Google Gemini 3.5 Flash Review — Flash-Tier Speed, Pro-Tier Agentic Performance

Google Gemini 3.5 Flash launched at Google I/O 2026 on May 19 as the first Flash-tier model to lead Pro-tier models on agentic benchmarks. It tops MCP Atlas (83.6%), MMMU-Pro, CharXiv Reasoning, and Finance Agent v2 while running at 289 tok/s — four times the speed of competing frontier models. We cover the launch, benchmarks, pricing, hallucination rate, limitations, and where Gemini 3.5 Flash fits against GPT-5.5 and Claude Opus 4.7.