whoami

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

With no annotations provided, the description carries the burden of behavioral disclosure. It clearly communicates the tool's diagnostic nature and how it differsiates between key and scope issues. It does not explicitly state side-effect safety, but the read-only implication of 'whoami' is strong, and the output schema covers return details.

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 description is two sentences: the first states the tool's purpose, and the second adds actionable usage guidance. It is front-loaded, concise, and contains no superfluous information.

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?

The tool is simple with no parameters and an output schema, so the description does not need to explain return values. It provides purpose and clear usage guidance, and the sibling context confirms the tool's unique role. The description is complete for effective tool selection and invocation.

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 accepts zero parameters, and the input schema is empty with 100% coverage. The description properly omits parameter details since there are none. This matches the baseline for zero-parameter tools.

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 clearly identifies the tool as an API-key introspection endpoint, stating that it reveals the key owner, scopes, and rate limit. This is a specific verb+resource description that distinguishes it from sibling tools, which all operate on sheets and reports.

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 description provides explicit when-to-use guidance: 'Call this first if anything is failing — it distinguishes a bad key from a scope problem.' It does not explicitly name alternatives, but the sibling list shows no overlapping tool, making the guidance clear enough for an agent to select it in troubleshooting scenarios.

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