MCP Ethers Wallet

Implementation Reference

• src/tools/erc721.ts:230-257 (handler)

  The core handler logic for the 'getNFTTokenURI' tool. It uses the EthersService to fetch ERC721 metadata for the given contract and token ID, extracts the token URI, and returns it in the MCP response format. Handles errors gracefully.

  async (params) => {
    try {
      // Get the metadata which includes the token URI
      const metadata = await ethersService.getERC721Metadata(
        params.contractAddress,
        params.tokenId,
        params.provider,
        params.chainId
      );
      
      const uri = metadata.uri || "";
      
      return {
        content: [{ 
          type: "text", 
          text: `Token URI for token ${params.tokenId} is ${uri}`
        }]
      };
    } catch (error) {
      return {
        isError: true,
        content: [{ 
          type: "text", 
          text: `Error getting NFT token URI: ${error instanceof Error ? error.message : String(error)}`
        }]
      };
    }
  }

• src/tools/erc721.ts:54-59 (schema)

  TypeScript type definition for the input parameters of the getNFTTokenURI tool.

  type GetNFTTokenURIParams = {
    contractAddress: string;
    tokenId: string | number;
    provider?: string;
    chainId?: number;
  };

• src/tools/erc721.ts:224-229 (schema)

  Zod-based input schema for validating parameters in the getNFTTokenURI tool registration.

  {
    contractAddress: contractAddressSchema.describe("The address of the ERC721 contract"),
    tokenId: tokenIdSchema.describe("The ID of the token to get the URI for"),
    provider: providerSchema.describe("Optional. The provider to use. If not provided, the default provider is used."),
    chainId: chainIdSchema.describe("Optional. The chain ID to use.")
  },

• src/tools/erc721.ts:222-259 (registration)

  Direct registration of the getNFTTokenURI tool with the MCP server via server.tool(), including schema and handler.

  server.tool(
    "getNFTTokenURI",
    {
      contractAddress: contractAddressSchema.describe("The address of the ERC721 contract"),
      tokenId: tokenIdSchema.describe("The ID of the token to get the URI for"),
      provider: providerSchema.describe("Optional. The provider to use. If not provided, the default provider is used."),
      chainId: chainIdSchema.describe("Optional. The chain ID to use.")
    },
    async (params) => {
      try {
        // Get the metadata which includes the token URI
        const metadata = await ethersService.getERC721Metadata(
          params.contractAddress,
          params.tokenId,
          params.provider,
          params.chainId
        );
        
        const uri = metadata.uri || "";
        
        return {
          content: [{ 
            type: "text", 
            text: `Token URI for token ${params.tokenId} is ${uri}`
          }]
        };
      } catch (error) {
        return {
          isError: true,
          content: [{ 
            type: "text", 
            text: `Error getting NFT token URI: ${error instanceof Error ? error.message : String(error)}`
          }]
        };
      }
    }
  );

• src/tools/index.ts:25-25 (registration)

  Invocation of registerERC721Tools in the main tools index, which registers the getNFTTokenURI tool among other ERC721 tools.

  registerERC721Tools(server, ethersService);