EVM MCP Server

Instructions

Implementation Reference

• src/core/tools.ts:32-78 (handler)

  The handler, schema, and registration for the 'get_chain_info' MCP tool. It takes an optional network parameter, fetches chainId via services.getChainId, blockNumber via services.getBlockNumber, and rpcUrl via getRpcUrl, then returns formatted JSON.

  server.tool(
    'get_chain_info',
    'Get information about an EVM network',
    {
      network: z
        .string()
        .optional()
        .describe(
          "Network name (e.g., 'ethereum', 'optimism', 'arbitrum', 'base', etc.) or chain ID. Supports all EVM-compatible networks. Defaults to Ethereum mainnet."
        )
    },
    async ({ network = 'ethereum' }) => {
      try {
        const chainId = await services.getChainId(network);
        const blockNumber = await services.getBlockNumber(network);
        const rpcUrl = getRpcUrl(network);
  
        return {
          content: [
            {
              type: 'text',
              text: JSON.stringify(
                {
                  network,
                  chainId,
                  blockNumber: blockNumber.toString(),
                  rpcUrl
                },
                null,
                2
              )
            }
          ]
        };
      } catch (error) {
        return {
          content: [
            {
              type: 'text',
              text: `Error fetching chain info: ${error instanceof Error ? error.message : String(error)}`
            }
          ],
          isError: true
        };
      }
    }
  );

• src/core/services/transactions.ts:45-49 (helper)

  Helper function getChainId(network) that creates a public client and calls client.getChainId() to get the numeric chain ID.

  export async function getChainId(network = 'ethereum'): Promise<number> {
    const client = getPublicClient(network);
    const chainId = await client.getChainId();
    return Number(chainId);
  } 

• src/core/services/blocks.ts:10-13 (helper)

  Helper function getBlockNumber(network) that retrieves the latest block number using the public client.

  export async function getBlockNumber(network = 'ethereum'): Promise<bigint> {
    const client = getPublicClient(network);
    return await client.getBlockNumber();
  }

• src/core/chains.ts:326-335 (helper)

  Helper function getRpcUrl(network) that maps network name or chain ID to the corresponding RPC endpoint URL.

  export function getRpcUrl(
    chainIdentifier: number | string = DEFAULT_CHAIN_ID
  ): string {
    const chainId =
      typeof chainIdentifier === 'string'
        ? resolveChainId(chainIdentifier)
        : chainIdentifier;
  
    return rpcUrlMap[chainId] || DEFAULT_RPC_URL;
  }

• src/server/server.ts:18-19 (registration)

  Call to registerEVMTools(server) which includes the registration of get_chain_info among other tools.

  registerEVMTools(server);
  registerEVMPrompts(server);