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

The annotations already mark the tool as destructive, and the description adds valuable behavioral detail: revoking the same id causes the old secret to fail with 401 invalid_api_key. It also discloses the auth header alias behavior. Nothing contradicts the annotations.

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 compact and front-loads the core action in the first sentence, with the consequence and auth preference following logically. The closing phrase 'No ops file-edit' is cryptic and adds limited value, preventing a top score.

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 zero-parameter destructive action, the description covers the essential facts: what is invalidated, the failure mode of the old secret, and the preferred authentication method. It could be slightly more complete by noting the expected response or handling of already-revoked keys, but nothing critical is missing for 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 input schema has zero parameters, so the baseline is 4. The description's reference to the 'presented secret' makes clear that the key is supplied via the request credentials rather than a schema parameter, which is sufficient for an agent to invoke the tool correctly.

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 uses a specific verb ('Invalidate') and a clear resource ('the presented secret'), and identifies the endpoint (POST /keys/revoke). The title also clearly marks this as 'Revoke caller key', which semantically separates it from issue_key, verify_key, and rotate_key, though it does not name those alternatives explicitly.

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 gives concrete invocation guidance by preferring Authorization: Bearer and noting that X-API-Key is only an alias, and it frames the tool's purpose as secret invalidation. However, it does not state when to choose revoke_key over rotate_key or verify_key, and it provides no exclusions or alternative routing.

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