Dual Agent Development Environment

A collaborative development environment that pairs Claude Code (Anthropic) with Codex CLI (OpenAI, GPT-5.3) and ChatGPT Pro (GPT-5.2 Pro), enabling you to leverage the strengths of multiple AI models.

Why Multiple Agents?

Claude Code (Primary)	Codex CLI (GPT-5.3)	ChatGPT Pro (GPT-5.2)
Fast iteration & prototyping	Deep, thorough code review	Extended thinking for complex analysis
Planning & orchestration	Complex algorithm implementation	200k context for large codebases
Quick fixes & refactoring	Security vulnerability analysis	Second opinion on architecture
Context switching & multitasking	Meticulous edge case handling	Long-running deep reviews (5-30 min)

By combining multiple models, you get rapid development velocity with rigorous quality checks and diverse perspectives.

Prerequisites

• tmux - Terminal multiplexer
• Claude Code - Anthropic's CLI
• Codex CLI - OpenAI's CLI
• jq - JSON processor
• Node.js - For the MCP server

# macOS
brew install tmux jq node

# Claude Code & Codex CLI - follow their respective installation guides

Installation

git clone https://github.com/antorsae/dual-agent.git
cd dual-agent
./setup-dual-agent.sh

This will:

• Build the codex-delegate MCP server
• Install Claude skills to ~/.claude/skills/
• Install Codex skills to ~/.codex/skills/
• Configure Claude Code with MCP server and permissions
• Initialize the .agent-collab/ directory

---

Three Ways to Use

Option 1: MCP Tools (Recommended)

After running setup, Claude Code has Codex tools available directly. Just ask naturally:

You: Review src/auth.ts for security vulnerabilities using codex

You: Have codex implement a rate limiter for the API

You: Ask codex to review my migration plan

Available MCP Tools:

Tool	Description
delegate_codex_review	Code review (security, bugs, performance)
delegate_codex_implement	Implement features with Codex
delegate_codex_plan_review	Review implementation plans
delegate_codex	Send any custom prompt to Codex

Option 2: Tmux Dual-Pane

For interactive side-by-side work with both agents visible:

./start-dual-agent.sh

This opens a split tmux session with Claude (left) and Codex (right).

Skills:

Claude Skills	Codex Skills
/codex-review	$read-task
/codex-implement	$respond
/codex-plan-review	$claude-status
/codex-read
/codex-status

Option 3: ChatGPT Code Review (Chrome)

Use GPT-5.2 Pro via Claude Code's Chrome integration for deep, extended-thinking code reviews:

# Start Claude Code with Chrome integration
claude --chrome

Then ask naturally:

You: Review src/auth.ts with ChatGPT

You: Get GPT-5.2 Pro to review this migration plan

Prerequisites:

• Claude Code with --chrome flag
• Claude in Chrome extension (v1.0.36+)
• Logged into chat.com with ChatGPT Pro subscription

Workflow:

1. Claude submits the code review request to GPT-5.2 Pro
2. Returns immediately (non-blocking) - GPT-5.2 can take 5-30 minutes
3. Ask Claude to "fetch ChatGPT results" when ready

Skill: /chatgpt-code-review

---

Quick Start

MCP Tools (Simplest)

# 1. Run setup
./setup-dual-agent.sh

# 2. Restart Claude Code to load MCP tools
claude

# 3. Use naturally
> Review src/auth.ts for security issues using codex

Tmux Dual-Pane

# 1. Run setup
./setup-dual-agent.sh

# 2. Start dual-agent environment
./start-dual-agent.sh

# 3. In Claude pane, use skills
> /codex-review

---

Detailed Example: Security Review

Using MCP Tools

You: I just implemented authentication. Review src/auth.ts using codex
     for security vulnerabilities.

Claude: I'll use the delegate_codex_review tool to have Codex analyze this file...

[Claude calls delegate_codex_review tool]

Claude: Codex found the following issues:

## Critical Issues

1. **SQL Injection (Line 45)**
   The query uses string concatenation instead of parameterized queries.

   Fix:
   ```python
   cursor.execute("SELECT * FROM users WHERE id = ?", (user_id,))
   ```

2. **Weak Password Hashing (Line 78)**
   Using MD5 instead of bcrypt/argon2.

...

Using Tmux Dual-Pane

[Claude Pane]
You: Review src/auth.ts for security issues

Claude: I'll delegate this to Codex for a thorough security review.
        Delegating to Codex...

