Claude Code Multi-Agent (Part 2): Automation, Communication, and Hands-On Example

This post covers automation scripts, inter-agent communication strategies, a full-stack hands-on example, and an FAQ for the Multi-Agent environment.

For the Multi-Agent concept, core tools (tmux, git worktree), and practical setup, see Part 1.

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Chapter 4. Automation Scripts

Summary

Manually setting up worktrees and tmux every time is tedious. Preparation/cleanup can be automated with shell scripts.

4.1 Multi-Agent Start Script

#!/bin/bash
# multi-agent-start.sh
# Usage: ./multi-agent-start.sh /path/to/project

PROJECT_DIR="${1:-.}"
cd "$PROJECT_DIR" || exit 1

echo "=== Preparing Multi-Agent environment ==="

# 1. Create worktrees
git worktree add ../wt-fe -b agent/frontend 2>/dev/null || echo "worktree-fe already exists"
git worktree add ../wt-be -b agent/backend 2>/dev/null || echo "worktree-be already exists"
git worktree add ../wt-test -b agent/test 2>/dev/null || echo "worktree-test already exists"

echo "worktrees created:"
git worktree list

# 2. Create tmux session and split panes
tmux new-session -d -s multi-agent -c ../wt-fe
tmux split-window -h -t multi-agent -c ../wt-be
tmux split-window -h -t multi-agent -c ../wt-test

# 3. Label each pane
tmux send-keys -t multi-agent:0.0 'echo "=== Frontend Agent ===" && claude' Enter
tmux send-keys -t multi-agent:0.1 'echo "=== Backend Agent ===" && claude' Enter
tmux send-keys -t multi-agent:0.2 'echo "=== Test Agent ===" && claude' Enter

# 4. Attach to session
tmux attach -t multi-agent

echo "=== Done ==="

Run:

chmod +x multi-agent-start.sh
./multi-agent-start.sh ~/my-project

4.2 Multi-Agent Cleanup Script

#!/bin/bash
# multi-agent-cleanup.sh
# Usage: ./multi-agent-cleanup.sh /path/to/project

PROJECT_DIR="${1:-.}"
cd "$PROJECT_DIR" || exit 1

echo "=== Cleaning up Multi-Agent environment ==="

# 1. Kill tmux session
tmux kill-session -t multi-agent 2>/dev/null && echo "tmux session killed"

# 2. Remove worktrees
git worktree remove ../wt-fe 2>/dev/null && echo "wt-fe removed"
git worktree remove ../wt-be 2>/dev/null && echo "wt-be removed"
git worktree remove ../wt-test 2>/dev/null && echo "wt-test removed"

# 3. Prune worktree leftovers
git worktree prune

echo "=== Cleanup complete ==="
echo "Remaining branches (delete if needed):"
git branch --list "agent/*"

Section Summary

• Automate repetitive work with start/cleanup scripts
• multi-agent-start.sh: worktree creation + tmux split + claude execution in one go
• multi-agent-cleanup.sh: tmux shutdown + worktree removal + leftover cleanup

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Chapter 4 Summary

Script	Role
multi-agent-start.sh	Create worktrees -> split tmux -> run claude
multi-agent-cleanup.sh	Kill tmux -> remove worktrees -> clean leftovers

Key terms: automation, shell script, tmux send-keys

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Chapter 5. Inter-Agent Communication Strategies

Summary

Agents working in parallel sometimes need to know each other’s progress. Two methods: file-based communication (WORK_LOG.md) and branch-based communication (merge).

5.1 WORK_LOG.md — File-Based Communication

Each agent records its work into a shared file.

# WORK_LOG.md

## [Frontend Agent] 2026-03-13 10:30
- src/pages/Login.tsx created
- LoginForm component will call POST /api/login
- **To Backend Agent**: Please make /api/login response shape { token: string, user: object }

## [Backend Agent] 2026-03-13 10:45
- POST /api/login implemented in backend/api/auth.py
- Response shape: { "token": "jwt...", "user": { "id": 1, "name": "..." } }
- **To Frontend Agent**: Integrate using the shape above

Editing the same file concurrently can cause conflicts. Operate WORK_LOG.md as append only (only add at the bottom).

