Claude Opus 4 and Sonnet 4: The New Gold Standard in AI Coding and Reasoning

Anthropic’s latest models redefine what’s possible—with speed, precision, and safety

The AI arms race just got a major upgrade. Anthropic has unveiled Claude Opus 4 and Claude Sonnet 4, two models that push the boundaries of coding, reasoning, and autonomous agent performance. Opus 4 now stands as the world’s best coding model, while Sonnet 4 delivers a significant leap from its predecessor, Sonnet 3.7. These aren’t just incremental improvements—they’re paradigm shifts.

“Opus 4 isn’t just faster—it’s smarter. We’re seeing 65% less reliance on shortcuts compared to Sonnet 3.7, meaning it tackles complex problems head-on,” says an Anthropic engineer.

Both models offer hybrid modes: near-instant responses for quick tasks and extended thinking for marathon coding sessions. Opus 4 and Sonnet 4 are available across Pro, Max, Team, and Enterprise plans, with Sonnet 4 also accessible to free users. Developers can tap into them via Anthropic’s API, Amazon Bedrock, or Google Cloud’s Vertex AI. Pricing is competitive—Opus 4 costs $15/$75 per million tokens (input/output), while Sonnet 4 sits at $3/$15.

Benchmarks That Speak for Themselves

The numbers don’t lie. Opus 4 dominates coding benchmarks, scoring 72.5% on SWE-bench and 43.2% on Terminal-bench, with unparalleled performance in long-running tasks (some spanning hours). Sonnet 4 isn’t far behind, hitting 72.7% on SWE-bench while offering improved steerability and efficiency. In high-compute scenarios, Opus 4 achieves 79.4%, and Sonnet 4 surprises at 80.2%.

“Sonnet 4’s navigation errors dropped from 20% to near zero. For multi-feature app development, that’s game-changing,” notes a Replit developer.

Anthropic didn’t just boost raw power—they refined the tools. Claude Code is now generally available, with beta extensions for VS Code and JetBrains. A new SDK lets developers build custom agents, while thinking summaries condense lengthy processes (needed in just ~5% of cases). Safety remains a priority: both models underwent rigorous evaluation to meet higher AI Safety Levels (ASL-3), with max reasoning steps increased from 30 to 100.

The Road Ahead

Anthropic’s focus is clear: advancing AI collaboration. Benchmarks reflect tests on 500 problems (compared to 477 for OpenAI models), with ongoing feedback loops ensuring continuous improvement. For developers, the message is simple—Opus 4 and Sonnet 4 aren’t just upgrades. They’re the new baseline.