llm-gemini 0.37

Google released Gemini 4 Hydrogen, the lowest-cost model in its Gemini 4 family, priced at $1.50 per million input tokens, $0.075 per million cached input tokens and $7.50 per million output tokens, according to Simon Willison's llm-gemini 0.37 release notes. Hydrogen is only a 25% discount to Gemini 4 Carbon and Gemini 4 Argon, which both cost $2.00/$0.10/$10.00 through November 30, 2026 and double to $4.00/$0.20/$20.00 from December 1, 2026, when Hydrogen becomes a 75% discount. Willison noted Hydrogen is still 15x the $0.10/$0.50 pricing of Claude Haiku 5.5 and GPT-6 Luna, and that Hydrogen will be the new free-tier model and power AI features in Google Search.

Release: llm-gemini 0.37 https://github.com/simonw/llm-gemini/releases/tag/0.37 Google launched Gemini 4 Hydrogen https://blog.google/innovation-and-ai/models-and-research/gemini-models/introducing-gemini-4-hydrogen/ today - the lowest cost member of the Gemini 4 family. It's actually not too far off the price of its much bigger siblings, Carbon and Argon. I'm finding Gemini 4's pricing really confusing. Here's the pricing scheme: | Model | Dates | Input $/M | Cached input | Output | |---|---|---|---|---| | Gemini 4 Carbon | Through Nov 30, 2026 | $2.00 | $0.10 | $10.00 | | | From Dec 1, 2026 | $4.00 | $0.20 | $20.00 | | Gemini 4 Argon | Through Nov 30, 2026 | $2.00 | $0.10 | $10.00 | | | From Dec 1, 2026 | $4.00 | $0.20 | $20.00 | | Gemini 4 Hydrogen | | $1.50 | $0.075 | $7.50 | Carbon and Argon are the same price , and both are scheduled to double in price on December 1st. If they're the same price, why have two different models? Google says https://aistudio.google.com/docs/pricing that Argon "delivers Gemini 4 intelligence with faster responses and lower token spend per turn compared to Gemini 4 Carbon" - so it may be priced the same, but it will use less tokens per task. Hydrogen, supposedly the cheap model, is currently only a 25% discount on its more capable peers. The Hydrogen price will make more sense after December 1st, when it will represent a 75% discount. It's still considerably more expensive than Claude Haiku 5.5 and GPT-6 Luna - they're both $0.10/$0.50, so Hydrogen is 15x that. I had Hydrogen generate some pelicans https://tools.simonwillison.net/markdown-svg-renderer?url=https%3A%2F%2Fgist.github.com%2Fsimonw%2Fce357e95149cd16f65ec7e7106ed4fed . Here's a full comparison grid https://static.simonwillison.net/static/2026/gemini-4-pelicans.html showing the pelicans for all three members of the Gemini 4 family at their three supported effort levels: Considering how close they are in price, the difference in pelican quality for Hydrogen is quite stark. Here's how Google describe https://blog.google/innovation-and-ai/models-and-research/gemini-models/introducing-gemini-4-hydrogen/ Hydrogen's intended position in their mix of models: In real-world software development, while teams rely on frontier models like Carbon and Argon for deep architectural judgment when designing systems or untangling subtle bugs, they still need a fast, disciplined execution model for writing code, running tests, and verifying changes. Hydrogen is built to stand on its own as a model for everyday work — or to pair with Carbon and Argon as the high-efficiency execution engine in multi-model workflows. Most notably, Hydrogen is the new free tier model, and is the model that will power AI features in Google Search. Tags: gemini https://simonwillison.net/tags/gemini , llm https://simonwillison.net/tags/llm , google https://simonwillison.net/tags/google , pelican-riding-a-bicycle https://simonwillison.net/tags/pelican-riding-a-bicycle , llm-pricing https://simonwillison.net/tags/llm-pricing , ai https://simonwillison.net/tags/ai , llms https://simonwillison.net/tags/llms