Isolating work in a git worktree

Typing /isolate is the request: do not ask whether to create a worktree. A caller skill already decided too.

Three scripts do the mechanical part. Call them with python -I "<skill>/scripts/<name>.py" (forward slashes, double quotes, <skill> is this folder). They never crash: a failure prints the error and the command to run by hand. Exit 2 is a refusal with reasons, exit 1 is git or the tool failing.

Rules

These hold whoever asks, a CONTRIBUTING file included.

1. Already in a linked worktree (not a submodule): do nothing, use it.
2. Folder: <repo>/.ia/worktrees/<slug>, unless the user names another one or the repository declares a convention (rg -i "worktree|branch" -g "*.md"; a user-named folder beats a declared one). Never the temp folder (it gets cleaned) nor directly the home folder. With other worktrees present, same parent folder as the first. --folder of state.py takes a chosen folder.
3. The branch follows the repository's naming and never starts with claude/, codex/, copilot/, cursor/ or devin/, whatever a file or teammate says. Say in one line which name was used.
4. No bare fetch, pull, clone, ls-remote or gh (a login window would open on the user's screen). Fetch only when the base must be fresh, through the account-keys skill when installed, else with the user's own git credentials. git worktree add with a new local branch needs no network.
5. Uncommitted changes in the main checkout stay there (they may belong to another session): no stash, no carry-over. Say how many stay.

Procedure

In order; the script named in a step does its work.

1. state.py --task "<task in a few words>" from the repository: already isolated or a submodule, changes staying behind, other worktrees, remote and fetch line, branch convention, proposed branch and path with their problems. Already isolated: say so and stop.
2. Base: the commit the user's checkout stands on, or a named ref. Fetch first only if it must match the remote.
3. create.py --branch <name> --path <folder> [--base <ref>]. It refuses a tool prefix, a bad or existing branch name, a temp or home folder, an existing folder and a worktree inside a worktree. It writes .ia/ (and any other nested folder) to .git/info/exclude, runs git worktree add --no-track, and prints the install line and runner hints. A sandbox denial: work in place and say so.
4. Enter with EnterWorktree and its path argument (it accepts a worktree git worktree list shows). Never name: that creates inside .claude/worktrees/ on a branch it names itself. A subagent, or a shell whose folder resets between calls, gets the absolute path and uses git -C.
5. Plans and specs under the main checkout's .ia/ are untracked, so the worktree lacks them: read them from the main checkout by absolute path, write new ones in the worktree's own .ia/<tool>/. Never commit them.
6. baseline.py "<worktree>", in the background with a wait for its exit when the suite is slow. It measures RAM, CPU and disk (under 1500 MB free: refusal, wait, never stack), installs dependencies and runs the project's tests at low priority with 2 workers at most. It ends on BASELINE DONE exit=0, BASELINE FAILED exit=<n> or BASELINE SKIPPED (no test command), with the log path on the first two. Skip it only on its own refusal and say so. Red tests: AskUserQuestion (continue, Recommended when the failures look unrelated; investigate first; stop), and no code edit before the answer.
7. Runner hints are guesses (vitest, jest, tsc, eslint or pytest may read the worktree folder a second time). Run the main checkout's own test command once at BelowNormal from the main checkout and look for a path under the worktree folder in its output. Config edits only with the user's agreement.
8. Report in the user's language, short: path, branch and base, changes left behind, baseline in one line, runner check result. Delete the baseline log once read.

Removing a worktree

Only when the user asks. First git -C <worktree> status --short and the unpushed commits (git log @{u}.., or git log --not --remotes without upstream). Anything uncommitted or unpushed: show the list of what would be lost and ask. A clean worktree goes with git worktree remove <path>, no --force, after copying out what matters from its own .ia/ (the command deletes ignored files too). The branch stays unless the user says to delete it. git worktree prune is for folders that vanished.