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

Annotations already declare readOnlyHint=false, so the agent knows this is a mutation. The description adds the specifics of what fields can be updated (description and status), which goes slightly beyond the schema. However, it doesn't disclose any side effects (e.g., whether existing values are overwritten, if authentication is required, or if updates are immediate). Given the mutation nature and the lack of additional details, a score of 3 is appropriate; it adds some behavioral context but not a comprehensive disclosure.

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, concise sentence that front-loads the action and scope. Every word earns its place, with no filler or redundancy. It efficiently conveys the tool's purpose without unnecessary elaboration.

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 update tool with only 3 parameters and no output schema, the description is largely complete. It covers the two main update actions. However, it does not mention the response format or error conditions (e.g., what happens if the id doesn't exist). Since the tool is straightforward, this is a minor gap, not a critical omission, so a 4 is warranted.

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 schema has no parameter descriptions (coverage 0%), so the description must compensate. It does so by explaining that 'description' corresponds to the description field and 'enable/disable it' refers to the status field. The id parameter is self-evident as the identifier. This adds meaning beyond the raw schema, clarifying the purpose of two of the three parameters. The description doesn't explicitly map each parameter, but it covers the updateable fields well, earning a 4.

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 clearly states a specific verb ('Update') and resource ('webhook endpoint'), and specifies the two editable aspects ('description or enable/disable it'). This directly distinguishes it from sibling webhook tools like create, delete, get, test, and rotateSecret, leaving no ambiguity about what this tool does.

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: when the goal is to modify a webhook endpoint's description or its enabled/disabled status. It doesn't explicitly mention alternatives (e.g., use create for new endpoints), but the scope is intuitive and distinct from other webhook operations. It could be improved by naming sibling tools for explicit routing, but the current phrasing is sufficient for most agents.

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