Form

import { zodResolver } from "@hookform/resolvers/zod"
import { useForm } from "react-hook-form"
import { z } from "zod"

import { Button } from "@/components/ui/button"
import {
  Form,
  FormControl,
  FormDescription,
  FormField,
  FormItem,
  FormLabel,
  FormMessage,
} from "@/components/ui/form"
import { Input } from "@/components/ui/input"

const formSchema = z.object({
  username: z.string().min(2, {
    message: "Username must be at least 2 characters.",
  }),
})

export default function FormDemo() {
  const form = useForm<z.infer<typeof formSchema>>({
    resolver: zodResolver(formSchema),
    defaultValues: {
      username: "",
    },
  })

  function onSubmit(values: z.infer<typeof formSchema>) {
    console.log(values)
  }

  return (
    <Form {...form}>
      <form
        onSubmit={form.handleSubmit(onSubmit)}
        className="w-full max-w-sm space-y-6"
      >
        <FormField
          control={form.control}
          name="username"
          render={({ field }) => (
            <FormItem>
              <FormLabel>Username</FormLabel>
              <FormControl>
                <Input placeholder="logic2b" {...field} />
              </FormControl>
              <FormDescription>
                This is your public display name.
              </FormDescription>
              <FormMessage />
            </FormItem>
          )}
        />
        <Button type="submit">Submit</Button>
      </form>
    </Form>
  )
}

Installation

npx logic2b@latest add form

Working with an AI assistant? Copy this prompt into Claude Code, Cursor or Copilot — it carries the install steps, a no-CLI fallback and a verification checklist.

Add the "form" item from the logic2b ui registry (https://ui.logic2b.com) to this project. Follow every step and verify at the end.

## Steps

1. If the project has no `components.json` yet, set up logic2b ui first:

   ```bash
   npx logic2b@latest init
   ```

2. Install the item (the CLI resolves registry dependencies automatically):

   ```bash
   npx logic2b@latest add form
   ```

3. Install any npm dependencies the command prints.

## If the CLI is not available

Do it manually from the registry payload:

1. Fetch https://ui.logic2b.com/r/form.json.
2. Write every entry in `files[]` to its mapped project path (see below).
3. Repeat (recursively) for each name in `registryDependencies`.
4. Install every package listed in `dependencies` across those payloads.

## Registry reference

- Index of every item: https://ui.logic2b.com/r/index.json
- Item payload (full source): https://ui.logic2b.com/r/<name>.json
- Usage examples per item: https://ui.logic2b.com/r/demos/index.json → https://ui.logic2b.com/r/demos/<demo>.json
- Docs index for agents: https://ui.logic2b.com/llms.txt (full docs: https://ui.logic2b.com/llms-full.txt)
- Every docs page is Markdown when you append `.md` to its URL.

Registry file paths map to project paths like this:
- `ui/*` → `@/components/ui/*`
- `blocks/<name>/*` → `@/components/*`
- `charts/*` → `@/components/charts/*`
- `hooks/*` → `@/hooks/*`
- `lib/utils.ts` → `@/lib/utils.ts`
- `theme.css` → next to the project's Tailwind entry stylesheet

## Conventions (do not break these)

- Tailwind CSS v4 (CSS-first config; no tailwind.config.js needed) and React 19.
- All colors go through semantic tokens (`bg-primary`, `text-muted-foreground`,
  `border-border`, …). Never hardcode hex/oklch values in components.
- Dark mode is class-based: toggle `.dark` on `<html>`.
- Icons come from lucide-react.

## Verify before finishing

1. The dev server starts and the app renders without console errors.
2. TypeScript compiles (`tsc --noEmit` or the framework's check).
3. Components use the theme: a `<Button>` shows the primary token color,
   and toggling `.dark` on `<html>` switches the palette.

