create_webhookRegister a webhook URL for a Fillout form so every new submission is sent to your endpoint, and receive the webhook ID.
Register a URL that Fillout calls on every new submission to a form. Returns the webhook id.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | HTTPS endpoint that receives submissions | |
| formId | Yes | The form's public ID (from list_forms or the form URL) |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true, so the agent knows this is a non-destructive write that reaches an external endpoint. The description adds the useful behavioral fact that the URL is invoked on every new submission and that the created webhook id is returned, but it says nothing about duplicate-URL handling, idempotency, or required permissions.
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 sentences, zero filler, with the core action and its trigger front-loaded and the return value noted last. Every clause earns its place.
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 two-parameter, all-required tool with no output schema, the description covers the action, the trigger, and the return value ('the webhook id'), while annotations cover the safety profile. It is nearly complete, missing only edge-case behavior such as duplicate webhook registration or failure modes.
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 100%, so both parameters (url, formId) are already fully documented with format and provenance hints. The description adds no syntax, format, or validation detail beyond what the schema provides, so the baseline of 3 applies.
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 gives a specific verb (register), the resource (a URL/webhook), and the exact trigger semantics (called on every new submission to a form), which is enough to know precisely what the tool does. It does not explicitly contrast itself with the sibling delete_webhook or explain how webhooks relate to submission-listing tools, so it stops short of full sibling differentiation.
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 event-driven framing ('on every new submission') implies the use case for the tool, but there is no explicit statement of when to create a webhook versus polling submissions, no prerequisites (e.g., form must exist, endpoint must be HTTPS), and no mention of delete_webhook as the way to undo it. Usage is only implied.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.