ADR 0259 — Journal records and derived caches have separate transfer policies

Invariants: I3, I8, I12, I13, I15.

Context

A runtime checkpoint input contains the complete streaming assistant. Its persisted journal record retains a hash, byte count and numeric part count to bound repeated draft storage. A SQLite conversation export also carries materialized application projections beside the runtime snapshot. Treating every projection as a snapshot, or every journal record as an executable mutation, refuses an ordinary export created by the runtime itself.

Decision

AgentStoreTransitionRecordSchema describes persisted full transitions and shortened checkpoint observations. The writer and branch replay share its checkpoint schema. Executable mutations keep their existing AgentStoreTransitionSchema. Inspection establishes shape; branch still validates the entire source, exact settled boundary and reference closure before writing.

Companion projections use one envelope schema shared with SQLite import. A branch checks envelope shape, unique names and checkpoints within the journal, then discards their application-defined cache values. Destination projections fold from its rekeyed ledger. State and effect events remain inert observations, never live rows or authority. A later companion cache cannot affect an earlier selected prefix.

Archive import and branch share the writer for replayed history, run and admission effects. This retains compacted history absent from the active snapshot. Branch additionally clears execution owners and fences; ordinary same-identity import retains its operational snapshot and exact live draft. Unknown opaque journal fields still refuse before a branch mutates its destination.

Consequences

Existing SQLite schema v4 exports remain branchable without application journal edits. A consumer can inspect both checkpoint forms using the public record contract. A branch does not copy opaque application caches; it rebuilds projections from historical facts under the new identity. The installed consumer proof exercises fresh and public 0.109.4 streaming archives on Bun and Node, with tools, compaction, artifacts and inert state/effect observations.