kmp-adapter-embedded

KMP is local-first agent memory that preserves what happened, when and why. This crate supplies its embedded storage adapters.

One EmbeddedKernelStore opens one data directory — a FORMAT_VERSION marker next to store/ — and implements every persistence port the kernel needs: graph reads over materialized adjacency, node detail, the append-only context event log, projection runtime state, snapshots and quality telemetry. No server, no cluster, no daemon.

One active engine, one compatibility reader

The ports are written once against a small storage seam. Every new directory is SQLite and records format 2; the legacy reader exists only so format-1 memory can still be opened and migrated.

Two agent hosts can open the same project memory, readers do not block the writer, and a second writer waits for the commit lock. Existing redb stores remain readable from their format stamp and never change engine implicitly; the public engine selector cannot create another one. SQLite passes the full conformance, kill -9 recovery and two-process no-lost-events suites. See ADR-018.

Quality telemetry uses its own WAL journal at telemetry/quality.sqlite3. An existing quality.redb is imported once, bounded by the same retention policy and preserved on disk. redb remains a private compatibility dependency for these format-1 reads; no active store, telemetry writer or public engine option uses it.

What durability means here

Canonical memory commits use SQLite synchronous=FULL in WAL, so the crash contract is explicit: nothing is lost beyond the in-flight event, and replay applies nothing twice. The bounded telemetry journal uses periodic FULL durability and a final durable checkpoint.

Not a special case

The observable semantics are pinned by the conformance suite that also certifies the in-memory store and the Neo4j / Valkey adapters. A store that passes it behaves like the others or it does not ship.

License

Apache-2.0.