Fork Session

Fork the current session, carrying context for continuity.

Usage

/fork <branch>                     # Default: open new terminal tab with interactive claude
/fork <branch> --base <ref>        # Fork from a specific base branch/ref
/fork <branch> --move              # Move this session into the worktree
/fork <branch> --team              # Spawn a coordinated teammate in the worktree
/fork <branch> --background        # Spawn autonomous fire-and-forget agent
/fork --local                      # Write handoff for manual pickup
/fork <branch> --dry-run              # Preview what would happen without creating anything

Modes

Critical: Invoking wt

wt is a shell function loaded by .zshrc. It is NOT available in Claude Code's Bash tool. Always invoke the script directly:

WT_SCRIPT="$HOME/.claude/skills/git-worktree/scripts/wt.sh"
bash "$WT_SCRIPT" <branch> [options]

Never use bare wt, $_WT_SCRIPT, or source wt.zsh. These all fail in non-interactive shells.

Instructions

Step 1: Determine Mode and Options

Check the user's input:

Options (combine with any worktree mode):

• --base <ref> — Create the worktree from a specific branch, tag, or commit instead of main. Passed through to wt as --base <ref>.
• --dry-run — Preview what would happen (worktree path, mode, base branch, handoff size) without creating anything. Compatible with all modes.

Step 1.5: Pre-flight Checks (all worktree modes)

Skip this step for --local mode.

Before generating the handoff, verify prerequisites:

1. Git repo check:

   git rev-parse --git-dir 2>/dev/null
   

   If this fails → tell user "Not in a git repository. Use /fork --local for non-git contexts."

2. wt.sh available:

   test -x "$HOME/.claude/skills/git-worktree/scripts/wt.sh"
   

   If missing → tell user: "git-worktree skill not installed. Install it or use /fork --local."

3. Branch collision:

   REPO_NAME=$(basename "$(git remote get-url origin 2>/dev/null || basename "$(git rev-parse --show-toplevel)")" .git)
   test -d "$HOME/.worktrees/$REPO_NAME/<branch>"
   

   If exists → ask: "Worktree <branch> already exists. Resume with wt cd <branch>, or pick a different name?"

4. claude CLI (for --open and --background modes only):

   command -v claude
   

   If missing → fall back to --local mode and explain why.

If all checks pass, proceed silently. Only report failures.

Step 1.7: Dry Run (if --dry-run)

If --dry-run was specified, report what would happen and stop:

Run the same pre-flight checks from Step 1.5, plus gather additional info, then report:

# Determine values for the report
REPO_NAME=$(basename "$(git remote get-url origin 2>/dev/null || basename "$(git rev-parse --show-toplevel)")" .git)
WORKTREE_PATH="$HOME/.worktrees/$REPO_NAME/<branch>"

# Branch existence
if [ -d "$WORKTREE_PATH" ]; then
  BRANCH_STATUS="yes — would reuse existing worktree"
else
  BRANCH_STATUS="no — would create new branch from $BASE"
fi

# Uncommitted changes
DIRTY_COUNT=$(git status --porcelain 2>/dev/null | wc -l | tr -d ' ')

# claude CLI
CLAUDE_AVAILABLE=$(command -v claude >/dev/null 2>&1 && echo "available" || echo "NOT available — would fall back to --local")

Print the report:

Dry run for `/fork <branch>`:
  Mode: {terminal|move|team|background}
  Worktree: {WORKTREE_PATH}
  Base: {base_branch}
  Branch exists: {BRANCH_STATUS}
  Uncommitted changes: {DIRTY_COUNT} files would be carried as patch
  claude CLI: {CLAUDE_AVAILABLE}
  Terminal: {TERM_PROGRAM or "Terminal"} (for --open/--launch-cmd)
  All pre-flight checks passed ✓

Do not create the worktree, handoff, or spawn any agents. Return after printing the report.

Step 2: Generate Context Summary

Create a handoff document summarizing:

1. Current Task - what we're working on
2. Progress - what's been done so far
3. Git State - current branch, dirty files, recent commits
4. Key Decisions - important choices made
5. Next Steps - what the new session should tackle
6. Relevant Files - files we've been working with
7. Open Questions - unresolved issues
8. When Done - how to merge back and clean up

Use this template:

# Session Handoff

## Current Task
{Brief description of what we're working on}

## Progress
- {What's been completed}
- {What's in progress}

## Git State
- Source branch: `{current branch}`
- Base for fork: `{base_branch or "main"}`
- Dirty files: {list of modified/untracked files, or "clean"}
- Recent commits (last 3):
  - `{short hash}` {message}
  - `{short hash}` {message}
  - `{short hash}` {message}

## Key Decisions
| Decision | Choice | Why |
|----------|--------|-----|
| {topic} | {choice} | {rationale} |

## Next Steps
1. {Immediate next action}
2. {Following action}

## Relevant Files
- `path/to/file.ts` - {why it matters}

## Open Questions
- {Unresolved question or blocker}

## When Done
1. Commit your work with conventional commits
2. Apply to main: `wt apply --push --archive`
3. Or return to parent: `cd {original_path}`

---
*Forked from `{repo}@{branch}` on {date}*
*Parent directory: `{original_path}`*

Step 3: Capture Uncommitted Changes (all worktree modes)

Before creating the worktree, check for uncommitted changes and save them as a patch. The worktree is created from a clean base — changes don't travel automatically.

