Gemini 4 Argon: the third $2/$10 model and your Azure gap
Gemini 4 Argon launched on 30 September at an introductory $2/$10 per million tokens, the third frontier model at that price in three days, but unlike Claude Sonnet 5.5 and GPT-6.1 Sol it is not in Microsoft Foundry, has no API model ID, and goes to vetted cyber defenders first. The standard price is $4/$20 with no published end date for the discount, so Azure teams in Sweden should budget on the higher figure and prepare a gateway route rather than switch now.
Sonnet 5.5 vs GPT-6.1 Sol on Azure: the $2/$10 cost math
Claude Sonnet 5.5 and GPT-6.1 Sol reached Microsoft Foundry a day apart at the same $2/$10 list price, yet a cache-heavy 60-turn agent session costs $3.45 on Sonnet 5.5 and $2.55 on GPT-6.1 Sol, or $3.06 in the EU Data Zone that Claude still lacks. Above 272K input tokens the order flips, because GPT-6.1 Sol doubles its input rate while Sonnet 5.5 keeps flat pricing to 1M tokens and can run with no up-front reasoning.
Claude Sonnet 5 vs Opus 4.8 vs GPT-5.5: agent cost math
Anthropic launched Claude Sonnet 5 on 30 June 2026 at an introductory 2/10 dollars per million tokens, posting 63.2% on SWE-bench Pro and near-Opus agentic performance at 40-60% of the cost per task. We run the cost math against Opus 4.8 and GPT-5.5, set out a routing framework for when the cheap model wins, and draw the continuity lesson from the eighteen-day Fable and Mythos export-control pause.