AI Governance Engineer
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Open-weight model

By Updated

A model whose trained weights are published for download under a licence that may be permissive, copyleft, use-restricted or custom 1. Open weights are not open source; the deployer produces almost all the evidence (hashes, scans, evals, red team) and must honour the licence and any acceptable-use policy.

Developed in
ch. 15, Open-weight licences
ch. 18, Open-source carve-outs and their limits
Chapters
ch. 15, Deployment · ch. 18, EU AI Act
Contrast with
Responsible-AI licence (OpenRAIL)
Source
1 numbered reference, listed below

Where it is used

3 chapters of the Body of Knowledge use the term. Each link opens the first section that does.

  • Acceptable-use policy (AUP)

    The staff-facing rules for using AI tools: which tools are approved, which data classes may go where, duties to review and disclose outputs, logging…

  • Deployer

    Under the EU AI Act, whoever uses an AI system under its own authority, other than in a purely personal, non-professional activity.

  • Evals

    Automated tests of a model's or agent's behaviour (capability, safety and adversarial), run as controls, not as one-off research.

Sources

  1. [1] Llama 3.1 Community License Agreement (an example of an open-weight licence with an incorporated acceptable-use policy and attribution terms). Meta. 2024-07-23. https://github.com/meta-llama/llama-models/blob/main/models/llama3_1/LICENSE (verified: primary)

Definitions of legal terms paraphrase the cited text, which governs. Dated statements are as of .

Cite this term

García Aibar, J. (2026). Open-weight model. In AI Governance Engineering: The Thesis & Body of Knowledge (v0.5.0), Glossary. https://doi.org/10.5281/zenodo.22956197. https://aigovernanceengineer.com/glossary/open-weight-model. CC BY 4.0

BibTeX

@misc{aige2026openweightmodel,
  author  = {Jorge García Aibar},
  title   = {{Open-weight model}},
  note    = {Glossary, AI Governance Engineering: The Thesis \& Body of Knowledge, version 0.5.0},
  year    = {2026},
  doi     = {10.5281/zenodo.22956197},
  url     = {https://aigovernanceengineer.com/glossary/open-weight-model}
}