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

Annotations already declare the tool as non-destructive and idempotent. The description adds useful context beyond that: the webhooks.manage permission requirement, the 409 conflict on duplicate URLs, and the behavior of reactivating an endpoint that was disabled after failed deliveries.

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?

Three compact sentences, front-loaded with the core action and followed by the most important behavioral caveats. Every sentence adds useful information without repetition.

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?

An output schema exists, so return values need not be described. The description covers the mutation's key side effects, permission requirement, and a specific error case. Minor gaps remain around whether URL changes affect delivery state, but the definition is otherwise complete.

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 coverage is 100%, so the baseline is 3. The description adds meaning beyond the schema for active by explaining that re-enabling after failed deliveries resumes sending, and it ties url updates to a 409 duplicate-registration failure.

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 verb and resource: changing a webhook endpoint's URL or toggling it with active. It is clearly distinct from create_webhook, delete_webhook, and test_webhook in practice, but it does not explicitly name sibling alternatives.

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 explains the two supported update modes: URL changes and active toggling. It also clarifies the reactivation case after failed deliveries, giving clear usage context, though it does not explicitly state when not to use this tool or name alternatives.

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