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

With annotations carrying only destructiveHint=true (and a title), the description does real work: it discloses that Oura verifies the callback URL before activation and that the subscription expires and must be renewed. It omits auth requirements and what the call returns (subscription id), so it is strong but not complete.

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 compact sentences, front-loaded with the core action, followed by the two behavioral facts an agent needs (verification, expiry) and the raw endpoint. No filler or repetition of the title.

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 mutation tool with no output schema and only destructiveHint in annotations, the description covers the critical lifecycle facts (verification handshake, expiry, renewal sibling) and the API endpoint. It does not mention permissions/scopes or the returned subscription identifier, leaving a small gap.

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 100% for all four required parameters (callback_url, verification_token, event_type, data_type), so the schema already carries parameter meaning. The description adds no additional syntax, constraints, or format detail beyond the endpoint path, making 3 the correct baseline.

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 ('Register a webhook so Oura notifies your callback URL when data changes') and clearly distinguishes itself from the renew/delete/list/get webhook siblings by naming the renewal path 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?

Gives clear context for when this tool matters (subscriptions expire) and routes the agent to oura_renew_webhook_subscription as the follow-up alternative. It lacks explicit when-not-to-use guidance or comparison against oura_get_webhook_subscription / oura_list_webhook_subscriptions, so it falls short of a 5.

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