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

Annotations already declare destructiveHint=true and idempotentHint=false, but the description adds real behavioral context beyond them: the required auth scope, the caveat that an in-flight delivery may still complete, the concrete response shape (revoked=true), and the explicit statement that case state and events survive. That is exactly the extra context the annotation set cannot convey.

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 short sentences, all front-loaded: action first, then preconditions and caveats, then the guarantee about what is not destroyed. No filler and every clause carries information.

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 single-parameter destructive tool with no output schema, the description covers everything an agent needs: prerequisite scope, irreversibility caveat (in-flight delivery), response contract, and non-effects. Nothing material is left to inference.

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 the single required 'id' parameter, and the schema already explains it is the webhook ID returned by create_webhook. The description's 'owned webhook' phrasing reinforces the ownership constraint but adds no format or syntax detail, so the 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+resource ('Deactivate an owned webhook') plus the secondary effect ('cancel its pending deliveries'). This clearly separates it from sibling create_webhook and the read-only get_webhook_deliveries, so an agent can pick it without opening any 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?

'Requires webhooks scope' and 'owned webhook' give clear preconditions for when this tool applies, and 'Does not delete case state or events' usefully bounds when it is not the right tool. It stops short of naming an alternative or an explicit when-not-to-use scenario, so it is not a full 5.

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