Monorepos promise simplicity: one repository, one source of truth, easier code sharing. The reality is more complex. As package counts grow from 5 to 50 to 500, maintenance becomes a coordination nightmare. Update a shared utility and break a dozen packages. Change a TypeScript version and trigger cascading rebuilds. Forget to update one package.json and spend an hour debugging why builds fail.
The same characteristics that make monorepos powerful - shared code, unified versioning, cross-package dependencies - create maintenance overhead that scales faster than team size. What one person could maintain at 10 packages becomes a full-time job at 100.
AI agents can handle monorepo maintenance at scale. They understand cross-package dependencies, coordinate updates across packages, and ensure consistency that humans struggle to maintain manually.
The Monorepo Maintenance Challenge
Monorepos create unique maintenance patterns.
Dependency Coordination
A single shared package might be used by 50 other packages. Update its interface and all 50 need updates. Miss one and builds break.
Configuration Proliferation
Each package has configuration files: package.json, tsconfig.json, .eslintrc, jest.config. Multiply by package count and you have hundreds of files to keep consistent.
Version Synchronization
Internal packages should stay synchronized. External dependencies should be consistent across packages. Version drift between packages creates subtle bugs and build failures.
Build Graph Complexity
Packages depend on packages that depend on packages. The build graph becomes complex enough that humans can't reason about it. Circular dependencies sneak in. Build order becomes non-obvious.
Cross-Package Changes
Simple refactorings touch many packages. Renaming a shared function means updating imports in dozens of files across dozens of packages.
Dependency Management
Cross-package dependencies need special handling.
Internal Dependency Updates
When shared packages change:
@devonair update all packages that depend on @company/shared-utils to use the new API
@devonair propagate breaking changes from @company/core to all dependent packages
Version Synchronization
Keep versions aligned:
@devonair synchronize React version across all packages to 18.2.0
@devonair ensure all packages use the same TypeScript version
Dependency Auditing
Find inconsistencies:
@devonair identify packages with different versions of the same dependency
@devonair find packages that could use shared dependencies but install their own
Circular Dependency Detection
@devonair detect and report circular dependencies between packages
@devonair suggest refactoring to break circular dependency chains
Configuration Standardization
Consistent configuration across packages.
Shared Configuration Extension
@devonair ensure all packages extend the root tsconfig.json properly
@devonair standardize ESLint configuration across all packages
Configuration Drift Detection
@devonair identify packages with configuration that doesn't match root standards
@devonair report on package.json fields that should be consistent but aren't
Configuration Updates
When standards change:
@devonair update all tsconfig.json files to use the new compiler options
@devonair propagate new ESLint rules to all packages
Template Enforcement
@devonair ensure all packages have required files: README.md, LICENSE, CHANGELOG.md
@devonair add missing package.json fields to all packages
Cross-Package Refactoring
Changes that span packages.
Renaming Exports
@devonair rename getUserById to findUserById across all packages
Updates the source and all import sites.
Moving Code Between Packages
@devonair move the validation utilities from @company/utils to @company/validation
@devonair update all imports after moving code between packages
Interface Changes
@devonair update all usages of UserService after interface change
The agent finds every import and usage across the entire monorepo.
Type Propagation
@devonair propagate type changes from @company/types to all consuming packages
Type definitions change; usages must follow.
Build and Test Optimization
Efficient builds in large monorepos.
Affected Package Detection
@devonair identify packages affected by changes in this PR
Only build and test what changed.
Build Order Optimization
@devonair optimize build order based on dependency graph
Build dependencies before dependents.
Cache Invalidation
@devonair clear caches for packages affected by configuration changes
Stale caches cause mysterious failures.
Parallelization
@devonair configure maximum parallelization for independent package builds
Build unrelated packages simultaneously.
Package Lifecycle Management
Managing packages over time.
New Package Creation
@devonair create new package @company/authentication following our templates
New packages start correct.
