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

Beyond the annotations (which already state idempotent, non-destructive, open-world), the description adds a genuinely valuable behavioral fact: setting is_enabled true re-enables an endpoint that Sendocado auto-disabled after repeated delivery failures. It does not disclose what happens to the existing event-type set when replaced, or whether the signing secret is affected by a URL change.

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, front-loaded with the replacement scope and followed by the one non-obvious state consequence. No filler or restatement of the tool name.

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 four-parameter mutation with no output schema and no parameter descriptions, the definition covers the core semantics but leaves gaps an agent would want: whether the secret survives a URL change, what a successful response contains, and whether event types are additive or overwritten. Annotations cover the safety profile, so these are the remaining holes.

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 0%, so the description carries the burden: it explains the meaning of is_enabled (including the re-enable case) and that url and event_types are replaced wholesale. However, webhook_endpoint_id gets no mention and no format constraints (e.g., URL scheme) are added, so compensation is only partial.

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 names a specific verb ("Replace") and the exact resources touched (URL, event types, on/off state), making it easy to distinguish from create_webhook_endpoint, delete_webhook_endpoint, and get_webhook_endpoint. It stops short of explicitly naming those siblings, but the resource is unambiguous.

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?

"all at once" implies full-replacement semantics (all four fields required), which is useful usage context, but the description never states when to use this versus rotate_webhook_endpoint_secret or delete/create. Usage is implied rather than stated, and no prerequisites or exclusions are given.

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