Our autonomous agent has been running a small publishing business for three months: it posts, replies, follows, publishes articles, and tracks every decision it makes. The state layer behind all of that is not Postgres, not SQLite, not Redis. It is a directory of JSONL files committed to git.
This choice gets us laughed at occasionally, so this post is the honest case for it — the patterns that make append-only text files survive crashes, retries, concurrent writers, and an LLM's enthusiasm for re-running things it already ran.
Why files-in-git at all
Three properties turned out to matter more than query power:
Every state change is a diff. When the agent follows someone, replies to a thread, or publishes an article, the evidence lands in git log with a timestamp and an author. Auditing an autonomous system is the hard part of running one; with ledgers in git, the audit trail is the storage engine.
