Spin an isolated worktree

Keep the ordinary checkout as the control checkout and create one worktree per task. Dirty files in the control checkout are preserved and do not block the helper: it updates Git refs and shared worktree metadata, creates the destination, and never switches, stashes, or edits files in the control checkout.

By default worktrees live under ${AGENT_WORKTREE_ROOT:-~/worktrees}:

~/worktrees/<repository>/<task>

Workflow

1. Resolve the ordinary checkout and pass it explicitly with --repo. Never substitute another task's linked worktree just because it is clean. If a linked worktree is passed accidentally, the helper resolves Git's primary worktree before deriving <repository> or running commands.
2. Resolve this installed skill's directory.
3. Run one of the commands below.
4. Report the exact path and use it as the working directory.
5. Do not remove the worktree automatically. Cleanup belongs to task closeout after merge.

New issue branch:

python3 <spin-worktree-skill-directory>/scripts/spin-worktree.py \
  --repo /path/to/repository \
  --issue 317 \
  --slug rescue-context

Existing pull-request branch, discovered with GitHub CLI:

python3 <spin-worktree-skill-directory>/scripts/spin-worktree.py \
  --repo /path/to/repository \
  --pr 321

Existing branch:

python3 <spin-worktree-skill-directory>/scripts/spin-worktree.py \
  --repo /path/to/repository \
  --branch issue-316 \
  --name pr321

Use --dry-run to inspect commands. Override defaults with --worktree-root, --remote, --base, or --branch-prefix.

Branch prefix

New issue branches resolve their prefix in this order: an explicitly supplied --branch-prefix flag, then the string branchPrefix in ~/.config/spin-worktree/config.json, then no prefix. For example:

{"branchPrefix": "my-prefix"}

With no resolved prefix, issue branches are issue-317 or 317-rescue-context; they never begin with /. Pass --branch-prefix '' to request that bare form for one invocation. Missing, unreadable, malformed, or otherwise unsuitable config files silently resolve to no prefix.

Guardrails

• Use one worktree path and branch per task.
• Never switch branches in another agent's active worktree.
• Do not reuse an existing target path unless inspection proves it belongs to the same task.
• New issue work updates the remote and starts from its current default branch unless --base is supplied.
• Existing local branches do not require a remote.
• Pull-request discovery requires authenticated gh. A same-repository head is fetched when needed. A fork head fails with the exact fork and branch to configure, rather than pretending it exists under origin.
• --name accepts one relative directory leaf, never a path.