getStorageAt.ts•2.54 kB
import { z } from "zod";
import { CallToolResult } from "@modelcontextprotocol/sdk/types";
import { INFURA_CHAIN_URLS } from "../../config/chains.js";
import { JsonRpcResponse } from "../../types/rpc.js";
export const getStorageAt = {
name: "eth_get_storage_at",
description:
"Returns the value from a storage position at a given address. Defaults to Ethereum mainnet if no chain is specified.",
schema: {
address: z.string().describe("Contract address (20 bytes)"),
position: z
.string()
.describe(
"Hexadecimal storage position (e.g. 0x0 or keccak slot hash for mappings)"
),
block: z
.string()
.describe(
"Hex block number (e.g. 0x65a8db) or tag (latest, earliest, pending, safe, finalized)"
),
chainid: z
.number()
.optional()
.describe("EVM chain ID (default: 1 for Ethereum mainnet)"),
},
handler: async ({
address,
position,
block,
chainid,
}: {
address: string;
position: string;
block: string;
chainid?: number;
}): Promise<CallToolResult> => {
try {
const selectedChainId = chainid ?? 1;
const url = INFURA_CHAIN_URLS[selectedChainId];
if (!url) {
return {
content: [
{ type: "text", text: `Unsupported chain ID: ${selectedChainId}` },
],
};
}
const body = {
jsonrpc: "2.0",
method: "eth_getStorageAt",
params: [address, position, block],
id: 1,
};
const res = await fetch(url, {
method: "POST",
headers: { "Content-Type": "application/json" },
body: JSON.stringify(body),
});
const data: JsonRpcResponse = await res.json();
if (!data.result) {
return {
content: [
{
type: "text",
text: `Error fetching storage: ${data.error?.message || "Unknown error"}`,
},
],
};
}
return {
content: [
{
type: "text",
text: `Storage at ${position} for ${address} at ${block} on chainid ${selectedChainId}: ${data.result}`,
},
],
};
} catch (err: unknown) {
const message =
err instanceof Error
? err.message
: typeof err === "string"
? err
: JSON.stringify(err);
return {
content: [
{ type: "text", text: `Error fetching storage: ${message}` },
],
};
}
},
};