Closes a documented coverage gap (P2#9): an AI Software/Make/Artist/ImageDescription
token in an EXIF item (its TIFF bytes live in mdat/idat) survived remove_ai_metadata
because the top-level box stripper and (absent pillow-heif) the PIL EXIF reader can't
reach it. New isobmff.blank_ai_exif_tokens finds EXIF TIFF blocks by their II/MM
byte-order header, validates each with piexif (a coincidental II/MM run in pixels
won't parse as a TIFF IFD, so it's ignored), and overwrites any AI_GENERATOR_TOKENS-
bearing value with same-length spaces -- so box sizes and iloc offsets stay valid and
the coded image is untouched (mirrors blank_ai_xmp_packets; no iinf/iloc surgery, no
exiftool dep). Camera/editor EXIF without an AI token is preserved. Wired into
remove_ai_metadata's ISOBMFF path. Covers the realistic AI-generator-token case; xAI-
signature-in-meta-box-EXIF (Grok is JPEG-only) stays out.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A 2026-06-14 oracle re-test on the deployed Modal controlnet worker (v0.10.0)
cleared SynthID at OpenAI 0.10 (2 photoreal) and Google 0.15 (2 native
2816x1536, retiring the "native >= 0.30" guess), while a pixel sweep showed the
2026-06-04 cert floors (0.20/0.30) over-regenerated for no efficacy gain
(Google MAE -20% at 0.15). Lowers OPENAI_STRENGTH 0.20->0.10, GEMINI_STRENGTH
and UNKNOWN_STRENGTH 0.30->0.15.
Caveats documented in watermark_profiles.py + docs: removal near this floor is
seed-non-deterministic (a service must pin a verified seed), and the n=2 re-test
did not cover flat-graphic hard cases.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Victor Kuznetsov