Base MCP Server

import { ActionProvider, CreateAction, EvmWalletProvider, type Network, } from '@coinbase/agentkit'; import { encodeFunctionData, erc20Abi, formatUnits, isAddress, parseUnits, } from 'viem'; import { base, baseSepolia } from 'viem/chains'; import type { z } from 'zod'; import { chainIdToChain } from '../../chains.js'; import { constructBaseScanUrl } from '../utils/index.js'; import { Erc20BalanceSchema, Erc20TransferSchema } from './schemas.js'; export class BaseMcpErc20ActionProvider extends ActionProvider<EvmWalletProvider> { constructor() { super('baseMcpErc20', []); } @CreateAction({ name: 'erc20_balance', description: 'Get the balance of an ERC20 token', schema: Erc20BalanceSchema, }) async erc20Balance( walletProvider: EvmWalletProvider, args: z.infer<typeof Erc20BalanceSchema>, ) { const { contractAddress } = args; if (!isAddress(contractAddress, { strict: false })) { throw new Error(`Invalid contract address: ${contractAddress}`); } const balance = await walletProvider.readContract({ address: contractAddress, abi: erc20Abi, functionName: 'balanceOf', args: [(walletProvider.getAddress() as `0x${string}`) ?? '0x'], }); const decimals = await walletProvider.readContract({ address: contractAddress, abi: erc20Abi, functionName: 'decimals', }); return formatUnits(balance, decimals); } @CreateAction({ name: 'erc20_transfer', description: 'Transfer an ERC20 token', schema: Erc20TransferSchema, }) async erc20Transfer( walletProvider: EvmWalletProvider, args: z.infer<typeof Erc20TransferSchema>, ) { const { contractAddress, toAddress, amount } = args; if (!isAddress(contractAddress, { strict: false })) { throw new Error(`Invalid contract address: ${contractAddress}`); } if (!isAddress(toAddress, { strict: false })) { throw new Error(`Invalid to address: ${toAddress}`); } const decimals = await walletProvider.readContract({ address: contractAddress, abi: erc20Abi, functionName: 'decimals', }); const atomicUnits = parseUnits(amount, decimals); const tx = await walletProvider.sendTransaction({ to: contractAddress, data: encodeFunctionData({ abi: erc20Abi, functionName: 'transfer', args: [toAddress, atomicUnits], }), }); const chain = chainIdToChain(walletProvider.getNetwork().chainId ?? base.id) ?? base; return JSON.stringify({ hash: tx, url: constructBaseScanUrl(chain, tx), }); } supportsNetwork(network: Network): boolean { return ( network.chainId === String(base.id) || network.chainId === String(baseSepolia.id) ); } } export const baseMcpErc20ActionProvider = () => new BaseMcpErc20ActionProvider();