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

Beyond annotations (destructiveHint=true, idempotentHint=false), the description discloses specific failure modes: unknown or already-revoked keys fail with api_key_not_found, and the last key is refused with cannot_revoke_last_key. It also explains the consequence that the key stops authenticating, adding substantial behavioral context.

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 long but each sentence earns its place, front-loading the action and id source, then detailing non-idempotency, error conditions, guardrails, and return value. It is structured logically with guardrails separated, though slightly verbose for a simple action.

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 destructive tool with no output schema, the description covers the return value (key_id with revoked: true), failure modes, the last-key guardrail, and the non-reversible consequence. It is complete enough for an agent to call it correctly and anticipate outcomes.

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 a clear description of key_id. The description adds the failure condition for unknown ids and clarifies the id comes from list_api_keys, which enhances parameter meaning beyond the schema's minimal note. This is a meaningful addition given the high coverage baseline.

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 clearly states the action (revoke) and resource (API key by id), and explicitly differentiates it from list and create operations. It also clarifies it is a credential revocation, not an idempotent delete, making its purpose unambiguous relative to siblings.

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?

It tells the agent how to obtain the id via list_api_keys, warns that the revocation cannot be undone, and provides the guardrail for the last key: create a replacement with create_api_key first. This gives explicit when-to-use and when-to-alternative guidance.

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