If you cannot find Claude 5.5 in Antigravity, look at your subscription status first, rather than changing model settings first. From 2 November 2026, Claude is no longer in the accounts of the free edition, Google AI Plus, and the Google AI Pro trial period. Claude Sonnet 5.5 and Opus 5.5 are only provided to paid Google AI Pro and Ultra subscriptions; trial periods and promotional periods are counted as trials, and likewise cannot see these two models.
What exactly changed on 2 November
On the same day, Claude Sonnet 4.6, Claude Opus 4.6, and GPT-OSS-120b were removed from the model list, and only Gemini-series models remained in free and Plus accounts. In other words, free users who previously used Claude through 4.6 have had no Claude option in Antigravity since that day. Paid Pro and Ultra accounts are unaffected: the two 5.5 models can be seen in the model selector, and when the quota is exceeded, AI credits can still be used to top up according to the settings.
Confirm in three steps, then decide whether to upgrade
Step one: open the subscription page and confirm whether it is a paid, non-trial Pro or Ultra; trial, promotional-period, and student-discount plans should all be treated first as not included. Step two: look for Claude 5.5 in Antigravity's model selector; if you cannot find it, go back to step one and do not repeatedly reinstall the app. Step three, then decide: if you cannot do without Claude, switch to a full-price paid subscription, and the models will unlock automatically after the switch; if you do not want to upgrade, keep working with Gemini models, or use Claude Code and the API to reach Claude directly. One more reminder before upgrading: the official side has not explained the treatment of promotional and student plans in one go, so check your own plan against the official model table first, then pay.
