Summary: Worktrees and parallel agents

The one-sentence definition

A worktree is a separate working directory attached to the same git repository: multiple folders sharing one .git/, each with its own branch checked out.

The essential commands

git worktree add <path> <branch>           # attach existing branch as new worktree
git worktree add -b <newbranch> <path> <baseref>   # create new branch in new worktree
git worktree list                          # see all attached worktrees
git worktree remove <path>                 # detach and delete (use --force for unsaved changes)
git worktree prune                         # clean up records for manually-deleted folders
git worktree lock <path> --reason "..."    # prevent accidental pruning
git worktree unlock <path>                 # release the lock

Worktree vs clone vs checkout-switching

Tool	When to use
Worktree	Parallel branches on one machine; frequent context-switching; multi-agent workflows; save disk space
Clone	Truly independent copies; across machines; want isolation from teammates’ pushes
Checkout-switching	Sequential work, done with one branch before starting another, occasional swaps

The constraint

One branch per worktree: cannot check out the same branch in two worktrees simultaneously. Workaround: different branches or detached HEAD if you need to inspect the same commit.

The four canonical use cases

1. Review a teammate’s PR without disturbing your current work
2. Hotfix during a feature: spin up a worktree off main, fix, ship, remove
3. Side-by-side version comparison: inspect v1.4 and main simultaneously
4. Multi-agent fleet: one worktree per agent, parallel work, shared history

Why worktrees are the Phase 4 substrate

L14-L16 assume you can spin up multiple parallel working directories cheaply. Worktrees deliver this: one command to create, one to remove, near-zero overhead. Multi-agent AI workflows go from “annoying” with multiple clones to “trivial” with worktrees.

Voice anchor

Git stores snapshots. Every other command is just navigating those snapshots.

Worktrees don’t change the snapshots. They just give you more windows looking at the snapshot database simultaneously. Each window shows one branch; together, they show many.

What you carry into L14

L14 covers the three multi-agent integration patterns built on top of worktrees: shared origin, per-agent fork, shared worktrees. Lead orchestration. Semantic-conflict catching at integration. All assume L13’s worktree foundation.