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

No annotations, so description carries full burden. It implies a read-only identity lookup with no side effects, but says nothing about token validity, error behavior, or whether it hits the network. Adequate but thin.

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?

One short sentence, front-loaded, zero waste. Hard to improve on for a zero-param identity call.

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?

Zero params and no output schema, so little is missing. The only gap is what the returned account object looks like, which the description could hint at.

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?

Zero parameters, so baseline is 4. Nothing to document and nothing misdocumented.

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 vague pronoun 'whoami' with a clarifying fragment 'the account this token belongs to.' This clarifies the return value but the fragment is a noun phrase, not a verb+resource statement, so it's only adequately distinct from siblings like list_threads and inbox.

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?

No guidance on when to call this vs other read tools such as inbox or list_threads. Opaque for an agent that can't read the name as a shell command.

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