isolate-work - SKILL.md Agent Skill

name: isolate-work description: "Create isolated git worktrees for feature work. Smart directory selection and safety verification." disable-model-invocation: true phase: any

Isolate Work

Create an isolated git worktree for feature work so the main working directory stays clean. User-invoked only: do not auto-trigger this skill.

Directory Selection Priority

Existing directory: check for .worktrees/ or worktrees/ in the project root. If both exist, .worktrees/ wins.
CLAUDE.md preference: check for a worktree directory preference in the project's CLAUDE.md.
Ask user: offer two choices:
- .worktrees/ in the project root (local, hidden)
- ~/.config/forge/worktrees/<project-name>/ (global location)

For project-local worktree directories (.worktrees or worktrees), verify the directory is in .gitignore BEFORE creating the worktree.

Check: git check-ignore -q <directory> 2>/dev/null

If NOT ignored:

Add the directory to .gitignore
Commit the .gitignore change
THEN proceed with worktree creation

One missed check means worktree contents committed to the repository. No exceptions.

Process Flow

digraph isolate_work {
    "Select directory" [shape=box];
    "Safety check" [shape=box];
    "gitignore verified?" [shape=diamond];
    "Add to gitignore + commit" [shape=box];
    "Create worktree" [shape=box];
    "Install deps" [shape=box];
    "Run baseline tests" [shape=box];
    "Report" [shape=doublecircle];

    "Select directory" -> "Safety check";
    "Safety check" -> "gitignore verified?";
    "gitignore verified?" -> "Create worktree" [label="yes"];
    "gitignore verified?" -> "Add to gitignore + commit" [label="no"];
    "Add to gitignore + commit" -> "Create worktree";
    "Create worktree" -> "Install deps";
    "Install deps" -> "Run baseline tests";
    "Run baseline tests" -> "Report";
}

Creation Steps

Create the worktree with a new branch:
```
git worktree add <dir>/<branch-name> -b <branch-name>
```
Branch naming: forge/<feature-name> by default, or user-specified.
Auto-detect project setup and install dependencies:
- package.json found: npm install (or yarn install if yarn.lock present)
- Cargo.toml found: cargo build
- pyproject.toml found: poetry install
- go.mod found: go mod download
- Nothing found: skip dependency install
Run baseline tests using the project's test command. This establishes a known-good state. If tests fail, report the failures and ask whether to proceed.
Report: worktree path, branch name, baseline test results.

Anti-Patterns

"Skip the gitignore check" One missed check means worktree contents committed to the repo. The HARD-GATE exists for a reason.

"Skip baseline tests" Without a known-good baseline, you cannot distinguish new regressions from pre-existing failures.

"Hardcode setup commands" Auto-detect from project manifest files. Different projects use different tools.

"Assume the directory location" Follow the priority: existing directory, then CLAUDE.md, then ask the user. Consistency matters.

Evidence Requirements

Worktree directory is in .gitignore (verified with git check-ignore)
Baseline tests pass in the new worktree
Worktree path and branch name reported to user

Cleanup

Handled by land-changes. When the user chooses merge, PR, keep, or discard, land-changes runs git worktree remove as part of workspace cleanup.