Simon Willison’s Weblog

Subscribe

1st April 2026 - Link Blog

Draft: This is a draft post. Please do not share this URL with anyone else.

Announcing 1-bit Bonsai. PrismML is a newly out-of-stealth AI lab with a focus on researching "can we massively multiply intelligence in models without increasing their size or complexity?".

Their first model release is a model called Bonsai, and it's very small indeed: it comes in 1.7B, 4B and 8B parameter sizes but uses 1 bit parameters. Here are the sizes of the resulting models on Hugging Face:

Model Size
Bonsai-8B-mlx-1bit 1.3 GB
Bonsai-8B-gguf 1.16 GB
Bonsai-4B-gguf 572 MB
Bonsai-4B-mlx-1bit 645 MB
Bonsai-1.7B-gguf 248 MB
Bonsai-1.7B-mlx-1bit 285 MB

This is a link post by Simon Willison, posted on 1st April 2026.

Monthly briefing

Sponsor me for $10/month and get a curated email digest of the month's most important LLM developments.

Pay me to send you less!

Sponsor & subscribe