Lost braintrust logger.

[HuberTRoy]

I following by this doc https://mongodb.github.io/chatbot/quick-start/ for test.
I have set MONGODB_CONNECTION_URI & OPENAI_API_KEY.
When I run npm run dev, the server side report an error when request http://localhost:3000/api/v1.

Encountered error when constructing records to flush
Failed to construct log records to flush after 3 attempts. Dropping batch
{"level":"info","message":"No matching content found","reqId":"67cff220636af398e02cfe06"}
{"level":"warn","message":"Sending static message to user: Unfortunately, I do not know how to respond to your message.\n\nPlease try to rephrase your message. Adding more details can help me respond with a relevant answer.","reqId":"67cff220636af398e02cfe06"}
Encountered error when constructing records to flush. Retrying
Error: Please specify an api key (e.g. by setting BRAINTRUST_API_KEY).

What is BRAINTRUST_API_KEY? Where to get it? I can't find the relative information in the doc.

[mongodben]

https://braintrust.dev/ is a tool that we use for observability. all braintrust config should be optional. is it possible that you have a dummy value for BRAINTRUST_API_KEY in your .env file?

[mongodben]

Related to #645

[HuberTRoy]

@mongodben no, i copied the .env.example. only MongoDB config & OpenAI config.