Union Alpha Launches on OpenRouter: Free Multimodal Model with 256K Context and Tool Calling

OpenRouter has launched a new model called Union Alpha. Described as a multimodal model for research, coding, and agentic workflows, it is free to use and features a 256K context window and tool calling capabilities. According to the announcement, the model delivers frontier-level general-purpose performance.

Union Alpha debuted as a "stealth model" on OpenRouter, where users can try it and share feedback. The platform also noted that significantly more capacity for Union Alpha will come online on the morning of September 18, 2026, after users experienced some hiccups during the initial rollout.

OpenRouter, an AI model aggregation platform, hosts a variety of large language models. Union Alpha adds a new multimodal option for tasks spanning research, coding, and agentic workflows. The announcement did not include detailed technical specifications, leaving real-world performance to be evaluated by users.