This repository lets you use Anthropic's Claude Code CLI with OpenAI's GPT-5 via a local LiteLLM proxy.

⚠️ ATTENTION ⚠️

If you're here to set up your own LiteLLM Server (potentially with LibreChat or similar UI), head over to the main-boilerplate branch. It contains a "boilerplate" version of this repo with Claude Code CLI stuff stripped away for simplicity, and with a version of README.md that specifically explains how to build on top of this repo as a boilerplate.

Quick Start ⚡

Prerequisites

• OpenAI API key 🔑
• Anthropic API key 🔑 - optional (if you decide not to remap some Claude models to OpenAI)
• Either uv or Docker Desktop, depending on your preferred setup method

First time using GPT-5 via API?

If you are going to use GPT-5 via API for the first time, OpenAI may require you to verify your identity via Persona. You may encounter an OpenAI error asking you to “verify your organization.” To resolve this, you can go through the verification process here:

• OpenAI developer platform - Organization settings

Setup 🛠️

1. Clone this repository:

   git clone https://github.com/teremterem/claude-code-gpt-5.git
   cd claude-code-gpt-5

2. Configure Environment Variables:

   Copy the template file to create your .env:

   cp .env.template .env

   Edit .env and add your OpenAI API key:

   OPENAI_API_KEY=your-openai-api-key-here
   # Optional: only needed if you plan to use Anthropic models
   # ANTHROPIC_API_KEY=your-anthropic-api-key-here
   
   # Optional (see .env.template for details):
   # LITELLM_MASTER_KEY=your-master-key-here
   
   # Optional: override the default remaps if you need to (the values you see
   # below are the defaults - see .env.template for more info)
   # REMAP_CLAUDE_HAIKU_TO=gpt-5-mini-reason-minimal
   # REMAP_CLAUDE_SONNET_TO=gpt-5-reason-medium
   # REMAP_CLAUDE_OPUS_TO=gpt-5-reason-high
   
   # Some more optional settings (see .env.template for details)
   ...

3. Run the proxy:

   1. EITHER via uv (make sure to install uv first):

      OPTION 1: Use a script for uv:

      ./uv-run.sh

      OPTION 2: Run via a direct uv command:

      uv run litellm --config config.yaml

   2. OR via Docker (make sure to install Docker Desktop first):

      OPTION 3: Run Docker in the foreground:

      ./run-docker.sh

      OPTION 4: Run Docker in the background:

      ./deploy-docker.sh

      OPTION 5: Run Docker via a direct command:

      docker run -d \
         --name claude-code-gpt-5 \
         -p 4000:4000 \
         --env-file .env \
         --restart unless-stopped \
         ghcr.io/teremterem/claude-code-gpt-5:latest

      NOTE: To run with this command in the foreground instead of the background, remove the -d flag.

      To see the logs, run:

      docker logs -f claude-code-gpt-5

      To stop and remove the container, run:

      ./kill-docker.sh

      NOTE: The Docker options above will pull the latest image from GHCR and will ignore all your local files except .env. For more detailed Docker deployment instructions and more options (like building Docker image from source yourself, using Docker Compose, etc.), see docs/DOCKER_TIPS.md

Using with Claude Code 🎮

1. Install Claude Code (if you haven't already):

   npm install -g @anthropic-ai/claude-code

2. Connect to GPT-5 instead of Claude:

   ANTHROPIC_BASE_URL=http://localhost:4000 claude

   If you set LITELLM_MASTER_KEY for the proxy (see .env.template for details), pass it as the Anthropic API key for the CLI:

   ANTHROPIC_API_KEY="<LITELLM_MASTER_KEY>" \
   ANTHROPIC_BASE_URL=http://localhost:4000 \
   claude

   NOTE: In this case, if you've previously authenticated, run claude /logout first.

3. That's it! Your Claude Code client will now use the selected GPT-5 variant(s) with your chosen reasoning effort level(s). 🎯

Available GPT-5 model aliases

• GPT-5:
  • gpt-5-reason-minimal
  • gpt-5-reason-low
  • gpt-5-reason-medium
  • gpt-5-reason-high
• GPT-5-mini:
  • gpt-5-mini-reason-minimal
  • gpt-5-mini-reason-low
  • gpt-5-mini-reason-medium
  • gpt-5-mini-reason-high
• GPT-5-nano:
  • gpt-5-nano-reason-minimal
  • gpt-5-nano-reason-low
  • gpt-5-nano-reason-medium
  • gpt-5-nano-reason-high

NOTE: Generally, you can use arbitrary models from arbitrary providers, but for providers other than OpenAI or Anthropic, you will need to specify the provider in the model name, e.g. gemini/gemini-pro, gemini/gemini-pro-reason-disable etc. (as well as set the respective API keys along with any other environment variables that the provider might require in your .env file).

KNOWN PROBLEM

The Web Search tool currently does not work with this setup. You may see an error like:

API Error (500 {"error":{"message":"Error calling litellm.acompletion for non-Anthropic model: litellm.BadRequestError: OpenAIException - Invalid schema for function 'web_search': 'web_search_20250305' is not valid under any of the given schemas.","type":"None","param":"None","code":"500"}}) · Retrying in 1 seconds… (attempt 1/10)

This is planned to be fixed soon.

NOTE: The Fetch tool (getting web content from specific URLs) is not affected and works normally.

P. S. You are welcome to join our MiniAgents Discord Server 👥

And if you like the project, please give it a Star 💫