Package Deprecation
@devonair deprecate @company/legacy-utils and migrate consumers to @company/utils
@devonair identify all usages of deprecated internal packages
Package Removal
@devonair safely remove @company/unused-package and verify no references remain
Dead packages create confusion.
Package Splitting
@devonair split @company/mega-utils into focused packages by domain
Large packages become harder to maintain.
Version Management
Coordinated versioning across packages.
Semantic Version Bumping
@devonair bump versions for all packages changed since last release
@devonair determine version bumps based on conventional commits
Changelog Generation
@devonair generate changelogs for all packages with changes
Each package gets its own changelog from its changes.
Release Coordination
@devonair create release for all changed packages with proper version dependencies
Dependent packages release together.
Pre-release Management
@devonair create beta releases for packages in /packages/experimental
Different packages may have different release tracks.
Workspace Tool Integration
Different monorepo tools have different patterns.
npm Workspaces
@devonair configure npm workspaces for optimal hoisting and linking
@devonair update workspace references after package rename
Yarn Workspaces
@devonair optimize Yarn workspace dependency hoisting
@devonair configure Yarn PnP for workspace packages
pnpm Workspaces
@devonair configure pnpm workspace with proper filtering
@devonair set up pnpm patch dependencies for monorepo
Nx
@devonair configure Nx project.json for new packages
@devonair update Nx affected commands after restructuring
Turborepo
@devonair configure Turborepo caching for all packages
@devonair optimize turbo.json pipeline for build performance
Lerna
@devonair configure Lerna for independent versioning
@devonair update lerna.json after adding new packages
Testing at Scale
Testing across many packages.
Affected Tests Only
@devonair run tests only for packages affected by current changes
Don't test unchanged packages.
Test Configuration Sharing
@devonair ensure all packages use shared Jest configuration
Consistent test setup.
Integration Test Coordination
@devonair run integration tests after all dependent packages are built
Test in correct order.
Coverage Aggregation
@devonair aggregate test coverage across all packages
See coverage for the entire monorepo.
Documentation Consistency
Documentation across packages.
README Standardization
@devonair ensure all package READMEs follow our template
@devonair update READMEs to reflect current installation commands
API Documentation
@devonair generate API documentation for all public packages
Internal Documentation
@devonair document package dependencies and relationships
Help developers understand the monorepo structure.
Migration Guides
@devonair generate migration guide when moving between package versions
Health Metrics
Monitor monorepo health.
Dependency Depth
@devonair report on package dependency depth and complexity
Deep dependencies slow builds and increase coupling.
Package Size Tracking
@devonair report on package sizes and identify unusually large packages
Large packages may need splitting.
Unused Dependencies
@devonair identify unused dependencies across all packages
Remove what's not needed.
Build Time Tracking
@devonair track and report on package build times
Identify slow packages.
Getting Started
Start with visibility:
@devonair analyze monorepo structure and report on package dependencies
Understand your monorepo's shape.
Fix immediate issues:
@devonair standardize dependency versions across all packages
@devonair ensure all packages extend shared configuration
Set up ongoing maintenance:
@devonair on PR: verify cross-package consistency
@devonair schedule weekly: report on monorepo health metrics
Monorepos at scale require automation. When changes propagate automatically, dependencies stay synchronized, and configuration remains consistent, monorepos deliver on their promise of simplified development.
FAQ
When should I split a monorepo?
When the coupling between packages is loose enough that teams work independently. If packages rarely change together and don't share much code, separate repos may make more sense.
How do I handle different release schedules?
Use independent versioning where packages can release separately. Group tightly coupled packages for coordinated releases. Document which packages release together.
What about build performance at 500+ packages?
Use affected package detection to build only what changed. Configure aggressive caching. Use distributed build caches. Consider incremental compilation for large TypeScript projects.
How do I onboard new developers?
Document the package structure and key packages. Create guides for common tasks (adding packages, updating dependencies). Use tooling that makes the monorepo structure visible and navigable.