Claude Opus terminated on Google AI Ultra for Business - works fine on Google AI Pro

Google Antigravity
1

Summary:
Claude Opus (claude-opus-4-5 or equivalent) consistently gets terminated mid-task when using a Google AI Ultra for Business account in Antigravity. The same model works correctly on a personal Google AI Pro account.

Models affected:

  • [FAIL] Claude Opus – terminated/fails on Google AI Ultra for Business
  • [OK] Claude Sonnet – works on Google AI Ultra for Business
  • [OK] All other models – work on Google AI Ultra for Business
  • [OK] Claude Opus – works correctly on Google AI Pro (personal account)

Steps to reproduce:

  1. Sign in to Antigravity with a Google AI Ultra for Business account.
  2. Select Claude Opus as the active model.
  3. Start a task with the agent.
  4. Observe the model session getting terminated/cut off.

Expected behavior:
Claude Opus should complete tasks on Google AI Ultra for Business accounts just as it does on Google AI Pro personal accounts.

Actual behavior:
The Opus session is terminated. Other models (Sonnet, etc.) work without issue on the same Business account.

Environment:
Windows, Google AI Ultra for Business subscription

Additional context:
Since Opus works on Pro but not Business, this appears to be an account-tier or API permission discrepancy rather than a model-level issue.