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

readOnlyHint=true already tells the agent this is a safe read, but the description adds meaningful context beyond annotations: the authentication requirement, the explicit note that start_login does not grant access, and the fact that retry history is included in the response. The auth caveat is valuable behavioral context the annotations do not 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?

The purpose sentence is front-loaded and dense with useful detail, and the access note is a separate, clearly delineated block. The authentication wording is slightly awkward and repetitive but every sentence 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?

With no output schema, the description compensates by naming the returned fields (request/response payloads, retry history) and by disclosing the auth prerequisite. For a simple one-parameter read tool this is close to complete; only the relationship to the listing/retry siblings is unaddressed.

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% and the single 'id' parameter is documented as 'Webhook delivery ID'. The description's phrase 'single webhook delivery attempt' reinforces that the id identifies one delivery, but adds no syntax or format detail beyond the schema. Baseline 3 is appropriate.

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 (Get) and resource (a single webhook delivery attempt) plus the returned content: request/response payloads and retry history. This clearly separates it from list_webhook_deliveries (plural listing) and get_webhook_stats (aggregates) among its siblings.

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?

It gives a real prerequisite (needs a Proof account, authenticate via /mcp before calling) and warns that start_login does not unlock this tool. However, it never says when to prefer this over list_webhook_deliveries or retry_webhook_delivery, so usage is only implied.

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