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

The destructiveHint annotation already signals a mutating write, and the description's 'Register' is consistent with that. Beyond restating the mutation, it discloses nothing about idempotency, uid uniqueness, what happens to an existing endpoint at the same URL, or required auth — so it adds only modest value over the annotation.

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?

Two tight sentences, front-loaded with the core action and scope; the REST path is a useful, compact addition. No filler or redundancy.

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 creation tool with fully documented parameters, no output schema, and a safety annotation already present, the description covers what it must: what is created, against which app, and the optional scoping. It would be stronger with a note on application prerequisites or duplicate-URL behavior, but nothing essential is missing.

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 all seven parameters are already documented in the schema (url as HTTPS, uid as stable id, event_types omit-to-receive-all, etc.). The description's mention of event types and channels roughly mirrors the schema without adding format or constraint detail, so 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?

The description gives a specific verb and resource ('Register a webhook endpoint URL') plus the scoping constraints (one application, optional event types/channels), and even names the underlying REST route. An agent can distinguish it immediately from siblings like svix_get_endpoint or svix_list_endpoints.

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 never states when to use this tool versus alternatives such as svix_create_application or the get/list endpoint variants, nor any prerequisites (e.g., the application must exist first). Usage is only implied by the verb 'Register'.

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