What should we read first?

Whether commercial use is permitted, whether your particular application is excluded, and what the terms say about the output. Those three decide whether a plan is viable, and they are usually a small part of a document that is otherwise standard.

Does open weights mean unrestricted?

No. It means the trained parameters are published, which is about availability. Conditions on commercial use, on specific applications and occasionally on scale can still apply, and the ease of downloading is precisely why those conditions are the ones that go unread.

Who owns what a model produces?

Genuinely unsettled and varying by place, which is why this page describes what the terms say rather than ruling on it. What is certain is that vendors write clauses about it and you agree to them, so your contractual position is knowable even where the wider question is not.

Glossary

Licence terms

The conditions attached to using a model or what it produces, including whether commercial use is permitted and what the output may be used for.

In plain terms

A model comes with conditions, and they are not always the ones people assume. Some permit anything, some permit commercial use with restrictions, and some rule out particular applications entirely. Separately there are conditions on what the model produces, which is a different question and is often the one that matters more for a business.

Why it matters

Because the assumption that available means unrestricted is common and occasionally expensive. A team can build something substantial on a model whose conditions rule out the very use it was built for, and the discovery generally comes late, when there is something to unpick rather than a decision to make differently.

How it works

Downloadable is not the same as unrestricted, and the gap catches people out. A model whose weights are published may still carry conditions on commercial use, on particular applications, or on scale, and those conditions are the licence rather than the availability. Reading it takes minutes and is skipped precisely because obtaining the model was so easy.

Conditions on the model and conditions on the output are separate questions. What you may do with the software is one clause; what you may do with what it produces is another, and for most businesses the second is the one that determines whether a plan works. They are frequently in the same document and are frequently read as though they were one thing.

Whether the output can be restricted in the way a licence asserts is genuinely unsettled and varies by place, which is why this page describes the clause rather than ruling on it. What is certain is that vendors write terms about it, buyers agree to them, and the resulting position is contractual whatever the wider legal answer turns out to be.

The clause about using output to improve other models exists in many terms and is the one most often breached inadvertently. A team using one product's output to make another system better may be doing something the terms address specifically, and it is worth knowing before rather than after, because the activity feels entirely ordinary while doing it.

Two questions in one document

The reason the right column is under-read is that it answers a question most people have not thought to ask. A team evaluating a model is thinking about capability and cost, treats the licence as a formality about the software, and confirms the part that looks like a software licence. What the output may be used for reads as a technicality until it is the reason something has to be unwound. The middle line of the right column deserves particular attention, because using one system's output to improve another is such an ordinary-feeling activity: it looks like using a tool to do work, and terms frequently address it specifically. Reading three clauses before building takes ten minutes and is the cheapest insurance available anywhere in this category.

Seen in the wild

Checking the conditions attached to a downloadable model before building anything commercial on it.
Ollama
Comparing the terms across providers reached through one interface, since each model carries its own.
OpenRouter
Reading what a coding assistant's terms say about the code it produces and what may be done with it.
Claude Code

Common misconceptions

People assume

Open weights means we can do anything with it.

In fact

It means the weights are published. Conditions on commercial use, on particular applications and sometimes on scale can still apply, and they are the licence rather than the availability. The ease of obtaining a model is exactly why the terms attached to it go unread.

People assume

The output is ours, so there is nothing to check.

In fact

There are terms about it whether or not the wider legal position is settled, and those terms bind you contractually. The clause about using output to improve other systems is the one most often breached without any intent, because the activity feels ordinary while it is happening.

Telling them apart

Licence terms vs Open weights

Licence terms

What you are permitted to do with a model and with what it produces.

Open weights

Whether the trained parameters are published at all.

Availability and permission are different questions, and only one of them is answered by a download button.

Questions

What should we read first?: Whether commercial use is permitted, whether your particular application is excluded, and what the terms say about the output. Those three decide whether a plan is viable, and they are usually a small part of a document that is otherwise standard.
Does open weights mean unrestricted?: No. It means the trained parameters are published, which is about availability. Conditions on commercial use, on specific applications and occasionally on scale can still apply, and the ease of downloading is precisely why those conditions are the ones that go unread.
Who owns what a model produces?: Genuinely unsettled and varying by place, which is why this page describes what the terms say rather than ruling on it. What is certain is that vendors write clauses about it and you agree to them, so your contractual position is knowable even where the wider question is not.

Key takeaways

Available and unrestricted are different things; the licence is the second.
Conditions on the model and on its output are separate clauses.
Terms about using output to improve other systems are breached inadvertently more than any other.
The wider legal position on output is unsettled; your contractual position is not.