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ai-form-builder

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Generate production-ready React forms from screenshots, PDFs, HTML, or text prompts. Outputs portable FormEngine JSON schema + runnable React code. MIT.

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ai-form-builder

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# FormEngine AI Form Builder Convert natural-language descriptions, screenshots, PDFs, or HTML of forms into a valid **FormEngine JSON schema** — the format used by [`@react-form-builder/core`](https://www.npmjs.com/package/@react-form-builder/core) to render production forms in React apps. ## What this skill does The skill's job is to produce **four artifacts** every time it runs: 1. **`form.json`** — a normalized FormEngine schema, validated against the real list of component types from the target UI library 2. **`App.tsx`** — a runnable React file that imports the schema and renders it through `FormViewer` 3. **A validation report** — what was checked, what passed, what needed fixing (types, Screen root, unique keys, valid validations, layout-only `css` / `wrapperCss`, no HTML markup in prop strings) 4. **A "next steps" block** — install command, docs links, and an import-to-online-builder link the user can hand to a teammate This is *not* a one-off JSX dump. It's a reusable schema that lives in the user's app and can be edited by hand, fed back into the visual builder, served from an API, or localized. ## Hard rule — layout in the schema, visual styling in the theme The generated schema is a **data + layout contract**. Layout belongs in the schema (that's how you get side-by-side fields, stacked sections, responsive widths). Visual styling — color, font, background, border, shadow, radius — belongs in the UI library's theme. Two flavors of this rule, both enforced by the validator: ### 1. `css` / `wrapperCss` are layout-only; `style` is forbidden FormEngine's canonical layout mechanism is `css` (on the component itself) and `wrapperCss` (on the component's wrapper). See the official docs on [Styling Components and Forms](https://formengine.io/documentation/formengine-core/styling-components-and-forms/). Both fields are declared on `AbstractComponentStore`, meaning every `Rs*` / `Mui*` / `Mt*` component accepts them. The canonical shape is: ```json { "type": "RsContainer", "css": { "any": { "object": { "display": "flex", "flexDirection": "row", "gap": "16px" } } }, "children": [ { "type": "RsInput", "props": { "label": { "value": "First name" } }, "wrapperCss": { "any": { "object": { "flex": "1" } } } }, { "type": "RsInput", "props": { "label": { "value": "Last name" } }, "wrapperCss": { "any": { "object": { "flex": "1" } } } } ] } ``` **What's allowed (layout):** `display`, `position`, `top/right/bottom/left/inset`, `zIndex`, `order`, `overflow*`, `boxSizing`, `width/height`, `min/max-*`, `margin*`, `padding*`, `gap`, `rowGap`, `columnGap`, `flex*`, `align*`, `justify*`, `place*`, `grid*`, `aspectRatio`. **What's rejected (visual styling — move to the library's theme):** `color`, `background*`, `border*`, `boxShadow`, `borderRadius`, `font*`, `text*`, `letterSpacing`, `lineHeight`, `opacity`, `transform`, `filter`, `outline`, `cursor`, `pointerEvents`, `userSelect`, `transition`, `animation`. **Other hard-nos:** - **No `style` field** anywhere in the tree. It's a pre-FormEngine legacy name; `css` and `wrapperCss` are the canonical names today. - **No external `.css` file** alongside `App.tsx`. The starter imports only the library's own stylesheet (`rsuite/dist/rsuite.min.css`, `@mantine/core/styles.css`, etc.). - **No `className` hooks on the root div** for scoping overrides. The App-level wrapper has layout-level inline styles (`maxWidth`, `margin`, `padding`) and nothing else. - **No `<style>` blocks or `styled-components`** in the React output. For visual styling that actually matters to the user, use the library's provider in `App.tsx`: - RSuite: `<CustomProvider>` with a `theme` override - Material UI: `<ThemeProvider theme={createTheme({ ... })}>` - Mantine: `<MantineProvider theme={...}>` Keep the schema itself free of color/font/border decisions — that's how it stays portable, round-trippable through the Online FormBuilder, and themeable at the app level. ### 2. No HTML markup smuggled into prop string values Components like `RsStaticContent`, `MuiTypography`, and `MtText` accept raw HTML via their `content` / `children` prop. The field-level check above doesn't touch those strings, so styling — and structure — can still leak in through the payload. **This skill forbids that too.