eth_getStorageAt

Retrieve storage values from smart contracts on EVM blockchains by specifying contract address and storage position to access contract state data.

Instructions

Returns the value from a storage position at a given address

Input Schema

TableJSON Schema

Name	Required	Description	Default
`address`	Yes	Contract address
`blockNumber`	No	Block number or 'latest', 'earliest', 'pending'	latest
`position`	Yes	Storage position (hex string)

Implementation Reference

src/index.ts:682-716 (handler)

The asynchronous handler function for the 'eth_getStorageAt' tool. It makes an RPC call to eth_getStorageAt with the provided address, position, and blockNumber, formats the result, and returns it in the MCP response format. Handles errors by returning an error message.

async ({ address, position, blockNumber }) => {
  try {
    const result = await makeRPCCall("eth_getStorageAt", [
      address,
      position,
      blockNumber,
    ]);

    return {
      content: [
        {
          type: "text",
          text: formatResponse(
            {
              address,
              position,
              value: result,
              block: blockNumber,
            },
            "Storage Value",
          ),
        },
      ],
    };
  } catch (error: any) {
    return {
      content: [
        {
          type: "text",
          text: `Error: ${error.message}`,
        },
      ],
    };
  }
},

src/index.ts:673-681 (schema)

Zod schema defining the input parameters for the eth_getStorageAt tool: address (string), position (string, hex), blockNumber (string, optional, default 'latest').

{
  address: z.string().describe("Contract address"),
  position: z.string().describe("Storage position (hex string)"),
  blockNumber: z
    .string()
    .optional()
    .default("latest")
    .describe("Block number or 'latest', 'earliest', 'pending'"),
},

src/index.ts:670-717 (registration)

The server.tool() call that registers the 'eth_getStorageAt' tool with the MCP server, including name, description, schema, and handler function.

server.tool(
  "eth_getStorageAt",
  "Returns the value from a storage position at a given address",
  {
    address: z.string().describe("Contract address"),
    position: z.string().describe("Storage position (hex string)"),
    blockNumber: z
      .string()
      .optional()
      .default("latest")
      .describe("Block number or 'latest', 'earliest', 'pending'"),
  },
  async ({ address, position, blockNumber }) => {
    try {
      const result = await makeRPCCall("eth_getStorageAt", [
        address,
        position,
        blockNumber,
      ]);

      return {
        content: [
          {
            type: "text",
            text: formatResponse(
              {
                address,
                position,
                value: result,
                block: blockNumber,
              },
              "Storage Value",
            ),
          },
        ],
      };
    } catch (error: any) {
      return {
        content: [
          {
            type: "text",
            text: `Error: ${error.message}`,
          },
        ],
      };
    }
  },
);

src/index.ts:89-96 (helper)

Generic helper function used by the eth_getStorageAt handler (and others) to make RPC calls to the Ethereum provider.

async function makeRPCCall(method: string, params: any[] = []): Promise<any> {
  try {
    const result = await provider.send(method, params);
    return result;
  } catch (error: any) {
    throw new Error(`RPC call failed: ${error.message}`);
  }
}

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