ADR 0003: SQLite default store, JSONL interchange

• Status: Accepted
• Date: 2026-11-11

Context

Traces and experiments must persist locally, offline, with zero setup, and be shareable/committable.

Decision

SQLite (stdlib sqlite3) behind a Store protocol; JSON columns for span payloads. JSONL export/import for fixtures, cassettes and sharing.

Consequences

Zero infra, good enough for tens of thousands of traces. Not for concurrent multi-writer production use (out of scope v1).