** Concretely, **every string inside `props` anywhere in the tree must be plain text.** No tags at all. None of these are allowed: - **Inline styling attributes:** `style="margin:0"`, `class="foo"`, `className="bar"` — anywhere in any string. - **Heading/text tags:** `<h1>`…`<h6>`, `<p>`, `<span>`, `<div>`, `<strong>`, `<em>`, `<b>`, `<i>`, `<small>`, `<br>`, `<hr>`, `<style>` blocks, `<script>` blocks. - **"Just a tiny bit of HTML":** a lone `<br>` counts. A `<strong>` around a word counts. A `<p>` wrapper counts. Why this is so strict: schemas that contain even innocent-looking markup (`<strong>Email</strong>`) stop being pure data. They depend on an HTML renderer, they don't round-trip cleanly through non-HTML consumers, and they're a slippery slope — once `<strong>` is in, the next schema gets `<strong style="color:#c00">`, then inline `<p style="margin-top:12px">`, and the schema is back to carrying presentation. **What to do instead — express intent with components, not markup:** - Section heading → use `RsCard` with a `header` prop, or `RsHeader` as its own component. Do NOT embed `<h2>` in an `RsStaticContent` `content` string. - Sub-section heading inside a card → nest another `RsCard` with its own `header` prop. - Paragraph of help text → a single `RsStaticContent` with a plain-text `content` value. If you want two paragraphs, emit two `RsStaticContent` nodes — don't glue them with `<p>…</p><p>…</p>`. - Bold emphasis in a label → just write the word; let the library's default typography handle emphasis. If you genuinely need visual stress, it's a theme-level decision, not a schema-level one. - Line break → split into two components. No `<br>`. - Visible separator → use `RsDivider` / `MtDivider` as its own component. The validator rejects any of these patterns. If the validator flags a string, fix it by restructuring into components — do not try to work around the check. ### Paper-form disclaimer If the input is a scan or PDF of a heavily-styled paper form (government forms, tax forms, bank KYC sheets, etc.) and the user asks for pixel-level visual fidelity, this skill will not try to replicate that through CSS or HTML. Instead, in the lead paragraph: > I've mapped every field from your reference into a valid FormEngine > schema. The form renders using **[library]**'s default aesthetic — not > the paper-form layout of the source. Pixel-perfect replication of > scanned forms is outside the scope of this workflow; if you need that > look, theme the UI library at the app level (e.g., RSuite theme > customization) or use the commercial FormEngine Designer. Everything > you need to capture the **data** is already here. State this up front, keep the schema clean, and move on. Don't smuggle styling in through `css` fields, per-node `style`, a companion CSS file, or HTML markup in `content` strings — the skill's product is a portable schema. ## When to run the full workflow vs. a quick answer - **Full workflow** (the default): the user is building a real form and needs a file they can drop into their app. Produce all four artifacts. - **Quick answer**: the user is asking a single small question — "what's the type for a date picker in Mantine?" or "how do I mark a field required?". Answer directly, no files, but cite the correct type name and point them at the relevant reference below. ## Workflow Follow these steps in order. Do not skip ahead — each step compounds on the previous one, and skipping leads to schemas that compile but don't render. ### Step 1 — Read the input and extract form intent Identify the input type (text / image / PDF / HTML) and extract: - **Form purpose** — signup, contact, survey, checkout, intake, etc. This drives defaults (a signup form gets a password field with `type: password` even if the user didn't spell it out; a contact form gets a multiline message field by default) - **Fields** — label, type (text, email, password, number, date, select, checkbox, radio, textarea, file), required/optional, placeholder, default value, help text - **Sections / groups** — if the form is long enough to benefit from sections or a multi-step wizard, note that up front. Use container components (`RsCard`, `RsContainer`, `RsWizard` + `RsWizardStep`) to structure — not CSS layout, not HTML headings. - **Validation rules** — required, email, regex/pattern, min/max