Weaker models expose harness bugs that frontier models quietly work around
arsenyinfo · reddit · 2026-07-27
A practitioner argues that debugging with weaker models is often more informative than testing only frontier models.
- Frontier models can bulldoze past broken plumbing such as malformed tool calls, odd error strings, or missing tools.
- Because they recover so well, they can hide bugs in the harness and surrounding infrastructure.
- Running the same suite on cheaper models exposed a dozen issues that Opus had simply learned to work around.
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