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Safari Connection Issues

Safari blocks plain-HTTP traffic on localhost. When running Studio with langgraph dev, you may see “Failed to load assistants” errors.

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Solution 1: Use Cloudflare Tunnel

pip install -U langgraph-cli>=0.2.6
langgraph dev --tunnel
The command outputs a URL in this format: 
https://smith.langchain.com/studio/?baseUrl=https://hamilton-praise-heart-costumes.trycloudflare.com
Use this URL in Safari to load Studio. Here, the baseUrl parameter specifies your agent server endpoint.

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Solution 2: Use Chromium Browser

Chrome and other Chromium browsers allow HTTP on localhost. Use langgraph dev without additional configuration.

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Brave Connection Issues

Brave blocks plain-HTTP traffic on localhost when Brave Shields are enabled. When running Studio with langgraph dev, you may see “Failed to load assistants” errors.

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Solution 1: Disable Brave Shields

Disable Brave Shields for LangSmith using the Brave icon in the URL bar. Brave Shields panel with Shields turned off for smith.langchain.com so LangGraph Studio can reach localhost.

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Solution 2: Use Cloudflare Tunnel

pip install -U langgraph-cli>=0.2.6
langgraph dev --tunnel
The command outputs a URL in this format: 
https://smith.langchain.com/studio/?baseUrl=https://hamilton-praise-heart-costumes.trycloudflare.com
Use this URL in Brave to load Studio. Here, the baseUrl parameter specifies your agent server endpoint.

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Graph Edge Issues

Undefined conditional edges may show unexpected connections in your graph. This is because without proper definition, LangGraph Studio assumes the conditional edge could access all other nodes. To address this, explicitly define the routing paths using one of these methods:

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Solution 1: Path Map

Define a mapping between router outputs and target nodes: 
graph.add_conditional_edges("node_a", routing_function, {True: "node_b", False: "node_c"})

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Solution 2: Router Type Definition

Specify possible routing destinations using Python’s Literal type: 
def routing_function(state: GraphState) -> Literal["node_b","node_c"]:
    if state['some_condition'] == True:
        return "node_b"
    else:
        return "node_c"

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Experiment troubleshooting in Studio

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Run experiment button is disabled

Check the following:
  • Deployed application: If your application is deployed on LangGraph Platform, you may need to create a new revision to enable this feature.
  • Local development server: If you are running your application locally, make sure you have upgraded to the latest version of the langgraph-cli (pip install -U langgraph-cli). Additionally, ensure you have tracing enabled by setting the LANGSMITH_API_KEY in your project’s .env file.

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Evaluator results are missing

When you run an experiment, any attached evaluators are scheduled for execution in a queue. If you don’t see results immediately, it likely means they are still pending.