Programming Assignment: Ethereum Trading MCP Server
Overview
This project is a Model Context Protocol (MCP) server built in Rust that enables AI agents to query balances and execute token swaps on Ethereum.
Features
get_balance: Query ETH and ERC20 token balances.get_token_price: Get current token price in USD using Chainlink price feeds.swap_tokens: Simulate a token swap on Uniswap V2.
Technical Stack
- Rust with Tokio for async runtime.
- ethers-rs for Ethereum RPC communication.
- rmcp for the MCP server framework.
- rust_decimal for financial precision.
- dotenv for managing environment variables.
Setup
-
Install Rust:
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
-
Clone the repository:
git clone <repository-url>
cd <repository-name>
-
Set up environment variables:
Create a .env file in the root of the project and add your Ethereum RPC endpoint and a private key for simulations. You can use a service like Infura or Alchemy.
# .env
INFURA_PROJECT_ID=your_infura_project_id
PRIVATE_KEY=your_wallet_private_key
-
Build the project:
cargo build --release
-
Run the server:
cargo run --release
The server will start on 127.0.0.1:8080.
Example MCP Tool Call
Here is an example of calling the get_balance tool using curl.
Request:
curl -X POST -H "Content-Type: application/json" -d '{
"jsonrpc": "2.0",
"method": "get_balance",
"params": {
"wallet_address": "0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B"
},
"id": 1
}' http://127.0.0.1:8080
Response:
{
"jsonrpc": "2.0",
"result": {
"balance": "..."
},
"id": 1
}
Design Decisions
- ethers-rs vs. alloy: I chose
ethers-rs as it is more mature and has extensive documentation, which is beneficial for a project with a tight deadline.
- Uniswap V2 for Swaps: I implemented swaps using Uniswap V2 for simplicity. The V2 router provides straightforward functions like
swapExactTokensForTokens, which is easier to integrate than V3's more complex architecture.
- Environment Variables for Secrets: Sensitive information like the Infura project ID and private keys are managed through a
.env file, which is a standard and secure practice.
Known Limitations
- Limited Token Support: The
get_token_price and swap_tokens tools currently support a hardcoded list of tokens (ETH, DAI, USDC). This could be extended by using a dynamic token list or a discovery mechanism.
- Uniswap V2 Only: The swap functionality is limited to Uniswap V2. Adding V3 support would require a more complex implementation to handle concentrated liquidity and path finding.
- Basic Error Handling: The error handling is basic. A production-ready server would need more robust error handling and reporting.
Tests
To run the tests, use the following command:
cargo test
The tests cover the core functionality of the MCP tools. Note that the tests require a valid INFURA_PROJECT_ID and PRIVATE_KEY in the .env file to run.
