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

Annotations only say destructive/openWorld/non-idempotent; the description adds the concrete behavior behind that: an outbound POST of {"test": true, ...} to the registered URL, signed with the same X-Webhook-Signature-256 HMAC as live deliveries, plus the required `webhooks:write` scope. It also discloses what is returned (status, attempt, timestamps). That is real context an agent cannot get from the structured fields.

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 sentences, front-loaded with what happens on the wire, then the reason to call it, then the return value and scope. Each sentence contributes distinct information with no repetition of the title or schema.

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 single-purpose action with no output schema, the description covers trigger, exact side effect, signature semantics, expected return shape, verification path via pm_list_webhook_deliveries, and the required API-key scope. Nothing an agent needs in order to invoke and interpret results is missing.

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 account/workspace/webhookIdentifier are already fully documented, and the baseline would be 3. The description still adds a bit of meaning by tying the call to a 'registered URL' belonging to the webhook being addressed, but it gives no hint about identifier format or how to obtain a webhook id (pm_list_webhooks).

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?

States a specific verb and resource: fires a synthetic 'webhook-test' delivery to a registered webhook on demand. It is clearly distinguishable from pm_get_webhook (read config), pm_replay_webhook_delivery (resend a real delivery) and pm_list_webhook_deliveries (inspect history), and it even spells out the exact event body, so the agent knows precisely what will be sent.

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 an explicit use case — verifying receiver reachability and that HMAC signature verification is correct during two-way setup — and points at pm_list_webhook_deliveries as the way to confirm the outcome. It lacks an explicit 'do not use this to retry a real failed delivery, use pm_replay_webhook_delivery instead' exclusion, which is the one remaining ambiguity against a close sibling.

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