Customers throughout X report sharper outputs and unusually lengthy response occasions in ChatGPT and Codex this week.
Some customers reported considerably improved internet design and 3D online game outputs from ChatGPT.
A proper launch for GPT-5.6 is rumored for subsequent week, however OpenAI has but to announce plans.
One thing felt completely different in ChatGPT this week—and lots of people seen directly.
Throughout X, testers spent the previous two days swapping screenshots and stopwatch occasions, all pointing to at least one principle: OpenAI is quietly A/B testing GPT-5.6 inside ChatGPT, swapped in for some customers who choose GPT-5.5 Professional.
Developer Anshu Chimala posted a side-by-side video on Thursday evaluating one-shot touchdown pages, captioning it: “Effectively properly properly, I am one of many fortunate ones with early GPT-5.6 Professional entry.”
Effectively properly properly, I am one of many fortunate ones with early GPT-5.6 Professional entry!
One-shot pages from 5.5 Professional vs 5.6 Professional. Are you able to inform which is which? Appears to be like like OpenAI’s lastly getting someplace with design: pic.twitter.com/xghxmsANMG
— Anshu (@anshuc) June 19, 2026
Developer Dobroslav Radosavljevič posted on X that no matter he is working inside Codex, OpenAI’s coding agent, “feels waaaaaaaay completely different than [the] 5.5 mannequin.” Replies beneath cut up between believers and other people calling it placebo.
The clearest sample throughout the posts is time. Conor Dart, one of many many X customers amplifying the rumors, ran the check with a one-prompt 3D browser recreation—with physics and digital camera controls—that took simply over an hour to generate, versus GPT-5.5 Professional’s traditional 10-minute mark.
“Not good, however for a one-prompt AI recreation dev check, that is severely spectacular,” Dart wrote.
Presumably GPT-5.6 Professional inside ChatGPT utilizing GPT 5.5 Professional….
I ran the identical fashion of recreation construct after testing GLM 5.2, and this truthfully felt so much smoother.
The total recreation took actually 60 minutes and 15 seconds to create. ( GPT 5.5 Professional at all times responded with in a 10min mark)
AI insider Chetas Lua reported an analogous slowdown testing a robotic simulation, additionally fairly certain his outcomes come from OpenAI’s new mannequin: “GPT 5.6 Professional continues to mog [Anthropic’s Fable 5] in 3D check,” he wrote. “Engaged on video games one shot too.”
In a separate put up, he famous response occasions stretching to twenty or 40 minutes, a tempo he stated hadn’t proven up since earlier than GPT-5.5 shipped.
🚨 GPT 5.6 Professional first output on the identical immediate
we’re getting began > frontend/ webdev will not be solved or improved but > however understanding elevated so much > it began to take 20-40 minutes once more prefer it used to do earlier than 5.5 professional https://t.co/zcLehTbe5c pic.twitter.com/C7u6ZRUfjT
— Chetaslua (@chetaslua) June 18, 2026
Not each comparability flattered the rumored mannequin. Chris, an AI benchmarker on X, gave two fashions the identical spaceship-building immediate—the suspected GPT-5.6 Professional labored for 87 minutes towards GPT-5.5 Additional Excessive’s 34 minutes and 42 seconds.
“As I’ve stated earlier than, based mostly on nice authority, GPT-5.6 will likely be an incremental/strong enchancment over GPT-5.5, not a Fable killer,” he wrote, whereas noting Fable 5 nonetheless beat each fashions on the spaceship’s core geometry. “My tough expectation has been that it will commerce blows with Fable 5 on some benchmarks, perhaps win round half relying on the class, however not clearly surpass it total.”
A separate put up attributed to leaker Pankaj Kumar detailed leaks going additional: a data cutoff pushed to December 2025, a reasoning-effort setting some testers name “Juice Worth” allegedly raised to 960 from 768, and SVG and 3D design era sturdy sufficient to beat Fable 5 on some duties.
None of it comes from OpenAI—however the particulars are constant throughout accounts: stronger reasoning, an unfinished entrance finish, and a launch candidate nicknamed Kindle-Alpha.
An AI influencer generally known as Leo, citing unnamed sources, wrote in a thread that the suspected mannequin is “now being stealth examined when 5.5 Professional is chosen in ChatGPT,” no less than for some Professional accounts, with a deliberate public launch the next Thursday, June 25.
For those who’re questioning how individuals in your timeline appear to have entry to GPT-5.6 Professional, it is now being stealth examined when 5.5 Professional is chosen in ChatGPT (*no less than for some Professional accounts)!
I’ve additionally been informed subsequent Thursday is the deliberate launch date for five.6
— leo 🐾 (@synthwavedd) June 18, 2026
The closest factor to an OpenAI fingerprint on any of this can be a memo, not a tweet. Chief scientist Jakub Pachocki reportedly informed employees the subsequent mannequin is a significant enchancment over GPT-5.5, in accordance with a report from The Data. That is nonetheless not affirmation of A/B testing, a launch date, or any spec floating round X, however it does affirm a brand new mannequin has been brewing.
Decrypt reached out to OpenAI to ask whether or not GPT-5.6 is being examined inside ChatGPT, however the firm didn’t reply by the point of publication.
Why OpenAI could be in a rush
If OpenAI is speeding a brand new flagship mannequin out the door, it has causes to. China’s open-source mannequin GLM-5.2 trails Claude Opus 4.8 by only one level on FrontierSWE—a benchmark that scores AI brokers on multi-hour, open-ended engineering tasks by dominance price—whereas beating GPT-5.5 outright on the identical check.
Anthropic, in the meantime, is coping with injury of its personal making. The corporate’s flagship Mythos 5 and Fable 5 fashions stay pulled underneath a U.S. export management directive issued June 12 over a disputed jailbreak vulnerability, leaving a spot on the prime of the market that GLM-5.2 and a hypothetical GPT-5.6 are each positioned to fill.
If Anthropic CEO Dario Amodei and President Donald Trump make peace, then Fable 5 can be rather more highly effective than some other mannequin at the moment accessible, with the standard hole between Anthropic’s prime mannequin and OpenAI’s changing into a lot larger than earlier than.
There’s additionally cash on the desk. OpenAI is reportedly weighing worth cuts on the tokens it prices builders and enterprises, in accordance with the Wall Avenue Journal, in anticipation of Anthropic doing the identical as each firms put together for dueling IPOs.
Whether or not any of it provides as much as an precise GPT-5.6 launch is one thing solely OpenAI can affirm, and the corporate has stayed quiet by way of per week of leaked checkpoints and stealth-testing claims. Polymarket merchants aren’t ready round, nonetheless—contracts on a launch between June 22 and June 28 have priced as excessive as 89% this week.
Day by day Debrief Publication
Begin day-after-day with the highest information tales proper now, plus authentic options, a podcast, movies and extra.