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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=false, so the safety profile is covered. The description adds a genuinely useful PATCH semantic not present in annotations: omitted fields retain their values, which tells the agent it need not resend the full resource. It stops short of describing side effects (e.g., whether changing events affects in-flight retries) or auth requirements.

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 action and followed immediately by the one behavioral rule that matters. No filler and nothing buried.

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?

The tool has a nested object parameter and no output schema, and the description says nothing about what an update returns or whether validation failures are reported per field. Critical context such as the one-time signing secret and event retry behavior lives in the schema's nested description rather than here, leaving the top-level description thin for a mutation with a nested payload.

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%, with per-field descriptions for id, url, events, and enabled, so the schema carries parameter meaning. The description adds only the high-level partial-update rule and does not name or clarify any individual field; baseline 3 is appropriate when the schema does the heavy lifting.

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 a specific verb and resource ("Update ... webhook") and identifies the operation as a partial update of selected fields. It does not distinguish itself from siblings such as create_webhook, delete_webhook, or list_webhooks, but the purpose 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?

Usage is implied: use this to modify an existing webhook rather than creating one, and send only the fields you want to change. There is no explicit when-to-use vs. when-not guidance, no mention of prerequisites such as needing an existing webhook id, and no routing to sibling tools.

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