Claude ↔ Codex MCP Relay (with logs + web UI)

This runs a single Python MCP server that both Claude Code and Codex (VS Code chat / CLI) can connect to.

It provides:

• MCP tools: post_message, fetch_messages, list_channels
• Rotating log file (all tool usage)
• A tiny web UI that renders conversations and highlights fenced code blocks

1) Setup

Requirements

• Python 3.10+
• pip

Install

python -m venv .venv
source .venv/bin/activate  # (Windows: .venv\Scripts\activate)
pip install -r requirements.txt

2) Run the server

python claude_codex.py

This reads host/port from config.json (or env vars, or defaults to 127.0.0.1:8010).

Alternatively, specify host/port directly:

uvicorn claude_codex:app --host 127.0.0.1 --port 8010

Open:

• Web UI: http://127.0.0.1:8010/
• MCP endpoint: http://127.0.0.1:8010/mcp

Logs:

• claude_codex.log (rotated, defaults: 5MB × 10 backups)

3) Configuration

Configuration is loaded from config.json (if present), then environment variables, then defaults.

Option A: config.json (recommended)

Create a config.json in the project root:

{
  "host": "127.0.0.1",
  "port": 8010,
  "log_path": "claude_codex.log",
  "log_max_bytes": 5242880,
  "log_backup_count": 10,
  "channels": ["proj-x", "codex", "claude"]
}

Option B: Environment variables

Example:

CLAUDE_CODEX_LOG_PATH=/tmp/relay.log uvicorn claude_codex:app --host 127.0.0.1 --port 8010

4) Configure Claude Code + Codex

See:

• docs/claude.md
• docs/codex.md

5) Suggested workflow

Use a shared channel like proj-x so both agents read/write the same thread.

1. Claude makes changes, then posts a review packet:

   • summary
   • unified diff (in a ```diff fenced block)
   • questions/focus

2. Codex fetches, reviews, then posts feedback:

   • verdict
   • major/minor issues
   • tests to add/run

3. Claude applies fixes and posts an updated packet.

6) Notes

• This server stores messages in memory. Restarting the server clears history.
• Want persistence? Swap the in-memory list for SQLite/Redis while keeping the same tools.