Chapter C93 · Interactive Course
Use it: diagnose a lost detail
Why a supplied fact went missing, and what to do about it.
Core Learning Concept
Locate an ignored requirement and confirm it was present in the prompt. Test a focused repair by restating instructions near the query, then verify whether the output actually respects the requested constraint.
What You’ll Learn in This Chapter
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The detail that went missing
Locate the supplied fact that a response ignored.
Start by verifying whether an ignored requirement was actually present in the model input context. A requirement documented elsewhere cannot guide generation unless it is explicitly supplied in the current prompt.
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Distance is not the whole story
Reject “it was too far away” as a complete explanation.
Long contexts can dilute attention across distant instructions or competing examples. When key constraints sit far from the generation prompt, models may overlook them in favor of more prominent local text patterns.
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Repeat the detail where it is used
Choose a repair that puts the fact near the task.
A reliable repair places critical instructions close to where generation begins, while pruning irrelevant background text. Moving vital constraints to prominent positions helps the model attend to them directly and accurately.
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A heatmap is not a reason
Refuse an attention picture as proof of a cause.
Testing an input modification provides causal evidence about whether that change improves prompt compliance. Compare before-and-after responses systematically across repeated runs rather than guessing internal motivations from a single lucky answer.
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Explain it in two sentences
Give a causal account without equations.
Document observed prompt failures alongside verified remedies using concrete before-and-after examples. Clear empirical evidence about what worked helps engineering teams maintain reliable and robust prompt designs over successive model updates.
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Apply it: diagnose a lost detail
Carry out the whole diagnosis once: find the dropped fact, explain it with position and competition, choose a repair and say what the evidence supports.
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Explain the Transformer without equations
Trace one attention operation on a translation diagram, place it inside the block, and say what the 2017 paper added.