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Observability with Langfuse

This guide shows you how to set up Langfuse to add observability to your agents for monitoring, tracing, and debugging. With observability enabled, you can track agent execution, view traces, and analyze performance in real-time using Langfuse.

Before starting this guide, follow the Quickstart guide to have your first agent running on Idun Agent Platform.

Setting Up Observability

You can add observability to your agent either when creating it or by editing an existing agent in the Manager UI.

Step 1: Get Your Langfuse API Keys

If you don't have Langfuse API keys yet:

  1. Go to Langfuse Cloud or your self-hosted instance
  2. Sign up or log in to your account
  3. Create a new project or select an existing one
  4. Navigate to Settings → API Keys
  5. Click Create New API Key
  6. Copy the Public Key and Secret Key

Step 2: Navigate to Observability Configuration

  1. On Idun Agent Platform main page, navigate to Observability
  2. Go to Add configuration
  3. Select Langfuse
  4. Enter a Configuration Name (e.g., "Langfuse Server 1")
  5. Fill in the required API credentials:
    • Host URL: Your Langfuse instance URL (e.g., https://cloud.langfuse.com or your self-hosted URL)
    • Public Key: Your Langfuse public key (starts with pk-lf-...)
    • Secret Key: Your Langfuse secret key (starts with sk-lf-...)
  6. Finally, click Create configuration

Add configuration Add langfuse configuration 2

Warning

Keep your secret key secure. Never commit it to version control or share it publicly.

Tip

Your observability configurations are saved and can be reused across multiple agents. You only need to set up your API keys once.

Step 3: Add Langfuse observability to your agent

  1. Navigate to your agent you want to trace and observe with Langfuse
  2. Click Edit Agent
  3. Click Next to go to the observability config
  4. Select Langfuse in observability
  5. Click on the Langfuse configuration you want to use for your agent.
  6. Click Next
  7. Finnalize with Save changes

Add langfuse configuration to agent

Finnaly, on your agent page, click đŸ”„Restart to reload the agent configuration and enable Langfuse observability.

Viewing Observability Data

Once your agent is running with observability enabled:

  1. Interact with your agent through the Manager UI or API
  2. Open your Langfuse dashboard at cloud.langfuse.com
  3. Navigate to your project to view traces

You'll see detailed traces showing: - Agent execution flow - LLM calls and responses - Tool usage and results - Execution time and costs - Error traces and debugging information

Langfuse tracing



Best Practices

  • Use descriptive names for observability configurations to identify them easily
  • Enable observability early to catch issues during development
  • Monitor costs through your observability dashboard

Troubleshooting

Warning

ADK does not currently support simultaneous tracing with both Langfuse and GCP tracing. If you are interested by this feature, please reach out via GitHub issues or join our Discord Server.

Observability not working?

  1. Check API keys: Ensure your public and secret keys are correct
  2. Verify host URL: Make sure the URL is accessible and correctly formatted
  3. Check agent logs: Look for connection errors in the agent runtime logs
  4. Test connectivity: Verify you can reach the Langfuse/Phoenix host from your agent

Next Steps