[Codex Pane - automatically receives task]
Codex: Reading task from Claude...
       Analyzing src/auth.ts for security vulnerabilities...
       [Deep analysis]
       Response ready.

[Claude Pane - automatically reads response]
Claude: Codex completed the review. Here are the findings:
        [Presents Codex's analysis]

---

Architecture

+-----------------------------------------------------------------------------------+
|                                    Claude Code                                    |
|                                                                                   |
|+-----------------------+  +-----------------------+  +---------------------------+|
||       MCP Tools       |  |     Skills (tmux)     |  |      Skills (Chrome)      ||
||   delegate_codex_*    |  |     /codex-review     |  |   /chatgpt-code-review    ||
|+-----------+-----------+  +-----------+-----------+  +-------------+-------------+|
+------------+--------------------------+----------------------------+--------------+
             |                          |                            |
             v                          v                            v
 +-----------------------+  +-----------------------+  +---------------------------+
 |    codex-delegate     |  |    .agent-collab/     |  |     Chrome + chat.com     |
 |      MCP Server       |  |   (file-based IPC)    |  |   (browser automation)    |
 |                       |  |                       |  |                           |
 |   Spawns codex CLI    |  |   requests/task.md    |  |   JavaScript injection    |
 +-----------+-----------+  +-----------+-----------+  +-------------+-------------+
             |                          |                            |
             v                          v                            v
 +-----------+--------------------------+-----------+  +-------------+-------------+
 |                Codex CLI (GPT-5.3)               |  |        GPT-5.2 Pro        |
 |                                                  |  |                           |
 |        Deep code review & Implementation         |  | Extended thinking (5-30m) |
 |         Security analysis & Plan review          |  |  200k context + analysis  |
 +--------------------------------------------------+  +---------------------------+

---

Configuration

Shared Context

Edit .agent-collab/context/shared.md to provide both agents with project context:

# Shared Project Context

## Project Overview
E-commerce platform using FastAPI + Redis + PostgreSQL

## Architecture Decisions
- All auth uses JWT with refresh rotation
- Redis for rate limiting and session storage

## Conventions
- Type hints required on all functions
- Pydantic models for all API schemas

Claude Settings

The setup script configures ~/.claude/settings.json with:

{
  "mcpServers": {
    "codex-delegate": {
      "command": "node",
      "args": ["/path/to/dual-agent/agent/dist/mcp.js"]
    }
  },
  "permissions": {
    "allow": [
      "Bash(cat .agent-collab:*)",
      "Bash(tmux send-keys:*)",
      ...
    ]
  }
}

---

Tmux Key Bindings

Keys	Action
Ctrl-b ←/→	Switch between Claude and Codex panes
Ctrl-b d	Detach from session
Ctrl-b z	Zoom current pane (fullscreen toggle)

---

Troubleshooting

MCP tools not available

1. Check the setup completed successfully:

   cat ~/.claude/settings.json | jq '.mcpServers'

2. Restart Claude Code:

   claude

Codex not receiving tasks (tmux mode)

1. Check tmux pane numbers: tmux list-panes
2. Ensure Codex is running in pane 1
3. Manually trigger: tmux send-keys -t 1 '$read-task' Enter

Status stuck (tmux mode)

echo "idle" > .agent-collab/status

Codex not working

# Verify codex is installed and authenticated
codex "hello"

---

Project Structure

dual-agent/
├── agent/                    # MCP server & CLI
│   ├── src/
│   │   ├── mcp.ts           # MCP server (delegate_codex_* tools)
│   │   ├── cli.ts           # CLI wrapper
│   │   └── codex.ts         # Codex subprocess spawner
│   └── dist/                # Compiled JS
├── .claude/skills/          # Claude Code skills
│   ├── codex-review/        # /codex-review (tmux mode)
│   ├── codex-implement/     # /codex-implement (tmux mode)
│   ├── codex-plan-review/   # /codex-plan-review (tmux mode)
│   ├── codex-read/          # /codex-read (tmux mode)
│   ├── codex-status/        # /codex-status (tmux mode)
│   └── chatgpt-code-review/ # /chatgpt-code-review (Chrome)
├── .codex/skills/           # Codex CLI skills
├── setup-dual-agent.sh      # Setup script
├── start-dual-agent.sh      # Tmux launcher
└── README.md

---

License

MIT