Imagine having a personal negotiation coach in your pocket, ready to help you snag the best deals. That's the promise of ACE, a new AI-powered system designed to boost your bargaining skills. Negotiation is a delicate dance, and many of us miss steps, especially when we're just starting out. ACE uses the power of large language models (LLMs), the same tech behind tools like ChatGPT, to analyze your negotiation style and provide personalized feedback. But how does it work? Researchers at Columbia University built ACE using real-world negotiation transcripts from MBA students. These transcripts, combined with expert insights, helped create a system that can spot common negotiation mistakes. ACE identifies errors in your approach, from setting your initial target price to how you close the deal. It then offers targeted feedback and suggests alternative strategies, much like a human coach would. But ACE goes beyond just pointing out flaws. It provides practical, in-the-moment advice, even offering revised versions of what you could have said to achieve a better outcome. The researchers put ACE to the test in a study with over 370 participants. They found that people who used ACE significantly improved their negotiation skills compared to those who didn't have any coaching. So, what does this mean for the future of negotiation? ACE suggests that AI can play a crucial role in democratizing access to high-quality negotiation training. Tools like this could be game-changers for underrepresented groups who often lack access to traditional coaching resources. While ACE is still under development, it shows the exciting potential of AI to transform how we learn and practice negotiation. The system still has some limitations, including a tendency to be too agreeable as a negotiating partner and a lack of memory between interactions. However, ACE represents a significant step toward personalized, accessible, and effective negotiation training for everyone.