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Troubleshooting LangGraph Studio

 Safari connection error with local dev server

Safari blocks plain‑HTTP traffic on localhost. If you start Studio with a vanilla
langgraph dev, the page may report a "Failed to load assistants" error (or something similar) and the browser DevTools will show network errors.

Quick fix — run Studio through a secure Cloudflare tunnel

pip install -U langgraph-cli>=0.2.6            # Python
langgraph dev --tunnel

# Requires @langchain/langgraph-cli>=0.0.26
npx @langchain/langgraph-cli dev

The command prints a URL like:

https://smith.langchain.com/studio/?baseUrl=https://hamilton-praise-heart-costumes.trycloudflare.com
where 
?baseUrl=https://hamilton-praise-heart-costumes.trycloudflare.com
indicates the endpoint where your agent server is exposed.

Open that URL in Safari and Studio should load immediately.

Alternative — use a Chromium‑based browser

Chrome, Edge, and Brave allow HTTP on localhost, so a plain langgraph dev should work without extra steps.

If it’s still not loading

  1. Make sure the baseUrl query parameter in the studio URL points to the tunnel URL NOT to localhost.
  2. Confirm your CLI version with langgraph --version.

No other configuration, certificates, or CORS tweaks are required.

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