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

Goes well beyond the destructiveHint annotation: it discloses that the new password is returned exactly once, that existing passwords retain their original grace deadlines capped at 24 hours, and that grace_seconds=0 invalidates all previous passwords immediately. These are the non-obvious operational consequences an agent needs before invoking a destructive, non-idempotent mutation.

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?

Three short sentences, each carrying distinct and useful information, with the one-time-return warning front-loaded before the grace-period rules. 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?

For a 3-parameter destructive mutation with no output schema, it covers the important gaps: it describes the return value (new password, shown once) and the lifetime of old credentials. Missing only error/precondition behavior (what happens if the key does not exist) and auth requirements.

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 0%, so the description must carry parameter meaning. It explains grace_seconds thoroughly (default 24h window, zero means immediate cutover) but leaves agent_id and key_id to their bare names; those names are largely self-explanatory, so this lands at adequate rather than compensating fully.

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?

A specific verb and resource ("Rotate a named PBX key") plus a key differentiator: the logical id is preserved. That implicitly separates it from create_pbx_key (new key) and revoke_pbx_key (destroys the key), though neither sibling is named explicitly.

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 rotation semantics imply when to use it (need a fresh credential without re-provisioning the key), but the description never states when to prefer revoke_pbx_key or create_pbx_key instead, nor any prerequisite such as the key existing or required permissions.

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