Someone asked, so here it is: Google Doc to Substack draft. Just prompt:

/gdoc-to-substack https://docs.google.com/document/d/...

What it does:

1. Fetches a Google Doc as Markdown with the gdoc CLI.
2. Opens Substack in Chrome and creates a draft post.
3. Handles details such as images, footnotes and tables.¹

Tested in Claude Code and Codex.

This skill took about 15 minutes to make. Fable one-shotted the initial brief. The improvement loop would have been faster if I had prompted better—most of the time went into us exploring and rejecting a specific approach to rendering tables. When Fable told me that Substack doesn’t support HTML tables, my first idea was “convert to ASCII”, so I asked directly to implement that. Instead, I should have said, “Hmm, what’s the best workaround here? Maybe a code block with an ASCII table?” When I recognised ASCII as a dead end, I then had the idea to do screenshots. I guess Fable would have done too, if I’d asked it to consider the options first.