Looking at some of the agentic coding benchmarks on the system card[0], pages 117-118, it seems that running it at low outperforms Sonnet 4.6 at any level, and is a good deal cheaper as well. So on low it could be a good workhorse for an Opus-planned task.
Re:Claude Sonnet 5
by port11 on Wednesday July 01, 2026 @12:06PM
(#48749108)
That is certainly an improvement then. Sonnet 4.6 is a great everyday agent for the limited Pro plan, but it’s not much better than M3 or Kimi 2.7, both significantly cheaper models.
[0] https://www.anthropic.com/claude-sonnet-5-system-card