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

No annotations are provided, so the description carries the full burden. It transparently discloses that the tool creates a new delivery attempt with the same payload, which is a meaningful behavioral effect beyond the tool name. It also flags an authentication prerequisite and warns that start_login does not open this tool. It could mention potential duplicate-delivery side effects, but the core behavior is disclosed.

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 main purpose is front-loaded in the first sentence, and the access note is compact and relevant. The authentication instructions add useful context rather than filler, though the phrasing around 'start_login does NOT open this tool' is slightly awkward.

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 one-parameter tool with no output schema, the description is nearly complete: it explains what the tool does, what happens, and the authentication requirement. It does not specify expected return values or failure modes, but those are not essential for a simple retry operation.

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 only parameter 'id' is already documented as 'Webhook delivery ID to retry.' The description does not add extra parameter-level detail such as where to obtain the ID, but with full schema coverage the baseline of 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?

The description uses a specific verb and resource: 'Retry a failed webhook delivery' and clarifies the concrete effect: 'Creates a new delivery attempt with the same payload to the configured endpoint.' This clearly distinguishes it from read-only siblings like get_webhook_delivery and list_webhook_deliveries.

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?

The description states the tool is for failed deliveries and gives explicit access prerequisites: needing a Proof account and authenticating before calling again. It does not explicitly name alternatives or when-not-to-use conditions, but the sibling context makes the intended use reasonably clear.

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