LangSmith studio context not properly passed to LangGraph

[axelwijnants-ixor]

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

import { createAgent, createMiddleware, SystemMessage } from 'langchain';
import { z } from 'zod';

const contextSchema = z.object({
  systemPromptRef: z.string(),
});

const agent = createAgent({
  name: 'testAgent',
  model: model,
  middleware: [dynamicPromptMiddleware],
  contextSchema: contextSchema,
});

const dynamicPromptMiddleware = createMiddleware({
  name: 'DynamicPrompt',
  beforeAgent: async (state, runtime) => {
    const systemMsg = runtime.context.systemPrompt ?? 'default test';

    return {
      messages: [new SystemMessage(systemMsg), ...state.messages],
    };
  },
  contextSchema: contextSchema,
});

export const testAgent = agent.graph;

Error Message and Stack Trace (if applicable)

No response

Description

The context passed through the LangSmith UI is not properly passed to the context object.

The parameter shows up in the LangSmith UI when I try to create a new assistant, but is not available on the context object when entering my custom middleware (the context object is empty).

I saw a related issue logged for LangchainJS: langchain-ai/langchainjs#9222

The fix proposed here seems to solve my issue.

System Info

Node version: v22.16.0
Operating system: darwin arm64
Package manager: npm
Package manager version: 11.2.1

@langchain/core -> @1.0.3, , @"1.0.3", @"^1.0.1", @"^0.3.59, @"^1.0.0", @"^1.0.3"
langsmith -> @0.3.79, , @"^0.3.79", @"^0.3.64", @"^0.3.33", @"~0.3.74"
zod -> @3.25.76, , @"3.25.76"
@langchain/langgraph-cli -> @1.0.3, , @"1.0.3"
@langchain/langgraph-api -> @1.0.3, , @"1.0.3"
@langchain/langgraph-checkpoint -> @1.0.0, , @"^1.0.0", @"~0.0.16
@langchain/langgraph-sdk -> @1.0.0, , @"^1.0.0", @"~1.0.0", @"~0.0.16
@langchain/langgraph-ui -> @1.0.3, , @"1.0.3"
@langchain/langgraph -> @1.0.1, , @"1.0.1", @"^0.2.57, @"^0.2.72, @"^1.0.0"
@langchain/langgraph-supervisor -> @1.0.0, , @"1.0.0"
@langchain/mcp-adapters -> @1.0.0, , @"^1.0.0"
@langchain/openai -> @1.0.0, , @"1.0.0"
langchain -> @1.0.3, , @"^1.0.3"

[MartijnLeplae]

@dqbd do you have time to look at this?

The issue seems to affect this part of the pregel code: https://github.com/langchain-ai/langgraphjs/blame/18abe1e813e1631a03bad39e20e64099d18d48d7/libs/langgraph-core/src/pregel/index.ts#L2013-L2018 which is part of this PR: #1451

config.context is {} and is not undefined while context.configurable contains the actual config/context

[ddewaele]

Any updates on this ? Or should this be moved to the langchainjs repo ?

Is there an easy way to track all of these v1 issues because we've found that there are numerous "basic" functionalities that appear to be broken in v1 + lots of snippets on docs.langchain.com that simply don't work.

Some can be patched, others can be worked around, but it makes the adoption to v1 very painful.