Open weights is not open source, and the boardroom is starting to notice. the osi's definition…
open weights is not open source, and the boardroom is starting to notice. the osi's definition requires the full training and inference code plus enough data detail to rebuild the model, which most releases don't ship.
the label is now a liability.
Context
The Open Source Initiative's Open Source AI Definition 1.0 says the preferred form for modification must include data information (sufficiently detailed information about the training data so that a skilled person can build a substantially equivalent system), the complete source code used to train and run the system, including data processing and filtering, training and inference code, and the parameters. It says open source models and open source weights must include the data information and code used to derive those parameters.
The note's paraphrase of the OSI requirements is close. The definition requires data information and not the data itself. The claim that most releases do not ship these was not supported by a survey or count, and no specific model was audited here. The boardroom is starting to notice has no evidence in what was read. No source read states whether Kimi K3, which AWS and Moonshot call open-weight and whose license has a commercial condition, meets the definition.
Related work
- Earlier note on Kimi K3 on Bedrock ↗An open-weight model with a commercial license condition.
Watch next
- An audit of which major releases meet the definition.
Sources
- The Open Source AI Definition 1.0 (OSI)opensource.org
Provenance
The note above is reproduced unedited from the original post, first published on Threads on 21 September 2026 at 17:22 IST. Sources are the papers and datasets the note draws on.
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