Union Alpha stealth AI model launches with frontier-level performance

A new stealth AI model named ‘Union Alpha’ has emerged, demonstrating performance comparable to frontier models such as ‘Claude Fable 5.1’ and ‘GPT-6 Astra’ on the Terminal-Bench 4.0 benchmark. Designed for research, coding, and agentic workflows, the multimodal model features a context window of approximately 260,000 tokens and maintains a policy that input data is not used for training.

To mark its release, the model is being offered for free for one week through providers including OpenRouter, Cloudflare AI Gateway, and the coding AI agent OpenCode. The sudden availability of a high-performance model at no cost led to a massive surge in traffic, with processing volumes reaching 1 billion tokens per minute shortly after launch. While the model’s specific architecture and parameter count remain undisclosed, it is noted for its low cost, priced at less than $2 per task.