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

No annotations exist, so the description carries the full burden and does: it discloses the return payload shape, the mandatory approval gate ('the approving user must be the target agent's owner, Agent.ownerUserId match'), the required post-call actions (print approval_url, poll polling_url), and expiry. This is rich behavioral context beyond what any structured field provides.

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?

Front-loads purpose and sibling distinction, then the return/approval mechanics, then the usage triggers. Dense but every sentence carries new information with no filler.

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?

Despite no output schema, the description explains the return fields and the required follow-up (print URL, poll for result), plus the authorization gate on the target owner. Nothing an agent needs to call this 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?

Schema coverage is 100%, so both parameters are already documented there, including the 'surfaces verbatim on the consent card' note. The description only reinforces the reason guidance ('why the human knows what they're saying yes to') without adding new syntax or constraints, so the baseline 3 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?

States a specific verb (revoke) plus resource (ANOTHER agent's active API key) and explicitly distinguishes itself from the self-only `revoke_api_key`, calling itself the 'cross-agent escalation path'. An agent can select it without opening any schema.

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 concrete when-to-use triggers (credential leakage, misbehaviour, a stuck sibling needing a clean kill) and names the alternative `revoke_api_key` it is not. The escalation condition is stated, not inferred.

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