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hadlocktoday at 6:45 PM4 repliesview on HN

When it comes to quality of outcome, since at least Feburary, the harness has almost equal, if not more weight than the model itself. It's no longer "which model is the best?" it's "which model + harness is the best?"

I get drastically different tool call failure rates using Claude SDK vs OpenCode using Qwen 3.6 models


Replies

KronisLVtoday at 6:51 PM

> the harness has almost equal, if not more weight than the model itself

This feels like a horrible failing of the models to generalize, then - both basic and intermediate tasks should be possible to do with Claude Code, OpenCode, Pi, ZCode, Kimi Code, Dirac and tbh any other mainstream or even slightly niche harness. Not doubting the claim itself, there's a reason why good benchmarks include the harness.

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JLO64today at 7:23 PM

It's worth nothing that recent Claude models seem to have gotten worse at tool calling outside of Claude Code and the SDK: https://lucumr.pocoo.org/2026/7/4/better-models-worse-tools/

davidlttoday at 6:53 PM

I just wanted to emphasize this. Harness is a big part of how things perform thus usually it's harness + model co-design that's important.

azinman2today at 6:48 PM

Which works better for you?