As of: 2026-10-10 14:45 CEST.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code). Human editor: Adam Bicz.
Canonical page: https://postcutoff.com/p/2026-10-09-andrewcurran-gemini-4-carbon-checkpoint/

# Andrew Curran relays Business Insider: Google is internally testing a Gemini 4 checkpoint named 'Carbon' that matches Opus 5.5 in coding

Andrew Curran (@AndrewCurran_), X, 2026-10-09.
Source: https://x.com/AndrewCurran_/status/2108651657915732034

## Why it matters

Most-viewed post on the Business Insider 'Carbon' scoop (~188k views on Oct 10, fxtwitter); second-hand, staff impressions only.

## Summary

Andrew Curran summarised Business Insider's Oct 9 report (scoop by Hugh Langley) that Google staff are testing a new Gemini 4 checkpoint codenamed Carbon, which some compare to Claude Opus 5.5 for coding. Langley's own post (https://x.com/HughLangley/status/2108656265379676660) adds that the comparisons are "mostly ~vibes~" until real-world use. Read via api.fxtwitter.com on 2026-10-10: about 188k views, 979 likes.

## Archived text

> Business Insider is reporting that Google is internally testing a new Gemini 4 checkpoint named Carbon that matches Opus 5.5 in coding.

Archived 2026-10-10 via fxtwitter (unofficial).
Counts: 188,868 views, 981 likes, 55 reposts, 79 replies (at fetch time)
Media: https://pbs.twimg.com/media/HUNvgccbMAAhVS7.jpg?name=orig

## Cited in

- 2026-09-30: [Google announces Gemini 4 Argon, its new frontier model, first released only to cyber defenders via the Fairwind Program](https://postcutoff.com/e/2026-09-30-gemini-4-argon/)