Polygon Blockchain MCP server

The Polygon MCP Server enables Claude AI to interact with the Polygon PoS blockchain, providing capabilities like calling contract functions, managing ERC20 tokens, and retrieving gas prices.

Installation

To install the Polygon MCP Server:

1. Clone the repository:

git clone https://github.com/your-username/polygon-mcp.git
cd polygon-mcp

2. Install dependencies:

npm install

3. Build the project:

npm run build

Configuration

Create a .env file in the root directory with your seed phrase:

SEED_PHRASE="your twelve word seed phrase here"

Running the Server

Start the MCP server with:

npm start

Connecting with Claude

VSCode Claude Extension

Add the MCP server to your Claude VSCode extension settings:

{
  "mcpServers": {
    "polygon": {
      "command": "node",
      "args": ["/path/to/polygon-mcp/build/index.js"],
      "env": {
        "SEED_PHRASE": "your twelve word seed phrase here"
      },
      "disabled": false,
      "autoApprove": []
    }
  }
}

Claude Desktop App

Similarly, add the server to your Claude desktop app configuration:

{
  "mcpServers": {
    "polygon": {
      "command": "node",
      "args": ["/path/to/polygon-mcp/build/index.js"],
      "env": {
        "SEED_PHRASE": "your twelve word seed phrase here"
      },
      "disabled": false,
      "autoApprove": []
    }
  }
}

Available Tools

call_contract

Call a contract function on Polygon PoS.

Parameters:

• contractAddress: The address of the contract to call
• functionName: The name of the function to call
• functionArgs: The arguments to pass to the function
• abi: The ABI of the contract
• value (optional): The value of MATIC to send with the transaction

erc20_balance

Get the balance of an ERC20 token.

Parameters:

• contractAddress: The address of the contract to get the balance of

erc20_transfer

Transfer ERC20 tokens.

Parameters:

• contractAddress: The address of the contract to transfer the token from
• toAddress: The address of the recipient
• amount: The amount of tokens to transfer

get_gas_price

Get the current gas price on Polygon PoS. This tool takes no parameters.

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":"node","args":["/path/to/polygon-mcp/build/index.js"],"env":{"SEED_PHRASE":"your twelve word seed phrase here"},"disabled":false,"autoApprove":[]}'

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": "node",
            "args": [
                "/path/to/polygon-mcp/build/index.js"
            ],
            "env": {
                "SEED_PHRASE": "your twelve word seed phrase here"
            },
            "disabled": false,
            "autoApprove": []
        }
    }
}

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": "node",
            "args": [
                "/path/to/polygon-mcp/build/index.js"
            ],
            "env": {
                "SEED_PHRASE": "your twelve word seed phrase here"
            },
            "disabled": false,
            "autoApprove": []
        }
    }
}

3. Restart Claude Desktop for the changes to take effect