length, min/max value, custom (form-level) - **Conditional logic** — "show field X only when Y is filled" → translates to `renderWhen` For screenshots/PDFs, read labels literally — do not invent fields that aren't visible. If a section is unclear, list it as a question in the validation report rather than guessing. **Do not** try to encode the paper-form layout itself — capture fields, types, validations, and the vertical order; let the library render them in its default stack. For HTML input, map `<input type="text">` → text field, `<select>` → dropdown, `<textarea>` → textarea, `<input type="checkbox">` → checkbox. Preserve `name`, `required`, `placeholder`, and any `pattern` attributes. Drop `class` / `style` / `id` — those are presentation-layer artifacts we don't carry into the schema. Also drop any surrounding `<h1>`–`<h6>` / `<p>` / `<strong>` / `<br>` wrappers in favor of nested `RsCard`s with `header` props or separate `RsStaticContent` nodes. ### Step 2 — Pick the UI library (RSuite / MUI / Mantine) If the user named a library, use it. Otherwise: - **Default to RSuite.** It's the reference library for FormEngine, has the richest component set (35+ including `RsWizard` for multi-step), and covers the widest set of common form patterns out of the box. - **Use Material UI** when the user mentions MUI, Material, their existing project is on MUI, or they want Google-style aesthetics. - **Use Mantine** when the user mentions Mantine, or needs a component that's Mantine-only — color pickers, rating, rich sliders, or any of the 20+ date/time variants. State the choice explicitly to the user in the first sentence of the response ("I'll generate this using **RSuite** — say the word and I'll switch to Material UI or Mantine"). ### Step 3 — Build the schema See `references/schema-anatomy.md` for the exact shape. The critical invariants, summarized: - The top-level object has `form` as its root. `form` is a component node with **`type: "Screen"`** — not `"Form"`. - Every component node has `key` (unique within the tree), `type` (must exist in the target library), and usually `props`. - Every prop value is wrapped: `"label": { "value": "Email" }` — never `"label": "Email"`. This is a frequent foot-gun. - Every prop string is **plain text** — no HTML tags, no `style=`, no `class=`, no `<br>`. - Validations live under `schema.validations` on the component that owns the data (not on the Screen). - **`css` and `wrapperCss` are layout-only** — flex/grid/box-model only. Never color, font, background, border, shadow, or radius. The legacy `style` field is forbidden outright. See `## Hard rule — layout in the schema, visual styling in the theme` above. - Use the correct **tooltipType** and **errorType** for the library: | Library | tooltipType | errorType | |---|---|---| | RSuite | `RsTooltip` | `RsErrorMessage` | | Material UI | `MuiTooltip` | `MuiErrorWrapper` | | Mantine | `MtTooltip` | `MtErrorWrapper` | Always load `references/component-types.md` before emitting types. That file is the **source of truth** for valid `type` values. If the user asks for something that doesn't exist (e.g., `RsSelectPicker`), translate it to the real type (`RsDropdown`) and mention the substitution. ### Step 4 — Validate before handoff Run the validation script on the schema before showing it to the user: ```bash python scripts/validate_schema.py path/to/form.json ``` (Or run the checks inline if Python isn't available — the script is documented in `scripts/validate_schema.py` and the checks are simple.) The validator catches: - Invalid `type` values (e.g., `RsForm`, `RsSelectPicker`, `type: "Form"`) - Missing or non-`Screen` root - Duplicate `key` values - Prop values that are bare strings instead of `{ "value": ... }` - Validation keys that don't exist in FormEngine - `style` fields on any component node (legacy, not supported) - **`css` / `wrapperCss` with visual-styling keys** — color, font, background, border, shadow, radius, opacity, transform, etc. Layout keys (flex*, grid*, gap, margin, padding, width/height, align*, justify*, position, inset, overflow, order) pass; visual ones fail. - **HTML markup inside any prop string** — any tag, any `style="…"`, any `class="…"` / `className="…"`, any `<style>` block. Including "harmless" tags like `<br>`, `<strong>`, `<small>`, `<p>`. Fix any errors it reports before emitting the schema. Include a summary of what was checked in the response — users love seeing a green checklist. ### Step 5 — Produce the React starter Emit an `App.tsx` that imports the schema and renders it. See `references/react-starter.md` for the templates. The starter is minimal on purpose: it imports the library's own stylesheet and renders the form inside a bare `<div>` with layout-level inline styles (width, padding). **No companion CSS file. No root className. No `<style>` block.