copilot-4-claude-code

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A local proxy server that exposes GitHub Copilot as a standard Anthropic API, enabling tools like Claude Code to use it as a backend.

How It Works

Claude Code  →  Anthropic API (localhost:8082)  →  GitHub Copilot API

1. The proxy runs a FastAPI server locally on port 8082
2. Claude Code sends requests to the proxy using the standard Anthropic /v1/messages format
3. The proxy authenticates with GitHub Copilot and forwards requests appropriately:
   • Claude models → direct passthrough to Copilot's /v1/messages endpoint (no conversion needed)
   • Other models (GPT-4o, etc.) → converted from Anthropic format to OpenAI format and sent to /chat/completions

Authentication Flow

1. GitHub OAuth Device Flow → access_token
2. access_token → Copilot API key via https://api.github.com/copilot_internal/v2/token
3. Copilot API key + required headers → GitHub Copilot API requests

Tokens are cached locally in .github_copilot_token/ and auto-refreshed on expiry.

Requirements

• Python 3.10+
• A GitHub account with an active GitHub Copilot subscription

Installation

pip install -r requirements.txt

Usage

Start the proxy

python cp4cc.py

On first run, you will be prompted to authenticate via GitHub OAuth Device Flow:

==================================================
  Visit: https://github.com/login/device
  Auth code: >>>  XXXX-XXXX  <<<
==================================================

Once authenticated, the proxy starts on port 8082.

Startup options

Flag	Description
(none)	Bind to 127.0.0.1, UI and audit enabled
--share	Bind to 0.0.0.0 — LAN accessible ⚠
--fast	Disable UI and audit for lower overhead
--port N	Listen on port N (default: 8082)

python cp4cc.py --share          # share with LAN
python cp4cc.py --fast           # proxy only, no UI
python cp4cc.py --fast --share   # both
python cp4cc.py --port 9000      # custom port
python cp4cc.py --help           # full help

Configure Claude Code

Option 1: Persistent environment variables

export ANTHROPIC_BASE_URL=http://127.0.0.1:8082
export ANTHROPIC_AUTH_TOKEN=dummy
claude

Option 2: Single launch

ANTHROPIC_BASE_URL=http://127.0.0.1:8082 ANTHROPIC_AUTH_TOKEN=dummy claude

If using --share or --port, replace the host/port accordingly.

Dashboard

A web dashboard is available at http://localhost:8082/ui with a responsive two-column layout:

Left panel — Models

• Lists all available Copilot models with their supported endpoints
• Claude models (direct /v1/messages passthrough) are grouped separately from other models

Right panel — Requests (current session)

• Live request list showing time, model, status, duration, message type breakdown, and a content preview
• Message types are color-coded: msg (blue) · tool↑ tool_use (orange) · tool↓ tool_result (purple)
• Preview column shows the last message's text; for tool messages the full body (tool name + input / result) is displayed
• List auto-refreshes every 5 seconds; only current session data is shown

The header strip also provides one-click copy of the Claude Code configuration commands and live stats (total / OK / error counts).

API Endpoints

Endpoint	Description
GET /health	Health check
GET /v1/models	List available models (Anthropic format)
POST /v1/messages	Main proxy endpoint (Anthropic format)
GET /v1/models/refresh	Force refresh model list
GET /audit/sessions	List all audit session files
GET /audit/current	Current session audit log (JSON)
GET /ui	Web dashboard

Model Name Mapping

Claude Code model names are automatically mapped to Copilot format:

Claude Code	Copilot
claude-opus-4-6	claude-opus-4.6
claude-opus-4-6-20250514	claude-opus-4.6
claude-haiku-4-5	claude-haiku-4.5
gpt-4o	gpt-4o (unchanged)

Logging & Audit

• Application logs: logs/app.log
• Per-session audit logs: logs/audit/session_YYYYMMDD_HHMMSS_<id>.json

Each audit entry captures: original model, mapped Copilot model, endpoint, stream flag, per-message breakdown (role / type / full body), status code, duration, and response body (up to 2000 chars for streamed responses).

Project Structure

.
├── cp4cc.py             # Proxy server (FastAPI)
├── requirements.txt     # Python dependencies
├── logs/
│   ├── app.log          # Application log
│   └── audit/           # Per-session audit JSON files
└── .github_copilot_token/
    ├── access-token     # GitHub OAuth access token
    └── api-key.json     # Copilot API key (auto-refreshed)