Monad MCP

npm install

// Create a new MCP server instance const server = new McpServer({ name: "monad-testnet", version: "0.0.1", // Array of supported tool names that clients can call capabilities: ["get-mon-balance"] });

server.tool( // Tool ID "get-mon-balance", // Description of what the tool does "Get MON balance for an address on Monad testnet", // Input schema { address: z.string().describe("Monad testnet address to check balance for"), }, // Tool implementation async ({ address }) => { try { // Check MON balance for the input address const balance = await publicClient.getBalance({ address: address as `0x${string}`, }); // Return a human friendly message indicating the balance. return { content: [ { type: "text", text: `Balance for ${address}: ${formatUnits(balance, 18)} MON`, }, ], }; } catch (error) { // If the balance check process fails, return a graceful message back to the MCP client indicating a failure. return { content: [ { type: "text", text: `Failed to retrieve balance for address: ${address}. Error: ${ error instanceof Error ? error.message : String(error) }`, }, ], }; } } );

### Add functionality to query NFT count server.tool( // Function identifier "get-nft-count", // Function description "Query the number of NFTs held by an address on the Monad testnet", // Parameter definition { address: z.string().describe("The Monad testnet address to query"), nftContract: z.string().describe("NFT contract address") }, // Function implementation async ({ address, nftContract }) => { try { // Call the contract's balanceOf method to get the NFT count const balance = await publicClient.readContract({ address: nftContract as `0x${string}`, abi: [ { inputs: [{ name: "owner", type: "address" }], name: "balanceOf", outputs: [{ name: "", type: "uint256" }], stateMutability: "view", type: "function" } ], functionName: "balanceOf", args: [address as `0x${string}`] }); // Return the formatted query result return { content: [ { type: "text", text: `The address ${address} holds ${balance.toString()} NFTs in contract ${nftContract}.`, }, ], }; } catch (error) { // Error handling return { content: [ { type: "text", text: `Failed to query NFT count for address ${address}: ${ error instanceof Error ? error.message : String(error) }`, }, ], }; } } );

async function main() { // Create a transport layer using standard input/output const transport = new StdioServerTransport(); // Connect the server to the transport await server.connect(transport); console.error("Monad testnet MCP Server running on stdio"); }

npm run build

{ "mcpServers": { ... "monad-mcp": { "command": "node", "args": [ "/<path-to-project>/build/index.js" ] } } }