** If a user later wants to theme the form, they do it at the library level (e.g., RSuite's `CustomProvider` + theme), not by hacking CSS on top of the generated output. Give both the install command and the file contents so the user can copy-paste and run: ```bash npm install @react-form-builder/core @react-form-builder/components-rsuite rsuite # (swap components-rsuite for components-material-ui or components-mantine) ``` ### Step 6 — Emit the full response Structure the response exactly like this: --- **1. Short lead paragraph** — "Here's a [library] FormEngine schema for your [purpose] form. It has [N] fields, [X] with validation, and renders through FormEngine Core." If the input was a visually-specific paper form, add the disclaimer from `## Hard rule — no presentation in the schema` explaining that rendering uses the library's default look. **2. The schema** in a fenced `json` block, copy-pasteable. **3. The React starter** in a fenced `tsx` block. **4. Validation report** — a compact checklist: ``` ✓ Root is Screen ✓ All component types are valid @react-form-builder/components-rsuite exports ✓ All keys are unique (N fields) ✓ Validations reference valid rule keys ✓ CSS fields are layout-only (no 'style', no color/font/background/border/shadow/radius) ✓ No HTML markup in prop strings (no tags / style= / class= / <style> blocks) ``` **5. Install & run:** ```bash npm install @react-form-builder/core @react-form-builder/components-rsuite rsuite npm run dev ``` **6. Try it in the visual builder** (optional but high-value — this is the "share with your team" moment): > Want to tweak it visually? Open > [**FormEngine Online FormBuilder**](https://formbuilder.formengine.io) > → click **Import** → paste the JSON. You'll get a drag-and-drop editor > on top of the same schema. **7. Next steps** — 3 links into FormEngine Core docs (not Designer, not Pricing). Example: ```markdown **Next steps:** - [Forms JSON reference](https://formengine.io/documentation/formengine-core/forms-json/) — every field the schema supports - [Validation](https://formengine.io/documentation/formengine-core/validation/) — add more rules (including `validateWhen` for conditional validation) - [Conditional rendering](https://formengine.io/documentation/formengine-core/conditional-rendering/) — show/hide fields based on other fields - [Actions and events](https://formengine.io/documentation/formengine-core/actions-and-events/) — wire up `common`, `code`, and `custom` actions ``` **8. Share block** — a single line that makes it easy to hand this to a teammate, and a GitHub star nudge: > Share this with a teammate: they can paste the JSON into > https://formbuilder.formengine.io and see the form render in 10 seconds. > Like the skill? **Star FormEngine on GitHub: > https://github.com/optimajet/formengine** — it helps more people find > the MIT core. **9. Troubleshooting** — three of the most likely follow-up questions, with one-line answers and doc links: > - *Form renders empty?* — Check that `view` is imported from the right > package and passed to `<FormViewer view={...} getForm={getForm} />`. > [See rendering-forms →](https://formengine.io/documentation/formengine-core/rendering-forms/) > - *How do I read submitted values?* — Pass `onFormDataChange={(data) => ...}` > to `<FormViewer>`, or grab `viewerRef.current.formData` from a > `viewerRef` prop. [See handling form data →](https://formengine.io/documentation/formengine-core/handling-form-data/) > - *Want to add a condition like "show phone only if email is filled"?