[nl]

I think you could well be surprised by the Sonnet vs Opus bill (assuming you are paying via the API)

In my experience Sonnet bills can be higher than Opus because it churns a lot more trying to get things right.

Example from my fairly simple but agentic benchmark:

Opus 4.7, 25/25, 81c: https://sql-benchmark.nicklothian.com/?highlight=anthropic_c...

Opus 4.6, 24/25, 61c: https://sql-benchmark.nicklothian.com/?highlight=anthropic_c...

Sonnet 4.6: 24/25, 41c: https://sql-benchmark.nicklothian.com/?highlight=anthropic_c...

I only tested the free OpenRouter version of Qwen 3.6 Plus, and it scored 23/25: https://sql-benchmark.nicklothian.com/?highlight=qwen_qwen3....

This doesn't quite show Opus cheaper, but it isn't the 10-20 times more either. Harder tasks close the gap even further.