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

Annotations already cover read-only, idempotent, non-destructive, and closed-world behavior. The description adds important context: it explicitly excludes secrets and requires an API key, which are security and auth traits not captured by annotations. It could mention pagination or response format, but for a simple list tool this is sufficient.

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?

The description is concise (two sentences, 22 words) and front-loads the key information about what is returned. The phrasing is slightly fragmented but 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?

Given zero parameters, no output schema, and annotations covering safety, the description provides enough context: it states what is returned, what is excluded, and the auth requirement. A minor gap is the lack of mention of ordering or pagination, but for a simple list endpoint this is reasonable.

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?

The tool has zero parameters, so parameter semantics are not applicable. The baseline for 0 parameters is 4, and the description does not need to provide parameter details.

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?

The description clearly states that the tool returns webhook endpoints and event types, which is a specific resource. It distinguishes itself from secret-related siblings by noting 'never their secrets', but it does not explicitly contrast with create_webhook, delete_webhook, or webhook_deliveries, leaving some ambiguity about its exact scope.

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 description provides no guidance on when to use this tool versus alternatives like webhook_deliveries or list_* siblings. 'Needs a key' indicates authentication but does not help an agent decide when listing webhooks is the right action.

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