, the description carries the full burden. It transparently describes the returned credential data, including conditional hosted-token details and expiry timing, but does not explicitly state that the operation is read-only or describe authentication failure behavior.

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, both front-loaded and purposeful: the first declares the returned identity data, the second declares when to call it. There is no wasted wording.

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 zero-parameter identity tool with an output schema and no risky side effects, the description covers what it returns, when to call it, and hosted-token behavior. Nothing an agent needs 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?

The tool has zero parameters, so the baseline is 4. The description correctly does not discuss parameters, and there is no parameter surface to clarify beyond the empty input schema.

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 identity action and enumerates the exact account details returned: email, plan, quota, and hosted-token expiration. This clearly distinguishes it from all sibling tools, which operate on pipelines, datasets, devices, or artifacts rather than credentials.

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?

It gives explicit usage contexts: 'Call this first when setup guidance appears' and 'to check which credential a session uses.' This is clear when-to-use guidance, though no when-not-to-use condition or alternative tool is named, which is acceptable because no sibling overlaps with auth introspection.

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