Monorepo Navigator
Tier: POWERFUL
Category: Engineering
Domain: Monorepo Architecture / Build Systems
Overview
Navigate, manage, and optimize monorepos. Covers Turborepo, Nx, pnpm workspaces, and Lerna. Enables cross-package impact analysis, selective builds/tests on affected packages only, remote caching, dependency graph visualization, and structured migrations from multi-repo to monorepo. Includes Claude Code configuration for workspace-aware development.
Core Capabilities
- Cross-package impact analysis — determine which apps break when a shared package changes
- Selective commands — run tests/builds only for affected packages (not everything)
- Dependency graph — visualize package relationships as Mermaid diagrams
- Build optimization — remote caching, incremental builds, parallel execution
- Migration — step-by-step multi-repo → monorepo with zero history loss
- Publishing — changesets for versioning, pre-release channels, npm publish workflows
- Claude Code config — workspace-aware CLAUDE.md with per-package instructions
When to Use
Use when:
- Multiple packages/apps share code (UI components, utils, types, API clients)
- Build times are slow because everything rebuilds when anything changes
- Migrating from multiple repos to a single repo
- Need to publish packages to npm with coordinated versioning
- Teams work across multiple packages and need unified tooling
Skip when:
- Single-app project with no shared packages
- Team/project boundaries are completely isolated (polyrepo is fine)
- Shared code is minimal and copy-paste overhead is acceptable
Tool Selection
| Tool |
Best For |
Key Feature |
| Turborepo |
JS/TS monorepos, simple pipeline config |
Best-in-class remote caching, minimal config |
| Nx |
Large enterprises, plugin ecosystem |
Project graph, code generation, affected commands |
| pnpm workspaces |
Workspace protocol, disk efficiency |
workspace:* for local package refs |
| Lerna |
npm publishing, versioning |
Batch publishing, conventional commits |
| Changesets |
Modern versioning (preferred over Lerna) |
Changelog generation, pre-release channels |
Most modern setups: pnpm workspaces + Turborepo + Changesets
Turborepo
→ See references/monorepo-tooling-reference.md for details
Workspace Analyzer
python3 scripts/monorepo_analyzer.py /path/to/monorepo
python3 scripts/monorepo_analyzer.py /path/to/monorepo --json
Also see references/monorepo-patterns.md for common architecture and CI patterns.
Common Pitfalls
| Pitfall |
Fix |
Running turbo run build without --filter on every PR |
Always use --filter=...[origin/main] in CI |
workspace:* refs cause publish failures |
Use pnpm changeset publish — it replaces workspace:* with real versions automatically |
| All packages rebuild when unrelated file changes |
Tune inputs in turbo.json to exclude docs, config files from cache keys |
| Shared tsconfig causes one package to break all type-checks |
Use extends properly — each package extends root but overrides rootDir / outDir |
| git history lost during migration |
Use git filter-repo --to-subdirectory-filter before merging — never move files manually |
| Remote cache not working in CI |
Check TURBO_TOKEN and TURBO_TEAM env vars; verify with turbo run build --summarize |
| CLAUDE.md too generic — Claude modifies wrong package |
Add explicit "When working on X, only touch files in apps/X" rules per package CLAUDE.md |
Best Practices
- Root CLAUDE.md defines the map — document every package, its purpose, and dependency rules
- Per-package CLAUDE.md defines the rules — what's allowed, what's forbidden, testing commands
- Always scope commands with --filter — running everything on every change defeats the purpose
- Remote cache is not optional — without it, monorepo CI is slower than multi-repo CI
- Changesets over manual versioning — never hand-edit package.json versions in a monorepo
- Shared configs in root, extended in packages — tsconfig.base.json, .eslintrc.base.js, jest.base.config.js
- Impact analysis before merging shared package changes — run affected check, communicate blast radius
- Keep packages/types as pure TypeScript — no runtime code, no dependencies, fast to build and type-check
