name: monorepo description: "MUST use for ANY query mentioning packages, monorepo, workspace, catalog, turbo, turborepo, or pnpm in a multi-package context. MUST use when sharing config (ESLint, tsconfig, prettier) across packages, fixing build order between packages, adding new packages, scoping CI installs/caching to changed packages, or debugging pnpm catalog version resolution. This skill OWNS all cross-package coordination problems — even when they look like build, CI, config, or dependency issues. If two or more packages interact in the query, this skill applies. Takes priority over other skills when the problem spans package boundaries."

Monorepo

Project-specific patterns for pnpm workspaces + Turborepo.

Architecture Decisions

Workspace Organization

1. Split apps from packages — apps/ for deployables, packages/ for shared libraries.
2. Namespace packages — Prefix with @org/ to avoid npm conflicts.
3. Single lockfile — pnpm-lock.yaml at root only. Never commit multiple lockfiles.
4. No cross-package file access — Never use ../ to reach into other packages; import via dependencies.

Dependency Management

1. Use workspace:* protocol — Always for internal package dependencies.
2. Hoist common devDependencies — Shared tooling (TypeScript, ESLint) in root.
3. Peer dependencies for frameworks — React, Vue, etc. as peers to avoid version conflicts.
4. Consider Catalogs (pnpm 9.5+) — Centralize versions in pnpm-workspace.yaml for large repos.

Turborepo Tasks

1. Use ^ for build dependencies — "dependsOn": ["^build"] for topological order.
2. Always define outputs — Without outputs, nothing gets cached.
3. Mark dev servers as persistent — "persistent": true, "cache": false.
4. Be explicit about environment — List all build-affecting vars in env or globalEnv.

Gotchas

• Missing outputs in turbo.json silently disables caching for that task. The task runs every time and you won't get an error — just slow builds. Always verify outputs are configured.
• pnpm install does NOT respect --filter for installation — it always installs the entire workspace. Filtering only works for pnpm run and pnpm exec.
• workspace:* resolves to the CURRENT version of the local package, not "latest from npm". If the package has "version": "0.0.0", published packages will have "dependency": "0.0.0" — set meaningful versions before publishing.
• Turborepo's env field in turbo.json uses GLOB patterns, not exact matches. "env": ["API_*"] captures API_KEY, API_URL, etc. Forgetting this causes over-invalidation.
• turbo run build --filter=app-a builds app-a AND all its workspace dependencies. If a dependency fails, app-a won't build. Check transitive deps.
• Adding a package to packages/ requires running pnpm install before the workspace recognizes it. The new package also needs a valid package.json with name matching the workspace pattern.
• TypeScript project references (references in tsconfig.json) must match the workspace dependency graph. Mismatches cause type errors that only appear during tsc --build, not in IDE.
• turbo.json's globalDependencies invalidates ALL tasks when listed files change. Don't put frequently-changed files here — use task-level inputs instead.
• Shared Tailwind configs need @source directives pointing to consuming packages' source directories, otherwise classes used in shared packages are purged.
• pnpm deploy (for production) copies a single package and its dependencies to a target directory. It does NOT run build scripts — build first, then deploy.
• Remote cache (Vercel or self-hosted) requires outputs to be correct. If outputs are wrong, cached artifacts will be incomplete and downstream tasks break silently.
• persistent: true tasks prevent turbo run from exiting. Don't include persistent tasks in CI pipelines unless they have a timeout.

References

External Resources

• pnpm Workspaces
• Turborepo Docs
• Configuring turbo.json