Parallel

/parallel -- Parallel Agent Orchestration via tmux + git Worktrees

Split a task into independent workstreams and run them as parallel Claude Code agents in separate tmux panes, each in its own git worktree.

Argument

Either a task description to plan and decompose, or the word "plan" to use the current plan from this conversation.

Procedure

Phase 1 -- Plan

If the argument is "plan": use the existing plan from the current conversation context.

Otherwise: create a plan for the given task. Identify what needs to be built, the modules involved, and the dependencies between them.

Phase 2 -- Decompose into Workstreams

Split the plan into 3-4 independent workstreams (hard maximum: 4).

Decomposition rules:

• Divide by domain/module, NOT by task type. Each agent owns a vertical slice (e.g., "auth module", "payment module"), not a horizontal layer (e.g., "write all tests", "write all implementations"). Horizontal decomposition causes 3-10x token waste because each agent must re-read the same context.
• Each agent owns its files exclusively. No two agents write to the same file. Shared dependencies are read-only for non-owning agents.
• If a workstream depends on another's output, mark it and sequence the launch accordingly.

Present the decomposition table and wait for user approval:

| Agent | Domain | Owned Files | Read-Only Files | Depends On |
|-------|--------|-------------|-----------------|------------|
| auth  | Authentication | src/auth/* | src/models/* | none |
| api   | API endpoints  | src/api/*  | src/auth/*   | auth |
| ui    | Frontend       | src/ui/*   | src/api/*    | none |

Do NOT proceed until the user approves this decomposition.

Phase 3 -- Setup Worktrees

For each agent in the approved decomposition:

git worktree add ./worktrees/{agent-name} -b parallel/{agent-name}

Add worktrees/ to .gitignore if not already present.

For each worktree:

# Copy environment files
cp .env ./worktrees/{agent-name}/.env 2>/dev/null || true
cp -r venv ./worktrees/{agent-name}/venv 2>/dev/null || true

# Create coordination directories
mkdir -p ./worktrees/{agent-name}/run
mkdir -p ./shared/progress

Install dependencies if needed:

cd ./worktrees/{agent-name} && source venv/bin/activate && uv pip install -e . 2>/dev/null || true

Phase 4 -- Generate Agent Prompts

For each agent, write ./worktrees/{agent-name}/run/prompt.md containing:

1. Scope: What this agent is responsible for building
2. File Ownership: Files this agent may create/modify (exclusive)
3. Read-Only Files: Files this agent may read but must not modify
4. Success Criteria: How to know when the work is done
5. Constraints:
   • Follow all CLAUDE.md conventions (copy relevant entries)
   • Add docstrings to all functions with algorithm in English
   • Expected schema for loose objects in docstrings
   • if __name__ == '__main__' blocks with hardcoded examples
   • No argparse, no emojis
   • Use uv pip install, source venv/bin/activate
6. Progress Tracking: Write status to ../shared/progress/{agent-name}.json after each major milestone using this format:

   {
     "agent": "{agent-name}",
     "timestamp": "ISO-8601",
     "status": "in_progress|blocked|done",
     "completed": ["list of completed items"],
     "remaining": ["list of remaining items"],
     "blocked_by": null,
     "notes": ""
   }
   

Phase 4.5 -- Create Launcher Script

Write ./run-agent.sh in the project root:

#!/bin/bash
# Usage: bash run-agent.sh /path/to/worktree [model]
# Pipes the agent prompt to claude -p with pre-approved tools.
# Writes output to run/output.md and prints a COMPLETE marker when done.
cd "$1"
source venv/bin/activate 2>/dev/null || true
MODEL="${2:-claude-sonnet-4-6}"
echo "=== Starting agent: $(basename $1) with model $MODEL ==="
echo "=== $(date) ==="
echo ""
cat run/prompt.md | claude -p \
  --model "$MODEL" \
  --allowedTools "Read,Write,Edit,Bash,Glob,Grep" \
  2>&1 | tee run/output.md
echo ""
echo "=== Agent $(basename $1) COMPLETE at $(date) ==="

Make it executable: chmod +x run-agent.sh

CRITICAL: Pipe the prompt via stdin (cat prompt.md | claude -p). NEVER pass the prompt content through tmux send-keys -- any quotes, backticks, $, backslashes, or newlines in the prompt will be shell-expanded or break the command. The launcher script avoids this entirely by keeping the prompt in a file and piping it.

Phase 5 -- Launch Agents

Create a tmux session and launch agents via the launcher script:

# Create session
tmux new-session -d -s parallel -x 200 -y 50

# First agent gets the first pane
tmux send-keys -t parallel "bash run-agent.sh $(pwd)/worktrees/{agent-1}" Enter

# Additional agents get split panes
tmux split-window -t parallel -h
tmux send-keys -t parallel "bash run-agent.sh $(pwd)/worktrees/{agent-2}" Enter

# Repeat for agents 3-4 if needed
tmux split-window -t parallel -v
tmux send-keys -t parallel "bash run-agent.sh $(pwd)/worktrees/{agent-3}" Enter

After launching, verify processes are running:

ps aux | grep "claude -p" | grep -v grep | wc -l

Print monitoring instructions for the user:

## Parallel Agents Running

Attach to the session:
  tmux attach -t parallel

Monitor progress:
  cat shared/progress/*.json | jq .

