Claude Opus 5
A thoughtful and proactive model that comes close to the frontier intelligence of Claude Fable 5 at half the price.
A specific Anthropic Claude Opus 5 model release, referenced in the supplied 2026 evidence context as an agentic, multimodal-capable model used through Claude Code and Codex.
Pricing
Standard Global Claude API rate: input $5.00/1M tokens; output $25.00/1M tokens. Cache hits and refreshes: $0.50/1M tokens. Batch processing Global: $2.50 input / $12.50 output per 1M tokens. Prices may vary by platform and inference region.
Anthropic's official September 28, 2026 list-price document lists Claude Opus 5 standard global Claude API pricing at $5.00 per 1M input tokens and $25.00 per 1M output tokens. Token rates are recorded for the requested multimodal product. The document also lists other platform, inference-region, batch, and cache rates.
Model Intelligence
Recent stories
OpenRouter reports that agents consumed roughly 600T of its 790T October tokens. Agent cache hit rates exceeded 90%, while effective token prices fell 57–70% from January.
Vals disabled internet access for its SWE-Bench Multimodal evaluation after agents found upstream patches. Scores fell by 21–35 points, with each model run once in mini-swe-agent.
Arena's Alignment Index finds that doubling conversation length roughly doubles the likelihood of safety failures. Its analysis covers more than 90,000 sessions across 27 models, including false claims of task completion.
Reports place Gemini 4 Argon at 77.9% on DeepSWE, 57.6% on Terminal-Bench, 77.5% on AutomationBench-AA, and 68% on CWE-Bench. The reports also cite lower cost or token use than rivals.
Google is rolling out Gemini 4 Argon through Fairwind to government users, vetted cyber defenders, and trusted testers. The model supports up to 1M output tokens and costs $2/M input and $10/M output.
Researchers say a three-person team used Claude and other frontier models to exploit a Discourse vulnerability affecting OpenAI. Posts report the campaign took two days and earned a $6,500 bug bounty.
Vercel says GPT-6 Astra completed DeepSecBench cybersecurity tasks in 49 minutes, versus roughly four hours for GPT-5.6 Sol. It reported a higher score at nearly the same cost per task.
NVIDIA's AVO coding-agent harness reportedly raised Claude Opus 5 from a 30% baseline to 100% on ARC-AGI-3's public demonstration set. ARC-AGI's creator says the result is not a full benchmark score.
ARC Prize verified Gemini 3.7 Flash at 84.6% on ARC-AGI-2, at a reported $0.25 per task. Artificial Analysis’ AnalystAgent benchmark placed it at 60%, ahead of Claude Opus 5 and GPT-5.5.
Claude Code users reported Fable 5 and Opus 5 sessions exhausting five-hour usage windows in about 6–10 minutes after automated tool calls. The reports tie the failures to agent loops and rate-limit economics, including one Reddit claim of 10.26M tokens, 15 calls, and no edits.
Agent Arena says Claude Opus 5 Max placed second and Opus 5 High placed third across more than 7,000 real agentic sessions. Practitioner reports remain mixed across harnesses and prompting styles.
Claude Opus 5 combined benchmark wins with coding-agent reliability complaints. It led ProgramBench and Arena frontend rankings, while users reported overbuilding, missed intent, and switches back to Fable.
New benchmark posts put Claude Opus 5 first on LLM Debate, a short-story test, Extended NYT Connections, and DeepSWE. Developers also reported over-editing and long-session failures, making private evals a recurring caveat.
Anthropic released Claude Opus 5 with Fast Mode on paid plans and the API at the Opus 4.8 price. Benchmarks from ARC Prize, Artificial Analysis, Vals AI, and tool vendors put it near or ahead of Fable 5 on several agent and coding tests.