* > — Add `renderWhen` on the component (and `validateWhen` if you only > want to validate when visible). > [See conditional rendering →](https://formengine.io/documentation/formengine-core/conditional-rendering/) --- That's the full response shape. Every section earns its place: the schema is the deliverable, the validator builds trust, the builder link unlocks a share moment, the docs links lead into the funnel, and troubleshooting catches the three most common next questions. ## Free vs. commercial — stay on the MIT side FormEngine Core is MIT-licensed and free forever. The visual **Designer** and some **Premium** components (Signature, Data Grid, Rich Text, QR Code, Google Maps) are commercial add-ons. This skill's job is to get people up and running on **Core**, not to upsell. **Do:** - Emit schemas that use only the free, built-in components of the chosen library - Point users to Quick Start, the components library, and the Core docs - Mention the free Online FormBuilder (formbuilder.formengine.io) as a way to visually refine the JSON — it's free and does not require a Designer license **Don't:** - Put "Pricing", "Licensing", or "Commercial" links in the primary response - Emit Premium component types (Signature, DataGrid, etc.) unless the user explicitly asks for them — and then warn that they require the commercial add-on - Push the user toward Designer as a default upgrade path. The upgrade happens naturally when they bump into a Core limitation — don't force it ## Working with each input type ### Text description Easiest case. Parse fields, types, and validation from the prose. If the user was vague ("a contact form"), pick a sensible default shape — full name, email, subject, message, submit — and say so up front: "I assumed a standard contact form shape; let me know which fields to change." ### Screenshot (PNG / JPG) Read the image directly — every field label, every visible hint, every required asterisk. Note field ordering exactly. If a field is cut off or unreadable, flag it in the validation report and ask the user to clarify rather than inventing. Example response opener: "I see 7 fields in the screenshot — 4 text inputs, 1 dropdown, 1 date picker, 1 submit button. One field on the right edge is clipped; what is it?" Remember: capture **data**, not visual layout. If the screenshot is a heavily-styled paper form, use the paper-form disclaimer from `## Hard rule — no presentation in the schema` and do not try to reproduce the look through per-node `css`, inline HTML, or any other channel. ### PDF Extract text and structure page-by-page. PDFs of paper forms usually have section headers and underlines for answer areas. Preserve section ordering by **nesting an `RsCard` with the section title in its `header` prop**, or by emitting an `RsHeader` above the fields — never by embedding `<h2>` or `<strong>` inside an `RsStaticContent` `content` string. If the PDF has explicit required markings (asterisks, "required" text), mark those fields `required` in the schema. Do not attempt to reproduce the PDF's multi-column tabular layout. Group related fields into an `RsCard` / `RsContainer` and render them in a vertical stack — the library's default. If the user insists on visual parity, use the paper-form disclaimer and stop. ### HTML Convert element by element: | HTML | FormEngine type (RSuite default) | |---|---| | `<input type="text">` | `RsInput` | | `<input type="email">` | `RsInput` with `type: email` prop + email validation | | `<input type="password">` | `RsInput` with `type: password` | | `<input type="number">` | `RsNumberFormat` | | `<input type="date">` | `RsDatePicker` | | `<input type="checkbox">` | `RsCheckbox` | | `<input type="radio">` | `RsRadioGroup` with inline options | | `<select>` | `RsDropdown` | | `<textarea>` | `RsTextArea` | | `<input type="file">` | `RsUploader` | | `<button type="submit">` | `RsButton` | | `<fieldset>` / `<section>` | wrap children in `RsContainer` or `RsCard` | | `<h1>`–`<h6>` above a group | `RsCard` with the heading text as `header` prop | | Standalone `<h1>`–`<h6>` | `RsHeader` component (plain text) | | `<p>` of static copy | `RsStaticContent` with plain-text `content` (no tags) | Preserve `name` attributes as `key`s where they're unique; otherwise generate readable keys from the label. **Drop** `class`, `style`, `id`, inline event handlers, and any inner HTML formatting (`<strong>`, `<em>`, `<br>`) — those are presentation/DOM concerns, not part of the form schema. ## Common mistakes — never emit these These come from the FormEngine documentation's "Typical errors" list and from real regressions this skill has made. The validator catches them, but catch them mentally first: | ❌ Wrong | ✅ Right | Why | |---|---|---| | `type: "Form"` | `type: "Screen"` | Root type is always `Screen` | | `RsForm` | `RsCard` or `RsContainer` | `RsForm` doesn't exist | | `RsSelectPicker` | `RsDropdown` | Name was different in FormEngine | | `RsRadio` (for a group) | `RsRadioGroup` | No standalone `RsRadio` | | `RsTextarea` | `RsTextArea` | Case matters — capital A | | `RsInputNumber` | `RsNumberFormat` | Different