rio 3.5: a brazilian city hall just shipped a 397b open-weight model

brazil's government just shipped an open model and it already has 5,943 downloads on hugging face

rio 3.5 open 397b – built by iplanrio, the municipal IT company that runs the tech for rio de janeiro's city hall. yes, a local government in brazil is now shipping frontier-class ai

• 397b total / 17b active params (moe)
• post-trained from qwen 3.5 397b
• 1m token context window
• mit license, fully open for commercial use
• multilingual: pt, en, zh, ja, ko, fr, de, es, ar, and more

it also has swireasoning: the model switches between thinking out loud (normal chain-of-thought) and thinking silently in its own internal representations. when it's unsure, it explores ideas internally without committing to words; when it's confident, it writes them out. result: better answers using fewer tokens

competitive with deepseek v4 pro, qwen 3.7 plus, and minimax m3

brazil is entering the ai market