SvelteKit + Drizzle + Tailwind rules for AI coding agents
Full stack: SvelteKit (Svelte 5) + Tailwind CSS v4 + Drizzle ORM + Vitest
Ready-to-commit rules for SvelteKit (Svelte 5) + Tailwind CSS v4 + Drizzle ORM + Vitest 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. SvelteKit full-stack with Drizzle ORM.
Last reviewed 2026-10-21 · Customise in the generator · Raw: AGENTS.md, CLAUDE.md
Agents run `drizzle-kit push` against production instead of committing migrations.
Generated files
# AGENTS.md - this project
Instructions for AI coding agents working in this repository.
## Project
A SvelteKit (Svelte 5) + Tailwind CSS v4 + Drizzle ORM + Vitest project.
Stack: SvelteKit (Svelte 5), Tailwind CSS v4, Drizzle ORM, Vitest.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type check: `npm run check`
- Generate migration: `npx drizzle-kit generate`
- Apply migrations: `npx drizzle-kit migrate`
- Unit tests: `npx vitest run`
## Project structure
- Routes in `src/routes/` (`+page.svelte`, `+page.server.ts`, `+layout.svelte`, `+server.ts`).
- Shared code in `src/lib/` (import as `$lib/...`), server-only code in `src/lib/server/`.
## How to work in this repo
- Read the relevant files before editing. Follow the patterns already in the codebase over these generic rules.
- Make the smallest change that solves the task. Do not refactor or reformat unrelated code.
- Before saying a task is done, run the type-check, lint and tests listed under Commands and fix what you broke.
- If requirements are ambiguous, ask one clear question instead of guessing.
- Never commit secrets, API keys or `.env` files. Use env vars and keep `.env.example` up to date.
- Do not add a new dependency when the standard library or an existing dependency already covers it.
- Ask before adding, removing or upgrading any dependency.
- Ask before changing database schemas, auth, payments or CI configuration.
- Never delete files, drop data or run destructive commands (`rm -rf`, `git push --force`, `DROP TABLE`) without explicit approval.
- Keep each change under ~200 changed lines where possible; split larger work into steps.
## SvelteKit (Svelte 5)
- Use Svelte 5 runes: `$state`, `$derived`, `$effect`, `$props`. Do not use legacy `export let` or `$:` syntax in new code.
- Prefer `$derived` over `$effect` for computed values. Use `$effect` only for real side effects.
- Load data in `+page.server.ts` / `+layout.server.ts` `load` functions, not in `onMount`.
- Handle form submissions with form actions and `use:enhance`.
- Read secrets from `$env/static/private` or `$env/dynamic/private`, only in server files.
- Use `error()` and `redirect()` from `@sveltejs/kit` for control flow in load functions and actions.
## Tailwind CSS v4
- Tailwind v4 is configured in CSS: `@import "tailwindcss";` plus `@theme { ... }` for design tokens. Do not create a `tailwind.config.js` unless the project already has one.
- Use theme tokens (colors, spacing) instead of arbitrary values like `w-[37px]`.
- Build responsive layouts mobile-first with `sm:`, `md:`, `lg:` prefixes.
- Extract repeated class lists into components, not `@apply` chains.
- Support dark mode with the `dark:` variant when the project uses it.
## Drizzle ORM
- Schema lives in TypeScript (`db/schema.ts`). Generate SQL migrations with `drizzle-kit generate` and commit them.
- `drizzle-kit push` is for local prototyping only, never for production databases.
- Infer types with `typeof table.$inferSelect` / `$inferInsert` instead of duplicating interfaces.
- Use the query builder or `sql` template tag; never build SQL with string concatenation.
- Use `db.transaction()` for multi-step writes.
## Vitest
- Co-locate tests next to the code as `*.test.ts(x)`.
- Test behaviour through public APIs; for components use Testing Library queries by role/label.
- Mock network calls at the boundary (e.g. MSW) rather than mocking internal modules.
- Every bug fix adds a test that fails without the fix.