# Check for changes
PATCH=""
if ! git diff --quiet HEAD 2>/dev/null || ! git diff --cached --quiet 2>/dev/null; then
    PATCH=$(mktemp)
    git diff HEAD > "$PATCH"
fi

Skip this step if there are no changes to carry.

Step 4: Create Worktree + Transition

All worktree modes use wt.sh directly. Determine the repo name for the worktree path:

WT_SCRIPT="$HOME/.claude/skills/git-worktree/scripts/wt.sh"
REPO_NAME=$(basename "$(git remote get-url origin 2>/dev/null || basename "$(git rev-parse --show-toplevel)")" .git)

Terminal mode (default)

HANDOFF=$(mktemp)
cat > "$HANDOFF" << 'EOF'
{generated handoff content}
EOF

bash "$WT_SCRIPT" <branch> --no-editor --context "$HANDOFF" --open  # add --base <ref> if specified

The --open flag opens a new terminal tab in the worktree with an interactive claude session. Since --context places a handoff file, --open automatically tells claude to read it.

Move mode

Move mode uses Claude Code's EnterWorktree tool, which is the only way to actually relocate the session's working directory. The Bash tool resets cwd after every call — cd does not persist.

HANDOFF=$(mktemp)
cat > "$HANDOFF" << 'EOF'
{generated handoff content}
EOF

bash "$WT_SCRIPT" <branch> --no-editor --context "$HANDOFF"  # add --base <ref> if specified

After the worktree is created:

1. Apply the patch if changes were captured:

WORKTREE_PATH="$HOME/.worktrees/$REPO_NAME/<branch>"
if [ -n "$PATCH" ] && [ -s "$PATCH" ]; then
    git -C "$WORKTREE_PATH" apply "$PATCH"
    rm "$PATCH"
fi

2. Restore the original working directory to clean state:

git checkout -- .

3. Use EnterWorktree tool to switch the session:

EnterWorktree(name: "<branch>")

Note: EnterWorktree creates its own worktree in .claude/worktrees/. If you already created one with wt.sh, the session will have two worktrees. To avoid this, you can skip wt.sh and use only EnterWorktree — but you lose --base, --context, and conductor setup. Choose based on what the session needs:

• Needs --base, conductor, or --context: Use wt.sh, then work via absolute paths (don't use EnterWorktree). Set WT_PATH and prefix all subsequent file operations with it.
• Just needs session relocation: Skip wt.sh, use EnterWorktree directly.

When using absolute paths without EnterWorktree:

WT_PATH="$HOME/.worktrees/$REPO_NAME/<branch>"
# All subsequent Read/Edit/Write calls use $WT_PATH/path/to/file

Tell the user: "Working in ~/.worktrees/<repo>/<branch> via absolute paths. All file operations target the worktree."

Team mode

HANDOFF=$(mktemp)
cat > "$HANDOFF" << 'EOF'
{generated handoff content}
EOF

bash "$WT_SCRIPT" <branch> --no-editor --context "$HANDOFF"  # add --base <ref> if specified

# Apply patch if changes were captured
WORKTREE_PATH="$HOME/.worktrees/$REPO_NAME/<branch>"
if [ -n "$PATCH" ] && [ -s "$PATCH" ]; then
    git -C "$WORKTREE_PATH" apply "$PATCH"
fi

After the worktree is created:

1. Create or reuse team:

TeamCreate(team_name: "fork-<branch>", description: "Forked work: <branch>")

2. Create task from handoff:

TaskCreate(
  subject: "<task from handoff Next Steps>",
  description: "<full handoff content>",
  activeForm: "Working on <branch>"
)

3. Spawn teammate in worktree:

Task(
  team_name: "fork-<branch>",
  name: "<branch>-worker",
  subagent_type: "general-purpose",
  prompt: "You are working in a forked worktree at ~/.worktrees/<repo>/<branch>.
    Use absolute paths for all file operations.
    Read .context/handoff.md at that path for full context.

    Work through the task list (TaskList). Update tasks as you progress (TaskUpdate).
    When blocked or done, message the team lead via SendMessage.
    Commit changes with conventional commits."
)

4. Assign task to teammate:

TaskUpdate(taskId: "<id>", owner: "<branch>-worker", status: "in_progress")

The main session stays active. Teammate messages arrive automatically when idle. The user can:

• Check progress: TaskList
• Send instructions: SendMessage to <branch>-worker
• Shut down: SendMessage(type: "shutdown_request", recipient: "<branch>-worker")

Rollback on failure:

If any step above fails, clean up what was created:

Report what happened: "Fork to <branch> failed at [step]. Cleaned up [resources]. Worktree exists at ~/.worktrees/<repo>/<branch> — you can use it manually."

