Claude Code solves Advent of Code 2025 in under 2 hours – with one command (richardgill.org)

Claude Code has achieved a remarkable feat by solving all 12 days of Advent of Code 2025 in less than two hours, demonstrating its advanced capabilities in tackling programming challenges. This year, while the author has struggled with the puzzles—taking significantly longer using previous AI models—Claude effortlessly produced high-quality solutions in short bursts, often in as little as 2 to 18 minutes per puzzle. The author leveraged automation to create custom commands that facilitate interaction between Claude Code and the Advent of Code platform, indicating a significant leap in the ability of AI tools to autonomously solve complex coding tasks. This achievement is noteworthy for the AI/ML community as it highlights not only the advancements in Claude's problem-solving abilities but also the potential for AI to tackle structured programming challenges more effectively than ever before. While Claude displayed impressive performance on simpler puzzles, it also demonstrated a more human-like approach when facing tougher problems by iterating through attempts and debugging in a manner reminiscent of experienced programmers. However, the author notes the specific nature of Advent of Code problems—self-contained and derived from known classes of challenges—which allows Claude's extensive training on similar tasks to shine through. The implications suggest that while AI's prowess can significantly augment coding efficiency, the nuances of real-world programming may still present unique challenges.