Building a 100x Cheaper Trace Judge with Fireworks (7 minute read) (opens in new tab)  🤖AI Agents  Content type: Blog

Fireworks and LangChain developed a cost-effective "perceived error" judge using the Qwen-3.5-35B model, capable of detecting user-identified errors in chatbot interactions. Fine-tuning this judge on chat-langchain data resulted in performance meeting or exceeding frontier models at reduced costs.