Google released Gemini 1.5 with a 1-million-token context window — an order of magnitude beyond rivals at the time — later extended to 2 million tokens. It could process hour-long videos, huge codebases, or entire books in a single prompt.

The release used a Mixture-of-Experts architecture for efficiency, delivering flagship-class quality at lower serving cost. Google pitched long context as the defining advantage of the Gemini line.

Gemini 1.5's context breakthrough forced the whole industry to compete on long context, a race that continued through the 2.x and 3.x generations.