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

Goes well past the annotations (readOnlyHint=false, openWorldHint=true, destructiveHint=false) by disclosing delivery headers, the exact HMAC signature construction, retry policy (5 attempts, exponential backoff), auto-disable after 20 consecutive failures, and the one-time-display property of the signing secret. It also names the failure modes (400 invalid URL/limit, 409 duplicate URL), which an agent needs to handle rather than guess at.

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 purpose is front-loaded in the first clause, and the dense remainder is all operational payload rather than repetition. It is a long, unstructured block, but virtually every sentence carries non-obvious information an agent would otherwise have to discover by error.

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, yet the description still surfaces the single most important return-value fact — that the response is the only time the signing secret is exposed. Combined with error codes and permission requirements, an agent can call this correctly with no further context.

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 both parameters are already documented in structured form and the baseline is 3. The description adds only marginal parameter meaning — that the registered URL receives every event, and that an invalid URL yields 400 — while workspaceId scoping is left entirely to the 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?

Opens with a specific verb and resource — "Register a URL that receives every workspace event as an HTTP POST" — and enumerates the exact event types delivered. This separates it unambiguously from sibling lifecycle tools like update_webhook, test_webhook, and list_webhooks.

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 establishes the trigger (registering a new endpoint), the prerequisite permission (webhooks.manage, held by Admin and Editor), and the caller's follow-up duty (hand the secret to the user because it is shown only once). It stops short of explicitly routing to siblings, e.g. saying to use update_webhook for an existing endpoint rather than registering a duplicate.

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