Claude Opus 5.5 matches Fable 5.1 performance at lower cost and promises less "Claudish" writing Ad Skip to content The Decoder AI, Menschen, Wirtschaft --> Log In Subscribe DE Switch to German Primary Menu The Decoder AI, Menschen, Wirtschaft --> Log In Subscribe DE Switch to German Primary Menu Sign In Register Subscribe Now The Decoder Opens discord in a new tab Opens LinkedIn in a new tab AI in practice Copy the url to clipboard Share this article Go to comment section Claude Opus 5.5 matches Fable 5.1 performance at lower cost and promises less "Claudish" writing Matthias Bastian View the LinkedIn Profile of Matthias Bastian Sep 22, 2026 Nano Banana Pro prompted by THE DECODER Ask about this article… Search Anthropic is launching Claude Opus 5.5, the first model in a new family. The company says it delivers Claude Fable 5.1-level performance while costing significantly less and running faster than its predecessor. According to Anthropic, Opus 5.5 matches Claude Fable 5.1 "on most tasks" while costing about 40 percent less to run than Opus 5. Claude Sonnet 5.5 and Haiku 5.5 are expected in the coming weeks, with similar gains in performance, efficiency, and safety. Anthropic's benchmarks show the new Opus model ahead of both Fable 5.1 and OpenAI's much more expensive GPT-6 Astra on most tasks. Benchmark / capability Opus 5.5 Fable 5.1 Opus 5 GPT-6 Astra GPT-5.6 Sol Agentic coding Terminal-Bench 4.0[1] 66.4% 55.8% 52.3% 57.9% 37.3% Agentic coding FrontierCode v1.1 (Main) 54.4% 50.3% 48.0% 53.3% 47.5% Agentic coding CursorBench 4.0 57.8% 51.8% 46.6% N/A 41.7% Knowledge work GDPval-AA v2.1 1,846 1,735 1,708 1,542 1,588 Business workflows AutomationBench[1] 40.0% 31.4% 26.9% 41.4% 28.8% Multidisciplinary reasoning Humanity's Last Exam 67.7% (with tools) 65.6% (with tools) 63.6% (with tools) 57.2% (with tools) N/A Agentic scientific research Terminal-Bench-Science 0.1[1] 58.7% 52.6% 29.0% 64.6% 22.4% Computer use OSWorld 2.0 81.8% (partial) 80.7% (partial) 74.0% (partial) N/A N/A Visual chart recognition Chartography 89.0% (with tools) 88.4% (with tools) 83.4% (with tools) N/A N/A Anthropic says the new series primarily addresses customer feedback on cost, efficiency, and communication quality, particularly in financial services, law, and software development. Ad Lower prices and token usage cut operating costs Anthropic prices Opus 5.5 at $4 per million input tokens and $20 per million output tokens, down from $5 and $25, respectively, for Opus 5. That's a 20 percent cut in token prices. The company also reduced cache read costs by 60 percent. Ad Anthropic says total operating costs, which account for both token prices and token usage , should be about 40 percent lower than Opus 5's. The model uses fewer tokens and generates output more than 30 percent faster. Prices per 1M tokens Claude Opus 5.5 Claude Opus 5 Cache reads $0.20 $0.50 Input tokens $4 $5 Output tokens $20 $25 Cache writes $5 $6.25 Five-hour usage limits for subscribers will increase by 20 percent. With the model's lower costs, Anthropic says those limits stretch 25 percent further overall. Users can also save a limit reset for when they need it most. Ad Anthropic is using coding benchmarks to make its case on price and performance. On FrontierCode, the company says Opus 5.5 beats OpenAI's GPT-6 Astra at about 20 percent of the cost per task. On Terminal-Bench 4.0, it claims the same performance as Astra at 40 percent of the cost. On CursorBench, it says Opus 5.5 beats GPT-5.6 Sol by 11 points at one-third of the cost. The price cut is a response to pressure from OpenAI and especially Chinese AI models, which offer lower performance but cost a fraction as much . Ad Anthropic promises less "Claudish" Opus 5.5 is also supposed to communicate more naturally than earlier models. Anthropic says it puts the most important information first, uses less jargon, and follows writing instructions more closely. Early testers described its writing as clearer and easier to understand, which Anthropic says makes it a better partner for long work sessions. Current Claude models have drawn plenty of criticism for their formulaic, convoluted writing, sometimes called "Claudish" . Ad Screenshot via PAW Opus 5.5 is also the first Opus model with safeguards for cybersecurity, biology, and frontier LLM development that match those of Fable 5.1. When those safeguards kick in, Anthropic says requests are transparently routed to another model. Users can still find and fix bugs in their code, but most cybersecurity tasks will go to the older Opus 4.8. Requests flagged by classifiers for biology or frontier LLM development will go to Opus 5. Verified organizations can apply to use the model for biological research through the Life Sciences Verification Program . Anthropic plans to extend its existing Cyber Verification Program to Opus 5.5 in the coming weeks. Claude Opus 5.5 is available now on all platforms, including Amazon Web Services, Google Cloud, and Microsoft Azure. Developers using the Claude Platform can access it with the model ID claude-opus-5-5 . Anthropic calls for higher safety standards as models become more capable Anthropic plans to screen reinforcement learning environments more strictly. The company says flawed training environments are a major source of misaligned model behavior . It's also working on better alignment rewards, automated ways to create safety training scenarios, and stronger safety and monitoring measures. AI labs are debating how quickly to release more capable models. OpenAI recently called for international standards for AI systems that could improve themselves , while several researchers have publicly urged labs to slow releases until alignment methods catch up . Anthropic is taking a similar position, calling for a higher safety standard for models that could automate AI research entirely. The company says public policy should have a greater role in setting that standard. External organizations Frontier Design