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Log traces to specific project

You can change the destination project of your traces both statically through environment variables and dynamically at runtime.

Set the destination project statically

As mentioned in the Tracing Concepts section, LangSmith uses the concept of a Project to group traces. If left unspecified, the project is set to default. You can set the LANGCHAIN_PROJECT environment variable to configure a custom project name for an entire application run. This should be done before executing your application.

export LANGCHAIN_PROJECT=my-custom-project

If the project specified does not exist, it will be created automatically when the first trace is ingested.

Set the destination project dynamically

You can also set the project name at program runtime in various ways, depending on how you are annotating your code for tracing. This is useful when you want to log traces to different projects within the same application.


Setting the project name dynamically using one of the below methods overrides the project name set by the LANGCHAIN_PROJECT environment variable.

import openai
from langsmith import traceable
from langsmith.run_trees import RunTree

client = openai.Client()

messages = [
{"role": "system", "content": "You are a helpful assistant."},
{"role": "user", "content": "Hello!"}

# Use the @traceable decorator with the 'project_name' parameter to log traces to LangSmith
# Ensure that the LANGCHAIN_TRACING_V2 environment variables is set for @traceable to work
name="OpenAI Call Decorator",
project_name="My Project"
def call_openai(
messages: list[dict], model: str = "gpt-3.5-turbo"
) -> str:

# Call the decorated function

# You can also specify the Project via the project_name parameter
# This will override the project_name specified in the @traceable decorator
langsmith_extra={"project_name": "My Overriden Project"},

# The wrapped OpenAI client accepts all the same langsmith_extra parameters
# as @traceable decorated functions, and logs traces to LangSmith automatically.
# Ensure that the LANGCHAIN_TRACING_V2 environment variables is set for the wrapper to work.
from langsmith import wrappers
wrapped_client = wrappers.wrap_openai(client)
langsmith_extra={"project_name": "My Project"},

# Alternatively, create a RunTree object
# You can set the project name using the project_name parameter
rt = RunTree(
name="OpenAI Call RunTree",
inputs={"messages": messages},
project_name="My Project"
chat_completion =
# End and submit the run

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