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React + Vite + Supabase + Zustand rules for AI coding agents

Full stack: React + Vite + Tailwind CSS v4 + Supabase + Zustand

Ready-to-commit rules for React + Vite + Tailwind CSS v4 + Supabase + Zustand in every major format: AGENTS.md (Codex, Cursor, Copilot), CLAUDE.md (Claude Code), Cursor .mdc project rules, legacy .cursorrules, Copilot instructions, Windsurf rules and GEMINI.md. A client-only React app talking straight to Supabase, popular for quick prototypes and internal tools.

Last reviewed 2026-10-21 · Customise in the generator · Raw: AGENTS.md, CLAUDE.md

The mistake agents make most on this stack

With no server, RLS is the only thing protecting your data, and agents forget to add it.

Generated files

AGENTS.md
# AGENTS.md - this project

Instructions for AI coding agents working in this repository.

## Project

A React + Vite + Tailwind CSS v4 + Supabase + Zustand project.

Stack: React + Vite, Tailwind CSS v4, Supabase, Zustand.

## Commands

- Dev server: `npm run dev`
- Build: `npm run build`
- Type-check: `npx tsc --noEmit`
- Lint: `npm run lint`
- New migration: `npx supabase migration new <name>`
- Generate TS types: `npx supabase gen types typescript --local > types/supabase.ts`

## Project structure

- Features live in `src/features/<name>/` with their components, hooks and tests together.
- Shared UI in `src/components/`, hooks in `src/hooks/`.

## How to work in this repo

- Read the relevant files before editing. Follow the patterns already in the codebase over these generic rules.
- Make the smallest change that solves the task. Do not refactor or reformat unrelated code.
- Before saying a task is done, run the type-check, lint and tests listed under Commands and fix what you broke.
- If requirements are ambiguous, ask one clear question instead of guessing.
- Never commit secrets, API keys or `.env` files. Use env vars and keep `.env.example` up to date.
- Do not add a new dependency when the standard library or an existing dependency already covers it.
- Ask before adding, removing or upgrading any dependency.
- Ask before changing database schemas, auth, payments or CI configuration.
- Never delete files, drop data or run destructive commands (`rm -rf`, `git push --force`, `DROP TABLE`) without explicit approval.
- Keep each change under ~200 changed lines where possible; split larger work into steps.

## React + Vite

- Function components and hooks only. No class components.
- Follow the Rules of Hooks: call hooks at the top level, never inside conditions or loops.
- Derive values during render instead of syncing them into state with `useEffect`.
- Every list item needs a stable `key` from the data, never the array index if the list can change order.
- Type component props with an exported `Props` type or interface. No `any`.
- Env vars must start with `VITE_` to reach the client, which also means they are public. Never put secrets in them.
- Lazy-load heavy routes with `React.lazy` and `Suspense`.

## Tailwind CSS v4

- Tailwind v4 is configured in CSS: `@import "tailwindcss";` plus `@theme { ... }` for design tokens. Do not create a `tailwind.config.js` unless the project already has one.
- Use theme tokens (colors, spacing) instead of arbitrary values like `w-[37px]`.
- Build responsive layouts mobile-first with `sm:`, `md:`, `lg:` prefixes.
- Extract repeated class lists into components, not `@apply` chains.
- Support dark mode with the `dark:` variant when the project uses it.

## Supabase

- Enable Row Level Security on every table and write explicit policies. No table ships without RLS.
- The anon/publishable key is public. The `service_role`/secret key bypasses RLS: use it only in trusted server code, never in the client.
- Change the schema with migration files in `supabase/migrations/`, not by clicking in the dashboard.
- On the server, verify the user with `supabase.auth.getUser()` (or `getClaims()`); do not trust `getSession()` alone for authorization.
- In SSR frameworks use `@supabase/ssr` (`createServerClient` / `createBrowserClient`), not the deprecated auth-helpers packages.
- Regenerate database types after each migration and type the client with them.

## Zustand

- Keep stores small and split by domain.
- Select only what a component needs (`useStore((s) => s.count)`) to avoid unnecessary re-renders.
- Use Zustand for client/UI state only. Server data belongs in the data-fetching layer.

## Avoid

- Do not reach for global state for data that only one component tree uses.

