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

The description explicitly states 'Side effects: none (read-only),' but this mostly restates what the annotations already provide (readOnlyHint, idempotentHint, destructiveHint: false). It adds the 'currently registered' and event-filtering behavior, but doesn't disclose additional behavioral details such as pagination or response characteristics, which are partly covered by the output schema.

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 concise sentences present the core operation first, then the optional filter behavior, then the side-effect note. There is no unnecessary padding, and the most important information is front-loaded.

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?

This is a simple one-parameter read-only tool, the output schema exists, and the annotations and description together cover safety and behavior. Nothing an agent needs to invoke it correctly 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% and the event parameter already has a full enum and explanation of the omitted behavior. The description adds little beyond repeating what the schema says, so the baseline of 3 is appropriate.

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 starts with a precise verb-resource pair: 'List webhooks currently registered for a given webhook event type.' It clearly differentiates from create-webhook and delete-webhook siblings and clarifies that omitting the event lists all supported events.

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 when to use the tool: to list webhooks for a specific event type or for all supported events if event is omitted. It doesn't explicitly name alternatives like create-webhook or delete-webhook, but the context makes the read-only listing use case clear.

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