I wrote a simple LLM backed chat application. My primary usage right now is to copy paste the code I have written (Java and Python) into the chat and ask it to generate unit test cases. I think it has reduced my development time a huge amount. It also generates tests for edge cases. The generated code usually are usable 90% of the time. It also is very good at making mocks for service calls. I'm using Claude 2.1 model with Bedrock.

It's nowhere as fancy as FB tool but I know it is blessed by company.