@maxencerb/foundry-mcp

A comprehensive Model Context Protocol (MCP) server for the Foundry Ethereum development toolkit. This server enables AI assistants like Claude to interact with Forge, Cast, Anvil, and Chisel directly.

Features

80+ Tools covering all major Foundry commands
Resources for project configuration, ABIs, bytecode, and documentation
Prompts for common workflows (deployment, testing, security review)
Self-documenting with live --help integration and official docs fetching

Tools Overview

| Category | Tools | Description | |----------|-------|-------------| | Forge | 18 | Build, test, deploy, verify contracts | | Cast | 38 | Interact with EVM chains, encode/decode data | | Anvil | 16 | Local node management, state manipulation | | Chisel | 6 | Solidity REPL operations | | Help | 6 | Live documentation from --help flags |

Prerequisites

Bun runtime
Foundry installed and in PATH

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

Installation

# Using bun
bunx @maxencerb/foundry-mcp

# Or install globally
bun install -g @maxencerb/foundry-mcp

Usage

With Claude Code

Add the MCP server using the CLI:

# Add with environment variables
claude mcp add --transport stdio --env RPC_URL=http://localhost:8545 foundry -- bunx @maxencerb/foundry-mcp

# Or add project-scoped (creates .mcp.json)
claude mcp add --transport stdio --scope project foundry -- bunx @maxencerb/foundry-mcp

Or create a .mcp.json file in your project root:

{
  "mcpServers": {
    "foundry": {
      "command": "bunx",
      "args": ["@maxencerb/foundry-mcp"],
      "env": {
        "RPC_URL": "${RPC_URL:-http://localhost:8545}"
      }
    }
  }
}

With Claude Desktop

Add to your Claude Desktop configuration (~/Library/Application Support/Claude/claude_desktop_config.json on macOS):

{
  "mcpServers": {
    "foundry": {
      "command": "bunx",
      "args": ["@maxencerb/foundry-mcp"],
      "env": {
        "RPC_URL": "http://localhost:8545"
      }
    }
  }
}

With Other MCP Clients

# Run the server directly
bunx @maxencerb/foundry-mcp

# Or if installed globally
foundry-mcp

Environment Variables

| Variable | Description | Default | |----------|-------------|---------| | RPC_URL | Default RPC endpoint for chain interactions | - | | PRIVATE_KEY | Default private key for transactions (⚠️ testing only) | - | | FOUNDRY_PROJECT | Path to Foundry project | Current directory |

Available Tools

Forge Tools

| Tool | Description | |------|-------------| | forge_init | Initialize a new Foundry project | | forge_build | Compile Solidity contracts | | forge_test | Run tests with filtering and forking | | forge_coverage | Generate test coverage reports | | forge_script | Execute deployment scripts | | forge_create | Deploy a single contract | | forge_verify | Verify contracts on block explorers | | forge_inspect | Inspect ABI, bytecode, storage layout | | forge_flatten | Flatten contract sources | | forge_remappings | Show import remappings | | forge_tree | Show dependency tree | | forge_clean | Remove build artifacts | | forge_install | Install dependencies | | forge_update | Update dependencies | | forge_fmt | Format Solidity code | | forge_snapshot | Generate gas snapshots | | forge_doc | Generate documentation | | forge_selectors | List function selectors |

Cast Tools

Chain & Block: cast_block, cast_block_number, cast_chain, cast_chain_id, cast_client, cast_gas_price, cast_base_fee

Account: cast_balance, cast_nonce, cast_code, cast_storage

Transactions: cast_call, cast_send, cast_publish, cast_tx, cast_receipt, cast_run, cast_estimate, cast_logs

Encoding/Decoding: cast_abi_encode, cast_abi_decode, cast_calldata, cast_calldata_decode, cast_sig, cast_sig_event, cast_4byte, cast_4byte_decode

Utilities: cast_to_wei, cast_from_wei, cast_to_hex, cast_to_dec, cast_to_base, cast_keccak, cast_resolve_name, cast_lookup_address, cast_compute_address, cast_create2, cast_interface, cast_age, cast_wallet_new, cast_wallet_address, cast_wallet_sign, cast_format_bytes32, cast_parse_bytes32, cast_concat_hex

Anvil Tools

| Tool | Description | |------|-------------| | anvil_start | Start a local Ethereum node | | anvil_stop | Stop a running node | | anvil_status | Check node status | | anvil_mine | Mine blocks | | anvil_setBalance | Set account balance | | anvil_setCode | Set contract bytecode | | anvil_setStorageAt | Set storage slot value | | anvil_impersonateAccount | Impersonate an account | | anvil_stopImpersonatingAccount | Stop impersonating | | anvil_snapshot | Create state snapshot | | anvil_revert | Revert to snapshot | | anvil_setNextBlockTimestamp | Set next block timestamp | | anvil_increaseTime | Increase block time | | anvil_setAutomine | Toggle auto-mining | | anvil_reset | Reset fork state | | anvil_getAccounts | List dev accounts |

Chisel Tools

| Tool | Description | |------|-------------| | chisel_eval | Evaluate Solidity expression | | chisel_run | Run Solidity statements | | chisel_list | List saved sessions | | chisel_load | Load a session | | chisel_view | View session source | | chisel_clear_cache | Clear cache |

Help Tools

| Tool | Description | |------|-------------| | forge_help | Get forge CLI help (supports subcommands) | | cast_help | Get cast CLI help (supports subcommands) | | anvil_help | Get anvil CLI help | | chisel_help | Get chisel CLI help | | foundry_version | Get installed Foundry versions | | foundry_list_commands | List available commands for a tool |

Available Resources

| Resource | URI | Description | |----------|-----|-------------| | Config | foundry://config | Project's foundry.toml | | Remappings | foundry://remappings | Import remappings | | Contracts | foundry://contracts | List of .sol files | | ABI | foundry://abi/{contract} | Contract ABI | | Bytecode | foundry://bytecode/{contract} | Contract bytecode | | Storage Layout | foundry://storage-layout/{contract} | Storage layout | | Method IDs | foundry://method-identifiers/{contract} | Function selectors | | Gas Estimates | foundry://gas-estimates/{contract} | Gas estimates | | Documentation | foundry://docs | Official Foundry docs | | Doc Links | foundry://docs/links | Documentation URLs |

Available Prompts

| Prompt | Description | |--------|-------------| | deploy_contract | Guide for deploying a contract | | debug_test | Help debug a failing test | | write_test | Generate tests for a contract | | explain_storage | Explain storage layout | | gas_optimization | Review for gas optimization | | security_review | Security review checklist | | fork_test | Test against forked state | | create_script | Create deployment script | | lookup_docs | Look up command documentation |

Development

# Clone the repository
git clone https://github.com/maxencerb/foundry-mcp.git
cd foundry-mcp

# Install dependencies
bun install

# Run in development mode
bun run dev

# Type check
bun run typecheck

# Test with MCP Inspector
bun run inspect

Contributing

Fork the repository
Create a feature branch
Add a changeset: bunx changeset
Submit a pull request

Security Notice

⚠️ Never use private keys with real funds when using this MCP server. LLMs can make mistakes and send unintended transactions. Use only for testing and development with test accounts.

Documentation

License

MIT

MCP Servers