Runtime.store always undefined

[etay2000]

Checked other resources

• I added a very descriptive title to this issue.
• I searched the LangGraph.js documentation with the integrated search.
• I used the GitHub search to find a similar question and didn't find it.
• I am sure that this is a bug in LangGraph.js rather than my code.
• The bug is not resolved by updating to the latest stable version of LangGraph (or the specific integration package).

Example Code

const store = new InMemoryStore();

const agent = createAgent({
  model: llm,
  store
});

beforeAgent: async (state, runtime) => {
  console.log('runtime', runtime); // runtime.store is always undefined
}

Error Message and Stack Trace (if applicable)

No response

Description

Providing a basic InMemoryStore to createAgent, and trying to access the runtime.store from middleware, runtime.store is always undefined.

System Info

npm

[Axadali]

Hi @etay2000, thanks for reporting this!

After reviewing the issue, it looks like runtime.store is undefined because the store you pass to createAgent() is not currently attached to the runtime object. This is why your middleware doesn’t see it.

A maintainer-friendly solution would be to attach the store to the runtime during agent creation. For example:

function createAgent({ model, store }: AgentOptions) {
  const runtime = {
    state: {},
    store, // ✅ attach store here
  };

  return new Agent({ model, runtime });
}

Additionally, updating the TypeScript types for Runtime ensures type safety:

interface Runtime {
  state: any;
  store?: Store;
}

This approach keeps the fix simple, backward-compatible, and ensures that runtime.store is accessible in all middleware hooks.

We can also add a small test case to verify that middleware can access the store:

test('runtime.store is accessible in middleware', async () => {
  const store = new InMemoryStore();
  const agent = createAgent({ model: mockLLM, store });

  let capturedRuntime;
  agent.beforeAgent = (state, runtime) => {
    capturedRuntime = runtime;
  };

  await agent.run({ input: 'test' });
  expect(capturedRuntime.store).toBe(store);
});

This should resolve the issue and make the runtime API more intuitive.