---
title: Guide: Claude Desktop Integration
category: guide
date: 2025-11-28
difficulty: intermediate
estimated_time: 15 minutes
---
# Claude Desktop Integration
## Overview
This guide shows how to integrate MCP Anvil Tools with Claude Desktop for AI-powered Ethereum development.
## Prerequisites
- MCP Anvil Tools installed and built
- Claude Desktop application installed
- Absolute path to the mcp-anvil-tools directory
## Configuration
### Step 1: Locate Config File
**macOS:**
```bash
~/Library/Application Support/Claude/claude_desktop_config.json
```
**Windows:**
```
%APPDATA%\Claude\claude_desktop_config.json
```
**Linux:**
```bash
~/.config/Claude/claude_desktop_config.json
```
### Step 2: Edit Configuration
Add the MCP server configuration:
```json
{
"mcpServers": {
"anvil-tools": {
"command": "node",
"args": [
"/absolute/path/to/mcp-anvil-tools/dist/index.js",
"--stdio"
],
"env": {
"AUDIT_MCP_PORT": "3000",
"MAINNET_RPC_URL": "https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY",
"ETHERSCAN_API_KEY": "your_etherscan_api_key"
}
}
}
}
```
**Important:**
- Use **absolute paths** (not relative)
- Include the `--stdio` flag
- Add your own API keys
### Step 3: Restart Claude Desktop
Close and reopen Claude Desktop for changes to take effect.
## Verification
### Check Server Availability
In Claude Desktop, you should see "anvil-tools" listed in available MCP servers.
### Test a Tool
Ask Claude:
> "Use the read_bytecode tool to get the bytecode at address 0x..."
Claude should be able to call the tool and return results.
## Example Prompts
### Read Contract Storage
> "Read storage slot 0 of the contract at 0x5fbdb2315678afecb367f032d93f642f64180aa3 on my local Anvil"
### Trace a Transaction
> "Trace this transaction with callTracer: 0x1234..."
### Create Snapshot
> "Create a snapshot called 'before-test' on Anvil"
### Simulate Transaction
> "Simulate calling the transfer function on this ERC20 contract"
## Troubleshooting
### Problem: Tools not appearing
**Symptom:** Claude doesn't see anvil-tools
**Solutions:**
1. Verify the path in config is absolute and correct
2. Check that `dist/index.js` exists (run `npm run build`)
3. Restart Claude Desktop completely
### Problem: Tool execution errors
**Symptom:** Tools return errors
**Solutions:**
1. Check environment variables are set correctly
2. Verify Anvil is running if using local tools
3. Check RPC URLs are valid
### Problem: stdio communication issues
**Symptom:** No response from tools
**Solutions:**
1. Ensure `--stdio` flag is included
2. Check there are no console.log statements polluting stdout
3. Verify Node.js version is 18+
## Advanced Configuration
### Multiple Networks
Configure multiple RPC endpoints:
```json
{
"mcpServers": {
"anvil-tools": {
"command": "node",
"args": [
"/path/to/mcp-anvil-tools/dist/index.js",
"--stdio"
],
"env": {
"MAINNET_RPC_URL": "https://eth-mainnet...",
"SEPOLIA_RPC_URL": "https://eth-sepolia...",
"ARBITRUM_RPC_URL": "https://arb-mainnet..."
}
}
}
}
```
### Custom Anvil Port Range
```json
{
"env": {
"ANVIL_PORT_START": "8545",
"ANVIL_PORT_END": "8555"
}
}
```
## Related Documents
- [Getting Started Guide](./guide-getting-started-2025-11-28.md)
- [Configuration Reference](../reference/reference-configuration-2025-11-28.md)
- [API Tools Reference](../api/api-tools-reference-2025-11-28.md)
