In this article
  1. What happened
  2. What Pro and Ultra get with Argon today
  3. Why it matters
  4. What to do

TL;DR: Antigravity removes Claude Sonnet 4.6, Claude Opus 4.6 and GPT-OSS-120b on November 2, 2026; switch any workflow that uses them before then.

What happened

Google’s Antigravity models page now marks three reasoning models with the note “Will be removed on November 2, 2026”: Claude Sonnet 4.6 (thinking), Claude Opus 4.6 (thinking) and GPT-OSS-120b.

According to that page’s availability table, the three models reach different plans today:

  • Free and Google AI Plus: Claude Sonnet 4.6, Claude Opus 4.6 and GPT-OSS-120b are all available.
  • Google AI Pro: all three are available.
  • Google AI Ultra: only GPT-OSS-120b is available.
  • Enterprise: none of the three is available.

The same table lists Gemini 4 Argon, which Google rolled out in Antigravity on October 13 “for Google AI Pro and Ultra subscribers — available in the Antigravity desktop app and the Antigravity CLI.”

What Pro and Ultra get with Argon today

Google’s three official pages describe Argon access in their own words:

  • Models page: Argon is ticked for Google AI Pro, Ultra and Enterprise, and not for Free or Google AI Plus. On Pro it is “Available on Google AI Pro for non-trial subscriptions only.” It is also “Not available in Antigravity IDE. Available in the Antigravity App, Antigravity CLI, and IDE extensions.”
  • Plans page: Pro users get “A high, generous quota, refreshed every five hours until the weekly limit is reached” and “A higher weekly rate limit.” Ultra users get “The highest, most generous quota, refreshed every five hours” and “The highest weekly rate limits.” Google adds that “Usage limits for this service are subject to modification.” The page publishes no fixed numbers.
  • Google One AI plans page: Ultra includes “Higher access to Gemini 4 Argon in Google Antigravity.” The Pro plan’s list doesn’t mention Antigravity.

When baseline quota runs out, the plans page says Pro and Ultra users “can use purchased AI credits (or any one-time promotional credits) for additional overage usage above the baseline quota.” An “AI Credit Overages” setting controls this, with two options: “Never” and “Always.” Antigravity does not currently support bring-your-own-key for extra rate limits.

Why it matters

The impact of the November 2 removal depends on your plan:

  • Free and Google AI Plus users lose all three models, Claude 4.6 included, because the table gives those plans no Claude 5.5 models. After the removal, the table lists Gemini 3.8 Flash as their only reasoning model.
  • Pro users on a paid plan keep Claude through Sonnet 5.5 and Opus 5.5. Pro trial users don’t get the 5.5 models or Argon, so after the removal the table lists Gemini 3.8 Flash as their only reasoning model.
  • Ultra users lose only GPT-OSS-120b.

If you rely on Argon, check two limits. Pro trials don’t include it, and the Antigravity IDE doesn’t run it. Google publishes no fixed quota for Argon, so the only way to judge how far a plan goes is the usage display in your own Settings page.

What to do

  1. Check which model your workflows use. If an automation, custom agent or saved setup uses Claude Sonnet 4.6, Claude Opus 4.6 or GPT-OSS-120b, switch it before November 2. Antigravity’s October 15 app update (v2.24.0) added a model choice for automations: Flash Lite, Flash or Pro.
  2. If you’re on a Pro trial, the models page says Argon and the Claude 5.5 models need a paid Pro plan, and that you can “submit an upgrade request” to switch.
  3. If you code in the Antigravity IDE, use the Antigravity App, the CLI or the IDE extensions to reach Argon.
  4. Watch your quota in Settings. Leave AI Credit Overages on “Never” unless you mean to spend credits once the baseline quota runs out.
  5. Recheck before you commit. Google says limits are “subject to modification,” so read the plans and models pages again before you choose a plan.

Sources & method

Sources

Method. Last checked October 19, 2026. All plan details and quotes come from Google’s own pages; Google publishes no fixed quota numbers, and we don’t cite any. No affiliate links on this page. How we work.

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