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

Annotations already declare destructiveHint: true and idempotentHint: true, so the safety profile is partially known. The description adds the Authorization header requirement, which is useful unfrastructure context. However, it does not disclose what happens to the revoked key, whether revocation is immediate, or any side effects—despite being a destructive operation. It adds some value but remains thin.

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 very short (one sentence), but the first half is redundant with the tool name ('Execute the canonical Direct Session revoke_direct_signing_key operation'). It is not efficient conciseness—it wastes words on tautology. The second half about the auth header is the only substantive content, making the overall structure slightly padded.

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 operation with an output schema and annotations, the description is under-specified. It fails to communicate the consequences of revocation, the scope of what is affected, or any caveats. The output schema exists, so return values are covered, but the operational context (what makes this different from other revoke tools, what to expect) is missing. This is a notable gap for a mutating tool.

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 provides descriptions for both required parameters (signing_key_id and idempotency_key), achieving 100% coverage. The description does not add any parameter-specific meaning, but with full schema coverage, that is acceptable. Baseline 3 is appropriate.

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 simply restates the tool name: 'Execute the canonical Direct Session revoke_direct_signing_key operation.' It does not explain what revoking a signing key entails or how it differs from sibling tools like revoke_worker_delegation. The verb and resource are evident from the name, but the description adds no semantic clarity beyond that.

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 only guidance provided is 'Requires an Authorization: Bearer header.' This is a technical requirement, not usage context. It does not indicate when to use this tool versus alternatives (e.g., register_direct_signing_key, create_direct_signing_key_challenge) or any scenarios to avoid. No exclusions or prerequisites beyond auth are mentioned.

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