Bonsai 27B: the first 27B-class open model that runs on a phone

PrismML released Bonsai 27B under Apache 2.0 in two low-bit variants: a 1-bit version (binary weights, 3.9 GB) that fits on an iPhone 17 Pro and a ternary version (5.9 GB) for laptops. Built on Qwen3.6 27B, PrismML reports the ternary variant keeps about 95% of full-precision benchmark performance across math, coding, tool-calling, and vision, with the 1-bit variant at about 90%.

What it means A 27B-class model in 3.9 GB moves serious multi-step agent work onto hardware you already own — no API bill, no data leaving the device.