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

The description adds critical behavioral context beyond the annotations: the signingSecret is shown once and cannot be retrieved again, warning the agent to preserve it. Annotations already indicate this is a write operation (readOnlyHint=false), and the description complements rather than contradicts them.

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, purposeful sentences. The first states the core behavior and the second flags a non-obvious, operationally important detail. No filler or redundancy; the most critical operational warning is placed prominently.

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?

Given the output schema exists and the request schema is fully documented, the description covers the essential extra context an agent needs: registering a webhook and preserving the one-time signing secret. It is slightly sparse on why one would create a webhook, but the schema and annotation coverage fill the remaining gaps.

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 input schema has 100% coverage with descriptions for all three parameters, so the description does not need to explain them. It adds no parameter-level detail, matching the baseline expectation. The mention of signingSecret relates to the response, not the request schema.

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 the verb 'Registers' and the resource 'webhook endpoint,' making the tool's purpose unambiguous. It distinguishes itself from the many sibling webhook tools (delete_webhook, update_webhook, get_webhook) by indicating creation. It is slightly terse but sufficient.

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 says what the tool does but not when to use it versus alternatives. It does not mention that creating a webhook is for receiving event notifications, nor does it contrast with update_webhook or list_webhooks. Usage context must be inferred entirely from the verb and tool name.

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