Twitter/X

@rahulgs claims OpenAI’s decision not to release Codex 5.3 in the API keeps it…

2026-02-06 · 19:03 UTC ·@rahulgs ·0 min read

Brief

Rahulgs argues that benchmark visibility is being shaped by product release decisions: if OpenAI withholds Codex 5.3 from the API, benchmark suites cannot test it, leaving 4.6 to benefit reputationally. The attached comparison post adds that Anthropic has taken the top spot on the Artificial Analysis Intelligence Index at 53, ahead of GPT-5.2 xhigh, with superior token efficiency.

Why it matters

@rahulgs claims OpenAI’s decision not to release Codex 5.3 in the API keeps it out of public benchmarks, which in turn makes version 4.6 look stronger by comparison.

Key details

  • A quoted post by @synthwavedd says Anthropic ranked first on the Artificial Analysis Intelligence Index with a score of 53, up 3 points from Opus 4.5 and 2 points ahead of GPT-5.2 xhigh.
  • The same quoted post claims Anthropic achieved the top index score while also delivering the best token efficiency among compared models.
Source evidence

title: @rahulgs: openai not releasing 5.3 codex in the api means no benchmarks have it, and default makes 4.6 look re...
author: @rahulgs
contenttype: tweet
publication: Twitter/X
published: 2026-02-06T19:03:33+00:00
sourceurl: https://x.com/rahulgs/status/2019849464144629792

word_count: 72

openai not releasing 5.3 codex in the api means no benchmarks have it, and default makes 4.6 look really good

leo 🐾 (@synthwavedd)

For what I'm pretty sure is the first time ever, Anthropic tops the @ArtificialAnlys Intelligence Index with a score of 53, a jump of 3 from Opus 4.5 and a lead of 2 versus GPT-5.2 xhigh

It does so with the best token efficiency of any model

— https://nitter.net/synthwavedd/status/2019816659574485423#m