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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds behavior beyond them by disclosing the return content (event name plus summary) and the fact that it covers every event, indicating no filtering or parameters are needed.

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 short sentences with zero waste: the first front-loads what is returned, the second routes to the sibling. Nothing is repeated from the schema or annotations.

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 simple zero-parameter, read-only listing tool with no output schema, the description supplies the missing return shape and the next step an agent would need. Only minor gaps remain, such as whether the list is a static catalog of event types versus actual delivered events.

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?

The tool takes no parameters and the schema is an empty object, so there is no parameter meaning to convey; the baseline for zero-param tools applies. The description correctly implies no filtering is possible by promising every event.

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 ("Lists") and resource ("every webhook event we send") and even names the returned fields, so the agent knows exactly what it gets back. It is clearly separable from the sibling get_webhook, which it explicitly names as the detail-fetching counterpart.

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 states a concrete follow-up: "Then call get_webhook for its fields and an example payload," which tells the agent when to chain rather than stop here. There is no explicit when-not guidance, but for a zero-argument enumeration tool the routing advice covers the main decision.

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