I kept hitting the same wall with coding agents. One Claude Code or Codex session in a repo works great. The moment I wanted two tasks moving at once - login in one terminal, payments in another - they started stepping on each other. Same working directory, same checked-out branch, two processes editing the same files. Chaos.
The fix turned out to be a Git feature that has been sitting there for years: git worktree. It gives you several working directories backed by the same repository. Each folder has its own checked-out branch, but all of them share the same objects, commits and branch list.
The setup
From your main checkout:
git worktree add ../integration -b integration main
