Express + Prisma + Vitest rules for AI coding agents
Full stack: Node.js + Express + Prisma + Zod validation + Vitest + Docker
Ready-to-commit rules for Node.js + Express + Prisma + Zod validation + Vitest + Docker 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 TypeScript REST API with Express 5, Prisma and Zod.
Last reviewed 2026-10-21 · Customise in the generator · Raw: AGENTS.md, CLAUDE.md
Agents skip input validation and return 500s for what should be 400s.
Generated files
# AGENTS.md - this project
Instructions for AI coding agents working in this repository.
## Project
A Node.js + Express + Prisma + Zod validation + Vitest + Docker project.
Stack: Node.js + Express, Prisma, Zod validation, Vitest, Docker.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type-check: `npx tsc --noEmit`
- Create and apply migration (dev): `npx prisma migrate dev --name <change>`
- Regenerate client: `npx prisma generate`
- Apply migrations (prod): `npx prisma migrate deploy`
- Unit tests: `npx vitest run`
- Local services: `docker compose up -d`
## Project structure
- `src/routes/` for routers, `src/services/` for business logic, `src/middleware/` for middleware.
- Keep route handlers thin: parse input, call a service, return a response.
## 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.
## Node.js + Express
- Express 5 forwards rejected promises from async handlers to the error middleware; do not wrap every handler in try/catch.
- Have one central error-handling middleware that logs the error and returns a consistent JSON error shape.
- Validate every request body, query and param before using it.
- Use `helmet`, a strict CORS allow-list and rate limiting on public endpoints.
- Read config from env vars once at startup in a typed config module; fail fast if a required var is missing.
- Return correct HTTP status codes (400 validation, 401 unauthenticated, 403 forbidden, 404 not found, 409 conflict).
## Prisma
- Change the database only through `schema.prisma` + `prisma migrate dev`. Never edit an applied migration.
- Reuse a single PrismaClient instance (cache it on `globalThis` in dev to survive hot reload).
- Use `select` / `include` to fetch only the fields you need.
- Wrap multi-step writes in `prisma.$transaction`.
- Run `npx prisma generate` after schema changes before type-checking.
## Zod validation
- Validate all untrusted input (request bodies, form data, env vars, third-party API responses) with a Zod schema at the boundary.
- Derive TypeScript types from schemas with `z.infer<typeof schema>`; do not hand-write duplicate types.
- Use `safeParse` where you need to return validation errors to the user.
## 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.
## Docker
- Use multi-stage builds and slim, pinned base images.
- Run the app as a non-root user in the final image.
- Keep a `.dockerignore` that excludes `.git`, `node_modules`, `.env` and build output.
- Never bake secrets into images; pass them at runtime.
## Reference docs
- [Express docs](https://expressjs.com)
- [Prisma docs](https://www.prisma.io/docs)
- [Zod docs](https://zod.dev)
- [Vitest docs](https://vitest.dev)
- [Dockerfile best practices](https://docs.docker.com/build/building/best-practices/)
# CLAUDE.md - this project
Project instructions for Claude Code.
## Project
A Node.js + Express + Prisma + Zod validation + Vitest + Docker project.
Stack: Node.js + Express, Prisma, Zod validation, Vitest, Docker.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type-check: `npx tsc --noEmit`
- Create and apply migration (dev): `npx prisma migrate dev --name <change>`
- Regenerate client: `npx prisma generate`
- Apply migrations (prod): `npx prisma migrate deploy`
- Unit tests: `npx vitest run`
- Local services: `docker compose up -d`
## Project structure
- `src/routes/` for routers, `src/services/` for business logic, `src/middleware/` for middleware.
- Keep route handlers thin: parse input, call a service, return a response.
## 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.
## Node.js + Express
- Express 5 forwards rejected promises from async handlers to the error middleware; do not wrap every handler in try/catch.
- Have one central error-handling middleware that logs the error and returns a consistent JSON error shape.
- Validate every request body, query and param before using it.
- Use `helmet`, a strict CORS allow-list and rate limiting on public endpoints.
- Read config from env vars once at startup in a typed config module; fail fast if a required var is missing.
- Return correct HTTP status codes (400 validation, 401 unauthenticated, 403 forbidden, 404 not found, 409 conflict).
