Add Markdown YAML header fields to notebook metadata

I would like to add custom fields to the Markdown YAML header (title: and author:) and have them end up in the notebook’s "metadata": field upon conversion from Markdown to .ipynb, instead of being copied as literal YAML into a raw cell at the beginning of the notebook. Is there a way to achieve that?

I tried the following but it doesn’t seem to work:

jupytext --to notebook test.md --update-metadata '{"jupytext": {"notebook_metadata_filter":"title,author"}}'

The title: and author: YAML fields stay in the raw cell, and the notebook’s "metadata": field contains just literally what I passed to the --update-metadata option, i.e. {"jupytext": {"notebook_metadata_filter":"title,author"}}.

[mwouts]

I have added a quick note about custom notebook metadata as you suggested it (and fixed the broken link). Thanks for your getting in touch!

[dlukes]

D’oh! So close 😃 On the other hand, if this information makes it into the docs, I hope it will have been worth it, I think it will be useful for other people who use Jupytext with Jupyter Book.

Where do you think we should add this?

I searched the docs for ‘metadata’, so I looked here (FYI, that section has a broken link to here which should probably point here instead?) and here.

However, I think it would be most natural to put it in the Jupytext Markdown format description. There’s already an example YAML block there, so add the custom metadata to that and one or two sentences commenting on it in the main text?

And thank you for Jupytext as well as for responding so quickly!