Modelpeers

GPT-5.5 changelog

Every change to GPT-5.5 that Modelpeers has recorded, newest first, each with the source it came from. The record starts Apr 23, 2026.

All (7)Releases (3)Retiring (2)Breaking changes (1)Quality (1)

July 2026

OpenAI Codex character

OpenAI Codex and GPT-5.5

2 products from OpenAI

Quality report · Reported, unverified

Codex users report GPT-5.5 reasoning tokens clustering at 516, linked to weaker answers

A GitHub issue analyzing Codex token metadata from February 1 to June 27, 2026 found gpt-5.5 responses landing disproportionately at exactly 516 reasoning tokens, consistent with a reasoning-budget threshold. The author says it does not prove truncation. The thread drew 372 points and 152 comments.

Who is affected:
Codex users running gpt-5.5 on complex tasks.
What to do:
No action needed. GPT-5.5 retired from Codex with ChatGPT sign-in on October 14, 2026.

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