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

Annotations already declare readOnlyHint=false, destructiveHint=true, and idempotentHint=true. The description adds the useful detail that fields are optional and thus the update is partial, which is not in the annotations. It does not disclose that eventTypes are replaced (though the schema covers that) or explain what destructiveHint implies (e.g., pausing deliveries). Overall, it adds some context but relies on schema and annotations for the rest.

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?

One sentence, front-loaded with the verb and resource, and the optionality note is the only extra detail. Zero wasted words; every element 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?

With an output schema present and full parameter coverage in the schema, the description adequately covers the tool's purpose and partial-update semantics. It does not mention error cases or prerequisites like 'id must reference an existing webhook', but the schema's required field and the id description ('as returned by list_webhooks') cover that. For a typical update operation, this is complete enough.

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%, so every parameter already has a thorough description in the schema. The description mentions 'URL, subscribed events, or active state' but adds no syntax, format, or constraint details beyond what the schema provides. This meets the baseline for high schema coverage.

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?

States a clear verb-resource pair ('Updates a webhook') and specifies the exact fields modified (URL, subscribed events, active state). This distinguishes it from siblings like create_webhook, delete_webhook, get_webhook, and list_webhooks without needing to inspect schemas.

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 clearly implies when to use this tool (for modifying an existing webhook) and signals the partial-update pattern ('Every field besides id is optional'), which guides usage. However, it does not explicitly name alternatives like create_webhook or state when not to use it, so it stops short of full explicit routing.

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