Since there are many comments here arguing that this is not open weight, I looked at the license. Basically, you're free to use this except this clause:

> If the Licensee or any of its affiliates provide a third party with access to artificial intelligence models as a product or service, via API or a similar interface, where the third party receives outputs of such models (“Model as a Service”), and the aggregate gross revenue of the Licensee and its affiliates exceeds twenty (20) million US dollars (or the equivalent in other currencies) during any consecutive twelve (12) month period, the Licensee must notify Meta and enter into a separate written agreement with Meta before offering the Software or any Derivatives as part of that Model as a Service business. This Section 3 does not apply to (a) internal use, research, or any commercial activity that is not Model as a Service, or (b) the Licensee's use of the Software as a component to power features of the Licensee's own product or service that is not a Model as a Service.

They're allowing the use of this in commercial products, just not selling the model directly.

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isityettime 2 hours ago | parent | next [-]

Still not an open-source license. Means no restrictions on "fields of endeavor", a.k.a. the free software definition's "freedom 0": the freedom to run the software for any purpose.

I'm sick to death of these shameless dilutions (including the notion that open-weight is open-source; the OSI is totally captured at this point)

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eli 2 hours ago | parent [-]

Neither the person you’re replying to nor the blog post call it open source

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input_sh 2 hours ago | parent | next [-]

But it compares itself to Qwen (Apache 2), GLM (MIT), Beam (Apache 2), Inklink (Apache 2)...

Although to be fair, Kimi contains an identical carve out.

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isityettime 2 hours ago | parent | prev [-]

Open-weights means weights are released under an open-source license.

I would, contra the OSI, not consider the model to be open-source even if the weights were under an open-source license. But that is the minimum condition under which it could be considered open-weight.

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SahAssar 2 hours ago | parent [-]

> Open-weights means weights are released under an open-source license.

According to who? From https://en.wikipedia.org/wiki/Open_weights:

> Publishing these values allows others to download and use the model, while permission to modify, fine-tune or redistribute it depends on its license.

Those restrictions are definitely not compatible with the definition of open-source/FOSS. I think you have a much stricter view of what open-weights means than the industry.

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isityettime 2 hours ago | parent [-]

"Open weights" is a correction that arose out of calling models whose weights were released under open-source licenses "open-source" before the OSI sold out. These companies trying to dilute the polite correction just like they tried to dilute "open-source" only reinforces my point.

There was an attempt to create an analogue of the OSI's Open-Source Definition that acknowledged the problems of merely releasing weights as "open-source". That project seems to have largely failed or fizzled, and "open weight" has come to be used mostly as a way of acknowledging that only the weights have been released under open-source terms.

This model of Meta's fails even that dramatically weakened standard.

This is just a series of dilutions by which giant corporations are trying (and apparently succeeding here on "hacker" news) to trade on the cachet of commitments they don't actually hold.

	▲	SahAssar an hour ago \| parent [-]
		I mostly agree, but again, You said "Open-weights means weights are released under an open-source license" and I asked "According to who?" "Open weights" is for the most part a term that is meaningless besides being technically able to run it on your own hardware. I don't think we have a proper term for what you are reaching for, and proper open-source models (training, training-data, etc. being fully open) are scarce.

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SSLy 3 hours ago | parent | prev | next [-]

This is close to GLM terms

	▲	reilly3000 2 hours ago \| parent [-]
		I think it is a fair license. It’s a bit of “Open”-washing but reasonable to the model trainer for their investment and to the public for having more base model options with novel architecture.

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cosmojg 3 hours ago | parent | prev | next [-]

Also, IANAL, but under U.S. copyright law, the weights of machine learning models are excluded from copyright as they are the product of an automated optimization process (e.g., stochastic gradient descent, expectation maximization, genetic algorithms) rather than human authorship. Granted, this has yet to be fully tested in court and going to court is expensive, so it's likely that your employer would prefer to err on the side of caution and respect such attempts at model licensing anyway, similar to how one might treat a ToS agreement. Nonetheless, this was partially tested last year in Thaler v. Perlmutter which affirmed that copyright requires human authorship, reading the Copyright Act's provisions on ownership, duration, and transferability as presupposing a human author[1].

