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

Annotations only flag readOnly=false/openWorld=true/destructive=false; the description adds substantial non-obvious behavior: the signing secret is generated externally and never returned, custom headers cannot be set here, the receiving endpoint can't verify until the user copies the secret, and hard failure limits (10 webhooks, duplicate URL).

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?

Front-loaded with purpose and the critical URL constraint, then operational caveats. All paragraphs carry real content, though the 'at the `dashboardUrl` in the response' clause is repeated near-verbatim, which is mild redundancy in an otherwise tight definition.

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-value detail is unnecessary. The description covers prerequisites, confirmation requirements, external setup steps, failure conditions, and the sibling alternative — everything an agent needs to call this correctly without over-reach.

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%, so the schema already documents url, name, and events thoroughly (including the full event enum and http-rejection rule). The description reinforces the URL requirement but adds little syntax or format detail beyond what the schema already provides; 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 and resource ('Register an HTTPS endpoint that receives Checkout Page event notifications') and enumerates the event domains covered. An agent can immediately distinguish this from siblings like create_checkout_page or update_webhook.

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?

Explicitly routes the agent: 'To point an existing webhook at a new URL, use `update_webhook` rather than registering a duplicate.' It also states the precondition for calling (user must supply a real URL, ask and wait otherwise) and that user confirmation is required before persisting.

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