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

Annotations already establish read-only, non-destructive, closed-world behavior, but the description adds substantial context beyond them: ordering is newest first, each endpoint shows whether it still receives events and why delivery stopped, secrets are not returned after creation, and the tool requires an API key plus a paid plan while costing no credits.

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 front-loaded with the core purpose and return content, followed by security, billing, and prerequisite details. Every sentence adds useful information, and none is redundant.

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?

With no input parameters and no output schema, the description carries the return-value burden well: it explains ordering, event-receiving status, stopped-delivery reasons, and secret handling. It also covers auth and plan requirements, making it complete for this zero-parameter list tool.

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 has zero parameters, so there are no parameter semantics to document and the baseline is 4. The description correctly does not invent parameters, though there is no additional parameter behavior to explain.

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 states a specific resource, webhook endpoints, and the scope, endpoints the user has added, newest first. It is clear what the tool returns, though it does not explicitly name or distinguish itself from the closest sibling, list_webhook_deliveries.

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 strongly implied by 'Every endpoint you have added,' and the description adds useful prerequisites: API key and paid plan required, no credit cost. However, it does not explicitly say when to use this versus alternatives such as list_webhook_deliveries or how to inspect a single webhook.

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