## Reference docs
- [SvelteKit docs](https://svelte.dev/docs/kit)
- [Svelte 5 runes](https://svelte.dev/docs/svelte/what-are-runes)
- [Tailwind CSS docs](https://tailwindcss.com/docs)
- [Drizzle docs](https://orm.drizzle.team/docs/overview)
- [Vitest docs](https://vitest.dev)
# CLAUDE.md - this project
Project instructions for Claude Code.
## Project
A SvelteKit (Svelte 5) + Tailwind CSS v4 + Drizzle ORM + Vitest project.
Stack: SvelteKit (Svelte 5), Tailwind CSS v4, Drizzle ORM, Vitest.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type check: `npm run check`
- Generate migration: `npx drizzle-kit generate`
- Apply migrations: `npx drizzle-kit migrate`
- Unit tests: `npx vitest run`
## Project structure
- Routes in `src/routes/` (`+page.svelte`, `+page.server.ts`, `+layout.svelte`, `+server.ts`).
- Shared code in `src/lib/` (import as `$lib/...`), server-only code in `src/lib/server/`.
## 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.
## SvelteKit (Svelte 5)
- Use Svelte 5 runes: `$state`, `$derived`, `$effect`, `$props`. Do not use legacy `export let` or `$:` syntax in new code.
- Prefer `$derived` over `$effect` for computed values. Use `$effect` only for real side effects.
- Load data in `+page.server.ts` / `+layout.server.ts` `load` functions, not in `onMount`.
- Handle form submissions with form actions and `use:enhance`.
- Read secrets from `$env/static/private` or `$env/dynamic/private`, only in server files.
- Use `error()` and `redirect()` from `@sveltejs/kit` for control flow in load functions and actions.
## 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.
## Drizzle ORM
- Schema lives in TypeScript (`db/schema.ts`). Generate SQL migrations with `drizzle-kit generate` and commit them.
- `drizzle-kit push` is for local prototyping only, never for production databases.
- Infer types with `typeof table.$inferSelect` / `$inferInsert` instead of duplicating interfaces.
- Use the query builder or `sql` template tag; never build SQL with string concatenation.
- Use `db.transaction()` for multi-step writes.
## Vitest
- Co-locate tests next to the code as `*.test.ts(x)`.
- Test behaviour through public APIs; for components use Testing Library queries by role/label.
- Mock network calls at the boundary (e.g. MSW) rather than mocking internal modules.
- Every bug fix adds a test that fails without the fix.
## Reference docs
- [SvelteKit docs](https://svelte.dev/docs/kit)
- [Svelte 5 runes](https://svelte.dev/docs/svelte/what-are-runes)
- [Tailwind CSS docs](https://tailwindcss.com/docs)
- [Drizzle docs](https://orm.drizzle.team/docs/overview)
- [Vitest docs](https://vitest.dev)
---
description: "Core rules for this project"
alwaysApply: true
---
# this project
A SvelteKit (Svelte 5) + Tailwind CSS v4 + Drizzle ORM + Vitest project.
Stack: SvelteKit (Svelte 5), Tailwind CSS v4, Drizzle ORM, Vitest.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type check: `npm run check`
- Generate migration: `npx drizzle-kit generate`
- Apply migrations: `npx drizzle-kit migrate`
- Unit tests: `npx vitest run`
## 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.
---
description: "SvelteKit (Svelte 5) conventions: SvelteKit with Svelte 5 runes and TypeScript."
globs: src/**/*.svelte, src/**/*.ts
alwaysApply: false
---
# SvelteKit (Svelte 5)
- Use Svelte 5 runes: `$state`, `$derived`, `$effect`, `$props`. Do not use legacy `export let` or `$:` syntax in new code.
- Prefer `$derived` over `$effect` for computed values. Use `$effect` only for real side effects.
- Load data in `+page.server.ts` / `+layout.server.ts` `load` functions, not in `onMount`.
- Handle form submissions with form actions and `use:enhance`.
- Read secrets from `$env/static/private` or `$env/dynamic/private`, only in server files.
- Use `error()` and `redirect()` from `@sveltejs/kit` for control flow in load functions and actions.
