MCP Ethers Wallet

Implementation Reference

• src/tools/core.ts:786-837 (registration)

  Registration of the 'lookupAddress' MCP tool using server.tool(), including schema and handler function.

  server.tool(
    "lookupAddress",
    {
      address: z.string().describe(
        "The Ethereum address to resolve"
      ),
      provider: z.string().optional().describe(PROVIDER_DESCRIPTION),
      chainId: z.number().optional().describe(
        "Optional. The chain ID to use. If provided with a named network and they don't match, the RPC's chain ID will be used."
      )
    },
    async ({ address, provider, chainId }) => {
      try {
        const ethProvider = await ethersService.getProvider(provider, chainId);
        
        // Look up the ENS name for an address
        const name = await ethProvider.lookupAddress(address);
        
        if (!name) {
          return {
            content: [{ 
              type: "text", 
              text: JSON.stringify({
                address,
                resolved: false,
                message: "No ENS name found for this address"
              }, null, 2)
            }]
          };
        }
        
        return {
          content: [{ 
            type: "text", 
            text: JSON.stringify({
              address,
              name,
              resolved: true
            }, null, 2)
          }]
        };
      } catch (error) {
        return {
          isError: true,
          content: [{ 
            type: "text", 
            text: `Error looking up ENS address: ${error instanceof Error ? error.message : String(error)}`
          }]
        };
      }
    }
  );

• src/tools/core.ts:797-836 (handler)

  Handler function that performs ENS reverse lookup: resolves Ethereum address to ENS name using ethers Provider.lookupAddress method.

  async ({ address, provider, chainId }) => {
    try {
      const ethProvider = await ethersService.getProvider(provider, chainId);
      
      // Look up the ENS name for an address
      const name = await ethProvider.lookupAddress(address);
      
      if (!name) {
        return {
          content: [{ 
            type: "text", 
            text: JSON.stringify({
              address,
              resolved: false,
              message: "No ENS name found for this address"
            }, null, 2)
          }]
        };
      }
      
      return {
        content: [{ 
          type: "text", 
          text: JSON.stringify({
            address,
            name,
            resolved: true
          }, null, 2)
        }]
      };
    } catch (error) {
      return {
        isError: true,
        content: [{ 
          type: "text", 
          text: `Error looking up ENS address: ${error instanceof Error ? error.message : String(error)}`
        }]
      };
    }
  }

• src/tools/core.ts:788-796 (schema)

  Zod input schema for the lookupAddress tool, validating address (required string), optional provider and chainId.

  {
    address: z.string().describe(
      "The Ethereum address to resolve"
    ),
    provider: z.string().optional().describe(PROVIDER_DESCRIPTION),
    chainId: z.number().optional().describe(
      "Optional. The chain ID to use. If provided with a named network and they don't match, the RPC's chain ID will be used."
    )
  },