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GitHub Copilot custom instructions: copilot-instructions.md generator

GitHub Copilot reads repository-wide custom instructions from .github/copilot-instructions.md, and path-specific instructions from .github/instructions/NAME.instructions.md files whose applyTo frontmatter holds glob patterns. Copilot coding agent and Copilot CLI also read AGENTS.md.

Generate a Copilot instructions file

Where the file goes

How it works

Tips for a good Copilot instructions

Example: Node.js + Express + Prisma + Zod validation

.github/copilot-instructions.md
# Copilot instructions - this project

A Node.js + Express + Prisma + Zod validation project.

Stack: Node.js + Express, Prisma, Zod validation.

## 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`

## 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.
.github/instructions/express.instructions.md
---
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).
.github/instructions/prisma.instructions.md
---
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.
.github/instructions/zod.instructions.md
---
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.

FAQ

Where do Copilot instructions go?

In .github/copilot-instructions.md in the repository, plus optional .github/instructions/*.instructions.md files.

Does Copilot read AGENTS.md?

The Copilot coding agent and Copilot CLI do. Copilot in VS Code also supports AGENTS.md.

Copilot instructions templates by stack

Official docs: GitHub Copilot custom instructions. Last reviewed 2026-10-21.