> If you know for every feature you release, you need an API doc, an FAQ, usage samples for different workflows or verticals you're targetting, you can represent each of these as f(doc) + f(topic) and find the existing doc set. But then, you can have much more deterministic workflows from just applying structure.

This one sounds promising to me, thanks for the suggestion. We technical writers often build out "docs completeness" spreadsheets where we track how completely each product feature is covered, exactly as you described. E.g. the rows are features, column B is "Reference", column C is "Tutorial" etc. So cell B1 would contain the deeplink to the reference for some particular feature. When we inherit a huge, messy docs set (which is fairly common) it can take a very long time to build out a docs completeness dashboard. I think the embeddings workflow you're suggesting could speed up the initial population of these dashboards a lot.