## Reference docs

- [React docs](https://react.dev)
- [Vite docs](https://vite.dev/guide/)
- [Tailwind CSS docs](https://tailwindcss.com/docs)
- [Supabase docs](https://supabase.com/docs)
- [Zustand docs](https://zustand.docs.pmnd.rs)

Commands your agent should run

TaskCommand
Dev servernpm run dev
Buildnpm run build
Type-checknpx tsc --noEmit
Lintnpm run lint
New migrationnpx supabase migration new <name>
Generate TS typesnpx supabase gen types typescript --local > types/supabase.ts

What the rules cover

React + Vite

Single-page React app built with Vite and TypeScript. Scoped to src/**/*.tsx, src/**/*.ts in Cursor, Copilot and Windsurf.

  • Function components and hooks only. No class components.
  • Follow the Rules of Hooks: call hooks at the top level, never inside conditions or loops.
  • Derive values during render instead of syncing them into state with useEffect.
  • Every list item needs a stable key from the data, never the array index if the list can change order.
  • Type component props with an exported Props type or interface. No any.
  • Env vars must start with VITE_ to reach the client, which also means they are public. Never put secrets in them.
  • Lazy-load heavy routes with React.lazy and Suspense.

Source docs: React docs, Vite docs

Tailwind CSS v4

Utility-first styling with Tailwind CSS v4. Scoped to **/*.css, **/*.tsx, **/*.vue, **/*.svelte, **/*.astro, **/*.html, **/*.blade.php, **/*.erb in Cursor, Copilot and Windsurf.

  • Tailwind v4 is configured in CSS: @import "tailwindcss"; plus @theme { ... } for design tokens. Do not create a tailwind.config.js unless the project already has one.
  • Use theme tokens (colors, spacing) instead of arbitrary values like w-[37px].
  • Build responsive layouts mobile-first with sm:, md:, lg: prefixes.
  • Extract repeated class lists into components, not @apply chains.
  • Support dark mode with the dark: variant when the project uses it.

Source docs: Tailwind CSS docs

Supabase

Postgres, auth and storage from Supabase. Scoped to supabase/**, **/supabase/**/*.ts, lib/supabase/** in Cursor, Copilot and Windsurf.

  • Enable Row Level Security on every table and write explicit policies. No table ships without RLS.
  • The anon/publishable key is public. The service_role/secret key bypasses RLS: use it only in trusted server code, never in the client.
  • Change the schema with migration files in supabase/migrations/, not by clicking in the dashboard.
  • On the server, verify the user with supabase.auth.getUser() (or getClaims()); do not trust getSession() alone for authorization.
  • In SSR frameworks use @supabase/ssr (createServerClient / createBrowserClient), not the deprecated auth-helpers packages.
  • Regenerate database types after each migration and type the client with them.

Source docs: Supabase docs

Zustand

Lightweight client state with Zustand. Scoped to **/store/**/*.ts, **/stores/**/*.ts in Cursor, Copilot and Windsurf.

  • Keep stores small and split by domain.
  • Select only what a component needs (useStore((s) => s.count)) to avoid unnecessary re-renders.
  • Use Zustand for client/UI state only. Server data belongs in the data-fetching layer.

Source docs: Zustand docs

How to install

  1. Copy AGENTS.md to your repo root. That covers Codex, Cursor, GitHub Copilot and most other agents.
  2. Using Claude Code? Add a CLAUDE.md with the single line @AGENTS.md, or use the standalone CLAUDE.md tab above.
  3. Want rules that only load for certain files in Cursor? Add the .cursor/rules/*.mdc files.
  4. Commit the files so your whole team (and every agent) shares them.

FAQ

Where do I put the AGENTS.md for React + Vite + Tailwind CSS v4 + Supabase + Zustand?

Save it as AGENTS.md in the root of your repository, next to your main config file. Codex, Cursor and GitHub Copilot pick it up automatically. For Claude Code, add a CLAUDE.md containing @AGENTS.md (or use the standalone CLAUDE.md on this page).

What is the most common mistake AI agents make with React + Vite?

With no server, RLS is the only thing protecting your data, and agents forget to add it.

Which commands should the agent run to check its work?

For this stack: npm run dev, npm run build, npx tsc --noEmit, npm run lint. They are listed in the generated files so the agent runs them before finishing a task.

Do these React + Vite + Tailwind CSS v4 + Supabase + Zustand rules work with Cursor and Claude Code?

Yes. This page includes the same rules as AGENTS.md, CLAUDE.md, Cursor .mdc project rules, a legacy .cursorrules file, GitHub Copilot instructions, Windsurf rules and GEMINI.md.

Can I customise these rules?

Yes. Open this stack in the generator to add or remove libraries, set your project name and package manager, switch beginner explanations on, and download everything as a zip.

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