Claude-Codex Duo

Claude codes. Codex reviews. Better code together.

A simple library for duo peer programming between Claude Code and Codex. Two AI coding assistants working together to write better code.

Why Use Both?

Claude	Codex
Superior tool calling & code generation	Excellent at catching bugs & edge cases
Great at understanding context	Strong code review capabilities
Creative problem solving	Thorough analysis

Together, they create a peer programming experience that's greater than either alone.

Quick Start

Prerequisites

• Python 3.10+
• Claude Code CLI installed
• Codex CLI installed

Installation

pip install claude-codex-duo

Or install from source:

git clone https://github.com/Sigma5C-Corp/claude-codex-duo
cd claude-codex-duo
pip install -e .

Basic Usage

from claude_codex_duo import create_session, Verdict

# Create a peer programming session
session = create_session("auth_feature", "Implement user authentication")

# Claude submits code for review
session.submit_code("""
def authenticate(username: str, password: str) -> bool:
    user = get_user(username)
    if user and verify_password(password, user.password_hash):
        return True
    return False
""")

# Wait for Codex's review
exchange = session.wait_for_review(timeout=120)

if exchange and exchange.verdict == Verdict.APPROVED:
    print("Consensus reached! Code approved.")
else:
    print(f"Feedback: {exchange.codex_review}")

How It Works

┌─────────────────────────────────────────────────────────────────┐
│                                                                 │
│    ┌──────────┐                           ┌──────────┐         │
│    │  Claude  │  ───── submits code ────► │  Codex   │         │
│    │  (coder) │                           │(reviewer)│         │
│    └──────────┘  ◄──── sends review ───── └──────────┘         │
│         │                                       │               │
│         │          ┌─────────────┐              │               │
│         └─────────►│   Session   │◄─────────────┘               │
│                    │   (files)   │                              │
│                    └─────────────┘                              │
│                                                                 │
│    Round 1: Claude writes → Codex reviews → Feedback           │
│    Round 2: Claude fixes  → Codex reviews → Approved!          │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

1. Claude writes code - Implements the task
2. Codex reviews - Checks for bugs, edge cases, best practices
3. Iterate - Claude addresses feedback, Codex re-reviews
4. Consensus - When Codex approves, the code is ready

All communication happens via file-based messaging (no database needed).

API Reference

create_session(session_id, task, workspace=None, max_rounds=10)

Create a new peer programming session.

session = create_session(
    "my_session",           # Unique session ID
    "Build a REST API",     # Task description
    workspace="/path/to/project",
    max_rounds=5
)

DuoSession.submit_code(content, files_modified=None)

Submit code from Claude for Codex review.

session.submit_code(
    "def hello(): return 'world'",
    files_modified=["src/utils.py"]
)

DuoSession.wait_for_review(timeout=300)

Wait for Codex's review response.

exchange = session.wait_for_review(timeout=120)
if exchange:
    print(f"Verdict: {exchange.verdict}")
    print(f"Feedback: {exchange.codex_review}")

Session Status

session.status        # SessionStatus.ACTIVE, REVIEWING, CONSENSUS, etc.
session.has_consensus # True if approved
session.is_complete   # True if done (approved or max rounds)
session.current_round # Current review round number

Configuration

Set the data directory via environment variable:

export CLAUDE_CODEX_DUO_DATA=~/.my-duo-data

Default: ~/.claude-codex-duo/

Session files are stored in:

~/.claude-codex-duo/
└── sessions/
    └── my_session/
        ├── session.json       # Session state
        ├── claude_inbox.json  # Messages for Claude
        ├── codex_inbox.json   # Messages for Codex
        └── conversation.jsonl # Full history

Advanced Usage

Manual Provider Control

from claude_codex_duo import ClaudeProvider, CodexProvider

# Direct Claude interaction
claude = ClaudeProvider(workspace="/my/project")
response = claude.execute("Write a function to validate emails")

# Direct Codex interaction
codex = CodexProvider(model="o3", reasoning_effort="high")
review = codex.execute(codex.review_prompt(code, task))
verdict = codex.extract_verdict(review)

Load Existing Session

from claude_codex_duo import load_session

session = load_session("my_session")
print(f"Round {session.current_round} of {session.max_rounds}")

Requirements

• Python 3.10+
• Unix-like OS (uses fcntl for file locking)
• Claude Code CLI
• Codex CLI

License

MIT License - see LICENSE

Contributing

Contributions welcome! Please read our contributing guidelines.

About

Built by Sigma5C - Leaders in multi-agent AI systems.

We believe AI tools work better together. Claude's superior reasoning and tool-calling combined with Codex's bug-catching creates a peer programming experience that's greater than either alone.

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"Two AIs are better than one."