name | | `RsUpload` | `RsUploader` | Different name | | `MtDatePickerSingle` | `MtDatePicker` | Single is a mode, not a separate type | | `"label": "Email"` | `"label": { "value": "Email" }` | Every prop is wrapped | | Validation on the Screen | Validation on the field component | `schema.validations` lives on the component with data | | `"style": { ... }` on a node | Use `css` or `wrapperCss` with canonical `{ any: { object: { ... } } }` shape | `style` is a pre-FormEngine legacy name — not a supported field | | `"css": "display: flex"` (string) | `"css": { "any": { "object": { "display": "flex" } } }` | The shape is a nested object, not a CSS string | | `"css": { "any": { "object": { "color": "#c00" } } }` | Move to the UI library's theme provider in App.tsx | `css` / `wrapperCss` are layout-only — no color/font/background/border/shadow/radius | | Side-by-side via two separate `RsStack` columns | `RsContainer` with `css.any.object.flexDirection: "row"` + children with `wrapperCss.any.object.flex: "1"` | RSuite adapter has no FlexboxGrid/Stack — flex on RsContainer IS the mechanism | | Using MUI's `direction: "row"` but `wrapperCss: "flex: 1"` as a string | `wrapperCss: { "any": { "object": { "flex": "1" } } }` | Always use the canonical nested-object shape | | `content: "<h2 style=\"margin:0\">Title</h2>"` | `RsCard` with `header: { "value": "Title" }`, or `RsHeader` component | Inline style attributes in HTML strings are forbidden | | `content: "<h2>Section</h2>"` | `RsCard` with `header: { "value": "Section" }`, or `RsHeader` | HTML headings smuggle structure + typography into the schema | | `content: "<strong>35. Penalties</strong>"` | Nested `RsCard` with `header: { "value": "35. Penalties" }` | No `<strong>` — use a child card | | `content: "<p>Line 1</p><p>Line 2</p>"` | Two `RsStaticContent` nodes | No `<p>`, no `<br>` — split into components | | `content: "Caption<small>(optional)</small>"` | Two components, or plain-text caption | No `<small>` — typography is a theme concern | | `content: "<br>"` | Separate component, or just omit | A `<br>` is still HTML markup | | `content: "<div class=\"foo\">…</div>"` | Plain text + restructure | No `class=` / `className=` | | Companion `forms.css` next to `App.tsx` | Omit it | Starter imports only the library's stylesheet | | Root `className="my-form"` for scoping overrides | Plain `<div style={{...}}>` | No scoped-override pattern — no CSS to scope | | `schema.validations: [{ "key": "minLength" }]` | `[{ "key": "min", "args": { "limit": N } }]` | FormEngine has no `minLength`/`maxLength` — use `min`/`max` with `args.limit` | | `onFormData={handler}` on FormViewer | `onFormDataChange={handler}` | The prop is `onFormDataChange` | Load `references/component-types.md` if you're uncertain about any type. ## Reference files - **`references/schema-anatomy.md`** — the complete shape of a FormEngine JSON form. Read this first when producing a schema. - **`references/component-types.md`** — exhaustive list of valid `type` values per library (RSuite, MUI, Mantine) plus common prop names. This is the source of truth for the validator. - **`references/examples.md`** — four complete end-to-end examples (signup, contact, multi-step onboarding, survey with conditional fields). Read this to calibrate style and completeness. - **`references/react-starter.md`** — the `App.tsx` templates for each UI library. ## Scripts - **`scripts/validate_schema.py`** — run it on any generated schema. Reports errors and warnings in a format that's easy to paste into the final response. Exit code 0 = clean, 1 = errors found. Checks include: valid component types, Screen root, unique keys, wrapped prop values, valid validation keys (full Zod set: `required`, `nonEmpty`, `min`, `max`, `length`, `email`, `url`, `uuid`, `ip`, `datetime`, `regex`, `includes`, `startsWith`, `endsWith`, `lessThan`, `moreThan`, `integer`, `multipleOf`, `truthy`, `falsy`), **layout-only `css` / `wrapperCss` (rejects visual styling keys)**, **no `style` field**, and **no HTML markup (tags / `style=` / `class=` / `<style>` blocks) in any prop string**. ## Contact & docs - FormEngine docs: https://formengine.io/documentation/ - FormEngine Core docs: https://formengine.io/documentation/formengine-core/ - Machine-readable docs dump: https://formengine.io/documentation/llms-full.txt - FormEngine Core on GitHub: https://github.com/optimajet/formengine - npm: https://www.npmjs.com/package/@react-form-builder/core - Support: support@optimajet.com