aws_whoami

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

Discloses that it returns a structured fix-it message if SSO is expired, adding behavioral context beyond the readOnlyHint, idempotentHint, and openWorldHint annotations. No contradictions.

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 with zero waste; front-loaded with purpose and ends with a specific behavior (fix-it message). Efficiently structured.

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?

Given no output schema, the description fully covers what the tool returns (identity fields, SSO status, time remaining, fix-it message). Annotations cover safety and idempotency, making the tool self-contained.

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?

Schema coverage is 100% with clear descriptions for both parameters (profile and region). Description does not add significant extra semantics beyond what the schema provides, so baseline score applies.

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?

Description clearly states it shows AWS identity (account, role ARN, user ID) plus SSO token status and time remaining, distinguishing it from siblings like aws_login_start (initiating login) or aws_session_get (session details).

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?

Explicitly advises 'Use this first to verify auth before running other AWS operations', providing clear context for when to invoke the tool over alternatives.

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