Google Antigravity Adds Claude Opus 5.5 and Sonnet 5.5 with Tier Access Policy

Google has officially integrated Anthropic's latest flagship models, Claude Opus 5.5 and Claude Sonnet 5.5, into Antigravity, its agentic development and coding workspace. The upgrade brings Anthropic's next-generation reasoning and long-context capabilities directly into the Antigravity developer environment.

Image source: @thtbee_ via X

Alongside the new model rollout, Google has clarified tier-specific access policies, excluded promotional and trial accounts from new Claude access, announced a November 2, 2026 deprecation date for legacy 4.6 models and open-weight models, and detailed an upcoming model restructuring for the consumer Gemini app.

Supported Subscription Tiers and Promotional Plan Exclusions

Access to Claude Opus 5.5 and Sonnet 5.5 in Antigravity is strictly segmented across Google's subscription tiers:

• Supported Tiers: Access is granted to standard paying subscribers of Google AI Pro ($19.99/month) and Google AI Ultra ($99.99+/month). Verified student plans also receive access to both models.
• Excluded Tiers: The Free tier, Google AI Plus ($4.99/month), and Enterprise plans are excluded from the new Claude 5.5 models.
• Promo and Trial Account Restrictions: Users holding Google AI Pro status through carrier partnerships, device bundles, or promotional trial periods will not receive access to the upgraded Claude 5.5 models despite holding a plan with the "Pro" label.

Developers and engineering teams should verify whether their Pro subscriptions are full commercial billing plans or promotional grants when configuring Antigravity workspaces.

November 2, 2026 Deprecation for Claude 4.6 and GPT-OSS-120B

In tandem with introducing the 5.5 series, Google established a formal sunset schedule for older platform models:

Claude Opus 4.6, Claude Sonnet 4.6, and the open-weight GPT-OSS-120B model will be permanently removed and retired from Antigravity on November 2, 2026.

• Transitional Availability: Until the November 2 retirement date, Opus 4.6 and Sonnet 4.6 remain accessible on Free, AI Plus, and Pro plans, while Ultra and Enterprise tiers do not offer them.
• Persistent Gemini Lineup: Gemini 3.8 Flash, Gemini 3.7 Flash, Gemini 3.6 Flash, and Gemini 3.1 Pro remain available across all tiers without interruption.

Teams with active automation pipelines or prompts anchored to the Claude 4.6 family or GPT-OSS-120B should migrate their agentic workflows to the 5.5 generation or Gemini models ahead of the November 2 cutoff.

Gemini App Restructuring from October 9 and Ecosystem Outlook

Beyond Antigravity, Google will restructure model access within the standalone Gemini consumer app starting October 9, 2026:

• Free Tier (Without a plan): Flash-Lite only
• Google AI Plus: Flash-Lite and Flash models
• Google AI Pro and Ultra: Flash-Lite, Flash, and Pro models (including Deep Think advanced reasoning)

This restructuring establishes clear performance boundaries between free/budget tiers and premium subscriptions, signaling that upcoming flagship releases—such as the anticipated Gemini 4 generation—will likely follow similar Pro and Ultra gating patterns.

Sources

• Bee (@thtbee_) Post on X: Antigravity Model Changes and Tier Policy