At Replit, a team of designers and engineers collaborated with Stanford University to design a creative coding environment called Spellburst, which aims to support rapid exploration and iteration for coders. The project's research prototype was evaluated through an evaluative study, highlighting the importance of non-linear research processes, designing for the future, and understanding user interface challenges such as control and power dynamics. The team's findings were showcased at the ACM Symposium on User Interface Software and Technology (UIST), where they attended talks from industry leaders and researchers exploring novel interfaces and AI architecture leveraging Large Language Models (LLMs). The project's results suggest a shift away from "GPT wrappers" and towards more interactive, node-based UIs, and emphasize the need for designers to prioritize control and empowerment in their work. Replit plans to release Spellburst as a public demo in Winter 2024, suitable for personal and educational use, and is hiring people interested in designing, building, and researching the future of user interfaces and AI.