{
  "id": 9224897,
  "title": "Claude Opus 5.5, GPT-6 Sol, GPT-6 Luna, and a new price war",
  "url": "https://urgent.news/2026/09/22/claude-opus-5-5-gpt-6-sol-gpt-6-luna-and-a-new-price-war",
  "topic": "ai",
  "section": "AI",
  "published": "2026-09-22T23:46:41.000Z",
  "source": {
    "name": "Simon Willison",
    "slug": "simon-willison",
    "url": "https://simonwillison.net/2026/Sep/22/opus-and-sol-and-luna/"
  },
  "original_language": "en",
  "account": "Yesterday, Anthropic unveiled Claude Opus 5.5 and OpenAI released GPT-6 Sol and GPT-6 Luna. The new models have stirred up a price war in the LLM landscape. GPT-6 Luna is half the price of its predecessor, GPT-5.6 Luna, while GPT-6 Sol has a similar discount compared to GPT-5.6 Sol. GPT-5.6 Luna was previously Anthropic's top pick for building applications due to its excellent performance and affordability. However, GPT-6 Luna now offers even better value at half the price, reducing any reasons to stick with GPT-5.6 Terra. GPT-6 Luna is the cheapest OpenAI model ever released, surpassing even GPT-4.1 Nano and GPT-5 Nano. Claude Opus 5.5 appears to address Opus's communication issues, being cheaper per token than Opus 5.0 with the intelligence of Fable 5.1. It is also token-efficient and works across all effort levels. The price for Opus 5.5 has dropped by 20%, now at $4/million for input and $20/million for output. The new price is identical to GPT-5.6 Sol's price, but OpenAI has since halved their Sol prices. Other models like Sonnet 5.5, Haiku 5.5, GPT-6 Astra, and Claude Fable 5.1 are expected to follow soon. Claude Opus 5.5 hit a maximum output token limit while reasoning about an SVG test, suggesting that the \"max\" level may not always yield the best results. Despite this, GPT-6 Sol and Claude Opus 5.5 have become the default models for Codex and Claude Code, with Anthropic's Datasette Agent demo upgraded to use GPT-6 Luna.",
  "summary": "Yesterday was Grok 4.7 ( pelicans ) and MiMo v2.6 Flash/Pro ( more pelicans ). Today Anthropic released Claude Opus 5.5 , and around an hour later OpenAI released GPT-6 Sol and GPT-6 Luna . It's going to take a while to get a good read on all of these new models, but here are my impressions so far. GPT-6 Sol and Luna are half the price of their GPT-5.6 equivalents GPT-5.6 Luna was already my…",
  "key_points": [
    "Anthropic releases Claude Opus 5.5 with improved communication",
    "OpenAI introduces GPT-6 Sol and GPT-6 Luna, half the price of predecessors",
    "Claude Opus 5.5 and GPT-6 Luna spark a new price war in LLM market"
  ],
  "editors_take": "The aggressive pricing of GPT-6 Luna and Claude Opus 5.5 intensifies competition in the LLM market, putting pressure on other model providers and likely benefiting developers building applications with these tools.",
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}