It is just as "vibe-ish" as vector search and notably does require chunking (document chunks are fed to the indexer to build the table of contents). That said, I don't find vector search any less "vibey". While "mathematical similarity" is a structured operation, the "conversion to high-dimensional vectors" part is predicated on the encoder, which can be trained towards any objective.
> scaling will become problematic as the doc structure approaches the context limit of the LLM doing the retrieval
IIUC, retrieval is based on traversing a tree structure, so only the root nodes have to fit in the context window. I find that kinda cool about this approach.But yes, still "vibe retrieval".