# update_field

> Change one field/question on a form: label, required, options, bounds, validation, or adaptive follow-up config. Identify the field by its key.

_MCP tool "Update a field" · writes data · https://forms.ax/help/tools/update_field_

## 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.

## Inputs

- `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, required): Field key to update
- `patch` (object, required): 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.