@skein-js/storage-memory

In-memory SkeinStore + run queue + event bus for development and tests.

Part of skein-js — a TypeScript Agent Protocol server for LangGraph.js, and a drop-in replacement for the LangGraph CLI.

Status: 🚧 Pre-alpha — implemented; passes the shared SkeinStore conformance suite.

What it does

Zero-dependency, in-process drivers that power skein dev and back the test fixtures. They implement the @skein-js/core contracts, so the engine uses them unchanged:

• MemorySkeinStore — a SkeinStore over plain Maps (assistants / threads / runs / store items), with the run-concurrency guard, thread→runs cascade delete, and naive prefix/substring store search. Every read and write deep-clones at the boundary — like a real serializing driver — so callers can't mutate stored rows or corrupt the store through a retained reference.
• MemoryRunQueue — a single-process FIFO of background runs.
• MemoryRunEventBus — buffered run-frame pub/sub with replay (afterSeq) and live-tail, so a client can join a run's stream late or reconnect.

Validated against the shared SkeinStore conformance suite, so it behaves identically to the Postgres driver — the same tests run against both.

Install

pnpm add @skein-js/storage-memory

No peer dependencies. Pair it with MemorySaver (from @langchain/langgraph) as the graph checkpointer — this package stores only Agent Protocol resources, never graph state.

Usage

Construct with new — there is no connect/migrate step:

import { MemorySkeinStore, MemoryRunQueue, MemoryRunEventBus } from "@skein-js/storage-memory";

const store = new MemorySkeinStore();
const thread = await store.threads.create({ metadata: { user: "a" } });
await store.threads.get(thread.thread_id);

Wired into an engine as a full set of in-memory drivers (this is what skein dev does):

import { MemorySaver } from "@langchain/langgraph";
import { createProtocolRuntime } from "@skein-js/agent-protocol";
import { MemoryRunEventBus, MemoryRunQueue, MemorySkeinStore } from "@skein-js/storage-memory";

const runtime = createProtocolRuntime({
  store: new MemorySkeinStore(),
  queue: new MemoryRunQueue(),
  bus: new MemoryRunEventBus(),
  checkpointer: new MemorySaver(),
  graphs, // a GraphResolver, e.g. from @skein-js/config
});

API

• class MemorySkeinStore implements SkeinStore — new MemorySkeinStore(). Exposes the four repos (assistants, threads, runs, store) defined by SkeinStore. Plus two methods used by skein dev's persistence:
  • snapshot(): MemoryStoreSnapshot — serialize all rows.
  • hydrate(snapshot: MemoryStoreSnapshot): void — restore a snapshot (used to survive restarts).
• interface MemoryStoreSnapshot — the serialized form (assistants / threads / runs / runKwargs / items entry arrays).
• class MemoryRunQueue implements RunQueue — new MemoryRunQueue(). enqueue(run) · consume(process, options?) (options.concurrency default 1) → a RunConsumer with close(force?).
• class MemoryRunEventBus implements RunEventBus — new MemoryRunEventBus(options?: { maxRetainedRuns?: number }) (default 1000; LRU-evicts closed runs' buffers). publish(runId, frame) · close(runId) · subscribe(runId, afterSeq = 0).

See @skein-js/core for the full SkeinStore / RunQueue / RunEventBus method signatures these implement.

Reuse

Pairs with MemorySaver (re-exported from @langchain/langgraph) for graph checkpoints — it stores only Agent Protocol resources, never graph state.

Learn more

• Storage · Runs & Redis
• skein-js overview · Reuse-first architecture · Root README

License

Apache-2.0