Langfuse integration

Langfuse is an AI platform that includes prompt management capabilities.

To reference prompts in Langfuse:

1. Install the langfuse SDK: npm install langfuse

2. Set the LANGFUSE_PUBLIC_KEY, LANGFUSE_SECRET_KEY, and LANGFUSE_HOST environment variables as desired.

3. Use the langfuse:// prefix for your prompts, followed by the Langfuse prompt id and version. For example:

   prompts:
     - 'langfuse://foo-bar-prompt:3'
   
   providers:
     - openai:gpt-3.5-turbo-0613
   
   tests:
     - vars:
         # ...

Variables from your promptfoo test cases will be automatically plugged into the Langfuse prompt as variables.