Add support for querying other wallet balance

src/tools/get_balance_other.ts

@@ -0,0 +1,50 @@
+import {
+  LAMPORTS_PER_SOL,
+  ParsedAccountData,
+  PublicKey,
+} from "@solana/web3.js";
+import { SolanaAgentKit } from "../index";
+
+/**
+ * Get the balance of SOL or an SPL token for the specified wallet address (other than the agent's wallet)
+ * @param agent - SolanaAgentKit instance
+ * @param wallet_address - Public key of the wallet to check balance for
+ * @param token_address - Optional SPL token mint address. If not provided, returns SOL balance
+ * @returns Promise resolving to the balance as a number (in UI units) or 0 if account doesn't exist
+ */
+export async function get_balance_other(
+  agent: SolanaAgentKit,
+  wallet_address: PublicKey,
+  token_address?: PublicKey,
+): Promise<number> {
+  try {
+    if (!token_address) {
+      return (
+        (await agent.connection.getBalance(wallet_address)) / LAMPORTS_PER_SOL
+      );
+    }
+
+    const tokenAccounts = await agent.connection.getTokenAccountsByOwner(
+      wallet_address,
+      { mint: token_address },
+    );
+
+    if (tokenAccounts.value.length === 0) {
+      console.warn(
+        `No token accounts found for wallet ${wallet_address.toString()} and token ${token_address.toString()}`,
+      );
+      return 0;
+    }
+
+    const tokenAccount = await agent.connection.getParsedAccountInfo(
+      tokenAccounts.value[0].pubkey,
+    );
+    const tokenData = tokenAccount.value?.data as ParsedAccountData;
+
+    return tokenData.parsed?.info?.tokenAmount?.uiAmount || 0;
+  } catch (error) {
+    throw new Error(
+      `Error fetching on-chain balance for ${token_address?.toString()}: ${error}`,
+    );
+  }
+}

src/tools/index.ts

@@ -2,6 +2,7 @@ export * from "./request_faucet_funds";
 export * from "./deploy_token";
 export * from "./deploy_collection";
 export * from "./get_balance";
+export * from "./get_balance_other";
 export * from "./mint_nft";
 export * from "./transfer";
 export * from "./trade";