Git Worktrees: From Running Multiple Agents to Real Multi-Agent Development

incident.io estimated a task would take two hours. It took ten minutes. Not because their AI agent was unusually fast — because they ran five of them, truly in parallel, each one autonomous from start to finish. Each agent had its own branch, its own directory, its own ability to commit and push and open a PR without waiting for anyone. That's not how most of us run multiple agents today. Two terminals, one directory Most multi-agent setups look like this: two Claude Code sessions open, both pointed at the same project directory. Terminal one is building an API endpoint. Terminal two is writing tests. You keep an eye on both, make sure they're working on different files. When terminal one finishes, you commit its work. Then terminal two. You coordinate. This works. But you're doing something that doesn't scale: you're the synchronization layer. You're mentally partitioning the codebase, sequencing commits, tracking which agent is in which part of the code. With two agents it's manageab