Claude Opus 5.5 and Sonnet 5.5 now available in Google Antigravity

Google Antigravity has recently opened access to the models Claude Opus 5.5 and Sonnet 5.5 for users with a Google AI Pro or Ultra subscription. This addition, which is documented in the official model documentation, is only available to users who do not have a trial period. Free users and those with a Google AI Plus subscription are not eligible for these advanced models.

Antigravity serves as Google’s platform for software development, employing AI agents to assist in coding, executing tasks, and building applications. With the expansion of Claude models in Antigravity, developers can now choose from the same environment they already use for their projects. This makes it easy to ask the AI questions about specific coding issues, such as modifying validation for a contact form.

The choice between the Opus and Sonnet models depends on the nature of the work. Anthropic positions Opus 5.5 as the best choice for long-term programming or knowledge work, while Sonnet 5.5 focuses on speed and intelligence. For smaller, straightforward adjustments, such as design changes, it is advisable to start with Sonnet. Opus can be useful for more complex tasks involving multiple components of the application, making it very valuable to compare models within one environment.

In addition to the new models, it is also important to consider the subscription and usage limits. Google emphasizes that only users of Google AI Pro and Google AI Ultra have access to the new functionalities, while Enterprise users currently do not enjoy support. Finally, users should pay attention to the upcoming removal of older models such as Claude Sonnet 4.6 and Opus 4.6 on November 2, 2026, which is important for current users of these models.

Read the full article from AI Insider.