Claude Opus 5 has leaked early, and netizens have already put it through a full round of testing.
In a 3D-generated scene posted by @chetaslua, a catapult is launching stones at a city wall. On the left side of the image, parameter cards for projectile tension and arrow weight are displayed, along with various other details, all rendered with exceptional clarity.
He said, having used Opus for so long, I've never seen this level of detail in a single image, not even by piecing together multiple screenshots.
Similar reactions have been popping up over the past couple of days, with some even saying they'd be willing to call it fable 6.
Of course, this video wasn't an isolated case. Others have been posting different real-world tests over these past days.
Netizens Take Opus 5 for a Spin First
@chetaslua didn't post just one video.
On the same day, he shared a weather card interface where lighting and shadows change as time progresses. When it's sunny, sunlight falls on a frosted glass panel; when clouds pass by, the shadows shift accordingly.
There was also a kitchen scene complete with fridge magnets, gaps between tiles, and the reflection on a kettle on the stovetop.
He attributed these effects to one statement: after using Opus for so long, it's the first time he's felt that three.js could achieve this level of quality.
Some users even found that Opus 5's handling of this scene has surpassed that of fable.
@birdabo conducted a head-to-head comparison.
For the same catapult siege scene, he fed it to both Opus 5 and the already-released Fable 5.
While Fable 5 generated the scene in one go, its tents were flat single-color planes, the grass lacked texture, and the catapult itself was missing parameter panels for tension and arrow weight. The density of detail was visibly lower.
At the same time, @xikhar shared a completely different scene—a real-world test of recreating Minecraft.
Asking models to recreate Minecraft has already become a classic test.
In the demo shown by the blogger, the physical effects of block breakage and the shadows cast by light on surfaces were reproduced vividly.
Later, he posted an SVG image of a PS5 controller, where the highlights and shadows on the joysticks, touchpad, and buttons looked like a product render.
The blogger therefore commented that Opus 5 is "strong in both 3D and 2D."
Hints of Opus 5 Already Appearing
The earlier traces of the Opus 5 leak appeared around July 9th.
On that day, a codename called Honeycomb EAP appeared in Cursor's model selector.
Key point: this mysterious model was listed alongside Opus 4.8 and Sonnet 4.5, and was annotated with a 1M context window and a setting called "extra high effort."
A few hours later, this mysterious model disappeared again.
On July 14th, another user posted that they saw an entry for Opus 5 in the Google Vertex AI model library.
This blogger estimated the model would be officially released as early as Thursday, while also expressing concern that Anthropic might use this as an excuse to remove Fable 5 from the Claude subscription plan.
The next day, another blogger posted the same news.
Last night, @M1Astra made a new post saying that preliminary traces of Opus 5 had appeared once more.
Not long after, he added another post, indicating that Opus 5 had begun rolling out to various provider platforms.
This morning, he updated again, stating that some users were already using Opus 5. Although the interface still displayed 4.8, the output difference was stark.
Also, in the early hours of this morning, a screenshot leaked.
A screenshot, seemingly mistakenly sent by someone posing as an Anthropic employee, showed that after triggering Fable 5's guardrail, the system routed him to Opus 5.
Furthermore, Opus 5 appeared under its real name within Cursor.
Specifically, it appeared in an error pop-up window, which contained the string "claude-opus-5-thinking-high". The pop-up indicated that Max Mode needed to be enabled to use it.
According to some users' speculation, Opus's official release isn't far off.
A Fable 5 Alternative?
As this round of real-world tests gained traction, talk of Opus 5's performance matching Fable 5's also began to circulate.
This claim is particularly enticing because Fable 5 is priced at $10 per million tokens for input and $50 for output, exactly twice the price of the Opus series.
If Opus 5 truly matches Fable 5's performance while remaining at the Opus price point, it would be a functional alternative at half the price.
However, as of now, no complete, independently verifiable benchmark results have been made public.
Also, whether it's actually cheaper overall cannot be judged solely by per-token price.
The blogger Chetaslua mentioned at the beginning stated that Opus 5 consumes tokens even more voraciously than Fable 5, exhausting his quota with just three prompts.
If token consumption is indeed that massive, then the per-token price advantage would disappear, shattering the expectation of being half the price.
Nevertheless, Opus 5's release is likely imminent. Whether it can truly be an alternative to fable will become clear with a bit more waiting.
References:
[1]https://x.com/chetaslua/status/2080290382315925911
[2]https://x.com/cheatyyyy/status/2080359098214953421
[3]https://x.com/M1Astra/status/2080246754104971356
[4]https://x.com/birdabo/status/2080340647622623315
This article is from the WeChat public account "QbitAI", author: Krei Xi
