Gemini 4 Argon opens to paid Gemini API keys at $2 in and $10 out

TL;DR

• On 13 October Google made Gemini 4 Argon (gemini-4-argon) generally available in the Gemini API and in Google AI Studio, for paid keys only.
• Until 30 November 2026 it costs $2.00 per 1M input tokens and $10.00 per 1M output tokens; from 1 December the prices are $4.00 and $20.00.
• Input, thinking and output share one 1,048,576-token window, a response can run past 64K tokens with background execution, and explicit caching and sampling parameters are gone.