If you want to assess the position of the U.S. Copyright Office for yourself, the relevant text can be found in the Compendium of U.S. Copyright Office Practices § 313.2, "Works That Lack Human Authorship"[2], which states:

> […] the Copyright Act protects “original works of authorship.” 17 U.S.C. § 102(a) (emphasis added). To qualify as a work of “authorship” a work must be created by a human being. See Burrow-Giles Lithographic Co., 111 U.S. at 58. Works that do not satisfy this requirement are not copyrightable.

> […] the Office will not register works produced by a machine or mere mechanical process that operates randomly or automatically without any creative input or intervention from a human author. The crucial question is “whether the ‘work’ is basically one of human authorship, with the computer [or other device] merely being an assisting instrument, or whether the traditional elements of authorship in the work (literary, artistic, or musical expression or elements of selection, arrangement, etc.) were actually conceived and executed not by man but by a machine.” U.S. COPYRIGHT OFFICE, REPORT TO THE LIBRARIAN OF CONGRESS BY THE REGISTER OF COPYRIGHTS 5 (1965).

Oh, and there's also a bit in the following Section 313.3, "Works That Do Not Constitute Copyrightable Subject Matter"[2], which explicitly excludes mathematical principles, formulas, algorithms, and equations, along with DNA sequences and other genetic or chemical compounds, regardless of whether they are produced by humans or by nature. If one takes the perspective that machine learning models are algorithms, the conclusions on copyrightability are pretty clear.

[1] https://media.cadc.uscourts.gov/opinions/docs/2025/03/23-523...

[2] https://www.copyright.gov/comp3/chap300/ch300-copyrightable-...

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LoganDark an hour ago | parent | next [-]

If the weights were produced by a purely mechanical process without any input, then I would be more inclined to believe the distinction there is significant. But as the optimization processes you've mentioned are merely tools that operate with a dataset, the provenance of that dataset becomes a factor towards copyright.

	▲	VanTheBrand 15 minutes ago \| parent [-]
		I mean, not according to the lawyers for every AI lab… they do want to have it both ways though.

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overfeed 2 hours ago | parent | prev [-]

> Granted, this has yet to be fully tested in court and going to court is expensive, so it's likely that your employer would prefer to err on the side of caution and respect such attempts at model licensing anyway, similar to how one might treat a ToS agreement.

You may be conflating 2 things - the Muse model weights themselves, and what the models output when run. The former is prima facie the product of human authorship and hence has full protection of copyright law, the latter fits your characterization of likely not having copyright coverage. Meta can use the copyright on the model weights to dictate licensing terms. IANAL too.

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alsosprachben 2 hours ago | parent [-]

Model weights are facts. Facts are not copyrightable.

	▲	overfeed an hour ago \| parent \| next [-]
		> Model weights are facts. Only in the way a math textbooks are facts. Model weights are bits on a medium,designed and derived from the combined efforts, judgement and expertise of many humans, before and after training. Software bits have been copyrighted for so long, there are 5¼" floppies with "(c) 1977" printed on them.
	▲	kevincox 2 hours ago \| parent \| prev \| next [-]
		The words in a novel and the order in which try appear are so facts. But somehow that is clearly copyrightable.
	▲	eli 2 hours ago \| parent \| prev [-]
		It’s really not that simple

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fhd2 3 hours ago | parent | prev [-]

Unless the total (!) revenue of the provider is under 20 MM USD, eh? Not exactly fully open, but not _that_ harsh.

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ithkuil 3 hours ago | parent [-]

Even if your revenue exceeds 20MM you can still use this model from inside a commercial product but you can't expose it directly as a "model as a service"

	▲	fhd2 2 hours ago \| parent \| next [-]
		Yup, I rather meant to point out that even if all you want to do is sell access to the model on your hardware, you can _still_ do so up until a non-trivial scale.
	▲	aniceperson 2 hours ago \| parent \| prev [-]
		if I have a Sass platform where the user pays per seat $8 and assess to the llm is a listed feature, the clause do apply.