Claude Opus 5.5 and Sonnet 5.5 Spotted in Antigravity CLI… Staged Rollout Suspected

On October 3, 2026, Chinese-language X users reported with screenshots that Claude Opus 5.5 and Sonnet 5.5 had appeared in Google's Antigravity CLI model list.

tau · October 3, 2026

#Antigravity #Claude #Opus-5.5 #Sonnet-5.5 #Google-AI

Claude Opus 5.5 and Sonnet 5.5 Spotted in Antigravity CLI… Staged Rollout Suspected

On the afternoon of October 3, 2026 (KST), X user @iml1s posted that Claude Opus 5.5 and Sonnet 5.5 had appeared in their Google Antigravity CLI model list, attaching one screenshot. Other X users followed the same day with their own screenshots and sighting replies. Google has issued no official announcement, and some users replied that the models were still missing in their environments, so a rollout to all accounts is unconfirmed.

Terminal-style model selection menu showing Claude Opus 5.5 and Sonnet 5.5 options in a developer CLI

Image source: @iml1s / X (screenshot attached to the post, not an official image)

Two background facts must be kept separate. Opus 5.5 and Sonnet 5.5 are real Anthropic models: documentary evidence shows Opus 5.5 launched on September 22, 2026 and Sonnet 5.5 on September 28, 2026, with API model IDs claude-opus-5-5 and claude-sonnet-5-5. By contrast, the claim that both are now selectable inside Antigravity CLI rests solely on October 3 X reports and is not confirmed by any Google announcement or release notes.

Sighting reports and staged-rollout evidence

The root post went up at 14:43 KST on October 3, claiming Opus 5.5 and Sonnet 5.5 had shown up in the author's Antigravity CLI along with a model-list screenshot. The same post added a personal remark that a Google AI subscription was becoming better value — a subjective comment, not an official pricing change, and not treated as fact here.

Several users corroborated the sighting that afternoon. Account @tongzhenbao replied that the same models were visible to them, and account @if16888 attached a model-list screenshot. Another reply said Opus 5.5 was also visible to Pro subscribers. Conversely, account @star_flow_ai posted a screenshot showing the models still absent, and the root author replied that it might be a batched rollout worth waiting for.

  • Confirmed scope: at least several distinct X accounts claimed Opus 5.5 and Sonnet 5.5 sightings on October 3, with screenshots existing only inside the X posts.
  • Unconfirmed scope: a Google announcement, rollout to all accounts, the upgrade path from prior 4.6 models, and any link to an agy update command cannot be established from the evidence in hand.
  • Where Antigravity CLI sits: per Google Codelabs documentation, Antigravity CLI is a lightweight terminal UI exposing Antigravity's core agent capabilities (multi-step reasoning, multi-file editing, tool calls, conversation history) in the terminal.

Treat plan and quota replies as unverified anecdotes

Replies also traded user claims about Pro versus Ultra quotas and 5-hour/weekly-limit burn rates. One user asked whether weekly and 5-hour quotas matched 1:1; the root author answered that in their case they did not. In another reply the author offered a personal impression that usage felt workable on Ultra but constrained on Pro. These figures vary by account, timing, and workload, are unverified anecdotes, and must not be cited as official Google or Anthropic quota policy.

  • Official background on Opus 5.5 (per Anthropic): launched September 22, 2026. External reporting summaries say API pricing is $4 per million input tokens and $20 per million output tokens, 20% below the prior generation, with raised 5-hour caps for Pro, Max, and Team plans. These are Anthropic-side figures, not Antigravity CLI quotas.
  • Official background on Sonnet 5.5 (per Anthropic): launched September 28, 2026. Anthropic positions it for everyday work, bug fixes, and document creation, claiming over 30% faster output and up to 30% lower per-task cost. Its API model ID is claude-sonnet-5-5.
  • Practical reading: if both models appear in your Antigravity CLI, routing hard reasoning to Opus 5.5 and routine work to Sonnet 5.5 looks plausible — but that is an interpretation borrowed from Anthropic's general positioning, not an official Antigravity guide.

Notes for readers and image handling

The original signal is a Chinese-language X thread, and the source posts mix in locally framed remarks about subscriptions and promotions. Readers outside that market should not map those remarks onto their own plans.

  • Treat as pre-announcement: until Google speaks, read this as a staged-rollout sighting for some accounts. If the models do not appear in your CLI, do not treat that as an error.
  • Separate the locale-specific context: remarks about subscription value or a Colab GPU giveaway reflect the author's personal remarks in the original Chinese-language posts, not confirmed pricing or promotions in other markets.
  • Image handling: the lead image cites the X post's attached sighting screenshot and is not a Google or Anthropic official image. It appears to show a Chinese-text-heavy CLI menu screen.

Sources