lookupAddress

lookupAddress

Resolve Ethereum addresses to human-readable ENS names using the MCP Ethers Wallet server. Specify network or RPC URL for cross-chain lookups.

Input Schema

TableJSON Schema

Name	Required	Description
`address`	Yes	The Ethereum address to resolve
`provider`	No	Optional. Either a network name or custom RPC URL. Use getAllNetworks to see available networks and their details, or getNetwork to get info about a specific network. You can use any network name returned by these tools as a provider value.
`chainId`	No	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.

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."
  )
},

MCP Ethers Wallet

Input Schema

Implementation Reference

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