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MemoryWriteNode

POC node (FR-27, design §3.4) that persists a single Episode into an injected memory-store provider — a MemoryStore such as stargraph.stores.sqlite_memory.SQLiteMemoryStore.

Constructor

Parameter Type Default Description
memory_store MemoryStore required (positional) Injected provider implementing the MemoryStore protocol.
episode_field str "episode" Name of the state field carrying the Episode payload.

memory_store is positional; episode_field is keyword-only.

State contract

  • Reads — state.<episode_field> (default state.episode).
  • Writes — {"memory_written": True, "episode_id": episode.id}.

The (user, session, agent) triple is read from ctx. Phase-1's ExecutionContext Protocol is intentionally minimal (run_id only), so the node falls back to "anon" / "default" / "default" when the concrete context object lacks the optional fields. Phase 2 tightens the Protocol (design §3.4).

Side effects + replay

Field Value
SIDE_EFFECTS SideEffects.write
REPLAY_POLICY ReplayPolicy.must_stub

Mutates external state — must be stubbed under replay (FR-33, design §3.4.2).

YAML

nodes:
  - id: persist_episode
    kind: memory
    spec:
      episode_field: episode
state_schema:
  episode: dict

The memory: store binding lives at the IR top level:

stores:
  memory: redis://localhost:6379/0

Errors

  • AttributeError — state.<episode_field> missing.
  • Whatever MemoryStore.put(...) raises — provider-specific.

See also