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

The annotations already declare readOnlyHint=true, so the read-only behavior is covered. The description adds the tailnet scoping and REST endpoint reference, but does not disclose output format, authorization needs, or rate limits. This is acceptable for a simple list operation but adds no major behavioral context beyond annotations.

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, information-dense sentence. It states the action, resource, scope, and REST endpoint without fluff. 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 zero-parameter read-only tool, the description is complete enough: it says what the tool returns (webhook endpoints) and the scope. No output schema exists, but the description provides sufficient context for an agent to invoke the tool correctly. It could be improved by noting any output fields or pagination, but that is not critical for invocation.

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, and schema coverage is 100% (vacuously). Per the rubric, a 4 is the baseline for zero-parameter tools. The description does not need to explain parameters since none exist.

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 uses the specific verb 'List' with the resource 'webhook endpoints' and scope 'for the tailnet', clearly distinguishing it from all sibling tools which focus on devices, keys, DNS, etc. It also provides the REST endpoint for precision.

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?

The description makes it clear this tool is for listing webhook endpoints, which is the only webhook-related tool among siblings, so context is clear. It lacks explicit when-not-to-use or alternative recommendations, but given its unique purpose, the usage context is adequately implied.

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