This an excerpt from a newsletter by Renjit Philip detailing his 30-day experience using "vibe coding"—AI-powered development—to build a financial planning tool for startup founders. Philip, who identifies as a beginner coder, outlines the challenging journey from idea to minimum viable product (MVP), including burning through $127 in Replit credits and encountering numerous technical errors in precision calculations. A key takeaway from his experience is the critical need for specific prompts and the discovery that founders preferred an AI financial "advisor" over another spreadsheet tool. Ultimately, the author shares a detailed scorecard, lessons learned, and principles for effective vibe coding, concluding that while it is excellent for rapid prototyping, complex financial features require a more traditional development approach.