On July 24, Anthropic released Claude Opus 5. Pricing unchanged ($5 / $25 per million tokens), 1M context, model id is claude-opus-5. Three API changes matter more than the benchmarks: thinking is on by default (in old code with thinking: {"type": "disabled"} paired with effort xhigh/max, you immediately 400), the minimum cacheable prompt is cut to 512 tokens, and the team explicitly advises developers to drop prompt phrases like "verify once more" — the model verifies itself, and re-asking it over-fits to over-verification. On benchmarks, on FrontierBench v0.1 (74 agentic tasks, the successor to Terminal-Bench 2.1), Opus 5 at max effort scores 43.3%, and at xhigh hits 44.4% — its best score; Opus 4.8 only scores 18.7%, Fable 5 is 33.7%, GPT-5.6 Sol is 37.5%. SWE-bench Verified 96.0%, Multimodal jumps from 38.4% to 59.4%. OSWorld 2.0 70.57% (4.8 was 55.7%), Zapier AutomationBench 26.0% (Fable 5 was 17.4%), GDPval-AA v2 takes the top two ELO slots at 1861/1827. Most explosive is ARC-AGI-3 at high effort scoring 30.16% — the previous leader was GPT-5.6 Sol at 7.78%, Opus 4.8 was 1.52%. The most memorable engineering signal from this version is "tools > thinking": Chartography without tools is 29.6%, hook it up to an image-cropping tool and it jumps straight to 83.0%; BenchCAD Vision2Code voxel IoU goes from 0.366 to 0.821, incidentally trampling Mythos 5's 0.678. On safety, Gray Swan's indirect prompt-injection attack success rate within 15 attempts dropped from 5.5% to 2.0% (GPT-5.6 Sol is 20.0%); in browser scenarios with Claude Cowork defaulting to auto mode, attack success across 129 test environments is 0%. Cyber capability rises with general capability, and Anthropic has unlocked "source-code vulnerability lookup", but binary scanning, pentest, and exploit generation remain locked — RSP places it at ASL-3, on par with Opus 4.8; UK AISI's 'The Last Ones' passed 8 of 10 runs. The model id stays at opus 5, pricing $5 / $25 unchanged, both as a tier-down to Fable 5 ($10 / $50) to continue the enterprise-market split, and as a defense against the open-source camp (Kimi K3 $3 / $15, DeepSeek V4 Flash even cheaper): 1M context + 1/2 the price + scores chasing Fable 5, Opus 5 pushes the whole Anthropic product line to a new water mark on agentic, coding, and long-context mid-tier.