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

Adds substantial context beyond the destructiveHint=true and non-idempotent annotations: the new secret is shown only once, both old and new secrets sign for 24 hours, a second rotation inside that window terminates the oldest secret immediately, and unrelated endpoint configuration is preserved. These details directly shape correct invocation and post-call handling.

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-loads the purpose, then moves logically through one-time return, the 24-hour overlap, the re-rotation caveat, invariants, and permissions. Every sentence conveys operational information an agent would otherwise have to guess.

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 an output schema covering the returned secret, the description needs only to explain lifecycle and side effects, and it does so thoroughly, including the overlap window and the one-time visibility constraint. No behaviorally relevant detail is missing for a destructive, non-idempotent operation.

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?

There is a single parameter with full schema description coverage ('The webhook endpoint's id'), so the schema already carries the semantics. The description confirms the target is a webhook endpoint but adds no format, lookup, or failure-mode guidance about the id beyond that.

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 precise verb and resource ('Replace a webhook endpoint's signing secret') and implicitly separates it from siblings such as update_webhook_endpoint and change_webhook_endpoint_url, which the description explicitly says do not apply here ('The address, events and status do not change'). An agent can tell exactly what this does without reading the schema.

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 a concrete trigger ('for example after it was exposed') and caller eligibility ('Only the account owner's API keys and connected apps can rotate a secret'). It also warns about re-rotating within the 24-hour overlap window. It does not name a sibling alternative for changing URL/events, but the statement that those fields do not change effectively routes that case elsewhere.

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