I'd like to have a model that just "knows" our code base and past issues, instead of having to query them for the same reason I don't want the model to have to query a dictionary to speak proper English.

I could be mistaken here, but I'm curious to see if it would improve both output speed and quality. Currently, every new prompt I start it basically spends 10-15 minutes "getting familiar with the code" which is both annoying to wait for and wasteful money-wise.