Developer builds FFT-based scanner after manual redaction missed username three times

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A developer creating a desktop AI agent named Wisp recorded a demo that inadvertently exposed their system username in file path dialogs. Three manual attempts to blur the username using a static FFT delogo filter failed because macOS dialogs animate into position, causing the text to move before settling. To solve this, the developer used FFT-based template correlation in Python to track the moving text across frames and apply dynamic redaction boxes. A final verification scan across 2,225 frames was run on the finished file, which caught one additional leaked frame that visual inspection had missed. The experience led to the conclusion that redactions cannot be reliably verified by eye alone, and that any moving UI element requires frame-rate-matched tracking rather than fixed bounding boxes.

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