#Gemini

GPT-6 Sol and Luna arrived at half the price of GPT-5.6, Claude Opus 5.5 delivers Fable 5.1 level at $4/$20 with four breaking changes in the API, and Google says Gemini 4 ships before the end of the year. What each one brings that's different, the catches (Luna regresses on agentic coding, Opus default effort dropped to medium), and which one to use now.

Google ran the same play and shipped Flash before Pro. Except the $0.75/M that took over the timeline isn't a low price: the official table shows it's the 3.6 Flash price with a 50% discount through December 31, 2026, and the bill doubles on January 1. Here are both numbers, the real benchmarks (FrontierCode 43.6%, AutomationBench 30.4%), what breaks when you migrate from 3.6, and the data point the release leaves out: hallucination went up from 55.6% to 64.5%.

Gemini 3.5 Pro still isn't out, and every week there's a new date going around. I separated what Google has confirmed in writing from what's just a leak with no reproducible data, with the timeline of delays since I/O in May. And I built a 20-line watcher on the Gemini API models endpoint that pings you the minute gemini-3.5-pro shows up, plus a model fallback in Laravel so the switch becomes one line of .env.