Gemini Krypton: testers post outputs from an unannounced Google model, and Google has said nothing

Gemini Krypton, a Google model codename nobody had used before, spread across AI accounts on X on November 9. Every sighting so far is a tester's own post. Google has not announced, named or acknowledged a Krypton model.

WHAT IS CIRCULATING

• 06:12 UTC: @chetaslua posted side-by-side outputs labelled Gemini Krypton, Gemini Carbon and Gemini Argon. He calls it the "krypton-a version first checkpoint" and says it takes about twice as long, and writes about twice as much code, on the same prompt.
• 07:55 UTC: he posted a short animated film he says Krypton wrote in code from a single prompt, with the code and prompt attached, and says the run took 39 minutes.
• 09:03 UTC: @Mr_Salio compared it with Claude Opus 5.5. By his account Opus finished faster and Krypton's visuals were better.
• 10:16 UTC: @lyraxana posted comparison videos labelled Gemini 4 Krypton vs Carbon vs Argon, the first use of a Gemini 4 prefix for it.
• @LuminaBench and @kimmonismus amplified the outputs. Kimmonismus says he cannot verify them himself.

WHAT WE CAN SAY

• Google names its Gemini 4 builds after elements. Argon shipped as gemini-4-argon on October 13. Carbon was announced on October 28 and is still not open to developers. Business Insider reported a third checkpoint, Barium, on October 9.
• None of the testers say where they are running Krypton.
• At 11:49 UTC, no model id containing krypton is listed on OpenRouter or models.dev.

WHAT WE DO NOT KNOW

Whether Krypton is a real Google release candidate, whether it would ship as a Gemini 4.x or a Gemini 5, and when. The outputs above are the testers' own and have not been checked independently. ArtificialWatch's radar watches for any Gemini model id containing krypton and alerts the moment one is listed.