Wt Setup

wt-setup

Create and maintain .wt/setup scripts -- the standard bootstrap entrypoint executed when a git worktree is created by a supporting tool.

Background

The wt tool (and other tools that follow the .wt/setup convention) creates git worktrees under ~/.wt/worktrees/<project>-<name>/. When a worktree is created, the tool looks for .wt/setup in the repository root and executes it inside the new worktree directory.

Convention

Directory layout

.wt/
  AGENTS.md          # Documentation for agents about the .wt/ directory
  setup              # Bootstrap script (executable, committed)
  setup.local        # Local overrides (gitignored)
  worktrees/         # Symlinks to worktrees (gitignored, created by wt)

Execution context

Design rules

1. Idempotent -- safe to run multiple times
2. Non-interactive -- no prompts; fail fast on missing prerequisites
3. Fast -- avoid slow network operations; cache where possible
4. Portable -- use #!/usr/bin/env bash and standard POSIX tools
5. Repository-local only -- tools MUST NOT read user-global setup scripts

Creating a .wt/setup

Step 1 -- Detect project type

Inspect the repository to determine what bootstrap actions are needed:

Step 2 -- Generate the script

Use the generator script or write manually:

# Using the generator
./wt-setup/scripts/generate.py

# Or manually
mkdir -p .wt
cat > .wt/setup << 'SETUP'
#!/usr/bin/env bash
set -euo pipefail

# --- Prerequisites ---
for cmd in make git; do
  if ! command -v "$cmd" >/dev/null 2>&1; then
    echo "error: $cmd not found" >&2
    exit 1
  fi
done

# --- Bootstrap ---
make setup
SETUP
chmod +x .wt/setup

Step 3 -- Add .wt/setup.local support (optional)

.wt/setup.local is gitignored, so it does not exist in worktrees. The script must reference the ROOT (source) repository via ROOT_WORKTREE_PATH.

Append to .wt/setup:

# --- Local overrides (from ROOT repo -- .local is gitignored) ---
_local="${ROOT_WORKTREE_PATH:-.}/.wt/setup.local"
if [ -f "$_local" ]; then
  # shellcheck source=/dev/null
  source "$_local"
fi

Ensure .wt/setup.local is in .gitignore.

Step 4 -- Add AGENTS.md (recommended)

Copy the template to .wt/AGENTS.md so AI agents understand the directory:

cp wt-setup/references/AGENTS.md.template .wt/AGENTS.md

Or use the generator with --agents-md flag. The template is at references/AGENTS.md.template.

Step 5 -- Update .gitignore

Add these entries if not present:

.wt/setup.local
.wt/worktrees/

Git hooks in worktrees

Worktrees do NOT inherit git hooks from the base repository. If the base repo uses pre-commit hooks, .wt/setup SHOULD re-establish them.

The strategy (in priority order):

1. pre-commit framework -- if .pre-commit-config.yaml exists, run pre-commit install
2. Husky (Node.js) -- if .husky/ exists, run npx husky install
3. Fallback -- point core.hooksPath to the base repo's hooks: git config core.hooksPath "${ROOT_WORKTREE_PATH}/.git/hooks"

All templates in references/ include this logic.

Templates

Template files are in references/. Copy one to .wt/setup and adjust as needed.

Example:

cp wt-setup/references/setup-python.sh .wt/setup
chmod +x .wt/setup

Validation checklist

After creating .wt/setup, verify:

• File is executable (chmod +x .wt/setup)
• Shebang is #!/usr/bin/env bash
• set -euo pipefail is present
• Prerequisite commands are checked before use
• Script is idempotent (safe to re-run)
• No interactive prompts
• .wt/setup.local is gitignored
• .wt/worktrees/ is gitignored

Reference

• wt tool: https://github.com/tumf/wt
• Git worktree docs: https://git-scm.com/docs/git-worktree