Claude Opus 5 has been leaked ahead of its official release, and the first wave of real-world test results from netizens have been unveiled.

Claude Opus 5 leaked early, and users have already run a full round of tests on it.

In a 3D generated scene shared by @chetaslua, a slingshot is launching projectiles at a city wall, with parameter panels for projectile tension and arrow weight clearly displayed on the left side of the frame. Every fine detail in the scene is rendered with exceptional clarity.

He noted that after using Opus for such a long time, he had never seen this level of detail in a single generated image before — no amount of stitching multiple captured frames together could produce an equivalent effect.

Similar reactions have been emerging nonstop these past few days, with some users even stating they would be willing to call it Fable 6.

This video is far from an isolated example, as more users have continued to share their own real-world test results over the past two days.

Users Are Already Testing Opus 5 Ahead of Official Launch

@chetaslua did not only share that single video.

On the same day, he posted another demo of a weather card interface, where lighting and shadows shift over time: on sunny days, the sun casts light across a frosted-glass style panel, and shadows move gradually as clouds drift across the view.

He also shared a kitchen scene, fully populated with fridge magnets, grout lines between tiles, and a reflective kettle on the stovetop — every element is rendered perfectly.

He summed up these effects in one line: after using Opus for so long, this is the first time he has seen this level of visual quality achievable with three.js.

Some users have even noticed that Opus 5's handling of this specific scene outperforms Fable.

@birdabo ran a head-to-head comparison test.

He submitted the exact same slingshot siege scene to both Opus 5 and the already released Fable 5 for generation.

While Fable 5 produced a complete output in one go, its tents were rendered as flat solid-color planes, the grass lacked natural undulations, and the slingshot was missing all the parameter panels for tension and arrow weight — the difference in detail density was clearly visible to the naked eye.

At the same time, @xikhar shared a completely different demo: a real-world test of a Minecraft recreation.

Getting AI models to recreate Minecraft has long been a classic benchmark challenge.

In the demo shared by the creator, the physical effects of block shattering and the shadows cast by light across surfaces are reproduced with remarkable accuracy.

He later posted an SVG diagram of a PS5 controller, where the reflections and shadows on the joysticks, trackpad, and buttons look indistinguishable from a physical product render.

The creator concluded that Opus 5 "excels at both 3D and 2D generation".

Early Signs of Opus 5 Are Emerging

The earliest traces of the Opus 5 leak appeared on July 9.

On that day, a codename named Honeycomb EAP showed up in Cursor's model selector.

Notably, this mysterious model was listed alongside Opus 4.8 and Sonnet 4.5, with labels indicating a 1M context window and a new "extra high effort" processing mode.

A few hours later, the mysterious model vanished from the interface.

On July 14, another user posted that they had spotted the Opus 5 entry in the Google Vertex AI model library.

The creator estimated the model could get an official release as early as that Thursday, while also expressing concern that Anthropic might use this as a reason to remove Fable 5 from the Claude subscription plan.

The next day, another creator shared the exact same piece of news.

Last night, @M1Astra published a new post stating that pre-launch traces of Opus 5 had appeared once more.

Shortly after, he added an update noting that Opus 5 had begun rolling out gradually across multiple service providers.

Early this morning, he updated his announcement again, confirming that some users have already gained access to Opus 5. Even though the interface still displays the model as 4.8, the difference in output quality is extremely noticeable.

And in the early hours of today, a screenshot was leaked online.

The screenshot, seemingly posted accidentally by an Anthropic employee, shows that after triggering Fable 5's safety guardrails, the user was automatically routed to Opus 5 by the system.

Opus 5 has also appeared under its official name in the Cursor editor.

It showed up in an error pop-up window, where the string "claude-opus-5-thinking-high" was displayed, alongside a notice that users need to enable Max Mode to use this model.

Based on the deductions of many users, the official public release of Opus is just around the corner.

A Budget Alternative to Fable 5?

As these real-world tests have gone viral, claims that Opus 5's performance can match Fable 5 have also been spreading widely.

This claim is particularly appealing because Fable 5 is priced at $10 per million input tokens and $50 per million output tokens — exactly double the cost of the Opus series.

If Opus 5 truly matches Fable 5's performance while retaining the Opus tier pricing, it would be a cost-effective alternative at half the price.

However, as of now, no complete, independently verifiable benchmark test results have been publicly released.

Additionally, whether the overall usage cost is lower cannot be judged by unit price alone.

The aforementioned creator Chetaslua noted that Opus 5 consumes tokens even faster than Fable 5, using up his entire credit limit with only three prompts.

If token consumption is really that high, the unit price advantage will disappear entirely, and the expectation of a 50% cost reduction will become unrealistic.

Still, Opus 5's official release should be coming very soon. We will only need to wait a little longer to find out if it can truly serve as a viable alternative to Fable.

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, written by Creasy, and republished with authorization from 36Kr.