Gemini 3.1 Pro vs UI-TARS-2

Gemini 3.1 Pro

Google DeepMind

Gemini 3.1 Pro is a multimodal language model from Google DeepMind, released in preview in February 2026 as a point-version upgrade to Gemini 3 Pro focused on improving reasoning depth, factual grounding, and coding and agentic task performance. The model accepts text, images, video, audio, and PDFs as inputs across a 1M token context window, extending the multimodal breadth of the Gemini 3 series with a companion endpoint specifically optimized for custom tool use in agentic pipelines. Google describes it as built to refine the reliability and performance of the Gemini 3 Pro series, reflecting an incremental engineering iteration rather than an architectural overhaul.

ByteDance

UI-TARS-2, released by ByteDance in September 2025, is a major generational upgrade of the UI-TARS family of GUI interaction models, with enhanced capabilities across computer control, game environments, code generation, and tool use. It targets agentic workflows requiring robust multimodal understanding of graphical interfaces across diverse application domains.