add configuration steps

Author: montycheese

docs/base-account/improve-ux/sub-accounts.mdx

@@ -264,6 +264,23 @@ console.log('Owner added to Sub Account');
 
 Auto Spend Permissions allows Sub Accounts to access funds from their parent Base Account when transaction balances are insufficient. This feature can also establish ongoing spend permissions, enabling future transactions to execute without user approval prompts, reducing friction in your app's transaction flow.
 
+### Configuration
+
+Auto Spend Permissions is only available in SDK version `2.0.2-canary.20250822164845` or later. This feature is **enabled by default** when using Sub Accounts.
+
+To disable Auto Spend Permissions when using Sub Accounts, set `unstable_enableAutoSpendPermissions` to `false` in your SDK configuration:
+
+```tsx
+const sdk = createBaseAccountSDK({
+  appName: 'Base Account SDK Demo',
+  appLogoUrl: 'https://base.org/logo.png',
+  appChainIds: [base.id],
+  subAccounts: {
+    unstable_enableAutoSpendPermissions: false, // Disable auto spend permissions
+  }
+});
+```
+
 ### How it works
 
 **First-time transaction flow:**