wt-create

What this skill does

# Create Git Worktree

## Script Location

**Scripts live next to this SKILL.md, not in the user's project.** Before
running any script, determine the directory containing this SKILL.md file. Use
that absolute path as `{SKILL_DIR}` when constructing script paths below.

## Overview

Git worktrees create isolated workspaces sharing the same repository, allowing
work on multiple branches simultaneously without switching.

**Announce at start:** "I'm using the wt-create skill to set up an
isolated workspace."

## Script Reference

This skill uses a single unified CLI script for all worktree operations:

| Script                | Description                                                       | Reference                |
| --------------------- | ----------------------------------------------------------------- | ------------------------ |
| `scripts/worktree.py` | Creates worktrees, syncs config files, and runs post-create hooks | `references/worktree.md` |

This script must be run with `uv` because it requires extra dependencies.

```bash
uv run {SKILL_DIR}/scripts/worktree.py <subcommand> [args...]
```

You should read the reference file for specifics about a subcommand's arguments,
output format, and error handling.

## Prerequisites

This skill accepts a **branch name** as the only argument. The branch can be
new (will be created) or existing (will be checked out).

All prerequisite checks (default branch detection, branch verification, and
freshness against origin) are handled by the `scripts/worktree.py create`
subcommand.

The `create` subcommand must be run as the first step in the process of creating
a worktree.

## Directory Selection Process

### 1. Worktree Directories Location

Worktree directories should be created in the parent directory of the primary
git repository, not inside it. This prevents pollution of the main workspace.

For example, if the current repository is at
`/Users/jesse/Code/myproject/myproject`, the new worktree directory should be
created in `/Users/jesse/Code/myproject/<worktree-dir-name>`.

### 2. Ask User If New Directory Doesn't Follow Conventions

If following the convention outlined above will result in a new worktree
directory that is outside of the project or in a directory that does not seem
right, prompt the user with information about your concern and ask where they
would like to create the worktree directory. For example:

```text
Creating a worktree directory at <path> does not conform to worktree directory conventions because <reason>.

Where should I create worktrees?
```

The directory is specified with the `--parent-dir` argument to the `create`
subcommand.

## Creation Steps

**Important:** Do not run any git commands directly (e.g., `git rev-parse`,
`git branch`). The `scripts/worktree.py` script handles all git operations
internally and its JSON output provides everything needed for this skill.

**Steps must be executed sequentially.** Each step depends on the previous
step completing successfully. Do not run any steps in parallel.

### 1. Setup & Create Worktree

```bash
uv run {SKILL_DIR}/scripts/worktree.py create <BRANCH_NAME> [--parent-dir <path>]
```

The script outputs JSON to stdout. Parse the result and handle accordingly:

| `status`        | Meaning                         | Action                                                      |
| --------------- | ------------------------------- | ----------------------------------------------------------- |
| `success`       | Worktree created          | Continue to step 2. Use `worktree_path` from the output.    |
| `wrong_branch`  | Not on the default branch | Ask user to switch to `default_branch`, then re-run step 1. |
| `error`         | Something else went wrong | Show `message` to the user and stop.                        |

### 2. Setup Worktree (Sync + Hooks)

```bash
uv run {SKILL_DIR}/scripts/worktree.py setup <worktree_path>
```

Where `<worktree_path>` is the `worktree_path` value from step 1's JSON output.

Combines sync and post-create hooks into one invocation:

1. Reads the `copy` list from `.worktreerc.yml` (or `.worktreerc.yaml`) in the
   main worktree and copies matching files (e.g., `.env`, IDE settings) that are
   gitignored but needed for the project.
2. Reads the `post_create` list and executes each command in the new worktree
   directory. Stops on first failure.

Safe to skip if there is no `.worktreerc.yml`/`.yaml` — the script handles that
gracefully.

### 3. Report Location

```text
Worktree ready at <full-path>
Branch: <branch> (<new branch|existing branch> based on <default_branch> at <base_sha>)
```

## Quick Reference

| Situation                           | Action                                             |
| ----------------------------------- | -------------------------------------------------- |
| Not on default branch               | Script returns `wrong_branch` — ask user to switch |
| Branch name has slashes             | Script sanitizes: replaces `/` with `-` in path    |
| `.worktreerc.yml`/`.yaml` exists    | Sync matching files and run post-create hooks      |
| `.worktreerc.yml`/`.yaml` not found | Sync and hooks skip gracefully (exit 0)            |
| Branch already exists               | Script checks out existing branch instead of `-b`  |
| Hook command fails                  | Stops immediately, reports which command failed    |

## Common Mistakes

### Creating worktree from non-default branch

- **Problem:** Worktree diverges from a stale base, not the latest mainline
- **Fix:** The setup script enforces this — handle `wrong_branch` status

## Red Flags

**Never:**

- Ignore `wrong_branch` or `error` status from the setup script
- Run git commands directly — the script handles all git operations
- Run `{SKILL_DIR}/scripts/worktree.py sync` with `python` directly — it requires `uv` for
  dependencies
- Run steps in parallel — each step depends on the previous one completing

**Always:**

- Use `{SKILL_DIR}/scripts/worktree.py create` for creation (handles branch verification +
  freshness)
- Run `{SKILL_DIR}/scripts/worktree.py setup` after creating the worktree