Three months back I released obs2nlm, a tool that takes an Obsidian vault and turns it into a single Markdown file so it can be used as a source for NotebookLM.

Since then I've been using it a lot and it's working out really well.

Meanwhile, one of my vaults has started to creep up towards the documented word limit for a single source in NotebookLM (500,000 words). Right now it's sitting at around 75% and is steadily creeping up.

So, with this in mind, I've made a change I've been planning from the start and have added a --split option. If used, if the generated file looks like it's going to hit the word limit, a second (or more) file will be created. The naming scheme is simple enough: if you ask obs2nlm to create an output file called dirt.md and it needs to run over, it'll then create dirt-2.md, dirt-3.md, and so on. The idea then is that, rather than upload that single Markdown file as a source, you upload all of the generated Markdown files.

Given you get up to 50 sources per notebook, this should see me right for any reasonable vault. As for if it will affect the quality of the results I get when I query the notebook... that's hard to say until I find myself in that situation. If Google are to be believed it shouldn't be an issue, and the alternative is to fall foul of the limit so this seems like the only sensible solution.

I've also added a --dry-run command line switch too; this should be handy for checking how big a vault is when compared to the word limit, without actually generating any files.