You absolutely need to let models access the Internet if you want consistently good results. Pretty much any non-trivial task requires the model to do things like look up APIs, code examples, or existing discussions of a given topic.
replyYou don't really need the Internet. Tons of documentation is available for download (either as a zip, or with the documentation site as its own git repo). Wikipedia is available for download. You can get reddit dumps, HN dumps, stack exchange dumps, etc. This can all easily fit on one hard drive.
replyReading the actual code is also always a better source of truth than docs anyway (this is true for people and LLMs). Just clone whatever libraries you use.