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

The annotation readOnlyHint=true already covers the read-only nature. The description adds the requirement of an API key, which is useful context, but does not disclose other behavioral aspects such as output format, pagination, or whether it lists all webhook URLs. With annotations present, the description provides some incremental value but not extensive.

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 a single, front-loaded sentence that conveys the purpose and a key requirement without redundancy. Every word earns its place.

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 read-only listing tool with no parameters and no output schema, the description is largely complete. It states the scope (account behind API key) and action. It could mention that it returns a list of URLs, but that is implied by 'List'. Minor gap: no mention of response structure, but that is not critical for invoking the 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 input schema has zero parameters and schema coverage is 100%. Baseline for no parameters is 4. The description adds no parameter-related details because none exist, which 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 states a clear action (List) and a specific resource (webhook URLs) scoped to the account behind the API key. It unambiguously distinguishes from siblings like list_webhook_requests, which handles requests rather than URLs.

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?

No explicit when-to-use guidance or differentiation from alternatives is provided. The only usage note is 'requires an API key', which is a prerequisite rather than a selection criterion. It does not mention that this is the tool for listing URLs as opposed to other webhook operations.

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