Docs: https://svelte.dev/docs/kit, https://svelte.dev/docs/svelte/what-are-runes
---
description: "Tailwind CSS v4 conventions: Utility-first styling with Tailwind CSS v4."
globs: **/*.css, **/*.tsx, **/*.vue, **/*.svelte, **/*.astro, **/*.html, **/*.blade.php, **/*.erb
alwaysApply: false
---
# 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.
Docs: https://tailwindcss.com/docs
---
description: "Drizzle ORM conventions: SQL-like TypeScript ORM with drizzle-kit migrations."
globs: db/**/*.ts, src/db/**/*.ts, drizzle/**
alwaysApply: false
---
# Drizzle ORM
- Schema lives in TypeScript (`db/schema.ts`). Generate SQL migrations with `drizzle-kit generate` and commit them.
- `drizzle-kit push` is for local prototyping only, never for production databases.
- Infer types with `typeof table.$inferSelect` / `$inferInsert` instead of duplicating interfaces.
- Use the query builder or `sql` template tag; never build SQL with string concatenation.
- Use `db.transaction()` for multi-step writes.
Docs: https://orm.drizzle.team/docs/overview
---
description: "Vitest conventions: Unit and component tests with Vitest."
globs: **/*.test.ts, **/*.test.tsx, **/*.spec.ts
alwaysApply: false
---
# Vitest
- Co-locate tests next to the code as `*.test.ts(x)`.
- Test behaviour through public APIs; for components use Testing Library queries by role/label.
- Mock network calls at the boundary (e.g. MSW) rather than mocking internal modules.
- Every bug fix adds a test that fails without the fix.
Docs: https://vitest.dev
# Cursor rules - this project
You are an expert SvelteKit (Svelte 5), Tailwind CSS v4, Drizzle ORM, Vitest engineer working on this codebase. Follow these rules.
## Project
A SvelteKit (Svelte 5) + Tailwind CSS v4 + Drizzle ORM + Vitest project.
Stack: SvelteKit (Svelte 5), Tailwind CSS v4, Drizzle ORM, Vitest.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type check: `npm run check`
- Generate migration: `npx drizzle-kit generate`
- Apply migrations: `npx drizzle-kit migrate`
- Unit tests: `npx vitest run`
## Project structure
- Routes in `src/routes/` (`+page.svelte`, `+page.server.ts`, `+layout.svelte`, `+server.ts`).
- Shared code in `src/lib/` (import as `$lib/...`), server-only code in `src/lib/server/`.
## How to work in this repo
- Read the relevant files before editing. Follow the patterns already in the codebase over these generic rules.
- Make the smallest change that solves the task. Do not refactor or reformat unrelated code.
- Before saying a task is done, run the type-check, lint and tests listed under Commands and fix what you broke.
- If requirements are ambiguous, ask one clear question instead of guessing.
- Never commit secrets, API keys or `.env` files. Use env vars and keep `.env.example` up to date.
- Do not add a new dependency when the standard library or an existing dependency already covers it.
- Ask before adding, removing or upgrading any dependency.
- Ask before changing database schemas, auth, payments or CI configuration.
- Never delete files, drop data or run destructive commands (`rm -rf`, `git push --force`, `DROP TABLE`) without explicit approval.
- Keep each change under ~200 changed lines where possible; split larger work into steps.
## SvelteKit (Svelte 5)
- Use Svelte 5 runes: `$state`, `$derived`, `$effect`, `$props`. Do not use legacy `export let` or `$:` syntax in new code.
- Prefer `$derived` over `$effect` for computed values. Use `$effect` only for real side effects.
- Load data in `+page.server.ts` / `+layout.server.ts` `load` functions, not in `onMount`.
- Handle form submissions with form actions and `use:enhance`.
- Read secrets from `$env/static/private` or `$env/dynamic/private`, only in server files.
- Use `error()` and `redirect()` from `@sveltejs/kit` for control flow in load functions and actions.
## Tailwind CSS v4
- Tailwind v4 is configured in CSS: `@import "tailwindcss";` plus `@theme { ... }` for design tokens. Do not create a `tailwind.config.js` unless the project already has one.
- Use theme tokens (colors, spacing) instead of arbitrary values like `w-[37px]`.
- Build responsive layouts mobile-first with `sm:`, `md:`, `lg:` prefixes.
- Extract repeated class lists into components, not `@apply` chains.
