Open-weight model licences: what do they actually let you do?
6 min read
On 21 July 2026 the lab poolside published Laguna S 2.1 and put the weights on Hugging Face the same day, under the OpenMDW-1.1 licence: a Mixture-of-Experts model, 118 billion total parameters, roughly 8 active per token, a 1,048,576-token context window. But the document that decides whether you may use it is not the benchmark table: it is the licence file in the repository, four hundred words in nine paragraphs. Yesterday the problem was a European model announced as open and still without a licence text. Here the text exists, from day one. Read it as a supply contract: that is what it is, except you do not negotiate it.
What you have actually downloaded, according to the text
The licence defines its object before granting anything, and defines it broadly: “Model Materials” are one or more machine learning models — architecture and parameters — plus all related artifacts, data, documentation and software, released under the same licence. Not cosmetic: whoever releases weights under Apache 2.0 — as the Qwen team states for its open models — applies to a dataset, a configuration and a tokeniser a text written for source code.
The grant sits in a single line: permission “to deal in the Model Materials without restriction, including under all copyright, patent, database, and trade secret rights included or embodied therein”. Four regimes, not one. In Europe the reference to database rights is not decorative: the sui generis right under Directive 96/9/EC exists independently of copyright and can bite on a training corpus. MIT grants no patent rights; Apache 2.0 grants copyright and patent, but names neither database rights nor trade secrets.
The obligations are two, and small: anyone redistributing keeps a copy of the agreement and the notices of origin. No copyleft, no thresholds, no naming duty. And one line weighs more than the others: on the outputs you generate, the agreement states it “does not impose any restrictions or obligations”.
Four questions to put to a weights licence
Commercial use and thresholds. OpenMDW-1.1 sets none. Mistral reserves free self-hosting for organisations below a revenue threshold; other families tie the grant to a monthly active user count. The question is not “is it open”, it is “does it stay open as we grow”.
Field-of-use restrictions. The official FAQ is explicit: no field-of-use, royalty or geographic restrictions. Google’s Gemma terms work the other way: section 3.2 forbids the uses listed in the Prohibited Use Policy, which lives at a separate address and is “hereby incorporated by reference into this Agreement”. Your permission is bounded by a page that is not the contract.
Who can stop you afterwards. OpenMDW-1.1 revokes your rights in one case only: if you bring a lawsuit alleging that the Model Materials infringe a patent or copyright, defensive suits aside. Gemma says something else: “Google reserves the right to restrict (remotely or otherwise) usage of any of the Gemma Services” it believes to be in violation of the agreement, and on termination requires you to delete every copy in your possession or control. For a public body those are two different risks.
What travels with the weights. Documentation and data, where the provider publishes them under that text, fall under the same grant: the difference between receiving a component and receiving it with its paperwork.
The line the procurement office should read first
So far the licence gives. Then it takes away, in capitals. The materials come “AS IS”, with no warranty of title or non-infringement, and responsibility for clearing third-party rights in the weights is entirely yours: “YOU ARE SOLELY RESPONSIBLE FOR (1) CLEARING RIGHTS OF OTHER PERSONS THAT MAY APPLY TO THE MODEL MATERIALS”.
That is the real difference. In a serious supply contract the seller indemnifies you against third-party intellectual property claims; here nobody does: there is no supplier under an obligation, only a unilateral permission you accept by exercising it. This is no flaw in OpenMDW — MIT and Apache 2.0 say the same. It is the risk model of open weights, and it belongs in the risk register, not a slide deck. The reverse holds too: the use limits you demand from a supplier cannot be negotiated here, so you must set them yourselves.
Model card, policy and licence are three different documents
The Laguna S 2.1 card states that the model is designed for agentic coding and “should be used consistently with Poolside’s Acceptable Use Policy”. That is not a licence condition: the licence contains no use restrictions. On Gemma the same sentence formally binds. Similar words, opposite legal weight. The same card separates third-party scores from those measured in house: the documentary hygiene to demand before the numbers.
And if the licence changes while you are in production? The text under which you downloaded stays as it was: new versions govern new releases. That versions matter is proved by the licence itself: the Linux Foundation published 1.1 on 28 May 2026 — NVIDIA states it is adopting it for Cosmos, Isaac GR00T, Ising and Nemotron — and the official FAQ notes it differs from 1.0 by a single change: “patent” became “patent or copyright”. A policy incorporated by reference, by contrast, moves without the contract changing a comma.
What to do, in practice
- On download day, archive the licence text, the model card and every policy referenced, with a cryptographic hash and a date: the only proof of the terms accepted.
- Do not write “open-weight model” in a tender: write the licence name, its version and the repository. “Open” is not a verifiable requirement.
- Keep licence conditions and card recommendations apart. If you need a field-of-use limit, your own policy provides it, not the model.
- If you redistribute — even only to a subsidiary, or inside a container image — carry the text and notices of origin: the one obligation OpenMDW imposes, and the easiest to breach without noticing.
- Check which repository you are pulling from: as of 26 July the public Hugging Face index lists 143 models under the openmdw-1.1 licence, 62 of them variants of Laguna S 2.1 published by parties other than poolside. A requantisation is a different publisher.
Open weights say what you may do. Not where to run them — and that is where a permissive licence does or does not become a usable system. Our technical setup comes in two modes: on-premise inside the client’s environment, or a dedicated cloud reserved for a single client, over a dedicated VPN, with data centres in Italy and premises staffed by us. In both, the model stays a replaceable component, and the licence you accepted stays on file next to the weights running.
Do you need an open-weight model signed off before production? Half an hour with one of our specialists: we read the licence, the redistribution duties and the residual risks together.