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

The description reveals the concrete outcome (old secret returns 401 invalid_api_key) and notes that the same id is revoked, which is useful behavioral context beyond the destructiveHint annotation. It also clarifies the acceptable auth header and that no ops files are edited, though it does not discuss side effects or rate limits.

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?

Three compact sentences, each carrying distinct information: the core action, the idempotent outcome, and the invocation preference. No filler or redundancy.

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 destructive tool, the description covers the action, the HTTP endpoint, the failure mode, and the required auth mechanism. No output schema exists, and the annotations already signal destructiveness, so the description is sufficient for an agent to call this tool correctly.

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, and the description adds meaning by explaining how the secret is presented (via Authorization header) rather than a schema property. Baseline for zero parameters is 4, and the description does not need to document any parameters.

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 opens with 'Invalidate the presented secret', a specific verb and resource, and the title adds 'caller key' to disambiguate from revoke_inbox. It also names the HTTP endpoint, making the action unambiguous even among sibling tools.

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 transport-level guidance (prefer Bearer, X-API-Key alias) and an exclusion ('No ops file-edit'), but does not explicitly state when to choose this tool over rotate_key or revoke_inbox. Usage context is implied by the destructive nature of invalidation, but no alternative tools are named.

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