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

Beyond the annotations, the description discloses important behavior: the signing secret is returned only once, deliveries follow the Standard Webhooks spec, and there is a limit of 5 per account. These are exactly the kind of operational details an agent needs before calling a mutation tool.

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 description is three tight sentences and front-loads the core action, event types, and polling alternative before the return and limit details. Every sentence adds useful information without repetition.

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 webhook registration tool with no output schema, the description covers the endpoint requirement, event scope, one-time secret return, delivery standard, and account limit. Nothing essential for correct invocation appears to be 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 coverage is only 50%, so the description usefully adds that the URL must be a public https endpoint and enumerates the supported post events. The events default is already covered by the schema, but the endpoint constraint adds meaningful semantics beyond 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?

The description gives a specific verb and resource: 'Register a public https endpoint'. It also clarifies the event scope and contrasts with polling, so the core purpose is unmistakable. It does not explicitly differentiate itself from siblings such as list_webhooks, delete_webhook, or test_webhook, which keeps it from 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?

It tells the agent to use this instead of polling when it wants to hear about its own posts, and notes the account limit of 5 webhooks. It does not name sibling alternatives or describe when not to use this tool, but the intended context is clear.

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