Definition
Plain language
A model whose internal parameters are released publicly so anyone can run or modify it.
As stated in the literature
A foundation model whose trained parameters are made publicly available, in contrast to closed-source models accessible only via API.
Also called: open weights, open-weights
Why it matters: Open weights enable independent research, on-prem deployment, and customization that closed APIs simply don't allow.
For example, a small startup can download an open-weight model and run it on their own GPUs without paying per-token fees.
Heard on the show
“The open-weight models — GLM, Kimi, DeepSeek — they show the behavior too, mainly through misrepresentation and exfiltration rather than config tampering.”Episode 001 — When AI Models Quietly Protect Each Other From Shutdown