@harness-pi/adapters

Concrete I/O behind the kernel protocols — JSONL/Postgres SessionStore, EventPump, WebSocket sink.

@harness-pi/adapters provides the concrete persistence and transport implementations that sit behind the protocols defined in @harness-pi/core. The kernel declares SessionStore and an event bus but ships no I/O of its own; this package supplies the file/Postgres stores you hand to a session, plus the pump and sink that carry live and recorded events to a WebSocket (or any other channel). It is part of harness-pi, a production harness for pi-ai-based agents.

Install

pnpm add @harness-pi/adapters

Requires @harness-pi/core. PostgresSessionStore expects a node-postgres client injected (run pnpm add pg in your app); this package bundles no pg.

Quick start

import { AgentSession } from "@harness-pi/core";
import { JsonlSessionStore, PostgresSessionStore } from "@harness-pi/adapters";
import { Pool } from "pg";

// --- JSONL store: append-only file, crash-tolerant replay on construct ---
const jsonlStore = new JsonlSessionStore("./.sessions/agent.jsonl");

const session = new AgentSession({
  model,           // a pi-ai Model<Api>
  tools: [],       // your HarnessTool[]
  store: jsonlStore,
});

await session.run("List the files in the current directory.");

// Later (or in another process): rebuild from disk and keep going.
const resumed = await AgentSession.resume(jsonlStore, session.id, {
  model,
  tools: [],
});
await resumed.continue();

// --- Postgres store: inject a node-postgres Pool (satisfies PgClient) ---
const pool = new Pool({ connectionString: process.env.DATABASE_URL });
const pgStore = new PostgresSessionStore(pool);
await pgStore.migrate(); // idempotent DDL; run once before first use

const pgSession = new AgentSession({ model, tools: [], store: pgStore });
await pgSession.run("Summarize the open issues.");

What's inside

• JsonlSessionStore — append-only JSONL file store with crash-tolerant replay and lineage indexing.
• PostgresSessionStore — Postgres-backed store; you inject a minimal PgClient (node-postgres Pool/Client satisfy it) — zero runtime pg dependency in this package.
• EventPump — packages live deltas + recorded SessionEvents into sequenced TransportEnvelopes for any sink.
• WebSocketSink — EventPump → WebSocket, with readyState awareness, injectable serialization, and graceful drops.

License

MIT