Polygon.io MCP server

The Polygon.io MCP server provides an LLM-friendly interface to access comprehensive financial market data through the Model Context Protocol. This server exposes Polygon.io API endpoints as MCP tools, making it easy to integrate financial data into AI applications.

Installation Requirements

Prerequisites

• Python 3.10+
• A Polygon.io API key
• Astral UV installed

Installing with Claude Code

First, install Claude Code:

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

Then add the Polygon MCP server to your environment:

claude mcp add polygon -e POLYGON_API_KEY=your_api_key_here -- uvx --from git+https://github.com/polygon-io/[email protected] mcp_polygon

To start Claude Code, run:

claude

If it's your first time, follow the authentication prompts.

Installing with Claude Desktop

1. Complete the initial Claude Desktop MCP installation following the instructions at https://modelcontextprotocol.io/quickstart/user
2. Find your configuration file
3. Add Polygon's MCP server using this example:

{
    "mcpServers": {
        "polygon": {
            "command": "<path_to_your_uvx_install>/uvx",
            "args": [
                "--from",
                "git+https://github.com/polygon-io/[email protected]",
                "mcp_polygon"
            ],
            "env": {
                "POLYGON_API_KEY": "<your_api_key_here>",
                "HOME": "<your_home_directory>"
            }
        }
    }
}

Make sure to replace:

• <path_to_your_uvx_install> with your uvx path (find using which uvx)
• <your_api_key_here> with your actual Polygon.io API key
• <your_home_directory> with your home directory path

Transport Configuration

By default, STDIO transport is used. To configure SSE or Streamable HTTP, set the MCP_TRANSPORT environment variable:

MCP_TRANSPORT=streamable-http \
POLYGON_API_KEY=<your_api_key_here> \
uv run entrypoint.py

Using the MCP Server

Once integrated, you can prompt Claude to access Polygon.io data with natural language queries such as:

• Get the latest price for AAPL stock
• Show me yesterday's trading volume for MSFT
• What were the biggest stock market gainers today?
• Get me the latest crypto market data for BTC-USD

Available Tools

The MCP server implements all Polygon.io API endpoints as tools, including:

• get_aggs - Stock aggregates (OHLC) data for a specific ticker
• list_trades - Historical trade data
• get_last_trade - Latest trade for a symbol
• list_ticker_news - Recent news articles for tickers
• get_snapshot_ticker - Current market snapshot for a ticker
• get_market_status - Current market status and trading hours
• list_stock_financials - Fundamental financial data

Each tool follows the Polygon.io SDK parameter structure while converting responses to standard JSON that LLMs can easily process.

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 "polygon" '{"command":"uvx","args":["--from","git+https://github.com/polygon-io/[email protected]","mcp_polygon"],"env":{"POLYGON_API_KEY":"${POLYGON_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": {
        "polygon": {
            "command": "uvx",
            "args": [
                "--from",
                "git+https://github.com/polygon-io/[email protected]",
                "mcp_polygon"
            ],
            "env": {
                "POLYGON_API_KEY": "${POLYGON_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": {
        "polygon": {
            "command": "uvx",
            "args": [
                "--from",
                "git+https://github.com/polygon-io/[email protected]",
                "mcp_polygon"
            ],
            "env": {
                "POLYGON_API_KEY": "${POLYGON_API_KEY}"
            }
        }
    }
}

3. Restart Claude Desktop for the changes to take effect