GPT-5.6 Rumors Heat Up as Users Swear ChatGPT Suddenly Got Smarter

This week, something felt different in ChatGPT, and many people noticed it right away.

On

Developer Anshu Chimala posted a side-by-side video on Thursday, he compares one-shot landing pages with the caption: “Well, I’m one of the lucky ones with early GPT-5.6 Pro access.”

Developer Dobroslav Radosavljevič posted on X that whatever he’s running in Codex, OpenAI’s coding agent, “feels waaaaaaaay different from [the] 5.5 model.” The comments below are split between believers and those who call it placebo.

The clearest pattern in the messages is time. Conor Dart, one of several

“Not perfect, but for a one-shot AI game developer test, this is seriously impressive,” Dart wrote.

AI insider Chetas Lua reported a similar delay when testing a robot simulation, and he is also quite sure that his results come from OpenAI’s new model: “GPT 5.6 Pro remains possible [Anthropic’s Fable 5] in 3D test,” he wrote. “Also working on games in one go.”

In a separate message, he noted response times stretching to 20 or 40 minutes, a pace he said had not appeared since before GPT-5.5 shipped.

Not every comparison flattered the rumor model. Chris, an AI benchmarker on

“As I’ve said before, based on strong authority, GPT-5.6 will be an incremental/solid improvement over GPT-5.5, not a Fable killer,” he says. wrotenoting that Fable 5 still beat both models in terms of core starship geometry. “My rough expectation was that it would draw blows with Fable 5 on some benchmarks, maybe gain about half of it depending on the category, but not clearly outperform it overall.”

A separate post attributed to leaker Pankaj Kumar detailed leaks going even further: a knowledge frontier pushed back to December 2025, a reasoning effort that some testers call “Juice Value” reportedly increased from 768 to 960, and SVG and 3D design generation strong enough to beat Fable 5 on some tasks.

None of it comes from OpenAI, but the details are consistent across accounts: stronger reasoning, an unfinished front end, and a release candidate nicknamed Kindle-Alpha.

An AI influencer known as Leo, citing unnamed sources: wrote in a thread that the suspected model is “now in stealth testing when 5.5 Pro is selected in ChatGPT”, at least for some Pro accounts, with a planned public launch on Thursday, June 25.

The closest thing to an OpenAI fingerprint in this area is a memo, not a tweet. Chief scientist Jakub Pachocki reportedly told staff that the next model would be a meaningful improvement above GPT-5.5, according to a report from The information. That still doesn’t confirm A/B testing, a release date, or any specs floating around X, but it does confirm that a new model is in the works.

Declutter reached out to OpenAI to ask if GPT-5.6 is being tested in ChatGPT, but the company did not respond by time of publication.

Why OpenAI might be in a hurry

If OpenAI is rushing a new flagship model out the door, it has reasons to do so. Chinese open-source model GLM-5.2 is just one point behind Claude Opus 4.8 on FrontierSWE – a benchmark that scores AI agents on multi-hour, open-ended engineering projects based on dominance percentage – while GPT-5.5 is roundly beaten on the same test.

Anthropic, meanwhile, is dealing with damage of his own making. The company’s Mythos 5 and Fable 5 flagship models remain under a US export control directive issued on June 12 due to a disputed jailbreak vulnerability, leaving a gap at the top of the market that GLM-5.2 and a hypothetical GPT-5.6 could both fill.

If Anthropic CEO Dario Amodei and President Donald Trump make peace, Fable 5 would be far more powerful than any other model currently available, with the quality gap between Anthropic’s top model and OpenAI becoming much wider than before.

There is also money on the table. OpenAI is reportedly weighing price cuts on the tokens it charges developers and enterprises, according to the Wall Street Journalin anticipation of Anthropic doing the same as both companies prepare for dueling IPOs.

Whether this will actually lead to a GPT-5.6 release, only OpenAI can confirm, and the company has remained silent throughout a week of leaked checkpoints and stealth test claims. Polymarkt However, traders are not waiting: contracts launched between June 22 and June 28 have returned a whopping 89% price this week.