Switch between panes:
  Ctrl-b + arrow keys

Kill session when done:
  tmux kill-session -t parallel

Phase 5.5 -- Wait for Completion

Use the wait-for-text.sh helper from the /tmux skill to automatically detect when each agent finishes:

WAIT="$HOME/Developer/personal_projects/agent-skills/skills/tmux/scripts/wait-for-text.sh"
TIMEOUT=600  # 10 minutes per agent; adjust as needed

all_done=true
for pane_id in {list of parallel:0.N targets}; do
  agent_name="{name for this pane}"
  if bash "$WAIT" -t "$pane_id" -p "COMPLETE" -T "$TIMEOUT" -i 5; then
    echo "$agent_name: DONE"
  else
    echo "$agent_name: TIMED OUT or FAILED -- check pane manually"
    all_done=false
  fi
done

if $all_done; then
  echo "All agents complete. Ready to merge."
else
  echo "Some agents did not finish. Check timed-out panes before merging."
fi

The loop watches for the COMPLETE marker that run-agent.sh prints when claude -p exits. Each agent gets the full timeout before moving to the next check.

You can also manually check progress via cat shared/progress/*.json.

Phase 6 -- Merge Strategy

After all agents report "done", provide merge commands:

# Merge each agent branch with --no-ff to preserve history
git merge --no-ff parallel/{agent-1} -m "Merge {agent-1}: {description}"
git merge --no-ff parallel/{agent-2} -m "Merge {agent-2}: {description}"
git merge --no-ff parallel/{agent-3} -m "Merge {agent-3}: {description}"

Conflict resolution guidance:

• If two agents touched the same file despite ownership rules, the owning agent's version wins
• For shared config files (package.json, pyproject.toml), merge both sets of changes manually
• Run the full test suite after each merge

Cleanup commands:

# Remove worktrees
git worktree remove ./worktrees/{agent-1}
git worktree remove ./worktrees/{agent-2}
git worktree remove ./worktrees/{agent-3}

# Delete branches
git branch -d parallel/{agent-1}
git branch -d parallel/{agent-2}
git branch -d parallel/{agent-3}

# Remove shared progress
rm -rf ./shared/progress/

Troubleshooting

Check agent status Run the health-check recipe from /tmux to classify every pane:

DIAG="$HOME/Developer/personal_projects/agent-skills/skills/tmux/scripts/diagnose-agents.sh"
bash "$DIAG" parallel "worktrees/*/run/output.md"

Each pane is classified as DONE, WORKING, FAILED, or UNKNOWN. See the /tmux skill's "Health-Check Running Agents" recipe for details on what each state means and how it's detected.

FAILED state -- what to do Inspect the pane for the root cause:

tmux capture-pane -t parallel:0.{pane} -p -S - | tail -30

Common causes: rate limit hit, permission denial (missing --allowedTools), Python/Node traceback, or OOM. Fix the cause and re-launch the agent (see below).

DONE but no run/output.md This is a tee buffering issue. The agent finished (COMPLETE marker present in the pane) but the file wasn't flushed. Capture the pane scrollback directly:

tmux capture-pane -t parallel:0.{pane} -p -S - > worktrees/{agent}/run/output.md

Re-running a single failed agent Send the launcher command to the same pane:

tmux send-keys -t parallel:0.{pane} "bash run-agent.sh $(pwd)/worktrees/{agent-name}" Enter

The previous output.md will be overwritten by tee.

tmux session died Re-create the session (Phase 5). Run diagnose-agents.sh or check which agents have the COMPLETE marker in their run/output.md. Only re-launch agents that didn't complete. Completed agents already committed their work to their worktree branch.

Worktree in a bad state after agent crash Check the branch for partial commits: cd worktrees/{agent} && git log --oneline -5. If the agent made useful partial progress, you can keep the branch and re-launch to continue. If the state is unrecoverable:

git worktree remove ./worktrees/{agent-name}
git branch -D parallel/{agent-name}

Then re-create the worktree (Phase 3) and re-launch.

Merge conflicts during Phase 6 If agents violated file ownership rules and both modified the same file, the owning agent's version wins. Use git checkout --theirs {file} or git checkout --ours {file} accordingly. Run tests after each merge.

Important

• Maximum 3-4 parallel agents. More than 4 has diminishing returns and burns credits rapidly.
• Always decompose by domain/module, never by task type.
• Always wait for user approval of the decomposition before creating worktrees.
• Each agent MUST have exclusive file ownership. Overlapping writes guarantee merge conflicts and wasted work.
• Do not launch agents for tasks that have sequential dependencies. If B depends on A's output, A must finish first.