Midpage has revolutionized its approach to building legal AI by integrating PromptLayer, allowing lawyers to work alongside engineers to refine prompt quality effectively. This collaboration has shifted from manual tracking in Notion to automated evaluation pipelines that identify issues before reaching users. The platform now supports 80 production prompts across 10 AI features, with a significant reduction in engineering oversight time, as the majority of prompt iteration is managed by lawyers spending 5-15 hours per week on this task. Midpage's platform, which functions similarly to Google Scholar for case law, enables users to search and annotate cases, with various AI features tailored to different tasks, such as summarizing search results and classifying cases. The use of multiple models, including 4o-mini for speed and Gemini 2.5 Flash for intelligence, facilitates this process. Previously, the absence of a systematic prompt management system resulted in engineers spending excessive time on prompt adjustments. Now, the "Lawyers in the Loop" workflow empowers non-technical team members to manage prompts independently, while PromptLayer's registry and evaluation pipelines enhance iteration and quality control. This setup enables rapid iteration, with fine-tuning and regression gates ensuring accuracy and reliability in production AI features. Midpage's experience underscores the importance of empowering domain experts with no-code tools and integrating robust evaluation processes from the start to transform prompt engineering from a bottleneck into a competitive advantage.