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

Without annotations, the description carries the full burden. It discloses key behaviors: immediate revocation and potential lockout of the current MCP connection. This provides sufficient transparency for a simple tool, though it could mention reversibility or permissions.

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 highly concise, using two sentences to convey the action, immediacy, and a critical edge case (locking the connection). No unnecessary words 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 single-parameter tool with no output schema, the description covers the essential action and a key behavioral consequence. It is complete enough for safe invocation, though it could mention the outcome when revoking a non-authenticated key.

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 schema already has 100% description coverage for the single parameter key_id, explaining it as a UUID from list_keys. The description does not add additional semantic meaning beyond what the schema provides, earning a baseline score of 3.

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 an API key') and the resource ('API key'), distinguishing it from sibling tools like create_key or list_keys. It also adds context about the immediate effect on the current session.

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 implies when to use (need to revoke a key) and warns about the consequence of locking out the current session if the authenticated key is revoked. However, it does not explicitly mention when not to use or suggest alternatives like deletion.

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