Background mode

HANDOFF=$(mktemp)
cat > "$HANDOFF" << 'EOF'
{generated handoff content}
EOF

bash "$WT_SCRIPT" <branch> --no-editor --context "$HANDOFF"  # add --base <ref> if specified

# Apply patch if changes were captured
WORKTREE_PATH="$HOME/.worktrees/$REPO_NAME/<branch>"
if [ -n "$PATCH" ] && [ -s "$PATCH" ]; then
    git -C "$WORKTREE_PATH" apply "$PATCH"
fi

After the worktree is created, run claude in the background with structured logging:

All paths must be absolute (use $HOME, not ~). WORKTREE_PATH is built from $HOME so LOG_DIR inherits that.

WORKTREE_PATH="$HOME/.worktrees/$REPO_NAME/<branch>"  # absolute via $HOME
LOG_DIR="$WORKTREE_PATH/.context"
mkdir -p "$LOG_DIR"

cd "$WORKTREE_PATH" && \
  claude --print 'Read .context/handoff.md and complete the work described there. Commit with conventional commits.' \
  > "$LOG_DIR/fork.log" 2>&1 &
FORK_PID=$!
echo "$FORK_PID" > "$LOG_DIR/fork.pid"

# Write completion marker when done
(wait $FORK_PID; echo $? > "$LOG_DIR/fork.exit") &

Use run_in_background: true on the Bash tool call.

Local mode

mkdir -p .context
cat > .context/handoff.md << 'EOF'
{generated handoff content}
EOF

No worktree created. User opens a new terminal and runs claude.

Step 5: Confirm

Mode-specific confirmation messages:

• Terminal: "Forked to <branch>. New terminal tab opened with interactive Claude session. Handoff at ~/.worktrees/<repo>/<branch>/.context/handoff.md."
• Move: "Moved into worktree <branch>. To return: cd <original_path>" (or if using absolute paths: "Working in ~/.worktrees/<repo>/<branch> via absolute paths.")
• Team: "Forked to <branch>. Teammate <branch>-worker is working in the worktree. Messages will arrive here when they need input or finish."
• Background: "Forked to <branch>. Background agent running (PID in .context/fork.pid).
  • Monitor: tail -f ~/.worktrees/<repo>/<branch>/.context/fork.log
  • Check status: test -f ~/.worktrees/<repo>/<branch>/.context/fork.exit && cat it
  • Kill: kill $(cat ~/.worktrees/<repo>/<branch>/.context/fork.pid)"
• Local: "Context written to .context/handoff.md. Open a new terminal here and run claude."

If --base was used, include it in the confirmation: "Based on <ref>."

Examples

Terminal Fork (default)

User: /fork feature-dark-mode

Claude: I'll fork this session to a new worktree with an interactive Claude session.

[Generates handoff summary]
[Runs: bash $WT_SCRIPT feature-dark-mode --no-editor --context /tmp/handoff.md --open]

Forked to `feature-dark-mode`. New terminal tab opened with interactive Claude session.
Handoff at ~/.worktrees/dotclaude/feature-dark-mode/.context/handoff.md

Move with uncommitted changes

User: /fork fix-timeout --move

Claude: I'll fork and move this session into the worktree, carrying your changes.

[Captures git diff as patch]
[Runs: bash $WT_SCRIPT fix-timeout --no-editor --context /tmp/handoff.md]
[Applies patch in worktree]
[Restores original working directory]
[Works via absolute paths to ~/.worktrees/myapp/fix-timeout/]

Moved into worktree `fix-timeout`. Working via absolute paths.
Changes from main applied. To return: work in /original/path.

Fork from a specific base

User: /fork fix-auth-bug --base release/v2.1

[Runs: bash $WT_SCRIPT fix-auth-bug --base release/v2.1 --no-editor --context /tmp/handoff.md --open]

Forked to `fix-auth-bug` based on `release/v2.1`. New terminal tab opened.

Team Fork

User: /fork feature-auth --team

[Creates worktree, applies any patches, creates team, spawns teammate]

Forked to `feature-auth`. Teammate `feature-auth-worker` is working in the worktree.
Messages will arrive here when they need input or finish.

Local Fork

User: /fork --local

[Writes to .context/handoff.md]

Context written to `.context/handoff.md`.
Open a new terminal here and run `claude`.

Troubleshooting

Notes

• Worktree naming: <repo> is derived from git remote get-url origin (e.g., ~/.claude with remote dotclaude.git → ~/.worktrees/dotclaude/<branch>)
• Requires: git-worktree skill for all modes except --local
• The handoff is a snapshot — it won't update if you continue working here
• Use /chronicle if you want persistent cross-session memory instead
• Worktree mode runs setup scripts from conductor.json if present
• Terminal mode uses wt --open which requires macOS (osascript)
• --base defaults to main if not specified (same as wt default)