1---2name: monorepo-navigator-23description: Navigate, manage, and optimize monorepos. Covers Turborepo, Nx, pnpm workspaces, and Lerna. Cross-package impact analysis, selective builds/tests on affected packages, remote caching, dependency graph visualization, and structured multi-repo to monorepo migrations. Use when setting up a new monorepo, optimizing CI for a large workspace, debugging cross-package dependency issues, or planning a multi-repo consolidation.4---56# Monorepo Navigator78**Tier:** POWERFUL 9**Category:** Engineering 10**Domain:** Monorepo Architecture / Build Systems 1112---1314## Overview1516Navigate, manage, and optimize monorepos. Covers Turborepo, Nx, pnpm workspaces, and Lerna. Enables cross-package impact analysis, selective builds/tests on affected packages only, remote caching, dependency graph visualization, and structured migrations from multi-repo to monorepo. Includes Claude Code configuration for workspace-aware development.1718---1920## Core Capabilities2122- **Cross-package impact analysis** — determine which apps break when a shared package changes23- **Selective commands** — run tests/builds only for affected packages (not everything)24- **Dependency graph** — visualize package relationships as Mermaid diagrams25- **Build optimization** — remote caching, incremental builds, parallel execution26- **Migration** — step-by-step multi-repo → monorepo with zero history loss27- **Publishing** — changesets for versioning, pre-release channels, npm publish workflows28- **Claude Code config** — workspace-aware CLAUDE.md with per-package instructions2930---3132## When to Use3334Use when:35- Multiple packages/apps share code (UI components, utils, types, API clients)36- Build times are slow because everything rebuilds when anything changes37- Migrating from multiple repos to a single repo38- Need to publish packages to npm with coordinated versioning39- Teams work across multiple packages and need unified tooling4041Skip when:42- Single-app project with no shared packages43- Team/project boundaries are completely isolated (polyrepo is fine)44- Shared code is minimal and copy-paste overhead is acceptable4546---4748## Tool Selection4950| Tool | Best For | Key Feature |51|---|---|---|52| **Turborepo** | JS/TS monorepos, simple pipeline config | Best-in-class remote caching, minimal config |53| **Nx** | Large enterprises, plugin ecosystem | Project graph, code generation, affected commands |54| **pnpm workspaces** | Workspace protocol, disk efficiency | `workspace:*` for local package refs |55| **Lerna** | npm publishing, versioning | Batch publishing, conventional commits |56| **Changesets** | Modern versioning (preferred over Lerna) | Changelog generation, pre-release channels |5758Most modern setups: **pnpm workspaces + Turborepo + Changesets**5960---6162## Turborepo63→ See references/monorepo-tooling-reference.md for details6465## Workspace Analyzer6667```bash68python3 scripts/monorepo_analyzer.py /path/to/monorepo69python3 scripts/monorepo_analyzer.py /path/to/monorepo --json70```7172Also see `references/monorepo-patterns.md` for common architecture and CI patterns.7374## Common Pitfalls7576| Pitfall | Fix |77|---|---|78| Running `turbo run build` without `--filter` on every PR | Always use `--filter=...[origin/main]` in CI |79| `workspace:*` refs cause publish failures | Use `pnpm changeset publish` — it replaces `workspace:*` with real versions automatically |80| All packages rebuild when unrelated file changes | Tune `inputs` in turbo.json to exclude docs, config files from cache keys |81| Shared tsconfig causes one package to break all type-checks | Use `extends` properly — each package extends root but overrides `rootDir` / `outDir` |82| git history lost during migration | Use `git filter-repo --to-subdirectory-filter` before merging — never move files manually |83| Remote cache not working in CI | Check TURBO_TOKEN and TURBO_TEAM env vars; verify with `turbo run build --summarize` |84| CLAUDE.md too generic — Claude modifies wrong package | Add explicit "When working on X, only touch files in apps/X" rules per package CLAUDE.md |8586---8788## Best Practices89901. **Root CLAUDE.md defines the map** — document every package, its purpose, and dependency rules912. **Per-package CLAUDE.md defines the rules** — what's allowed, what's forbidden, testing commands923. **Always scope commands with --filter** — running everything on every change defeats the purpose934. **Remote cache is not optional** — without it, monorepo CI is slower than multi-repo CI945. **Changesets over manual versioning** — never hand-edit package.json versions in a monorepo956. **Shared configs in root, extended in packages** — tsconfig.base.json, .eslintrc.base.js, jest.base.config.js967. **Impact analysis before merging shared package changes** — run affected check, communicate blast radius978. **Keep packages/types as pure TypeScript** — no runtime code, no dependencies, fast to build and type-check
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