@harness-kernel/storage-file

@harness-kernel/storage-file provides FileSessionStorage for persistent session-centric storage. FileRunStorage remains available for legacy run-centric hosts.

import { FileSessionStorage } from "@harness-kernel/storage-file";

const storage = new FileSessionStorage();

The runtime host attaches it to the session store:

const store = await createHarnessSessionStore({
  agent: { definition: agent },
  providers: [new OpenAIProvider()],
  defaultModel: "openai/gpt-5.1",
  storage,
});

Each session run directory can contain events.jsonl, transcript.json, cursor files, snapshots, and context snapshots. The legacy FileRunStorage can also write metrics.json.

The default layout is .harness-kernel/sessions/index.json plus .harness-kernel/sessions/<sessionId>/runs/<runId>/....

This package is optional. Use MemorySessionStorage from core for tests.