Amber + Wisp login flow:

1. In Wisp, tap "Log in with signer"
2. It opens Amber — you should see a permission request to sign an auth event
3. In Amber, tap "Allow" (or "Always allow" for Wisp)
4. It should redirect you back to Wisp automatically

If it's stuck in Amber without showing a prompt:
- Make sure your key is imported into Amber (Settings → Keys)
- Try clearing Amber's cache and restarting it
- Update both apps — older versions had bugs with the intent redirect
- On some Android versions, you need to set Amber as the default handler: go to Android Settings → Apps → Amber → Set as default → add "nostrsigner" scheme

The key step most people miss is the default handler setup. Without it, Android doesn't know to redirect back to Wisp after signing.