Opus 5 handles multi-file refactors and end-to-end feature work natively; set reasoning effort via `reasoning: 'medium'` in AI SDK 7, handle safety blocks with model fallbacks.
Summary
Long-horizon agentic tasks complete full features instead of stubs, cutting token spend and latency at medium effort levels. Safety classifier blocks require fallback chains—AI Gateway fallbacks let you skip manual retry logic.
Why it matters
Long-horizon agentic tasks complete full features instead of stubs, cutting token spend and latency at medium effort levels. Safety classifier blocks require fallback chains—AI Gateway fallbacks let you skip manual retry logic.
Implementation verdict
Replaces Opus 4 and 4.8 for coding agents; requires AI SDK 7+ and Anthropic provider setup. Reasoning enabled by default (configure via top-level option). Worth trying now if you're already routing through AI Gateway; test `speed: 'fast'` mode first for latency-sensitive paths. Plan for occasional safety blocks on security audit code—fallback to Claude Sonnet 5 or 4.8 as tested strategy.
Sources
Dev Signal
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