graph LR
    A[AI Agent] --> B[Node.js MCP Server]
    B --> C[Python FastAPI Server]
    C --> D[xCOMET Model<br/>Persistent in Memory]
    D --> C
    C --> B
    B --> A

    style D fill:#9f9

# If using uv (recommended - auto-downloads the correct Python version)
uv venv ~/.xcomet-venv --python 3.12
source ~/.xcomet-venv/bin/activate
uv pip install "unbabel-comet>=2.2.0" "fastapi>=0.100.0" "uvicorn>=0.23.0" "pydantic>=2.0.0"

# Or using standard venv (requires Python 3.9-3.12 already installed)
python3 -m venv ~/.xcomet-venv
source ~/.xcomet-venv/bin/activate  # Windows: ~/.xcomet-venv\Scripts\activate
pip install "unbabel-comet>=2.2.0" "fastapi>=0.100.0" "uvicorn>=0.23.0" "pydantic>=2.0.0"

source ~/.xcomet-venv/bin/activate
python -c "from comet import download_model; download_model('Unbabel/XCOMET-XL')"

# Clone the repository
git clone https://github.com/shuji-bonji/xcomet-mcp-server.git
cd xcomet-mcp-server

# Set up Python virtual environment and install dependencies
uv venv .venv --python 3.12    # or: python3 -m venv .venv
source .venv/bin/activate
pip install -r python/requirements.txt

# Install Node.js dependencies and build
npm install
npm run build

{
  "mcpServers": {
    "xcomet": {
      "command": "npx",
      "args": ["-y", "xcomet-mcp-server"],
      "env": {
        "XCOMET_PYTHON_PATH": "~/.xcomet-venv/bin/python3"
      }
    }
  }
}

claude mcp add xcomet --env XCOMET_PYTHON_PATH=~/.xcomet-venv/bin/python3 -- npx -y xcomet-mcp-server

npm install -g xcomet-mcp-server

{
  "mcpServers": {
    "xcomet": {
      "command": "xcomet-mcp-server",
      "env": {
        "XCOMET_PYTHON_PATH": "~/.xcomet-venv/bin/python3"
      }
    }
  }
}

{
  "mcpServers": {
    "xcomet": {
      "command": "node",
      "args": ["/path/to/xcomet-mcp-server/dist/index.js"],
      "env": {
        "XCOMET_PYTHON_PATH": "~/.xcomet-venv/bin/python3"
      }
    }
  }
}

TRANSPORT=http PORT=3000 npm start

{
  "source": "The quick brown fox jumps over the lazy dog.",
  "translation": "素早い茶色のキツネが怠惰な犬を飛び越える。",
  "source_lang": "en",
  "target_lang": "ja",
  "use_gpu": true
}

{
  "score": 0.847,
  "errors": [],
  "summary": "Good quality (score: 0.847) with 0 error(s) detected."
}

{
  "pairs": [
    {"source": "Hello", "translation": "こんにちは"},
    {"source": "Goodbye", "translation": "さようなら"}
  ],
  "use_gpu": true,
  "batch_size": 16
}

sequenceDiagram
    participant Agent as AI Agent
    participant DeepL as DeepL MCP Server
    participant xCOMET as xCOMET MCP Server
    
    Agent->>DeepL: Translate text
    DeepL-->>Agent: Translation result
    Agent->>xCOMET: Evaluate quality
    xCOMET-->>Agent: Score + Errors
    Agent->>Agent: Decide: Accept or retry?

{
  "mcpServers": {
    "deepl": {
      "command": "npx",
      "args": ["-y", "@anthropic/deepl-mcp-server"],
      "env": {
        "DEEPL_API_KEY": "your-api-key"
      }
    },
    "xcomet": {
      "command": "npx",
      "args": ["-y", "xcomet-mcp-server"],
      "env": {
        "XCOMET_PYTHON_PATH": "~/.xcomet-venv/bin/python3"
      }
    }
  }
}

{
  "mcpServers": {
    "xcomet": {
      "command": "npx",
      "args": ["-y", "xcomet-mcp-server"],
      "env": {
        "XCOMET_MODEL": "Unbabel/XCOMET-XXL"
      }
    }
  }
}

{
  "mcpServers": {
    "xcomet": {
      "command": "npx",
      "args": ["-y", "xcomet-mcp-server"],
      "env": {
        "XCOMET_PYTHON_PATH": "/Users/you/.pyenv/versions/3.11.0/bin/python3"
      }
    }
  }
}

{
  "mcpServers": {
    "xcomet": {
      "command": "npx",
      "args": ["-y", "xcomet-mcp-server"],
      "env": {
        "XCOMET_PRELOAD": "true"
      }
    }
  }
}

graph LR
    A[MCP Request] --> B[Node.js Server]
    B --> C[Python FastAPI Server]
    C --> D[xCOMET Model<br/>in Memory]
    D --> C
    C --> B
    B --> A

    style D fill:#9f9

✅ Fast: First call loads model, subsequent calls reuse it
   xcomet_evaluate(pair1)  # ~90s (model loads)
   xcomet_evaluate(pair2)  # ~500ms (model cached)
   xcomet_evaluate(pair3)  # ~500ms (model cached)

✅ Even faster: Batch all pairs in one call
   xcomet_batch_evaluate(allPairs)  # Optimal throughput

# Check which Python is being used
python3 -c "import sys; print(sys.executable)"

# If using a virtual environment, make sure it's activated
source .venv/bin/activate
pip install -r python/requirements.txt

# For MCP hosts (e.g., Claude Desktop), specify the venv Python path
export XCOMET_PYTHON_PATH=~/.xcomet-venv/bin/python3

# Login to HuggingFace (required for XCOMET-XL/XXL)
huggingface-cli login

# Pre-download the model manually
python -c "from comet import download_model; download_model('Unbabel/XCOMET-XL')"