Gemini 3.5 hits Arena AI in stealth leak

The "leak" follows a classic Google pattern of stealth-testing top-tier models on the Arena to build hype and validate ELO ratings before an official keynote. Stealth checkpoints are reportedly outperforming Claude 4.7 and GPT-5.2 in "vibe coding" and UI generation, with users successfully generating complex, multi-file apps including a Minecraft clone in a single prompt. The May 16 timing aligns with the May 19 Google I/O schedule, while Arena AI's recent rebrand and spin-out from LMSYS cements its role as the industry's de facto kingmaker for LLM launches.