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Observability with Langfuse

Langfuse is an open-source observability and analytics platform for LLM-powered applications. It collects traces, generations, and custom metrics so that you can debug, evaluate, and monitor your AI features in production.

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Integration inside Cognee

Cognee ships with Langfuse support out of the box. The integration is intentionally lightweight and consists of just a few lines of code. Anywhere in the codebase where we want observability we add: 
from cognee.modules.observability.get_observe import get_observe
observe = get_observe()

@observe(as_type="generation")  # optional label
async def acreate_structured_output(...):
    ...
The decorator is a thin wrapper around Langfuse and automatically creates a span every time the function is executed.
The data is sent to the Langfuse backend specified via environment variables and can be inspected in the Langfuse UI.

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Quick start

  1. Install cognee (it comes with Langfuse) Langfuse is already declared in pyproject.toml, so you can skip this step if you already installed cognee.
  2. Create a project at Langfuse Cloud and copy the public and secret keys.
  3. Export the following environment variables (for example in your .env file): 
LANGFUSE_PUBLIC_KEY=<your public key>
LANGFUSE_SECRET_KEY=<your secret key>
LANGFUSE_HOST=https://cloud.langfuse.com
BaseConfig reads these values on startup, so nothing else is required. Start Cognee as usual and open the Langfuse UI – traces will appear in real time.

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Run your regular Cognee workflows:

import cognee
import asyncio
from cognee.modules.observability.get_observe import get_observe

observe = get_observe()

@observe(name="simple_example_run", as_type="example")
async def main():
    await cognee.add("Natural language processing (NLP) is ...")
    await cognee.cognify()
    results = await cognee.search("Tell me about NLP")
    for r in results:
        print(r)

asyncio.run(main())

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Adding your own spans

You can instrument any function in your codebase: 
from cognee.modules.observability.get_observe import get_observe
observe = get_observe()

@observe(as_type="my_tool", metadata={"foo": "bar"})
def my_helper(arg1, arg2):
    ...
All keyword arguments accepted by langfuse.decorators.observe (name, as_type, metadata, …) are forwarded unchanged – see the Langfuse Python SDK docs for the full reference.
Join Langfuse and cognee communities on Discord for any questions.