- Support dark mode with the `dark:` variant when the project uses it.
## Drizzle ORM
- Schema lives in TypeScript (`db/schema.ts`). Generate SQL migrations with `drizzle-kit generate` and commit them.
- `drizzle-kit push` is for local prototyping only, never for production databases.
- Infer types with `typeof table.$inferSelect` / `$inferInsert` instead of duplicating interfaces.
- Use the query builder or `sql` template tag; never build SQL with string concatenation.
- Use `db.transaction()` for multi-step writes.
## Vitest
- Co-locate tests next to the code as `*.test.ts(x)`.
- Test behaviour through public APIs; for components use Testing Library queries by role/label.
- Mock network calls at the boundary (e.g. MSW) rather than mocking internal modules.
- Every bug fix adds a test that fails without the fix.
## Reference docs
- [SvelteKit docs](https://svelte.dev/docs/kit)
- [Svelte 5 runes](https://svelte.dev/docs/svelte/what-are-runes)
- [Tailwind CSS docs](https://tailwindcss.com/docs)
- [Drizzle docs](https://orm.drizzle.team/docs/overview)
- [Vitest docs](https://vitest.dev)
# Copilot instructions - this project
A SvelteKit (Svelte 5) + Tailwind CSS v4 + Drizzle ORM + Vitest project.
Stack: SvelteKit (Svelte 5), Tailwind CSS v4, Drizzle ORM, Vitest.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type check: `npm run check`
- Generate migration: `npx drizzle-kit generate`
- Apply migrations: `npx drizzle-kit migrate`
- Unit tests: `npx vitest run`
## 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.
---
applyTo: "src/**/*.svelte,src/**/*.ts"
---
# SvelteKit (Svelte 5)
- Use Svelte 5 runes: `$state`, `$derived`, `$effect`, `$props`. Do not use legacy `export let` or `$:` syntax in new code.
- Prefer `$derived` over `$effect` for computed values. Use `$effect` only for real side effects.
- Load data in `+page.server.ts` / `+layout.server.ts` `load` functions, not in `onMount`.
- Handle form submissions with form actions and `use:enhance`.
- Read secrets from `$env/static/private` or `$env/dynamic/private`, only in server files.
- Use `error()` and `redirect()` from `@sveltejs/kit` for control flow in load functions and actions.
---
applyTo: "**/*.css,**/*.tsx,**/*.vue,**/*.svelte,**/*.astro,**/*.html,**/*.blade.php,**/*.erb"
---
# Tailwind CSS v4
- Tailwind v4 is configured in CSS: `@import "tailwindcss";` plus `@theme { ... }` for design tokens. Do not create a `tailwind.config.js` unless the project already has one.
- Use theme tokens (colors, spacing) instead of arbitrary values like `w-[37px]`.
- Build responsive layouts mobile-first with `sm:`, `md:`, `lg:` prefixes.
- Extract repeated class lists into components, not `@apply` chains.
- Support dark mode with the `dark:` variant when the project uses it.
---
applyTo: "db/**/*.ts,src/db/**/*.ts,drizzle/**"
---
# Drizzle ORM
- Schema lives in TypeScript (`db/schema.ts`). Generate SQL migrations with `drizzle-kit generate` and commit them.
- `drizzle-kit push` is for local prototyping only, never for production databases.
- Infer types with `typeof table.$inferSelect` / `$inferInsert` instead of duplicating interfaces.
- Use the query builder or `sql` template tag; never build SQL with string concatenation.
- Use `db.transaction()` for multi-step writes.
---
applyTo: "**/*.test.ts,**/*.test.tsx,**/*.spec.ts"
---
# Vitest
- Co-locate tests next to the code as `*.test.ts(x)`.
- Test behaviour through public APIs; for components use Testing Library queries by role/label.
- Mock network calls at the boundary (e.g. MSW) rather than mocking internal modules.
- Every bug fix adds a test that fails without the fix.
---
trigger: always_on
---
# this project
A SvelteKit (Svelte 5) + Tailwind CSS v4 + Drizzle ORM + Vitest project.
