Launch GTR Issue Worktree

Set up an isolated worktree for a GitHub issue with full context injection.

Workflow

1. Parse Input

Extract the issue number from user input. Accept formats:

• 42, #42, issue 42

2. Fetch Issue

gh issue view <NUMBER> --json number,title,body,labels,assignees

If the command fails, check:

• gh auth status for authentication
• Whether the issue number exists

3. Derive Branch Name

Convert issue title to a branch name:

• Format: issue-<NUMBER>-<slugified-title>
• Slugify: lowercase, replace spaces/special chars with -, truncate to 50 chars
• Example: Issue #42 "Add user authentication" -> issue-42-add-user-authentication

4. Create Worktree

git gtr new <branch-name>

If gtr is not installed, show install instructions:

brew tap coderabbitai/tap && brew install git-gtr

Capture the worktree path from gtr output or derive it:

git gtr go <branch-name>

5. Generate ToDo Checklist

Analyze the issue body and generate a checklist of actionable tasks.

Rules:

• Parse the issue body to identify concrete, actionable steps
• Each task should be a single, verifiable action (not vague)
• Format as GitHub-flavored markdown checkboxes: - [ ] task description
• Typically 3-7 items depending on issue complexity
• Include setup/preparation steps if needed
• End with a verification/confirmation step

Example output:

## ToDo

- [ ] Set up environment / prerequisites
- [ ] Implement core feature
- [ ] Test the feature works as expected
- [ ] Document findings or observations

6. Update Issue Description

Append the generated ToDo checklist to the issue body on GitHub:

# Get current issue body
CURRENT_BODY=$(gh issue view <NUMBER> --json body -q .body)

# Append ToDo section (only if no checklist exists yet)
# Check: if body already contains "- [ ]" or "- [x]", skip this step
NEW_BODY="${CURRENT_BODY}

## ToDo

- [ ] task 1
- [ ] task 2
..."

gh issue edit <NUMBER> --body "$NEW_BODY"

Important:

• Do NOT overwrite existing content — always append
• If the issue body already contains a checklist (- [ ] or - [x]), skip this step and reuse the existing checklist
• Preserve all original markdown formatting

7. Ensure CLAUDE.local.md is in .gitignore

Before writing CLAUDE.local.md, ensure it is listed in the worktree's .gitignore.

WORKTREE_PATH="$(git gtr go <branch-name>)"
if ! grep -q 'CLAUDE.local.md' "$WORKTREE_PATH/.gitignore" 2>/dev/null; then
  echo -e '\n# Worktree用ローカルコンテキスト\nCLAUDE.local.md' >> "$WORKTREE_PATH/.gitignore"
fi

This prevents CLAUDE.local.md from being accidentally committed. Also add to the main repo's .gitignore if not already present:

MAIN_GITIGNORE="$(git rev-parse --show-toplevel)/.gitignore"
if ! grep -q 'CLAUDE.local.md' "$MAIN_GITIGNORE" 2>/dev/null; then
  echo -e '\n# Worktree用ローカルコンテキスト\nCLAUDE.local.md' >> "$MAIN_GITIGNORE"
fi

8. Generate CLAUDE.local.md

Write CLAUDE.local.md in the worktree root directory using the template at assets/worktree-claude-md.template.

Replace placeholders:

• {{NUMBER}} -> issue number
• {{TITLE}} -> issue title
• {{BODY}} -> issue body (the updated body including ToDo checklist)
• {{LABELS_SECTION}} -> formatted labels list, or empty string if none
• {{TODO_SECTION}} -> the ToDo checklist (same one added to the issue)

Important: Write to CLAUDE.local.md (project root), NOT .claude/CLAUDE.md. CLAUDE.local.md is automatically loaded by Claude Code and is excluded via .gitignore (ensured in step 7), so it won't cause merge conflicts when PRs from different worktrees are merged.

9. Report Completion

Show the user:

• Worktree path
• Branch name
• ToDo items added to the issue
• How to start working: git gtr ai <branch-name> or cd "$(git gtr go <branch-name>)" && claude