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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description still adds real context that annotations cannot convey: results are bounded, failure reasons are coarse (not raw errors), and payloads are deliberately omitted from the response. It does not mention retention windows or rate limits, which keeps it from a 5.

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?

A single dense sentence with no filler, and the most important constraint (payloads excluded) is placed at the end of a short string. The adjective 'bounded' is slightly ambiguous about whether it means pagination caps or retention, which costs a point.

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?

An output schema exists, so return shape need not be explained, and all four parameters are documented in the schema. The description is sufficient for an agent to call this correctly and to know it will not get payloads back. Missing only routing guidance toward alternatives when payloads are needed.

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%, with webhook_id, organization_id, page, and page_size all self-documented, so the schema carries the parameter burden. The description adds no meaning about any parameter, e.g., that page_size caps at 100 or that webhook_id comes from list_webhooks. Baseline 3 is appropriate here.

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 ('List') plus resource ('delivery attempts') and enumerates what the response contains: status codes and coarse failure reasons. It also scopes out payloads, which sharpens the distinction from a payload-fetching read. It does not name a sibling such as get_webhook or list_webhooks to differentiate, so it stops short of a 5.

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 explicit when-to-use or when-not-to-use guidance and no named alternative. The clause 'without payloads' implies you should look elsewhere if you need bodies, but it never says which tool to use or what prerequisites (e.g., an active organization membership) apply. Usage is only inferable from the verb itself.

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