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

Annotations already declare non-readOnly, non-idempotent, openWorld, non-destructive, so the bar is lower; the description adds genuine value: the 10-second timeout, the fact that a signed preview test is sent, that receiver signature verification is exercised, and that the action is audit-logged. It does not spell out error/return shapes, but with no output schema that is a minor 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?

Three short sentences, each carrying distinct information, with the action and its key constraint (10-second wait) front-loaded. No filler.

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?

No output schema exists, and the description partially compensates by stating what is reported back and the timeout, plus audit logging. It leaves the exact response shape and failure behavior implicit, a small gap for a network-touching test tool.

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 documented in the schema, including the useful 'omit to test active revision; drafts testable before activation' note. The description itself adds no parameter-level syntax or format detail beyond referencing 'a revision's URL', so baseline 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 (Send one signed test delivery) and resource (webhook endpoint revision URL), plus concrete artifacts: the delivery type 'webhook_endpoint.test', the preview flag, and the 10-second wait. Clearly distinguishable from siblings such as get_webhook_endpoint or list_webhook_endpoint_revisions.

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?

Clear context is implied (verifying a receiver accepts a signed delivery, including signature verification), but the description never states when to choose this versus alternatives like activate_webhook_endpoint_revision, nor names any exclusion. Usage is inferable rather than explicit.

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