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

Annotations already flag non-idempotent, destructive, open-world writes, so the safety bar is lower; the description adds the valuable, non-obvious behavior that the signing secret is returned only once and must therefore be captured. It does not explain why the operation is marked destructive or whether existing endpoints are affected.

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 with no filler; the core purpose leads and the critical return-value caveat comes second.

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 4-parameter, no-output-schema mutation tool, the description covers the essential thing an agent cannot infer elsewhere: the one-time signing secret. Remaining gaps (filtering semantics, effects on other endpoints) are largely covered by the schema or annotations.

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 only 50%, and the description only indirectly supports the `events` parameter through its event-name examples. It adds nothing about `numbers` filtering or the `description` label, leaving those to the schema.

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+resource (register an endpoint to receive named events) and enumerates concrete event types, which makes the intent unambiguous. It does not name or differentiate from siblings like update_webhook, test_webhook, or rotate_webhook_secret, so it stops short of a 5.

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?

Usage is only implied: the examples of destinations (your app, a CRM, an automation tool) hint at when you would register a webhook, but there is no explicit when-to-use vs. update_webhook/test_webhook guidance and no prerequisites or exclusions.

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