Review of Claude Code (Sonnet)
Claude Code, Anthropic's CLI coding agent, supports multiple models. The two main options in 2026 are Sonnet 3.5 (the latest) and Opus 4.8 (the premium). Each has different strengths. We benchmarked both on 10 real coding tasks to see which one wins for which work.
10 real coding tasks across three categories: (1) Daily refactors — renaming, extracting functions, simple bug fixes. (2) Complex features — new API endpoints, multi-file changes, test writing. (3) Hard bugs — race conditions, performance issues, edge cases. Each task was scored on speed, accuracy, and token usage.
Sonnet wins. For simple refactors, both models produce correct code, but Sonnet is 2-3x faster and uses 50% fewer tokens. If you're doing routine code maintenance, Sonnet is the clear choice.
Sonnet wins by a small margin. The new Sonnet 3.5 (2025) was specifically tuned for code. It handles complex features almost as well as Opus, with faster response times. The cost difference is significant: Sonnet is $3/M input tokens vs Opus at $15/M.
Opus wins. For really hard bugs — race conditions, subtle logic errors, performance issues — Opus 4.8 still has the edge. It found the root cause 8/10 times; Sonnet found 6/10. The extra reasoning power matters here.
Claude Pro ($20/month): Default is Sonnet 3.5. Limited Opus access. Claude Max ($200/month): 5x more usage, can use Opus for hard tasks. API: Sonnet $3/M input, Opus $15/M input. For most use cases, Sonnet is 5x cheaper.
Use Sonnet for: daily coding, refactors, new features, documentation, tests. Use Opus for: hard debugging, architecture decisions, security reviews, anything that requires careful reasoning. The Max plan lets you switch per task.
Sonnet 3.5 is the default for 90% of coding work. Opus is worth the premium for hard bugs and architecture. The 5x cost difference makes Sonnet the right choice for most teams.
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