Strands Decider 2B Strands Decider 2B is a 2-billion-parameter open-source decision model released by AWS Strands Labs. Built on a Qwen3.5-2B torso with the language-model head replaced by a 1-million-parameter pointer head, it scores a supplied list of options and returns a calibrated choice in tens of milliseconds without generating text, making it suitable for local agent routing, tool selection and action gating.