Developers working with AI coding agents often face a frustrating workflow problem: sharing one working directory means either watching the agent work in real-time or risking conflicts by working on other tasks. Git worktrees offer a practical solution by creating separate directories for different branches, allowing developers and agents to work in parallel without stepping on each other's toes.

A worktree is essentially a second window onto the same Git repository, locked to a different branch. The command `git worktree add .worktrees/myrepo-auth -b feature/auth` creates a new folder with files for a specific branch while leaving your original directory untouched. This means you can have one terminal running an agent on a long refactor while you work on documentation in another worktree, with each having its own dev server, environment variables, and dependencies.

The key insight is that worktrees parallelize branches, not agents. You cannot check out the same branch in multiple worktrees, which prevents the chaos of multiple agents overwriting each other's work. Instead, decompose large tasks into sub-branches (like `feat/frontend-redo-nav` and `feat/frontend-redo-auth`) and run each in its own worktree. This approach transforms how developers collaborate with AI agents, turning what was once a serial process into true parallel development.