Arize Phoenix MCP server

The Phoenix MCP Server provides a unified interface to Arize Phoenix's capabilities, allowing you to manage projects, analyze spans and annotations, work with prompts, explore datasets, and visualize experiment results. It integrates with clients like Claude Desktop and Cursor through the Model Context Protocol.

Installation

You can use the Phoenix MCP Server via npx by configuring it in your MCP client settings. Here's how to set it up:

{
  "mcpServers": {
    "phoenix": {
      "command": "npx",
      "args": [
        "-y",
        "@arizeai/phoenix-mcp@latest",
        "--baseUrl",
        "https://my-phoenix.com",
        "--apiKey",
        "your-api-key"
      ]
    }
  }
}

Replace https://my-phoenix.com with your Phoenix instance URL and your-api-key with your actual API key.

Configuration

Environment Variables

The server requires the following environment variables:

• PHOENIX_API_KEY: Your Phoenix API key
• PHOENIX_BASE_URL: The base URL for your Phoenix instance

You can set these in a .env file in your project directory.

Usage

Once installed and configured, the Phoenix MCP Server provides several capabilities:

Projects Management

Access and explore projects that organize your observability data through your MCP client.

Spans & Annotations

Retrieve spans and their annotations for in-depth analysis and debugging of your models.

Prompts Management

Create, list, update, and iterate on prompts to improve your model interactions.

Datasets

Explore existing datasets and synthesize new examples for training and evaluation.

Experiments

Pull experiment results and visualize them with the assistance of an LLM to gain insights into model performance.

Running the MCP Inspector

For debugging purposes, you can run the MCP inspector with:

npx @arizeai/phoenix-mcp@latest inspect

This provides a diagnostic interface to ensure your MCP server is functioning correctly.

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "phoenix" '{"command":"npx","args":["-y","@arizeai/phoenix-mcp@latest","--baseUrl","https://my-phoenix.com","--apiKey","your-api-key"]}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "phoenix": {
            "command": "npx",
            "args": [
                "-y",
                "@arizeai/phoenix-mcp@latest",
                "--baseUrl",
                "https://my-phoenix.com",
                "--apiKey",
                "your-api-key"
            ]
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "phoenix": {
            "command": "npx",
            "args": [
                "-y",
                "@arizeai/phoenix-mcp@latest",
                "--baseUrl",
                "https://my-phoenix.com",
                "--apiKey",
                "your-api-key"
            ]
        }
    }
}

3. Restart Claude Desktop for the changes to take effect