Claude Code API Gateway (Fork)

Fork of codingworkflow/claude-code-api with custom patches.

Fork patches

• OpenAI-compatible tool calling — parse tools from requests, format them into the system prompt, extract tool_calls from Claude responses
• Conversation history — pass full message history (including system/cron events) as context, not just the last user message
• Large system prompt handling — write system prompts >10KB to a temp CLAUDE.md file instead of passing via CLI argument (avoids Linux execve 128KB arg limit)
• Model aliases — cc-* prefixed model IDs to avoid name collisions with proxy providers
• Streaming fixes — correct SSE Content-Type, wrap non-streaming tool responses as SSE when the client requests stream: true
• Updated models — Claude Opus 4.6, Sonnet 4.5, Haiku 4.5

Getting Started

Use the Makefile to install the project or pip/uv.

Python Implementation

# Clone and setup
git clone https://github.com/codingworkflow/claude-code-api
cd claude-code-api

# Install dependencies & module
make install 

# Start the API server
make start

Limitations

• There might be a limit on maximum input below normal "Sonnet 4" input as Claude Code usually doesn't ingest more than 25k tokens (despite the context being 100k).
• Claude Code auto-compacts context beyond 100k.
• Currently runs with bypass mode to avoid tool errors.
• Claude Code tools may need to be disabled to avoid overlap and background usage.
• Runs only on Linux/Mac as Claude Code doesn't run on Windows (you can use WSL).
• Note that Claude Code will default to accessing the current workspace environment/folder and is set to use bypass mode.

Features

• Claude-Only Models: Supports exactly the 4 Claude models that Claude Code CLI offers
• OpenAI Compatible: Drop-in replacement for OpenAI API endpoints
• Streaming Support: Real-time streaming responses
• Simple & Clean: No over-engineering, focused implementation
• Claude Code Integration: Leverages Claude Code CLI with streaming output

Supported Models

• claude-opus-4-20250514 - Claude Opus 4 (Most powerful)
• claude-sonnet-4-20250514 - Claude Sonnet 4 (Latest Sonnet)
• claude-3-7-sonnet-20250219 - Claude Sonnet 3.7 (Advanced)
• claude-3-5-haiku-20241022 - Claude Haiku 3.5 (Fast & cost-effective)

Quick Start

Prerequisites

• Python 3.10+
• Claude Code CLI installed and accessible
• Valid Anthropic API key configured in Claude Code (ensure it works in current directory src/)

Installation & Setup

# Clone and setup
git clone https://github.com/codingworkflow/claude-code-api
cd claude-code-api

# Install dependencies
make install

# Run tests to verify setup
make test

# Start the API server
make start-dev

The API will be available at:

• API: http://localhost:8000
• Docs: http://localhost:8000/docs
• Health: http://localhost:8000/health

Makefile Commands

Core Commands

make install     # Install production dependencies
make install-dev # Install development dependencies  
make test        # Run all tests
make start       # Start API server (production)
make start-dev   # Start API server (development with reload)

Testing

make test           # Run all tests
make test-fast      # Run tests (skip slow ones)
make test-hello     # Test hello world with Haiku
make test-health    # Test health check only
make test-models    # Test models API only
make test-chat      # Test chat completions only
make quick-test     # Quick validation of core functionality

Development

make dev-setup      # Complete development setup
make lint           # Run linting checks
make format         # Format code with black/isort
make type-check     # Run type checking
make clean          # Clean up cache files

Information

make help           # Show all available commands
make models         # Show supported Claude models
make info           # Show project information
make check-claude   # Check if Claude Code CLI is available

API Usage

Chat Completions

curl -X POST http://localhost:8000/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-3-5-haiku-20241022",
    "messages": [
      {"role": "user", "content": "Hello!"}
    ]
  }'

List Models

curl http://localhost:8000/v1/models

Streaming Chat

curl -X POST http://localhost:8000/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-3-5-haiku-20241022", 
    "messages": [
      {"role": "user", "content": "Tell me a joke"}
    ],
    "stream": true
  }'

Project Structure

claude-code-api/
├── claude_code_api/
│   ├── main.py              # FastAPI application
│   ├── api/                 # API endpoints
│   │   ├── chat.py          # Chat completions
│   │   ├── models.py        # Models API
│   │   ├── projects.py      # Project management
│   │   └── sessions.py      # Session management
│   ├── core/                # Core functionality
│   │   ├── auth.py          # Authentication
│   │   ├── claude_manager.py # Claude Code integration
│   │   ├── session_manager.py # Session management
│   │   ├── config.py        # Configuration
│   │   └── database.py      # Database layer
│   ├── models/              # Data models
│   │   ├── claude.py        # Claude-specific models
│   │   └── openai.py        # OpenAI-compatible models
│   ├── utils/               # Utilities
│   │   ├── streaming.py     # Streaming support
│   │   └── parser.py        # Output parsing
│   └── tests/               # Test suite
├── Makefile                 # Development commands
├── pyproject.toml          # Project configuration
├── setup.py                # Package setup
└── README.md               # This file

Testing

The test suite validates:

• Health check endpoints
• Models API (Claude models only)
• Chat completions with Haiku model
• Hello world functionality
• OpenAI compatibility (structure)
• Error handling

Run specific test suites:

make test-hello    # Test hello world with Haiku
make test-models   # Test models API
make test-chat     # Test chat completions

Development

Setup Development Environment

make dev-setup

Code Quality

make format        # Format code
make lint          # Check linting
make type-check    # Type checking

Quick Validation

make quick-test    # Test core functionality

Deployment

Check Deployment Readiness

make deploy-check

Production Server

make start-prod    # Start with multiple workers

Use http://127.0.0.1:8000/v1 as OpenAPI endpoint

Configuration

Key settings in claude_code_api/core/config.py:

• claude_binary_path: Path to Claude Code CLI
• project_root: Root directory for projects
• database_url: Database connection string
• require_auth: Enable/disable authentication

Design Principles

1. Simple & Focused: No over-engineering
2. Claude-Only: Pure Claude gateway, no OpenAI models
3. Streaming First: Built for real-time streaming
4. OpenAI Compatible: Drop-in API compatibility
5. Test-Driven: Comprehensive test coverage

Health Check

curl http://localhost:8000/health

Response:

{
  "status": "healthy",
  "version": "1.0.0", 
  "claude_version": "1.x.x",
  "active_sessions": 0
}

License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.