Foundry MCP Server

A simple, lightweight and fast MCP (Model Context Protocol) server that provides Solidity development capabilities using the Foundry toolchain (Forge, Cast, and Anvil).

Overview

This server connects LLM assistants to the Foundry ecosystem, enabling them to:

• Interact with nodes (local Anvil instances or remote RPC endpoints)
• Analyze smart contracts and blockchain data
• Perform common EVM operations using Cast
• Manage, deploy, and execute Solidity code and scripts
• Work with a persistent Forge workspace

Features

Network Interaction

• Start and manage local Anvil instances
• Connect to any remote network (just specify the RPC)
• Get network/chain information

Contract Interaction

• Call contract functions (read-only)
• Send transactions to contracts (if PRIVATE_KEY is configured)
• Get transaction receipts
• Read contract storage
• Analyze transaction traces
• Retrieve contract ABIs and sources from block explorers

Solidity Development

• Maintain a dedicated Forge workspace
• Create and edit Solidity files
• Install dependencies
• Run Forge scripts
• Deploy contracts

Utility Functions

• Calculate contract addresses
• Check contract bytecode size
• Estimate gas costs
• Convert between units (hex to decimals, etc.,)
• Generate wallets
• Get event logs
• Lookup function and event signatures

Smart Contract Analysis (Heimdall)

• Disassemble EVM bytecode into human-readable opcodes
• Decode raw calldata without requiring ABI
• Decompile EVM bytecode to Solidity source code and ABI
• Generate visual control flow graphs for EVM bytecode
• Detailed transaction inspection with calldata decoding and trace analysis

Usage

The server is designed to be used as an MCP tool provider for MCP Clients. When connected to a client, it enables the clients(claude desktop, cursor, client, etc.,) to perform Solidity and onchain operations directly.

Requirements

• Node.js v18+
• Foundry toolchain (Forge, Cast, Anvil)
• Heimdall-rs (for smart contract analysis)

Manual Setup

1. Ensure Foundry tools (Forge, Cast, Anvil) are installed on your system:

   curl -L https://foundry.paradigm.xyz | bash
   foundryup
   

2. Clone and build the server.

   bun i && bun build ./src/index.ts --outdir ./dist --target node
   
   

3. Update your client config (eg: Claude desktop):

 "mcpServers": {
    "foundry": {
      "command": "node",
      "args": [
        "path/to/foundry-mcp-server/dist/index.js"
      ],
      "env" :{
        "PRIVATE_KEY": "0x1234",
      }
    }
 }

[!NOTE] PRIVATE_KEY is optional

Setup using NPM Package

You can now install and run the server directly using npm:

Global Installation

npm install -g @pranesh.asp/foundry-mcp-server

Direct Usage with npx

npx @pranesh.asp/foundry-mcp-server

MCP Client Configuration

Claude Code

 claude mcp add-json foundry-mcp-server '{"type":"stdio","command":"npx","args":["@pranesh.asp/foundry-mcp-server"],"env":{"RPC_URL":"","PRIVATE_KEY":""}}'   

Other MCP Clients (Cursor, Claude, Windsurf)

Add to your MCP settings:

{
  "mcpServers": {
    "foundry": {
      "command": "npx",
      "args": ["@pranesh.asp/foundry-mcp-server"],
      "env": {
        "RPC_URL": "http://localhost:8545",
        "PRIVATE_KEY": "0x..."
      }
    }
  }
}

Configuration

The server supports the following environment variables:

• RPC_URL: Default RPC URL to use when none is specified (optional)
• PRIVATE_KEY: Private key to use for transactions (optional)

[!CAUTION] Do not add keys with mainnet funds. Even though the code uses it safely, LLMs can hallicunate and send malicious transactions. Use it only for testing/development purposes. DO NOT trust the LLM!!

[!TI

... View full README on GitHub