Summary

Only SQLite is implemented. The spec plans additional backends for production deployments.

Design Spec Reference

• §7.6 Operational Data Persistence — backend options
• §15.2 Technology Stack — Database row

Scope

• Implement at least one production-grade PersistenceBackend (e.g. PostgreSQL — evaluate at implementation time)
• All repository protocol implementations
• Migration strategy for the chosen database
• Connection pooling

Notes

• Specific database technology should be evaluated at implementation time — reference DESIGN_SPEC.md §7.6 for options
• Must implement the full PersistenceBackend protocol + all repository protocols

Research Context

PostgreSQL for Agentic Future (InfoWorld, 2026-03-14) — Confirms direction:

• EDB-sponsored article (no benchmarks, vendor marketing) but validates PostgreSQL as convergence point for agentic workloads
• Extensions to evaluate: pgvector (alternative to external Qdrant for custom stack), TimescaleDB (cost/performance time-series), pgraph (org memory graph queries)
• Our persistence layer already has PostgreSQL migration designed: PersistenceBackend protocol + create_backend() factory ready for a PostgresPersistenceBackend branch
• MemoryStorageConfig already declares {"sqlite", "postgresql"} as valid history_store values
• Trigger: scaling needs exceeding SQLite WAL mode, multi-process concurrency, or multi-tenant deployments