MCP tool Inputs
update_field
Update a field
writes data renders an in-chat view
Change one field/question on a form: label, required, options, bounds, validation, or adaptive follow-up config. Identify the field by its key.
Ask your assistant
Make the phone field optional and rename it to Best number to reach you.
Targets a single field via its stable key and patches only what you name — everything else stays put.
| Parameter | Type | Description |
|---|---|---|
| form_id | string | Form id (authenticated). From create_form/list_forms. |
| draft_token | string | Draft token (anonymous drafts, before sign-in). From create_form's draftToken. |
| key * | string | Field key to update |
| patch * | object | Properties to change |
| patch.type | "short_text" | "long_text" | "email" | "phone" | "number" | "single_choice" | "multi_choice" | "date" | "file_upload" | "signature" | "rating" | "url" | Field type. There is no password/PIN type — forms.ax never collects credentials. |
| patch.label | string | What the respondent sees, e.g. 'Describe your project' |
| patch.description | string | Optional help text shown under the label |
| patch.required | boolean | |
| patch.options | array of string | For single_choice/multi_choice: 2+ unique options |
| patch.min | number | number/rating lower bound (rating default 1) |
| patch.max | number | number/rating upper bound (rating default 5) |
| patch.adaptive | object | AI follow-up questions on thin answers (short_text/long_text only) |
| patch.validation | object | |
| patch.page | string | Page key this field belongs to (multistep forms). Omit for single-page forms or the first page. |
* required
Guides using this tool