Files over tools: how we built our agent with a virtual filesystem and bash
In this technical retrospective (2026), @cjbell shares practical architectural lessons learned from running, scaling, or migrating production software under lean constraints.
Core Principles for Independent Builders:
Defaulting to simpler architectures (such as monolithic frameworks, SQLite, or managed VPS) prevents early engineering bankruptcy.
Evaluating true compute and egress costs reveals that high cloud bills can often be slashed by 80%+ through judicious re-platforming.
Code you write at 2 AM as a solo engineer must be easy to debug six months later without complex microservice dependencies.
Community Debate Themes:
HN engineers debated the tradeoffs between cloud convenience and raw server economics, database indexing strategies, and resisting premature architectural complexity.
CATEGORY Frugal Engineering →
HISTORICAL ERA Post-ZIRP & AI (2023–2026)
COMMUNITY SCORE ★ 5 points
TOTAL DISCUSSIONS 0 comments
I thought it would be bash+fuse but it's actually running in the matrix: simulated bash in Elixir ported from Vercel's just-bash:
https://github.com/vercel-labs/just-bash/tree/main/packages/just-bash
See also (credited by TFA):
https://vercel.com/blog/how-to-build-agents-with-filesystems-and-bash
We ended up doing the same, own harness with a world view (schema.org) and map reduce rather than a RAG. Happy with the results and context hydration speed