My current hypothesis here is that the way to make coding assistants as reliable as possible is to shift the balance towards making their output rely on context provided in-prompt rather than information stored in LLM weights. As all the major providers shift towards larger context-windows, it seems increasingly viable to give the LLM the necessary docs for whatever libraries are being used in the current file. I've been working on an experiment in this space[0], and while it's obviously bottle-necked by the size of the documentation index, even a couple-hundred documentation sources seems to help a ton when working with less-used languages/libraries.
[0]: https://indexical.dev/