## Prisma
- Change the database only through `schema.prisma` + `prisma migrate dev`. Never edit an applied migration.
- Reuse a single PrismaClient instance (cache it on `globalThis` in dev to survive hot reload).
- Use `select` / `include` to fetch only the fields you need.
- Wrap multi-step writes in `prisma.$transaction`.
- Run `npx prisma generate` after schema changes before type-checking.
## Zod validation
- Validate all untrusted input (request bodies, form data, env vars, third-party API responses) with a Zod schema at the boundary.
- Derive TypeScript types from schemas with `z.infer<typeof schema>`; do not hand-write duplicate types.
- Use `safeParse` where you need to return validation errors to the user.
## 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.
## Docker
- Use multi-stage builds and slim, pinned base images.
- Run the app as a non-root user in the final image.
- Keep a `.dockerignore` that excludes `.git`, `node_modules`, `.env` and build output.
- Never bake secrets into images; pass them at runtime.
## Reference docs
- [Express docs](https://expressjs.com)
- [Prisma docs](https://www.prisma.io/docs)
- [Zod docs](https://zod.dev)
- [Vitest docs](https://vitest.dev)
- [Dockerfile best practices](https://docs.docker.com/build/building/best-practices/)
---
description: "Core rules for this project"
alwaysApply: true
---
# this project
A Node.js + Express + Prisma + Zod validation + Vitest + Docker project.
Stack: Node.js + Express, Prisma, Zod validation, Vitest, Docker.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type-check: `npx tsc --noEmit`
- Create and apply migration (dev): `npx prisma migrate dev --name <change>`
- Regenerate client: `npx prisma generate`
- Apply migrations (prod): `npx prisma migrate deploy`
- Unit tests: `npx vitest run`
- Local services: `docker compose up -d`
## 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: "Node.js + Express conventions: Express 5 REST API in TypeScript on Node.js."
globs: src/**/*.ts
alwaysApply: false
---
# Node.js + Express
- Express 5 forwards rejected promises from async handlers to the error middleware; do not wrap every handler in try/catch.
- Have one central error-handling middleware that logs the error and returns a consistent JSON error shape.
- Validate every request body, query and param before using it.
- Use `helmet`, a strict CORS allow-list and rate limiting on public endpoints.
- Read config from env vars once at startup in a typed config module; fail fast if a required var is missing.
- Return correct HTTP status codes (400 validation, 401 unauthenticated, 403 forbidden, 404 not found, 409 conflict).
Docs: https://expressjs.com
---
description: "Prisma conventions: Type-safe ORM with Prisma schema and migrations."
globs: prisma/**, **/*.prisma
alwaysApply: false
---
# Prisma
- Change the database only through `schema.prisma` + `prisma migrate dev`. Never edit an applied migration.
- Reuse a single PrismaClient instance (cache it on `globalThis` in dev to survive hot reload).
- Use `select` / `include` to fetch only the fields you need.
- Wrap multi-step writes in `prisma.$transaction`.
- Run `npx prisma generate` after schema changes before type-checking.
Docs: https://www.prisma.io/docs
---
description: "Zod validation conventions: Runtime schema validation with Zod."
globs: **/*.ts, **/*.tsx
alwaysApply: false
---
# Zod validation
- Validate all untrusted input (request bodies, form data, env vars, third-party API responses) with a Zod schema at the boundary.
- Derive TypeScript types from schemas with `z.infer<typeof schema>`; do not hand-write duplicate types.
- Use `safeParse` where you need to return validation errors to the user.
Docs: https://zod.dev
---
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
---
description: "Docker conventions: Containerised builds and local services with Docker."
globs: Dockerfile, **/Dockerfile, compose.yaml, docker-compose.yml, .dockerignore
alwaysApply: false
---
# Docker
- Use multi-stage builds and slim, pinned base images.
- Run the app as a non-root user in the final image.
- Keep a `.dockerignore` that excludes `.git`, `node_modules`, `.env` and build output.
- Never bake secrets into images; pass them at runtime.
Docs: https://docs.docker.com/build/building/best-practices/
# Cursor rules - this project
You are an expert Node.js + Express, Prisma, Zod validation, Vitest, Docker engineer working on this codebase. Follow these rules.