Stack: SvelteKit (Svelte 5), Tailwind CSS v4, Drizzle ORM, Vitest.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type check: `npm run check`
- Generate migration: `npx drizzle-kit generate`
- Apply migrations: `npx drizzle-kit migrate`
- Unit tests: `npx vitest run`
## 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.
---
trigger: glob
globs: src/**/*.svelte, src/**/*.ts
---
# SvelteKit (Svelte 5)
- Use Svelte 5 runes: `$state`, `$derived`, `$effect`, `$props`. Do not use legacy `export let` or `$:` syntax in new code.
- Prefer `$derived` over `$effect` for computed values. Use `$effect` only for real side effects.
- Load data in `+page.server.ts` / `+layout.server.ts` `load` functions, not in `onMount`.
- Handle form submissions with form actions and `use:enhance`.
- Read secrets from `$env/static/private` or `$env/dynamic/private`, only in server files.
- Use `error()` and `redirect()` from `@sveltejs/kit` for control flow in load functions and actions.
---
trigger: glob
globs: **/*.css, **/*.tsx, **/*.vue, **/*.svelte, **/*.astro, **/*.html, **/*.blade.php, **/*.erb
---
# Tailwind CSS v4
- Tailwind v4 is configured in CSS: `@import "tailwindcss";` plus `@theme { ... }` for design tokens. Do not create a `tailwind.config.js` unless the project already has one.
- Use theme tokens (colors, spacing) instead of arbitrary values like `w-[37px]`.
- Build responsive layouts mobile-first with `sm:`, `md:`, `lg:` prefixes.
- Extract repeated class lists into components, not `@apply` chains.
- Support dark mode with the `dark:` variant when the project uses it.
---
trigger: glob
globs: db/**/*.ts, src/db/**/*.ts, drizzle/**
---
# Drizzle ORM
- Schema lives in TypeScript (`db/schema.ts`). Generate SQL migrations with `drizzle-kit generate` and commit them.
- `drizzle-kit push` is for local prototyping only, never for production databases.
- Infer types with `typeof table.$inferSelect` / `$inferInsert` instead of duplicating interfaces.
- Use the query builder or `sql` template tag; never build SQL with string concatenation.
- Use `db.transaction()` for multi-step writes.
---
trigger: glob
globs: **/*.test.ts, **/*.test.tsx, **/*.spec.ts
---
# Vitest
- Co-locate tests next to the code as `*.test.ts(x)`.
- Test behaviour through public APIs; for components use Testing Library queries by role/label.
- Mock network calls at the boundary (e.g. MSW) rather than mocking internal modules.
- Every bug fix adds a test that fails without the fix.
# GEMINI.md - this project
Project context for Gemini CLI.
## Project
A SvelteKit (Svelte 5) + Tailwind CSS v4 + Drizzle ORM + Vitest project.
Stack: SvelteKit (Svelte 5), Tailwind CSS v4, Drizzle ORM, Vitest.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type check: `npm run check`
- Generate migration: `npx drizzle-kit generate`
- Apply migrations: `npx drizzle-kit migrate`
- Unit tests: `npx vitest run`
## Project structure
- Routes in `src/routes/` (`+page.svelte`, `+page.server.ts`, `+layout.svelte`, `+server.ts`).
- Shared code in `src/lib/` (import as `$lib/...`), server-only code in `src/lib/server/`.
## 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.
## SvelteKit (Svelte 5)
- Use Svelte 5 runes: `$state`, `$derived`, `$effect`, `$props`. Do not use legacy `export let` or `$:` syntax in new code.
- Prefer `$derived` over `$effect` for computed values. Use `$effect` only for real side effects.
- Load data in `+page.server.ts` / `+layout.server.ts` `load` functions, not in `onMount`.
- Handle form submissions with form actions and `use:enhance`.
- Read secrets from `$env/static/private` or `$env/dynamic/private`, only in server files.
- Use `error()` and `redirect()` from `@sveltejs/kit` for control flow in load functions and actions.
## 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.
## Drizzle ORM
- Schema lives in TypeScript (`db/schema.ts`). Generate SQL migrations with `drizzle-kit generate` and commit them.
- `drizzle-kit push` is for local prototyping only, never for production databases.
