whoami

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: it distinguishes a missing token from a revoked/expired one, telling the agent what failure modes to expect.

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 compact sentences with zero filler. The core action and its diagnostic value are front-loaded, with the endpoint reference tucked at the end where it costs nothing.

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 parameterless read tool with no output schema, the description covers what the agent needs: what it confirms and what it reports. It stops short of describing the returned account fields or the error payload shape, which is a minor gap given the simplicity.

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 the baseline is 4. Nothing about parameter meaning needs to be conveyed, and the description correctly implies the token comes from configuration rather than an argument.

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 verb+resource (confirm token liveness, report owning account) and even names the underlying endpoint. It is clearly distinguishable from the login/session siblings, which deal with acquiring credentials rather than validating them.

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?

Gives clear context for when to reach for it: verifying a configured token is live and diagnosing whether a failure is a missing token versus a revoked/expired one. It does not name an alternative tool, but no sibling plausibly overlaps with this diagnostic role.

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