ContextEngine

Stop re-explaining your codebase to AI. Every. Single. Session.

npx @strifero/contextengine

Free. Open source. Runs entirely on your machine. No account required.

See It In Action

The Problem

Every AI coding session starts blank. You ask Claude Code to add an endpoint, and it suggests pages/api/ because it doesn't know you're on the App Router. You ask Cursor to write a query, and it ignores your Prisma setup. You spend 10 minutes re-establishing context before doing any real work.

CLAUDE.md, .cursorrules, and copilot-instructions.md fix this: your AI tool reads them automatically and starts with full context. But writing a good one is tedious.

ContextEngine generates them automatically from your actual codebase.

Before / After

Before (any agent, empty repo context):

You: Where should I add a new API endpoint?
Agent: Create pages/api/users.ts and export a default handler...

Wrong. This is an App Router project.

After. Run ContextEngine once. It reads your package.json, tsconfig.json, prisma/schema.prisma, and friends, and writes a real AGENTS.md at the project root. On a minimal Next.js 14 (App Router) + Prisma + Tailwind repo, this is the actual file:

# nextjs-app

> AGENTS.md: instructions for AI coding agents working on this project.
> Human contributors: see README.md.

## Stack

- TypeScript 5.5.0
- Next.js (App Router) 14.2.0
- React 18.3.0
- Node.js
- Tailwind CSS 3.4.0
- Prisma 5.15.0
- Prettier
- Playwright

## Commands

- `npm run dev`: `next dev`
- `npm run build`: `next build`
- `npm run start`: `next start`
- `npm run lint`: `next lint`
- `npm run test`: `vitest`
- `npm run db:migrate`: `prisma migrate dev`

## Conventions

- App Router by default. Server Components unless the file declares `"use client"`.
- Database access lives in Server Components, Route Handlers, or Server Actions, never client code.
- Route Handlers at `app/<path>/route.ts` export named methods (GET, POST, etc.).
- Single PrismaClient instance at `lib/prisma.ts`. Import that, never `new PrismaClient()` in request paths.
- Schema changes go through `prisma migrate dev` locally and `prisma migrate deploy` in CI.
- Run with `strict: true` in tsconfig. Prefer `interface` for object shapes and `type` for unions.
- Role-based selectors (`getByRole`, `getByLabel`) before `getByTestId`. Avoid CSS selectors.
- Prettier is the source of truth for formatting. Run `prettier --write` or wire it into the editor.

## What to avoid

- `getServerSideProps` and `getStaticProps`. The App Router replaced them.
- Importing server-only modules from client components.
- `$executeRawUnsafe` with user input. Use `$executeRaw` tagged templates.
- `page.waitForTimeout`. Assert visibility or wait on a network response.

(Trimmed for brevity: the full file has a few more TypeScript and React bullets. Nothing is hand-written; every section above is derived from files in the repo.)

For Claude Code, --tool claude also writes .claude/CLAUDE.md plus a skill library under .claude/skills/ (e.g. nextjs-app/SKILL.md, prisma/SKILL.md) so Claude lazy-loads per-topic guidance on demand.

What It Does

ContextEngine scans your project root, reads your actual config files and dependencies, and generates:

| Tool | Output | Reads AGENTS.md? | Auto-loaded? | |------|--------|------------------|-------------| | Claude Code | .claude/CLAUDE.md + skill files | no (uses CLAUDE.md) | ✅ Yes | | Cursor | .cursor/rules/*.mdc | no | ✅ Yes | | GitHub Copilot | .github/copilot-instructions.md | no | ✅ Yes | | Codex CLI | AGENTS.md | yes | ✅ Yes | | OpenCode | .opencode/AGENTS.md | yes | ✅ Yes | | Aider | CONVENTIONS.md | yes (recent versions) | ✅ Yes | | Windsurf | .windsurfrules | no | ✅ Yes | | Gemini CLI | GEMINI.md | no (uses GEMINI.md) | ✅ Yes | | Cline | .clinerules | no | ✅ Yes | | Roo Code | .roo/rules.md | no | ✅ Yes | | JetBrains (Junie) | .junie/guidelines.md | no | ✅ Yes | | Amazon Q | .amazonq/rules/project.md | no | ✅ Yes | | Zed | .rules | no | ✅ Yes |

AGENTS.md at the repo root is the cross-tool standard (agents.md). The column above reflects native support at the time of this release; the list is growing as more agents adopt the spec. For tools without native support, ContextEngine writes the body at the tool-specific path the agent expects.

One tool:

npx @strifero/contextengine

All tools at once:

npx @strifero/contextengine --tool all

Usage

# Detect stack and generate context files
npx @strifero/contextengine

# Target a specific tool
npx @strifero/contextengine --tool cursor
npx @strifero/contextengine --tool copilot
npx @strifero/contextengine --tool all

# Re-sync after your stack changes (preserves your edits)
npx @strifero/contextengine --update

# Specific directory
npx @strifero/contextengine --dir /path/to/project

Commit It

git add .claude/ .cursor/ .github/copilot-instructions.md
git commit -m "add AI context files via contextengine"

Every contributor who clones the repo gets full AI context from day one. When the stack changes, re-run with --update.

Why auto-generate?

The honest critique of auto-generated context files: they rot, they inflate every session with boilerplate, and a stale CLAUDE.md is worse than none. ContextEngine treats its output as a starting point, not a finished document. On first run it scans your lockfiles, configs, and dependencies and writes AGENTS.md, CLAUDE.md, and the matching skill files. Everything past the detected-stack summary is yours to edit; --update reconciles on the next run instead of overwriting.

The baseline context cost stays small. Skill files in .claude/skills/ are lazy-loaded by description match, so Claude Code only pulls in a skill when the task touches it. A dozen skills on disk costs you the CLAUDE.md header plus the one or two skills the agent actually selects. AGENTS.md and the tool-specific equivalents are single files capped at a few KB, biased toward stack-derived facts (versions, scripts, conventions) and away from prose. The generated file is short enough to read; the repo is still the source of truth.

Detected Stacks

Languages and runtimes. TypeScript · Node.js · Go · Python · Rust · PHP · C# · Bun

React family. Next.js (App Router and Pages Router, detected separately) · Remix · Vite · React

Other web frameworks. Vue · Nuxt · SvelteKit · Angular · Astro

Server / API frameworks. Express · NestJS · FastAPI · Django · Ruby on Rails · Laravel

Mobile. Swift / SwiftUI · Flutter

Data and infrastructure. Prisma · PostgreSQL · MongoDB · Docker · Azure · Stripe · Tailwind CSS

Testing. Vitest · Jest · Playwright · Cypress

Linters and formatters. ESLint (flat and legacy config) · Biome · Prettier

Package managers surfaced in the detected output. npm · pnpm · yarn · bun · bundler · composer · pub, plus a Python-tool annotation (poetry / uv / pip) on FastAPI conventions. Monorepos (Turbo, Nx, pnpm-workspaces, Lerna, Rush) get a dedicated section.

Don't see yours? Open an issue or submit a PR. Skills are plain markdown; detection is plain filesystem checks.

Requirements

• Node.js 18+
• Any project directory (any language or framework)

See Real Examples

Generated output files for common stacks: 👉 contextengine-examples

Contributing

Skills are plain markdown files in src/skills/. To add a stack:

1. Create src/skills/<name>.ts
2. Add detection to src/detect.ts
3. Wire up in src/registry.ts
4. Open a PR

See CONTRIBUTING.md for details.

License

MIT, by Strife Technologies