Arcee AI released Trinity Large Thinking on April 1 — the reasoning-optimized variant of their 400B sparse MoE, trained by a 30-person startup on 2,048 Nvidia B300 GPUs. It ranks #2 on PinchBench for agentic tasks at roughly 96% lower cost than the top model, under Apache 2.0. The architecture — 256 experts with 4 active per token — is worth understanding.
PrismML launched Bonsai on March 31, claiming the first commercially viable true 1-bit LLMs: an 8B model that fits in 1.15 GB and runs at 131 tokens/sec on an M4 Pro. The key word is "true" — every layer, including embeddings and attention, is 1-bit, not just the weights in isolation.
Microsoft released Harrier-OSS-v1, a family of decoder-only multilingual embedding models (270M, 0.6B, 27B) with a 32,768-token context window — roughly 30–60x longer than the 512–1,024 token ceiling most practitioners hit today. The 27B model takes SOTA on Multilingual MTEB v2 at 74.3; all three variants are MIT licensed.
Mr. Chatterbox is a 340M-parameter model trained exclusively on 28,000 Victorian-era texts from the British Library — definitively public domain, zero copyright exposure. Simon Willison's writeup documents both what it proves and what it falls short of: the corpus is large enough to train something coherent, but not large enough to be useful by Chinchilla norms.