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

Annotations already declare destructive and non-idempotent; the description goes beyond them by naming exactly what is destroyed ('the old secret stops signing at once') and that the value is returned only once, so it must be captured immediately. It does not cover rate limits or whether concurrent rotations invalidate each other, keeping it short of a 5.

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?

Four short sentences, front-loaded with the operation and followed by the critical consequence. The endpoint mapping sentence is slightly gratuitous for an agent but cheap and useful to some callers.

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?

With no output schema, the description correctly explains the return ('returns it once'), the invalidation semantics, and sandbox/live applicability — everything needed to call and handle the result. Missing only error/retry behavior if the caller loses the returned secret.

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?

Only one optional parameter, and the schema description already covers it fully at 100% coverage, including the key pattern and pointers to get_sandbox_key/request_access. The description adds no parameter-level detail, so the high-coverage baseline of 3 applies.

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 and resource ('Makes a new webhook signing secret') and narrows scope to 'the API key making the call', which separates it from revoke_key and the set/get webhook-event siblings. The REST endpoint mapping reinforces the operation.

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 operational timing ('update your verifier right away') is implied, but there is no explicit statement of when an agent should rotate versus use revoke_key, test_webhook, or set_job_webhook. Usage is inferable from the purpose rather than spelled out.

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