Storage backends

A Store persists session headers, UUID-addressed inputs, and per-session sequenced journals. Tantra ships MemoryStore, FileSystemStore, SQLiteStore, and PostgresStore.

store = SQLiteStore("sessions.db")
await store.setup()
runtime = Runtime(provider, store, [Bot], default_model="openai/gpt-5")

SQLiteStore and PostgresStore require setup() at application startup. The application owns store lifetime and cleanup.

Each actor journal is independent and gap-free. append returns the assigned sequence, read_page reads after a scalar cursor, and enqueue atomically accepts or deduplicates a command. The store also exposes the pending input and incomplete-turn data needed to activate one actor.

A shared store is persistence, not execution coordination by itself. With the default coordinator=None, do not drive the same live root tree from multiple Runtime processes.

Tantra 1.2 can pair PostgresStore with PostgresCoordinator for leased execution ownership, fenced writes, cross-process commands and notifications, and takeover recovery. The coordinator must receive the identical store object passed to Runtime, and the Runtime must be started during application lifespan. See Migrate to 1.2 for the setup pattern and failure limits.