What a licence is: copyright by default, permission by licence
Code, text and data have an owner the moment they are created. A licence is the owner's written permission, with conditions. This episode is the base for the whole season.
In most legal systems, writing code, a document or a piece of documentation creates copyright for its author at once, with no registration needed. The practical effect is simple: nobody else may copy, modify or distribute the work without permission.
A licence is that permission. The rights holder states in writing what others may do and on what conditions. A licence does not transfer ownership; the owner keeps the work and grants some rights under defined terms.
Three questions are enough to read any licence:
- Permissions: commercial use, modification, distribution, private use, sometimes patent use.
- Conditions: keep the copyright notice, state changes, or release source code.
- Limitations: usually no warranty and no liability, and sometimes no trademark rights.
The choosealicense site, maintained by GitHub, summarises common licences in exactly these three columns, and this season uses it often. The Open Source Initiative's Open Source Definition sets out what a licence must allow to be called open source.
For teams building agents this is not theory. Every package, model and dataset an agent stack pulls in brings a licence, and that licence decides how the product can be sold, deployed or delivered to a bank.
This is general information, not legal advice.
Sources: choosealicense.com: Licenses, Open Source Initiative: The Open Source Definition