Inform’s Standard Rules provide some fairly complex code governing the way that room descriptions work. Although various pieces of this code are touched on in the included documentation, there’s not much in the way of a comprehensive overview of how it all works together as a system.
I’ve written a draft of a document that tries to do this, detailing the logic of each of the pieces of the system and pointing out where the various provided hooks operate within the larger scheme. The intended audience is intermediate and advanced users who want a reference for the subsystem, but it could also be useful to a beginner who’s willing to do some pre-reading in the main documentation (a list of relevant sections is provided).
Would anyone be interested in a copy of that? If so, let me know, and I’ll set up a PM for distribution.