Git Worktrees Changed How I Run Parallel AI Agents

The first time I ran three AI coding agents on the same repo, they all edited src/main.rs within 30 seconds of each other. Two hours of merge conflict resolution later, I discovered a git feature I'd never used: worktrees. They solve the multi-agent conflict problem completely, and they've been in git since 2015. The Problem If you've ever run more than one AI coding agent on the same project — two Claude Code sessions, or a mix of Claude Code, Codex, and Aider — you've hit this wall: Agent A is editing src/auth.rs . Agent B is also editing src/auth.rs . Someone loses. It doesn't matter how smart the agents are. If two processes write to the same file at the same time, one overwrites the other. You end up with broken code, lost work, or a merge conflict that takes longer to resolve than the task itself. The naive fix is telling agents to work on different files. But you can't always guarantee that. A refactoring that touches the module interface will affect every file that imports it.