- Infer types with `typeof table.$inferSelect` / `$inferInsert` instead of duplicating interfaces.
- Use the query builder or `sql` template tag; never build SQL with string concatenation.
- Use `db.transaction()` for multi-step writes.
## Vitest
- Co-locate tests next to the code as `*.test.ts(x)`.
- Test behaviour through public APIs; for components use Testing Library queries by role/label.
- Mock network calls at the boundary (e.g. MSW) rather than mocking internal modules.
- Every bug fix adds a test that fails without the fix.
## Reference docs
- [SvelteKit docs](https://svelte.dev/docs/kit)
- [Svelte 5 runes](https://svelte.dev/docs/svelte/what-are-runes)
- [Tailwind CSS docs](https://tailwindcss.com/docs)
- [Drizzle docs](https://orm.drizzle.team/docs/overview)
- [Vitest docs](https://vitest.dev)
Commands your agent should run
| Task | Command |
|---|---|
| Dev server | npm run dev |
| Build | npm run build |
| Type check | npm run check |
| Generate migration | npx drizzle-kit generate |
| Apply migrations | npx drizzle-kit migrate |
| Unit tests | npx vitest run |
What the rules cover
SvelteKit (Svelte 5)
SvelteKit with Svelte 5 runes and TypeScript. Scoped to src/**/*.svelte, src/**/*.ts in Cursor, Copilot and Windsurf.
- Use Svelte 5 runes:
$state,$derived,$effect,$props. Do not use legacyexport letor$:syntax in new code. - Prefer
$derivedover$effectfor computed values. Use$effectonly for real side effects. - Load data in
+page.server.ts/+layout.server.tsloadfunctions, not inonMount. - Handle form submissions with form actions and
use:enhance. - Read secrets from
$env/static/privateor$env/dynamic/private, only in server files. - Use
error()andredirect()from@sveltejs/kitfor control flow in load functions and actions.
Source docs: SvelteKit docs, Svelte 5 runes
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 atailwind.config.jsunless 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
@applychains. - Support dark mode with the
dark:variant when the project uses it.
Source docs: Tailwind CSS docs
Drizzle ORM
SQL-like TypeScript ORM with drizzle-kit migrations. Scoped to db/**/*.ts, src/db/**/*.ts, drizzle/** in Cursor, Copilot and Windsurf.
- Schema lives in TypeScript (
db/schema.ts). Generate SQL migrations withdrizzle-kit generateand commit them. drizzle-kit pushis for local prototyping only, never for production databases.- Infer types with
typeof table.$inferSelect/$inferInsertinstead of duplicating interfaces. - Use the query builder or
sqltemplate tag; never build SQL with string concatenation. - Use
db.transaction()for multi-step writes.
Source docs: Drizzle docs
Vitest
Unit and component tests with Vitest. Scoped to **/*.test.ts, **/*.test.tsx, **/*.spec.ts in Cursor, Copilot and Windsurf.
- Co-locate tests next to the code as
*.test.ts(x). - Test behaviour through public APIs; for components use Testing Library queries by role/label.
- Mock network calls at the boundary (e.g. MSW) rather than mocking internal modules.
- Every bug fix adds a test that fails without the fix.
Source docs: Vitest docs
How to install
- Copy
AGENTS.mdto your repo root. That covers Codex, Cursor, GitHub Copilot and most other agents. - Using Claude Code? Add a
CLAUDE.mdwith the single line@AGENTS.md, or use the standalone CLAUDE.md tab above. - Want rules that only load for certain files in Cursor? Add the
.cursor/rules/*.mdcfiles. - Commit the files so your whole team (and every agent) shares them.
FAQ
Where do I put the AGENTS.md for SvelteKit (Svelte 5) + Tailwind CSS v4 + Drizzle ORM + Vitest?
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 SvelteKit (Svelte 5)?
Agents run drizzle-kit push against production instead of committing migrations.
Which commands should the agent run to check its work?
For this stack: npm run dev, npm run build, npm run check, npx drizzle-kit generate. They are listed in the generated files so the agent runs them before finishing a task.
Do these SvelteKit (Svelte 5) + Tailwind CSS v4 + Drizzle ORM + Vitest 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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