## Project
A Node.js + Express + Prisma + Zod validation + Vitest + Docker project.
Stack: Node.js + Express, Prisma, Zod validation, Vitest, Docker.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type-check: `npx tsc --noEmit`
- Create and apply migration (dev): `npx prisma migrate dev --name <change>`
- Regenerate client: `npx prisma generate`
- Apply migrations (prod): `npx prisma migrate deploy`
- Unit tests: `npx vitest run`
- Local services: `docker compose up -d`
## Project structure
- `src/routes/` for routers, `src/services/` for business logic, `src/middleware/` for middleware.
- Keep route handlers thin: parse input, call a service, return a response.
## 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.
## Node.js + Express
- Express 5 forwards rejected promises from async handlers to the error middleware; do not wrap every handler in try/catch.
- Have one central error-handling middleware that logs the error and returns a consistent JSON error shape.
- Validate every request body, query and param before using it.
- Use `helmet`, a strict CORS allow-list and rate limiting on public endpoints.
- Read config from env vars once at startup in a typed config module; fail fast if a required var is missing.
- Return correct HTTP status codes (400 validation, 401 unauthenticated, 403 forbidden, 404 not found, 409 conflict).
## Prisma
- Change the database only through `schema.prisma` + `prisma migrate dev`. Never edit an applied migration.
- Reuse a single PrismaClient instance (cache it on `globalThis` in dev to survive hot reload).
- Use `select` / `include` to fetch only the fields you need.
- Wrap multi-step writes in `prisma.$transaction`.
- Run `npx prisma generate` after schema changes before type-checking.
## Zod validation
- Validate all untrusted input (request bodies, form data, env vars, third-party API responses) with a Zod schema at the boundary.
- Derive TypeScript types from schemas with `z.infer<typeof schema>`; do not hand-write duplicate types.
- Use `safeParse` where you need to return validation errors to the user.
## 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.
## Docker
- Use multi-stage builds and slim, pinned base images.
- Run the app as a non-root user in the final image.
- Keep a `.dockerignore` that excludes `.git`, `node_modules`, `.env` and build output.
- Never bake secrets into images; pass them at runtime.
## Reference docs
- [Express docs](https://expressjs.com)
- [Prisma docs](https://www.prisma.io/docs)
- [Zod docs](https://zod.dev)
- [Vitest docs](https://vitest.dev)
- [Dockerfile best practices](https://docs.docker.com/build/building/best-practices/)
# Copilot instructions - this project
A Node.js + Express + Prisma + Zod validation + Vitest + Docker project.
Stack: Node.js + Express, Prisma, Zod validation, Vitest, Docker.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type-check: `npx tsc --noEmit`
- Create and apply migration (dev): `npx prisma migrate dev --name <change>`
- Regenerate client: `npx prisma generate`
- Apply migrations (prod): `npx prisma migrate deploy`
- Unit tests: `npx vitest run`
- Local services: `docker compose up -d`
## 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/**/*.ts"
---
# Node.js + Express
- Express 5 forwards rejected promises from async handlers to the error middleware; do not wrap every handler in try/catch.
- Have one central error-handling middleware that logs the error and returns a consistent JSON error shape.
- Validate every request body, query and param before using it.
- Use `helmet`, a strict CORS allow-list and rate limiting on public endpoints.
- Read config from env vars once at startup in a typed config module; fail fast if a required var is missing.
- Return correct HTTP status codes (400 validation, 401 unauthenticated, 403 forbidden, 404 not found, 409 conflict).
---
applyTo: "prisma/**,**/*.prisma"
---
# Prisma
- Change the database only through `schema.prisma` + `prisma migrate dev`. Never edit an applied migration.
- Reuse a single PrismaClient instance (cache it on `globalThis` in dev to survive hot reload).
- Use `select` / `include` to fetch only the fields you need.
- Wrap multi-step writes in `prisma.$transaction`.
- Run `npx prisma generate` after schema changes before type-checking.
---
applyTo: "**/*.ts,**/*.tsx"
---
# Zod validation
- Validate all untrusted input (request bodies, form data, env vars, third-party API responses) with a Zod schema at the boundary.