Install the dependencies:

npm install radix-ui react-hook-form @hookform/resolvers zod

Copy into ui/form.tsx:

"use client"

import * as React from "react"
import { Slot } from "radix-ui"
import {
  Controller,
  FormProvider,
  useFormContext,
  useFormState,
  type ControllerProps,
  type FieldPath,
  type FieldValues,
} from "react-hook-form"

import { cn } from "@/lib/utils"
import { Label } from "@/components/ui/label"

const Form = FormProvider

type FormFieldContextValue<
  TFieldValues extends FieldValues = FieldValues,
  TName extends FieldPath<TFieldValues> = FieldPath<TFieldValues>,
> = {
  name: TName
}

const FormFieldContext = React.createContext<FormFieldContextValue>(
  {} as FormFieldContextValue
)

function FormField<
  TFieldValues extends FieldValues = FieldValues,
  TName extends FieldPath<TFieldValues> = FieldPath<TFieldValues>,
>({ ...props }: ControllerProps<TFieldValues, TName>) {
  return (
    <FormFieldContext.Provider value={{ name: props.name }}>
      <Controller {...props} />
    </FormFieldContext.Provider>
  )
}

function useFormField() {
  const fieldContext = React.useContext(FormFieldContext)
  const itemContext = React.useContext(FormItemContext)
  const { getFieldState } = useFormContext()
  const formState = useFormState({ name: fieldContext.name })
  const fieldState = getFieldState(fieldContext.name, formState)

  if (!fieldContext) {
    throw new Error("useFormField should be used within <FormField>")
  }

  const { id } = itemContext

  return {
    id,
    name: fieldContext.name,
    formItemId: `${id}-form-item`,
    formDescriptionId: `${id}-form-item-description`,
    formMessageId: `${id}-form-item-message`,
    ...fieldState,
  }
}

type FormItemContextValue = {
  id: string
}

const FormItemContext = React.createContext<FormItemContextValue>(
  {} as FormItemContextValue
)

function FormItem({ className, ...props }: React.ComponentProps<"div">) {
  const id = React.useId()

  return (
    <FormItemContext.Provider value={{ id }}>
      <div
        data-slot="form-item"
        className={cn("grid gap-2", className)}
        {...props}
      />
    </FormItemContext.Provider>
  )
}

function FormLabel({
  className,
  ...props
}: React.ComponentProps<typeof Label>) {
  const { error, formItemId } = useFormField()

  return (
    <Label
      data-slot="form-label"
      data-error={!!error}
      className={cn("data-[error=true]:text-destructive", className)}
      htmlFor={formItemId}
      {...props}
    />
  )
}

function FormControl({ ...props }: React.ComponentProps<typeof Slot.Root>) {
  const { error, formItemId, formDescriptionId, formMessageId } =
    useFormField()

  return (
    <Slot.Root
      data-slot="form-control"
      id={formItemId}
      aria-describedby={
        !error
          ? `${formDescriptionId}`
          : `${formDescriptionId} ${formMessageId}`
      }
      aria-invalid={!!error}
      {...props}
    />
  )
}

function FormDescription({ className, ...props }: React.ComponentProps<"p">) {
  const { formDescriptionId } = useFormField()

  return (
    <p
      data-slot="form-description"
      id={formDescriptionId}
      className={cn("text-muted-foreground text-sm", className)}
      {...props}
    />
  )
}

function FormMessage({ className, ...props }: React.ComponentProps<"p">) {
  const { error, formMessageId } = useFormField()
  const body = error ? String(error?.message ?? "") : props.children

  if (!body) {
    return null
  }

  return (
    <p
      data-slot="form-message"
      id={formMessageId}
      className={cn("text-destructive text-sm", className)}
      {...props}
    >
      {body}
    </p>
  )
}

export {
  useFormField,
  Form,
  FormItem,
  FormLabel,
  FormControl,
  FormDescription,
  FormMessage,
  FormField,
}

Anatomy

import { useForm } from "react-hook-form"
import { zodResolver } from "@hookform/resolvers/zod"
import { z } from "zod"

import {
  Form,
  FormControl,
  FormDescription,
  FormField,
  FormItem,
  FormLabel,
  FormMessage,
} from "@/components/ui/form"

const formSchema = z.object({
  username: z.string().min(2),
})

function ProfileForm() {
  const form = useForm<z.infer<typeof formSchema>>({
    resolver: zodResolver(formSchema),
    defaultValues: { username: "" },
  })

  return (
    <Form {...form}>
      <form onSubmit={form.handleSubmit(console.log)}>
        <FormField
          control={form.control}
          name="username"
          render={({ field }) => (
            <FormItem>
              <FormLabel>Username</FormLabel>
              <FormControl>
                <input {...field} />
              </FormControl>
              <FormDescription>Your public display name.</FormDescription>
              <FormMessage />
            </FormItem>
          )}
        />
      </form>
    </Form>
  )
}

FormField wraps react-hook-form’s Controller and provides field context to FormLabel, FormControl, FormDescription and FormMessage — they read validation state (error, id) from that context, so labels and messages stay wired to the right input automatically.

