--- title: How we built a virtual filesystem for our Assistant description: Mintlify replaced expensive sandbox environments with ChromaFs, a virtual filesystem built on top of their existing Chroma vector database, to power their... canonical: https://daily.dev/posts/how-we-built-a-virtual-filesystem-for-our-assistant-eiuwvtbmm twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: How we built a virtual filesystem for our Assistant | daily.dev og:description: Mintlify replaced expensive sandbox environments with ChromaFs, a virtual filesystem built on top of their existing Chroma vector database, to power their... og:url: https://daily.dev/posts/how-we-built-a-virtual-filesystem-for-our-assistant-eiuwvtbmm og:image: https://api.daily.dev/og/posts/eIUWvtBmM.png og:image:alt: How we built a virtual filesystem for our Assistant og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # How we built a virtual filesystem for our Assistant **[Hacker News](https://daily.dev/sources/hn)** · 6 min read · 0 upvotes · 0 comments ## Summary Mintlify replaced expensive sandbox environments with ChromaFs, a virtual filesystem built on top of their existing Chroma vector database, to power their documentation AI assistant. The sandbox approach had a ~46-second p90 boot time and would cost over $70,000/year at scale. ChromaFs intercepts UNIX shell commands (grep, cat, ls, find) and translates them into Chroma queries, reducing session creation to ~100ms with near-zero marginal cost. Key implementation details include: bootstrapping a gzipped directory tree stored in Chroma, per-user access control via metadata filtering, lazy file pointers for large OpenAPI specs in S3, a two-phase grep optimization using Chroma as a coarse filter and Redis caching, and a read-only design that keeps sessions stateless. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Build knowledge agents without embeddings](https://daily.dev/posts/build-knowledge-agents-without-embeddings-u3xwj6efy) · Vercel · 2 upvotes · 0 comments - [GitHub - adammiribyan/zeroboot: Sub-millisecond VM sandboxes for AI agents via copy-on-write forking](https://daily.dev/posts/github---adammiribyan-zeroboot-sub-millisecond-vm-sandboxes-for-ai-agents-via-copy-on-write-forking-0kztys81s) · Hacker News · 1 upvotes · 0 comments - [Agents have their own computers with Sandboxes GA](https://daily.dev/posts/agents-have-their-own-computers-with-sandboxes-ga-bvcsfels6) · Cloudflare · 3 upvotes · 0 comments --- Tags: [#ai-agents](https://daily.dev/tags/ai-agents), [#rag](https://daily.dev/tags/rag), [#vector-search](https://daily.dev/tags/vector-search) [View this post on daily.dev](https://daily.dev/posts/how-we-built-a-virtual-filesystem-for-our-assistant-eiuwvtbmm) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"How we built a virtual filesystem for our Assistant","url":"https://daily.dev/posts/how-we-built-a-virtual-filesystem-for-our-assistant-eiuwvtbmm","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/how-we-built-a-virtual-filesystem-for-our-assistant-eiuwvtbmm"},"datePublished":"2026-04-03T19:36:11.716Z","dateModified":"2026-10-15T02:21:52.846Z","description":"Mintlify replaced expensive sandbox environments with ChromaFs, a virtual filesystem built on top of their existing Chroma vector database, to power their...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b8eb9e31d8d8b5b5839330a432aa3ef0?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b8eb9e31d8d8b5b5839330a432aa3ef0?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Hacker News","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Hacker News","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/hn","url":"https://daily.dev/sources/hn"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/how-we-built-a-virtual-filesystem-for-our-assistant-eiuwvtbmm","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"ai-agents,rag,vector-search","timeRequired":"PT6M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Hacker News","item":"https://daily.dev/sources/hn"},{"@type":"ListItem","position":3,"name":"How we built a virtual filesystem for our Assistant"}]} ```