5.2 Communication via a Shared Branch

When one agent’s work output needs to be referenced by another:

# In the Backend Agent's worktree
cd ~/wt-be

# Pull the latest Frontend code
git fetch origin
git merge agent/frontend

5.3 Orchestrator Pattern

A pattern where a human or a separate Claude session manages the overall work.

graph TD
    O["Orchestrator\n(separate tmux pane or human)"]
    O -- "Distribute work" --> FE["FE Agent\n(executor)"]
    O -- "Distribute work" --> BE["BE Agent\n(executor)"]
    O -- "Distribute work" --> TE["Test Agent\n(executor)"]
    FE -- "Report result" --> O
    BE -- "Report result" --> O
    TE -- "Report result" --> O

    O -.- R["Role:\n- Task distribution\n- Progress check (WORK_LOG.md, git log)\n- Conflict resolution\n- Quality control (review)"]

    style O fill:#f3e5f5,stroke:#6a1b9a
    style FE fill:#e3f2fd,stroke:#1565c0
    style BE fill:#e8f5e9,stroke:#2e7d32
    style TE fill:#fff3e0,stroke:#e65100
    style R fill:#fafafa,stroke:#bdbdbd

Section Summary

• WORK_LOG.md for async message exchange between agents (append only)
• Use git merge to pull code from another agent
• An Orchestrator distributing and integrating work is the most stable approach

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Chapter 5 Summary

Communication	Suitable When	Caveats
WORK_LOG.md	Sharing API interfaces, progress updates	Operate as append only
git merge	When another agent’s code is required	Conflicts possible
Orchestrator	Managing overall work	Human or separate agent

Key terms: WORK_LOG.md, append only, Orchestrator, branch merge

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Chapter 6. Hands-On Example: Building a Full-Stack Login Feature

Summary

A step-by-step scenario for developing a login feature in parallel with 3 agents.

6.1 Scenario

Goal: Implement login (Frontend + Backend + Test)
Estimated time: single agent 30 min -> Multi-Agent 10-15 min

6.2 Full Command Flow

# === 1. Prepare ===
cd ~/login-project
git worktree add ../wt-fe -b agent/frontend
git worktree add ../wt-be -b agent/backend
git worktree add ../wt-test -b agent/test

tmux new -s login-dev

# === 2. Split panes and run each agent ===
# (Pane 1) cd ~/wt-fe && claude
# (Pane 2) cd ~/wt-be && claude
# (Pane 3) cd ~/wt-test && claude

# === 3. Give each agent a task ===
# Pane 1: "Build the login page UI with React + TailwindCSS."
# Pane 2: "Build a POST /api/login JWT auth API with FastAPI."
# Pane 3: "Write unit tests for existing utils/ functions."

# === 4. After all agents complete, integrate ===
cd ~/login-project
git merge agent/frontend --no-edit
git merge agent/backend --no-edit
git merge agent/test --no-edit

# === 5. Clean up ===
git worktree remove ../wt-fe
git worktree remove ../wt-be
git worktree remove ../wt-test
git branch -d agent/frontend agent/backend agent/test
tmux kill-session -t login-dev

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Chapter 6 Summary

Step	Estimated Time	Task
Prepare	1 min	Set up worktrees + tmux
Parallel run	10 min	3 agents work simultaneously
Integrate	2 min	Branch merges
Clean up	1 min	Remove worktrees/branches

Key terms: parallel development, branch integration, full stack

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Chapter 7. Frequently Asked Questions (FAQ)

Q: What happens if agents modify each other’s files?

Since they are isolated via worktrees, no real-time conflicts occur. However, if the same file was modified at merge time, a git conflict may arise. Specify assigned directories in CLAUDE.md to prevent this.

Q: How many agents can run concurrently?

There is no technical limit, but practically 2–4 is reasonable. Reasons:

# of agents	Characteristics
2	Easy to manage, the most common config (FE + BE)
3	FE + BE + Test, balanced setup
4+	Increased orchestrator load, more complex merges

Q: Will I hit API rate limits?

Claude Code makes independent API calls per session. With many concurrent sessions you may hit rate limits, so check the concurrent-request limit for your plan.

Q: Does this work on Windows?

• WSL2: both tmux + git worktree work (recommended)
• PowerShell: use Windows Terminal tabs instead of tmux; git worktree still works
• Git Bash: tmux is not supported; open multiple terminals instead

Q: Can I create a worktree from an existing branch?

# Check out an existing branch without -b
git worktree add ../wt-fe agent/frontend

Omitting -b uses an existing branch instead of creating a new one.

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[Appendix A] Command Summary

Command	Description
git worktree add ../path -b branch	Create new worktree + branch
git worktree add ../path branch	Create worktree from existing branch
git worktree list	List worktrees
git worktree remove ../path	Remove worktree
git worktree prune	Clean up worktree references
tmux new -s name	Create tmux session
tmux attach -t name	Reattach to session
Ctrl+b %	Horizontal pane split
Ctrl+b "	Vertical pane split
Ctrl+b d	Detach (keep session)

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[Appendix B] Comparison of Composition Patterns

Pattern	# of agents	Suitable for
Solo	1	Small work, single feature
Pair	2	FE + BE, code + tests
Trio	3	FE + BE + Test/Docs
Squad	4+	Large features, microservices