MCP Ethers Wallet

Implementation Reference

• src/tools/core.ts:567-624 (registration)

  Registers the 'contractCall' tool with the MCP server, including schema and handler function.

  server.tool(
    "contractCall",
    {
      contractAddress: z.string().describe(
        "The address of the contract to call"
      ),
      abi: z.string().describe(
        "The ABI of the contract function to call, in JSON format"
      ),
      method: z.string().describe(
        "The name of the method to call"
      ),
      args: z.array(z.any()).optional().describe(
        "Optional. The arguments to pass to the contract function"
      ),
      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 ({ contractAddress, abi, method, args = [], provider, chainId }) => {
      try {
        const result = await ethersService.contractCallView(
          contractAddress,
          abi,
          method,
          args,
          provider,
          chainId
        );
        
        // Format the result
        let formattedResult = '';
        if (result === null || result === undefined) {
          formattedResult = 'null';
        } else if (typeof result === 'object') {
          formattedResult = JSON.stringify(result, null, 2);
        } else {
          formattedResult = String(result);
        }
        
        return {
          content: [{ 
            type: "text", 
            text: formattedResult
          }]
        };
      } catch (error) {
        return {
          isError: true,
          content: [{ 
            type: "text", 
            text: `Error calling contract function: ${error instanceof Error ? error.message : String(error)}`
          }]
        };
      }
    }
  );

• src/tools/core.ts:587-623 (handler)

  The handler function that performs the contractCall by invoking ethersService.contractCallView with the input parameters, formats the result, and returns it as MCP content.

  async ({ contractAddress, abi, method, args = [], provider, chainId }) => {
    try {
      const result = await ethersService.contractCallView(
        contractAddress,
        abi,
        method,
        args,
        provider,
        chainId
      );
      
      // Format the result
      let formattedResult = '';
      if (result === null || result === undefined) {
        formattedResult = 'null';
      } else if (typeof result === 'object') {
        formattedResult = JSON.stringify(result, null, 2);
      } else {
        formattedResult = String(result);
      }
      
      return {
        content: [{ 
          type: "text", 
          text: formattedResult
        }]
      };
    } catch (error) {
      return {
        isError: true,
        content: [{ 
          type: "text", 
          text: `Error calling contract function: ${error instanceof Error ? error.message : String(error)}`
        }]
      };
    }
  }

• src/tools/core.ts:569-586 (schema)

  Zod schema defining the input parameters for the contractCall tool: contractAddress, abi, method, optional args, provider, and chainId.

  {
    contractAddress: z.string().describe(
      "The address of the contract to call"
    ),
    abi: z.string().describe(
      "The ABI of the contract function to call, in JSON format"
    ),
    method: z.string().describe(
      "The name of the method to call"
    ),
    args: z.array(z.any()).optional().describe(
      "Optional. The arguments to pass to the contract function"
    ),
    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."
    )
  },