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

Beyond the destructiveHint annotation, the description reveals key behavioral traits: immediate effect with no overlap window, callers start failing, successor revocations block predecessor rotation, and permission scoping. This adds substantial context that annotations alone do not provide.

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?

Four dense sentences each earn their place: immediate behavior, downtime replacement guidance, successor edge case, and permission note. The most critical information is front-loaded, with no filler or repetition.

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 single-parameter tool with no output schema, the description covers the operation's effects, edge cases, alternatives, and authorization requirements. Nothing essential for correct invocation or expectation-setting 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?

The input schema fully documents keyId as 'UUID of the key to revoke,' so schema coverage is 100%. The description adds no additional parameter-specific meaning, matching the baseline for full schema coverage.

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 a specific verb and resource: 'Revoke a key immediately,' and clearly distinguishes this from rotate_api_key and reveal_rotation_successor. An agent can tell exactly what the tool does and how it differs from related 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 explicitly provides decision guidance: use rotate_api_key for downtime-free replacement, use reveal_rotation_successor if a successor already exists, and warns when revocation is inappropriate. It also names the permission requirement, making when-to-use very clear.

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