- Derive TypeScript types from schemas with `z.infer<typeof schema>`; do not hand-write duplicate types.
- Use `safeParse` where you need to return validation errors to the user.
---
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.
---
applyTo: "Dockerfile,**/Dockerfile,compose.yaml,docker-compose.yml,.dockerignore"
---
# Docker
- Use multi-stage builds and slim, pinned base images.
- Run the app as a non-root user in the final image.
- Keep a `.dockerignore` that excludes `.git`, `node_modules`, `.env` and build output.
- Never bake secrets into images; pass them at runtime.
---
trigger: always_on
---
# this project
A Node.js + Express + Prisma + Zod validation + Vitest + Docker project.
Stack: Node.js + Express, Prisma, Zod validation, Vitest, Docker.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type-check: `npx tsc --noEmit`
- Create and apply migration (dev): `npx prisma migrate dev --name <change>`
- Regenerate client: `npx prisma generate`
- Apply migrations (prod): `npx prisma migrate deploy`
- Unit tests: `npx vitest run`
- Local services: `docker compose up -d`
## 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/**/*.ts
---
# Node.js + Express
- Express 5 forwards rejected promises from async handlers to the error middleware; do not wrap every handler in try/catch.
- Have one central error-handling middleware that logs the error and returns a consistent JSON error shape.
- Validate every request body, query and param before using it.
- Use `helmet`, a strict CORS allow-list and rate limiting on public endpoints.
- Read config from env vars once at startup in a typed config module; fail fast if a required var is missing.
- Return correct HTTP status codes (400 validation, 401 unauthenticated, 403 forbidden, 404 not found, 409 conflict).
---
trigger: glob
globs: prisma/**, **/*.prisma
---
# Prisma
- Change the database only through `schema.prisma` + `prisma migrate dev`. Never edit an applied migration.
- Reuse a single PrismaClient instance (cache it on `globalThis` in dev to survive hot reload).
- Use `select` / `include` to fetch only the fields you need.
- Wrap multi-step writes in `prisma.$transaction`.
- Run `npx prisma generate` after schema changes before type-checking.
---
trigger: glob
globs: **/*.ts, **/*.tsx
---
# Zod validation
- Validate all untrusted input (request bodies, form data, env vars, third-party API responses) with a Zod schema at the boundary.
- Derive TypeScript types from schemas with `z.infer<typeof schema>`; do not hand-write duplicate types.
- Use `safeParse` where you need to return validation errors to the user.
---
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.
---
trigger: glob
globs: Dockerfile, **/Dockerfile, compose.yaml, docker-compose.yml, .dockerignore
---
# Docker
- Use multi-stage builds and slim, pinned base images.
- Run the app as a non-root user in the final image.
- Keep a `.dockerignore` that excludes `.git`, `node_modules`, `.env` and build output.
- Never bake secrets into images; pass them at runtime.
# GEMINI.md - this project
Project context for Gemini CLI.
## Project
A Node.js + Express + Prisma + Zod validation + Vitest + Docker project.
Stack: Node.js + Express, Prisma, Zod validation, Vitest, Docker.
## Commands
- Dev server: `npm run dev`
- Build: `npm run build`
- Type-check: `npx tsc --noEmit`
- Create and apply migration (dev): `npx prisma migrate dev --name <change>`
- Regenerate client: `npx prisma generate`
- Apply migrations (prod): `npx prisma migrate deploy`
- Unit tests: `npx vitest run`
- Local services: `docker compose up -d`
## Project structure
- `src/routes/` for routers, `src/services/` for business logic, `src/middleware/` for middleware.
- Keep route handlers thin: parse input, call a service, return a response.
## 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.
## Node.js + Express
- Express 5 forwards rejected promises from async handlers to the error middleware; do not wrap every handler in try/catch.
- Have one central error-handling middleware that logs the error and returns a consistent JSON error shape.
- Validate every request body, query and param before using it.
- Use `helmet`, a strict CORS allow-list and rate limiting on public endpoints.
- Read config from env vars once at startup in a typed config module; fail fast if a required var is missing.
- Return correct HTTP status codes (400 validation, 401 unauthenticated, 403 forbidden, 404 not found, 409 conflict).
