Simon Willison: One 'Make Sure It Is Fun' Line Got Opus to Build a Game in 3 Hours
Simon Willison · rss · 2026-10-15
Simon Willison shares another game experiment, this time in the Claude iPhone app (chat mode, not Claude Code): one prompt asking Claude Opus 5.5 Max to build a three.js game called "Tree Appreciator" — two algorithmically generated trees, and the mechanic is appreciating the differences between them.
Key takeaway: telling Opus 5.5 "make sure it is fun" works "uncomfortably well" — Claude crunched for 3 hours 7 minutes and returned a cosy spot-the-difference game with music, animation, and achievements that's genuinely compelling to play. A good case for putting subjective experience goals into long-run vibe coding prompts.
More from coding & agent
- Ethan Mollick's new book charts 30 months of AI progress, from cyborg to conjurer work — rseroter · 2026-10-23
- OpenJet claims Qwen3.8-27B coding runs 1.9x faster than llama.cpp on one RTX 3090 — JeremyCMorgan · 2026-10-23
- Jensen Huang details Vera Rubin agentic stack: NVL72, MGX, CMX and RTX — rohanpaul_ai · 2026-10-23
- Building an autonomous SEO agent in Hermes with three skills: programmatic pages, Keywords Everywhere, DataForSEO — EXM7777 · 2026-10-23
- Building a sports betting AI agent with onchain execution and human approval by default: architecture and lessons — Dry-Comfortable-2678 · 2026-10-23
- Capy 0.5.0 lets Claude Pro/Max subscribers reuse their plan quota, adds OIDC cloud access — garrytan · 2026-10-23