Circuits

A circuit is a bounded route through which work, state, or evidence moves.

Circuits connect terminals without hiding ownership.

Circuit Rules

A circuit has known inputs, outputs, and failure modes.

Crossing a circuit does not make one battery own another battery’s state.

If durable state changes through an unmodeled route, the route must be exposed or removed.

batpak composes multiple store roots through explicit circuits and observations — not through a hidden cross-directory Store API.

Term	Meaning
Journal	One `Store` on one `data_dir`; one writer owner; lifetime-held directory lock.
Stream	One `Coordinate` chain inside a journal — a logical context stream.
Observation	A foreign fact recorded locally: journal B may reference journal A’s event or receipt without A’s writer executing inside B.
Multi-journal	Composition and scaling layer — not an extra mutation layer inside one `data_dir`.

Facts that govern scale-out:

One writer per data_dir. Two live owners of the same mutable directory are not supported under today’s lock contract.
No single global_sequence spans separate store roots.
Coordinate sharding gives logical order inside one journal; journal sharding gives physical relief when a domain outgrows one writer.
Bridges and tail consumers read exported or copied snapshots from another journal; they must not open the same live data_dir beside the owner.

append path from host input to event receipt
replay path from event history to projection
cursor delivery from durable checkpoint to ordered observation
NETBAT route: netbat → syncbat → embedder host → Store
multi-journal observation: journal B records a witness of journal A’s event or receipt
netbat route from network frame to operation handling
release path from just seal to manifest evidence