## Prisma
- Change the database only through `schema.prisma` + `prisma migrate dev`. Never edit an applied migration.
- Reuse a single PrismaClient instance (cache it on `globalThis` in dev to survive hot reload).
- Use `select` / `include` to fetch only the fields you need.
- Wrap multi-step writes in `prisma.$transaction`.
- Run `npx prisma generate` after schema changes before type-checking.
## Zod validation
- Validate all untrusted input (request bodies, form data, env vars, third-party API responses) with a Zod schema at the boundary.
- Derive TypeScript types from schemas with `z.infer<typeof schema>`; do not hand-write duplicate types.
- Use `safeParse` where you need to return validation errors to the user.
## 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.
## Docker
- Use multi-stage builds and slim, pinned base images.
- Run the app as a non-root user in the final image.
- Keep a `.dockerignore` that excludes `.git`, `node_modules`, `.env` and build output.
- Never bake secrets into images; pass them at runtime.
## Reference docs
- [Express docs](https://expressjs.com)
- [Prisma docs](https://www.prisma.io/docs)
- [Zod docs](https://zod.dev)
- [Vitest docs](https://vitest.dev)
- [Dockerfile best practices](https://docs.docker.com/build/building/best-practices/)
Commands your agent should run
| Task | Command |
|---|---|
| Dev server | npm run dev |
| Build | npm run build |
| Type-check | npx tsc --noEmit |
| Create and apply migration (dev) | npx prisma migrate dev --name <change> |
| Regenerate client | npx prisma generate |
| Apply migrations (prod) | npx prisma migrate deploy |
| Unit tests | npx vitest run |
| Local services | docker compose up -d |
What the rules cover
Node.js + Express
Express 5 REST API in TypeScript on Node.js. Scoped to src/**/*.ts in Cursor, Copilot and Windsurf.
- Express 5 forwards rejected promises from async handlers to the error middleware; do not wrap every handler in try/catch.
- Have one central error-handling middleware that logs the error and returns a consistent JSON error shape.
- Validate every request body, query and param before using it.
- Use
helmet, a strict CORS allow-list and rate limiting on public endpoints. - Read config from env vars once at startup in a typed config module; fail fast if a required var is missing.
- Return correct HTTP status codes (400 validation, 401 unauthenticated, 403 forbidden, 404 not found, 409 conflict).
Source docs: Express docs
Prisma
Type-safe ORM with Prisma schema and migrations. Scoped to prisma/**, **/*.prisma in Cursor, Copilot and Windsurf.
- Change the database only through
schema.prisma+prisma migrate dev. Never edit an applied migration. - Reuse a single PrismaClient instance (cache it on
globalThisin dev to survive hot reload). - Use
select/includeto fetch only the fields you need. - Wrap multi-step writes in
prisma.$transaction. - Run
npx prisma generateafter schema changes before type-checking.
Source docs: Prisma docs
Zod validation
Runtime schema validation with Zod. Scoped to **/*.ts, **/*.tsx in Cursor, Copilot and Windsurf.
- Validate all untrusted input (request bodies, form data, env vars, third-party API responses) with a Zod schema at the boundary.
- Derive TypeScript types from schemas with
z.infer<typeof schema>; do not hand-write duplicate types. - Use
safeParsewhere you need to return validation errors to the user.
Source docs: Zod 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
Docker
Containerised builds and local services with Docker. Scoped to Dockerfile, **/Dockerfile, compose.yaml, docker-compose.yml, .dockerignore in Cursor, Copilot and Windsurf.
- Use multi-stage builds and slim, pinned base images.
- Run the app as a non-root user in the final image.
- Keep a
.dockerignorethat excludes.git,node_modules,.envand build output. - Never bake secrets into images; pass them at runtime.
Source docs: Dockerfile best practices
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 Node.js + Express + Prisma + Zod validation + Vitest + Docker?
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 Node.js + Express?
Agents skip input validation and return 500s for what should be 400s.
Which commands should the agent run to check its work?
For this stack: npm run dev, npm run build, npx tsc --noEmit, npx prisma migrate dev --name <change>. They are listed in the generated files so the agent runs them before finishing a task.
Do these Node.js + Express + Prisma + Zod validation + Vitest + Docker 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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