TWITTER_ARTICLE

Mintlify's AI assistant now uses ChromaFS, a virtual filesystem that turns UNIX…

2026-04-02 · 18:02 UTC ·cdxker ·1 min read

Brief

Mintlify's AI assistant now uses ChromaFS, a virtual filesystem that turns UNIX commands into database queries to simulate a sandbox. Announced 2026-04-02 by @cdxker, this replaced chunk-based RAG (which missed cross-page context) and avoided slow sandboxes (~46s startup, $70k/yr), cutting latency to ~10ms and serving 30,000+ conversations daily.

Source evidence

title: @cdxker: We killed RAG, We killed Sandboxes, We gave our Assistant a virtual filesystem a...
author: cdxker
contenttype: twitterarticle
published: 2026-04-02T18:02:13+00:00
source_url: https://x.com/cdxker/status/2039776981362110608

word_count: 268

We killed RAG, We killed Sandboxes, We gave our Assistant a virtual filesystem and dropped latency t

We killed RAG, We killed Sandboxes, We gave our Assistant a virtual filesystem and dropped latency to 10ms

  • Our Assistant was a glorified search bar.
  • The moment it had to cross reference multiple searches it fell apart
  • Sandboxes couldn't work
  • We went virtual

Traditional RAG only sends relevant chunks of a document. Never a full doc. Answers in docs span multiple pages: eg
- Product Overview page
- Configuration page
- API reference page.

With rag the model can only see pieces and chunks of a page but never the full doc a user sees. This gap lead to many responses feeling half baked

We first tried putting the agent in a sandbox and found responses to be better, however sandbox startup time was ~46 seconds and would cost us at least $70k/year. Sandboxes didn't work.

We built a virtual filesystem that translates UNIX commands into queries against our database. We call it Chroma FS. Output quality remained the same while completely removing a sandbox.

What we realized was the agent doesn't need a real sandbox. It just needs to think its in a sandbox.

ChromaFs now powers the docs assistant across 30,000+ conversations a day across all our users.

No containers. No VMs. No session cleanup. Just Chroma queries behind a bash interface.

Full technical breakdown in the blog

Building a Virtual Filesystem for Mintlify's AI Assistant

RAG is great, until it isn't.
Our assistant could only retrieve chunks of text that matched a query. If the answer lived across multiple pages, or the user needed exact syntax that didn't land in a...

Posted: 2026-04-02T18:02:13.000Z

Engagement: 1019 likes, 69 retweets, 47 replies