Deleting One Line Fooled Pangram: 100 Classic Texts Expose AI Detector's Truncation Weakness

GolinoHudson · x · 2026-09-25

A systematic test ran 100 public-domain classics in 7 languages through Pangram's API in 5 versions each (original, straight quotes, removed line breaks, both, and a Hugo-style truncation). Typography manipulations barely moved the needle (3/100 vs 1/100 flagged, p=.37), but cutting the final line flipped 8/100 texts from human to AI — 7 at 100% AI (p=.009), including Shakespeare's Sonnets 29/30 and Keats's "Bright Star". Truncation appears necessary but not sufficient; short poems were most vulnerable, and A Tale of Two Cities' opening was flagged 65% AI untouched. Takeaway: the detector is robust to typography but brittle to truncation — exactly the form of excerpts people paste — and no single detector score should decide academic-integrity cases.

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