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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the effect ('Stop calling one of your URLs') and reassures that the inbox is unaffected, but it does not disclose whether the operation is reversible, whether it requires specific permissions, what happens to the webhook configuration, or what the response looks like. For a mutation tool, this is a significant gap.

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 very short and front-loaded: the main action is in the first sentence, and the second sentence adds a useful clarification. It is appropriately concise, though it could add a bit more context without becoming verbose.

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 the tool has no annotations, no output schema, and 0% parameter coverage, the description is too thin. It does not explain how to identify the webhook, what ownership means, whether the action is idempotent, or what success/failure looks like. An agent would likely need to guess or consult other tools to call this correctly.

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 description coverage is 0%, and the description does not explain the meaning of 'owner' or 'id'. The agent must infer that 'id' identifies the webhook and 'owner' identifies the owning account, but this is not stated. The description adds no parameter-level meaning beyond the schema's bare property names.

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 uses a clear verb ('Stop calling') and resource ('one of your URLs'), which makes the tool's purpose understandable. It doesn't explicitly name sibling tools like set_webhook or list_webhooks, but the contrast with 'Your inbox is unaffected' helps distinguish it from inbox-related operations.

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 implies usage context: it is for stopping webhook calls to a URL, and the note about the inbox suggests it is not for inbox operations. However, it does not explicitly state when to use this tool versus alternatives like set_webhook or list_webhooks, nor does it mention prerequisites like ownership or existing webhook IDs.

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