Verify a webhook signature

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

Goes well past the annotations by disclosing the algorithm, the five-minute freshness window, and that 'nothing is sent anywhere', which confirms the openWorldHint=false annotation in plain language. It stops short of saying what a failure result looks like (boolean vs. error), which matters for a verification tool with no output schema.

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 and the local/no-network guarantee are front-loaded in the first sentence; the second paragraph carries the raw-body warning. Efficient overall, with only slight redundancy in restating the `secret` default that the schema already documents.

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 four-parameter, read-only tool with no output schema, the description covers the mechanism, the network-free guarantee, and the one non-obvious input pitfall. The remaining gap is the return value: it never says what a success or stale-signature result looks like, which an agent must infer.

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 baseline is 3, but the description earns extra credit by adding the operationally critical detail that the body must be raw text captured 'before JSON parsing' — a classic source of false negatives that the schema wording alone would not convey. It otherwise restates the documented default for `secret`.

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 (verifies) plus the exact resource and mechanism: an HMAC-SHA256 check of the Perly-Signature header against the raw body and signing secret. That is clearly distinct from the neighbouring webhook tools (list_webhook_endpoints, create_webhook_endpoint, delete_webhook_endpoint), which all manage endpoint configuration rather than validate a delivery.

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?

Gives an explicit use case — 'debug a webhook handler that rejects real events' — and an implicit exclusion by framing it as a local debugging aid, while every sibling tool is a CRUD/configuration action. An agent can decide whether to call it without opening the schema.

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