A mysterious high-performance AI model, 'Union Alpha,' has been unveiled, achieving benchmark scores equivalent to GPT-6 Astra and Claude Fable 5.1.



The AI relay service 'OpenRouter' has released a model called 'Union Alpha' as a 'stealth model' with its developer hidden. It achieved benchmark scores at the same level as GPT-6 Astra, and was later identified as unbiased.ai 's new model 'Pareto 26.9'.

Union Alpha - API Pricing & Providers | OpenRouter
https://openrouter.ai/stealth/union-alpha#activity

Union Alpha is a multimodal model built for research, coding, and agent workflows, and is touted as delivering state-of-the-art performance across a wide range of tasks.

It was released on OpenRouter on September 16, 2026. It was initially planned to be offered for free for one week on a trial basis, but the trial period ended after only one day. It has a context window of 262,144 tokens and has achieved benchmark scores comparable to GPT-6 Astra and Claude Fable 5.1.




Union Alpha's official X account also appeared, posting that it was 'processing 1 billion tokens per minute' during the trial period, highlighting the significant amount of traffic it was receiving.




Then, just one day after its release, it was revealed that Union Alpha is unbiased.ai's new model, 'Pareto 26.9'. According to Union Alpha's X account, 'We released it anonymously because we wanted to know the actual user reactions, understand the challenges that come with scaling up, and reflect them in the official release scheduled for October 10, 2026.'




However, after its release, usage far exceeded expectations. The day after its release, demand reached billions of tokens per minute, causing processing speeds to drop to an unusable level. With the help of AWS, processing capacity was tripled overnight, but even then, it was not enough to meet the demand. As a result, they decided to end the free anonymous service early and switch to paid access.

The prices after the introduction of fees are $2.50 (approximately 390 yen) for input, $0.25 (approximately 39 yen) for cash, and $7.50 (approximately 1170 yen) per million tokens for output. Union Alpha added that this is 'less than a quarter of Astra's original price.'

Union Alpha is also available on Cloudflare.

Union Alpha (stealth) · Cloudflare AI docs · Cloudflare AI docs
https://developers.cloudflare.com/ai/models/stealth/union-alpha/

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in AI, Posted by log1p_kr