alt Hacker NewsIt bothers me that you have to explicitly state this to the agent. Makes me think what else is missing from that file which also needs to be explicitly stated, but I don't know what don't know. "Do a good job"?
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Will, it depends on the AI. Anthropic used to have a lecture-length system prompt for their models to explain this stuff—part of the secret sauce for Claude Code—and famously found that the 5 series models no longer need it.
As usual, if you use anything but the best model available I’m going to state that the better ones do better. If you do use the best model available, then I’ll just mention that Fable still has limits and still needs some guidance.
One thing it does not do is deliberately build tests which test nothing at all, or which restate the code under test. I mention this because certain other models absolutely would.
This is where the harness shines. It's why products like Cursor have been growing like crazy. If you drop an extremely intelligent person into a problem they've never seen before, the initial context and knowledge-sharing just to get them up to speed is immense. They'll make a lot of mistakes until they're ready to fix your problem. The harness can leapfrog most of that. There is a booming industry in harnesses with no saturation in sight. We're not even close to maximising the utility of current models, let alone the amazing improvements which are happening week to week.