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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is covered. The description adds real value beyond that: it states the concrete effect (events no longer delivered to that URL) and what persists (delivery attempts remain in the audit log). It stops short of noting irreversibility or error behavior on repeat calls, consistent with idempotentHint=false.

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?

It is short and front-loads the site scoping, but the opening is a dangling fragment ("On one site of the account, named in site.") and the phrasing 'its event goes to that URL no more' / 'Its tries stay in the audit log' is awkward and vague compared to plain prose.

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 two-parameter destructive tool with full schema coverage, annotations covering safety, and no output schema, the description supplies the key missing piece—what stops happening and what is retained. Only the absence of reversibility/retry guidance keeps it below a 5.

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 coverage is 100%, so both parameters are already documented ('site as list_sites names it', 'its id or name'). The description only restates that the site is named in the site parameter and adds nothing about accepted identifier forms.

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 names a specific verb ("Deletes") and resource ("a webhook"), scoped to a single site. It is clearly distinguishable from siblings like update_webhook or list_webhooks, though it never names them 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?

There is no guidance on when to delete versus disabling via update_webhook, and no prerequisites or warnings stated. The only implied usage is that the webhook must exist on the named site, which comes from the schema, not the description.

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