Model Launch Articles
11 articles across AI Catchup's news, guides, tutorials, and comparisons.
All Model Launch articles
Anthropic Releases Claude Haiku 5.5, Its Fastest Model and First Haiku With Effort Levels
Anthropic released Claude Haiku 5.5 on October 7, 2026, its fastest model to date and the first Haiku with effort levels. It scores 72.4% on OSWorld 2.1 against Haiku 4.5's 15.7%, and costs $0.10 per million input and $0.50 per million output tokens for prompts up to 100,000 tokens, 90% less than Haiku 4.5.
Claude Sonnet 5.5 Launches With Lower Task Costs and Cursor Support
Anthropic introduced Claude Sonnet 5.5 on September 28 with model ID `claude-sonnet-5-5`. It keeps Sonnet 5's $2 input and $10 output price per million tokens; Anthropic reports output generation more than 30% faster and up to 30% lower cost per task. Cursor lists the model in Settings > Models. Cache reads dropped to $0.10 per million tokens on October 7.
GPT-6.1 Sol: Astra-Level Coding at a Fifth of the Price, With Cost at Every Effort Level
OpenAI released GPT-6.1 Sol on September 29, 2026, at $2 input and $10 output per million tokens, a fifth of GPT-6 Astra's price, with cached input at $0.10. On OpenAI's charts it edges past Astra's best DeepSWE score at high effort and trails Astra by 2.1 points on OSWorld offline. The API model ID is gpt-6.1-sol.
Claude Opus 5.5: Fable 5.1-Level Scores at $4 and $20, With Benchmarks, Effort Costs, and Migration Guide
Claude Opus 5.5, released September 22, 2026, beats Claude Fable 5.1 on every benchmark Anthropic published and costs $4 and $20 per million tokens, 60% less than Fable 5.1. It scores 66.4% on Terminal-Bench 4.0 against 57.9% for GPT-6 Astra. Thinking is always on, the default effort is medium, and four API changes can break Opus 5 code.
GPT-6 Sol and Luna: Half the Price of GPT-5.6, With Benchmarks and Cost at Every Effort Level
OpenAI released GPT-6 Sol and GPT-6 Luna on September 22, 2026, at $2 and $10 and $0.10 and $0.50 per million tokens, half the price of GPT-5.6. Luna scores 66.6% on DeepSWE for about $0.22 a task. Since October 7 the pair has been rolling out as ChatGPT's Chat models, and GPT-6.1 Sol has succeeded Sol at the same price.
Claude Fable 5.1 and Mythos 5.1: Same Price, Cheaper Cache Reads, Fewer Safeguard Interventions
Anthropic released Claude Fable 5.1 on September 1, 2026 as claude-fable-5-1 at $10 per million input and $50 per million output tokens, with cache reads cut 75% to $0.25 per million. Anthropic estimates typical workloads cost about 25% less than Fable 5. Claude Mythos 5.1 is the same model with fewer cyber and life-science safeguards, limited to vetted US organizations.
Claude Sonnet 5 Launch: Anthropic's Most Agentic Sonnet, Since Replaced by Sonnet 5.5
Anthropic launched Claude Sonnet 5 on June 30, 2026 as its most agentic Sonnet yet, and made its $2 input and $10 output per million token pricing permanent. Claude Sonnet 5.5 replaced it on September 28; Anthropic now lists Sonnet 5 as a legacy model, still available on the API as claude-sonnet-5.
OpenAI Previews GPT-5.6: Sol, Terra, and Luna in Limited Preview
OpenAI previewed the GPT-5.6 family in June 2026 with trusted partners: Sol, a frontier flagship it called a step function better than GPT-5.5; Terra, competitive with GPT-5.5 at 2x lower cost; and Luna, its most cost-efficient model. All three became generally available on July 9, 2026, and GPT-6 has since superseded them.
Claude Fable 5 and Mythos 5: Mythos-Class Capability Goes General, With Caveats
Anthropic launched Claude Fable 5 on June 9, 2026 as a Mythos-class model made safe for general use, plus Claude Mythos 5 for vetted cyberdefenders via Project Glasswing, both at $10 per million input and $50 per million output tokens. Fable 5.1 and Mythos 5.1 replaced them on September 1; Anthropic now lists Fable 5 as a legacy model.
GPT-5.5 Launch: State-of-the-Art Agentic Coding, 1M Context, and a New Pro Tier
OpenAI launched GPT-5.5 on April 23, 2026, with state-of-the-art scores on Terminal-Bench 2.0 (82.7%) and GDPval (84.9%) and a GPT-5.5 Pro tier. GPT-6.1 Sol and GPT-6 Astra have since replaced it, and it retires from ChatGPT and Codex on October 14, 2026. The API keeps it at $5/M input and $30/M output.
Claude Opus 4.7 Launch: Stronger Coding, xhigh Effort, and a New Cyber Safeguards Tier
Anthropic launched Claude Opus 4.7 on April 16, 2026, with gains over Opus 4.6 in advanced software engineering at the same $5/$25 pricing, a new xhigh effort level, /ultrareview, higher-resolution vision and the first cyber safeguards. It is now a legacy model, succeeded by Opus 4.8, Opus 5 and Opus 5.5.