API

Form is an alias for react-hook-form’s FormProvider, so spread your useForm return value onto it. The pieces below consume field context.

Prop	Type	Default
`control` (FormField)	`Control` — from `useForm()`	—
`name` (FormField)	`string` — the field path	—
`render` (FormField)	`({ field, fieldState, formState }) => ReactElement`	—
`...form` (Form)	the object returned by `useForm()`	—
`useFormField()`	hook returning `{ id, name, error, formItemId, formDescriptionId, formMessageId }`	—

Examples

Validate an email and password with zod.

"use client"

import { zodResolver } from "@hookform/resolvers/zod"
import { useForm } from "react-hook-form"
import { z } from "zod"

import { Button } from "@/components/ui/button"
import {
  Form,
  FormControl,
  FormField,
  FormItem,
  FormLabel,
  FormMessage,
} from "@/components/ui/form"
import { Input } from "@/components/ui/input"

const formSchema = z.object({
  email: z.email({ message: "Enter a valid email address." }),
  password: z.string().min(8, {
    message: "Password must be at least 8 characters.",
  }),
})

export default function FormSigninDemo() {
  const form = useForm<z.infer<typeof formSchema>>({
    resolver: zodResolver(formSchema),
    defaultValues: {
      email: "",
      password: "",
    },
  })

  function onSubmit(values: z.infer<typeof formSchema>) {
    console.log(values)
  }

  return (
    <Form {...form}>
      <form
        onSubmit={form.handleSubmit(onSubmit)}
        className="w-full max-w-sm space-y-6"
      >
        <FormField
          control={form.control}
          name="email"
          render={({ field }) => (
            <FormItem>
              <FormLabel>Email</FormLabel>
              <FormControl>
                <Input placeholder="you@example.com" {...field} />
              </FormControl>
              <FormMessage />
            </FormItem>
          )}
        />
        <FormField
          control={form.control}
          name="password"
          render={({ field }) => (
            <FormItem>
              <FormLabel>Password</FormLabel>
              <FormControl>
                <Input type="password" {...field} />
              </FormControl>
              <FormMessage />
            </FormItem>
          )}
        />
        <Button type="submit">Sign in</Button>
      </form>
    </Form>
  )
}

Textarea

"use client"

import { zodResolver } from "@hookform/resolvers/zod"
import { useForm } from "react-hook-form"
import { z } from "zod"

import { Button } from "@/components/ui/button"
import {
  Form,
  FormControl,
  FormDescription,
  FormField,
  FormItem,
  FormLabel,
  FormMessage,
} from "@/components/ui/form"
import { Textarea } from "@/components/ui/textarea"

const formSchema = z.object({
  bio: z
    .string()
    .min(10, { message: "Bio must be at least 10 characters." })
    .max(160, { message: "Bio must not exceed 160 characters." }),
})

export default function FormTextareaDemo() {
  const form = useForm<z.infer<typeof formSchema>>({
    resolver: zodResolver(formSchema),
    defaultValues: {
      bio: "",
    },
  })

  function onSubmit(values: z.infer<typeof formSchema>) {
    console.log(values)
  }

  return (
    <Form {...form}>
      <form
        onSubmit={form.handleSubmit(onSubmit)}
        className="w-full max-w-sm space-y-6"
      >
        <FormField
          control={form.control}
          name="bio"
          render={({ field }) => (
            <FormItem>
              <FormLabel>Bio</FormLabel>
              <FormControl>
                <Textarea
                  placeholder="Tell us a little bit about yourself"
                  className="resize-none"
                  {...field}
                />
              </FormControl>
              <FormDescription>
                This appears on your public profile.
              </FormDescription>
              <FormMessage />
            </FormItem>
          )}
        />
        <Button type="submit">Save</Button>
      </form>
    </Form>
  )
}

Accessibility

FormControl sets id, aria-describedby and aria-invalid from field context, so the label, description and error message are all wired to the input without manual htmlFor / id bookkeeping.
On validation failure FormMessage renders the error text with the id referenced by aria-describedby, and FormLabel turns destructive — the invalid state is conveyed both visually and to screen readers.
Because each control gets a unique generated id, labels always point at the right input even when the field is reused in a list.

Installation

Anatomy

API

Examples

Sign In

Textarea

Accessibility