Hey everyone, I’m having trouble getting LangSmith to properly track my LangChain applications. I’ve been working with the latest version (v3) and trying to implement v2 tracing but nothing seems to work.
I’ve tried setting up different project configurations and API keys in LangSmith but can’t get any traces to show up. I’ve also modified environment variables multiple times but still no luck.
Some AI assistants suggested that just setting environment variables might not be enough for v2 tracing. Is this accurate? Do I need additional configuration steps?
I’ve attempted various code modifications but none of them are working. This seems like it should be a common issue but I can’t find a clear solution. Any help would be appreciated!
This drove me nuts for weeks! My project wasn’t actually created in the LangSmith dashboard - I just thought it was. Make sure you’re calling LangSmithTracer explicitly in your chain. Environment variables alone don’t work for v2 like Emma mentioned. Also double-check your API key has the right permissions.
Been down this rabbit hole more times than I’d like to admit. The tracing issue is usually callback configuration.
You need to pass the LangSmith callback handler directly to your chain or LLM calls. Environment variables alone won’t work for v2 tracing.
Here’s what worked for me:
from langsmith import Client
from langchain.callbacks import LangChainTracer
client = Client()
tracer = LangChainTracer(project_name="your-project")
# Then pass it to your chain
chain.run(input_text, callbacks=[tracer])
Don’t mix v2 and v3 syntax. I wasted hours using v3 LangChain with v2 tracing patterns.
One more thing - restart your Python session after changing environment variables. Sometimes the old config gets cached and you’ll keep hitting the same wall.
I encountered similar difficulties when transitioning to v3. The main resolution for me was realizing that v2 tracing cannot function solely with environment variables; you must explicitly initialize it within your code using langsmith.configure() or employ the @traceable decorator. Additionally, ensure that your LangSmith client version aligns with your LangChain version; in my case, downgrading the client was necessary. Furthermore, verify that the project name in your environment variable exactly corresponds with the one in your LangSmith dashboard—any minor typo can disrupt trace visibility. Finally, check that your API endpoint isn’t configured for the incorrect region.