Google staff reportedly test Gemini 4 Carbon, compare coding to Opus 5.5
Business Insider reports that Google staff are testing a new Gemini 4 version codenamed Carbon on the internal coding platform Jetski. One employee said it “feels like Opus 5.5” for coding but cautioned that more testing is needed; Google has tested Argon, Barium and Carbon variants, and it is unclear whether Carbon will ship as an Argon update or a separate model. Google declined to comment, while the already-announced Argon is not yet broadly available and Antigravity has shown references and subscription prompts for it.
The reported feedback suggests Carbon could narrow Google's coding-agent gap with Anthropic, though the comparison is subjective and Google has not confirmed it.
Google is preparing Antigravity for Gemini 4 Argon, with new labels appearing around usage limits, subscriptions, and prompts to upgrade to Google AI Ultra. These additions suggest Ultra subscribers could be among the first users to access Argon in the coding app. Google’s September 30 announcement already names Ultra subscribers and paid API customers as the starting point for its broader rollout, after giving access to trusted cyber defenders.
UTM links in Antigravity already point to destinations mentioning "Argon" related params: utm_source=antigravity&utm_campaign=argon_model_selector
Google says Argon is already powering internal workflows and reports a 77.9% score on DeepSWE v1.1, which evaluates longer software engineering tasks. This places Antigravity in Google’s push toward agents that can handle complex coding work over extended periods. The new subscription labels point to rollout preparations, although they do not establish an Antigravity release date.
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We also spotted an agent prototype internally called Concierge, with support for real-time voice. It appears to be an early implementation, so its presence does not establish that Google plans to ship it. If released, Concierge could let developers direct agent work through spoken requests.
#Google#Gemini 4 Carbon#Gemini 4 Argon#Antigravity#Jetski#Claude Opus 5.5#Google DeepMind#Barium