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

Adds substantial behavior beyond the annotations (which only say write/not-idempotent/open-world/not-destructive): a test event is POSTed first and the webhook is persisted only on a 2xx response, non-Slack payloads are signed with an X-SimpleDock-Signature header, and signingSecret is exposed only at creation time. The one-time-secret disclosure and the conditional-save behavior are exactly the kind of facts an agent cannot get from annotations.

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?

Four dense sentences, each carrying distinct payload: purpose/plan, save semantics, signature verification, and input constraints. Nothing is restated from the schema or annotations, and the most decision-relevant facts (test event, signingSecret returned only now) come early.

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 mutation tool with no output schema, it covers creation semantics, security, failure mode (non-2xx = not saved) and input constraints well, and even names the one returned value the caller must capture. It stops short of describing the response payload shape beyond signingSecret or what happens on retries/duplicate URLs, which leaves a small gap.

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 only 20%, so the description must compensate, and it does: it explains the https:// requirement for url, the required hosts for ZAPIER/SLACK kinds, and the 'empty = every event / every location' defaults for eventTypes and locationIds. Only label (maxLength 80) is undocumented, and the schema already constrains it.

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+resource and scope: 'Send appointment events to a URL (Pro).' No sibling tool in the list touches webhooks, so there is zero ambiguity about which tool to reach for. The parenthetical '(Pro)' also flags the plan gate, which no sibling states.

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?

Gives concrete preconditions and constraints rather than a vague 'use this to add a webhook': https-only URLs, host restrictions per kind, and empty-array semantics. It does not state when *not* to use it or name an alternative, but no alternative webhook tool exists among the siblings, so the gap is minor.

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