Parallel AI Coding with Git Worktrees: Run Multiple Agents Without Conflicts
Most parallel AI development problems stem from a single architectural mistake: multiple agents sharing the same working directory. Teams spin up three Claude Code instances, point them at the same project folder, and watch as file writes collide, branch checkouts interrupt each other, and lock files corrupt. The symptom looks like a race condition. The root cause is filesystem design.
Git worktrees solve this by giving each agent its own isolated working directory while sharing a single .git repository. This distinction is critical. Developers get parallel execution without the storage overhead of full clones, and agents operate on separate branches without stepping on each other's file handles. The pattern has existed since Git 2.5, but AI coding workflows finally make it essential infrastructure.
The Collision Problem: Why Multiple AI Agents Can't Share a Working Directory
When you run git checkout feature-A in a directory where another process is reading files, the filesystem state changes underneath that reader. The other process doesn't see atomic transitions—it sees partial writes, missing files, and inconsistent dependency graphs. TypeScript compilers fail with "Cannot find module" errors. Dev servers crash because watched files disappeared mid-read. Lock files from package managers become corrupted when two agents run npm install simultaneously on different branches with different dependency trees.
