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

Annotations already declare destructiveHint=true, but the description adds genuinely non-obvious behavior: the public key stays published forever, and signatures dated before revocation still verify while later ones do not. That asymmetry is exactly what an agent needs and is not derivable from the annotations or schema.

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?

Two short sentences plus a reference link, with the core effect front-loaded. Every sentence earns its place.

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 3-param mutation with annotations covering the safety profile and no output schema, the description supplies the key semantic consequence and points to the API reference. Minor gaps remain: no permission requirements and no note that 'reason' is mandatory.

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 67% (kid and reason are documented; worker_id is only typed as a UUID). The description adds no parameter-level detail, so the schema carries the load; 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?

States a specific verb (mark revoked) and resource (a signing key) with the precise scope 'from now on', and the title confirms 'signing key'. It does not explicitly distinguish itself from the nearby siblings revoke_worker_api_key or rotate_worker_key, so an agent must infer the difference from context.

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?

Usage is implied by the irreversible framing rather than stated: you revoke when a key should stop signing. There is no 'use this instead of rotate_worker_key' routing, and no distinction from the sibling revoke_worker_api_key, which an agent could easily pick by mistake.

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