Most prompt failures are boundary failures, not reasoning failures
This story is from 2026-09-02. It is preserved in the archive; the latest stories are on the live feed.
The model isn't reasoning badly. It literally can't tell where your instruction ends and your data begins. That's the core failure mode Anthropic calls out in their own docs, and it's why they treat XML tags as a first-class technique, not a style choice. Their guidance is concrete: separate , , ,…
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- 2026-09-02 15:29 · r/PromptEngineering
Most prompt failures are boundary failures, not reasoning failures - 2026-09-02 15:25 · r/PromptEngineering
Most prompt failures are boundary failures, not reasoning failures