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

With annotations only declaring readOnlyHint=false and destructiveHint=false, the description adds meaningful behavior: the previous kid stays published and verifies pre-rotation signatures but can no longer sign. That is exactly the post-mutation side effect an agent needs, and it confirms non-destructiveness without contradicting annotations. It does not mention auth/permission requirements or rate limits.

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?

Front-loaded with the action, then the side effect, then the mode branch, then a reference link. Four tight sentences with no filler.

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?

There is no output schema, and the description covers the essential workflow (mode branching, prior-key behavior, follow-up tools) for a non-destructive mutation. The only gap is the undocumented worker_id/reason semantics, which is minor given the required UUID is self-explanatory.

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 only 33%, so the description carries extra burden. It effectively explains the key_mode enum via the delegated/attested discussion, but adds nothing about the required worker_id or the optional reason field. Partial compensation warrants a middling score.

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 ('Issue a new signing key') and resource ('for a worker'), and the behavioral contrast with issue_worker_key/register_worker_key is implicit in the rotation semantics. An agent can tell this apart from the sibling key-management 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?

Gives mode-dependent routing: delegated mode generates the key immediately, while attested mode requires calling request_key_challenge then register_worker_key. This is clear conditional guidance, though it doesn't explicitly contrast with issue_worker_key or state when a plain issue is preferred over a rotation.

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