Claude Sonnet 5 matches Opus 4.8 performance on agentic tasks—planning, tool use, coding—at $2/$10 per million tokens, replacing Sonnet 4.6 as the default reasoning model across all plans.
Summary
Developers can now deploy multi-step autonomous workflows (bug fixes, data exploration, form automation) without paying Opus prices. Early testers report tasks that previously stalled midway now complete end-to-end, reducing manual intervention in agent loops.
Why it matters
Developers can now deploy multi-step autonomous workflows (bug fixes, data exploration, form automation) without paying Opus prices. Early testers report tasks that previously stalled midway now complete end-to-end, reducing manual intervention in agent loops.
Implementation verdict
Drop-in replacement for Sonnet 4.6 via `claude-sonnet-5` API endpoint. Requires zero integration changes; pricing is lower through August 31 2026 then steps to $3/$15. Worth migrating existing agents immediately if you're hitting Sonnet 4.6 limits on brownfield code, tool use, or multi-step reasoning. Start with staging deployment to verify your cost-per-task improvement.
Sources
Dev Signal
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