- Remove "NeDonald's → McDonald's" from LLM vendor correction examples; the
example was biasing the model to return McDonald's for any ambiguous receipt
(Home Depot, Sergio's/HMSHost). Replace with neutral brand examples and add
an explicit instruction not to substitute a brand name absent from the OCR text.
- Add `net\s*fee` to _TOTAL_RE so MIA Parking kiosk receipts ("net fee: 150.00 USD")
are captured by Pass 1 rather than the max-scan which could pick a larger line.
- Add Step 5b grayscale fallback in receipt_parser: if all binarized PSM attempts
yield < 20 chars, retry OCR on the pre-binarization grayscale image. Fixes
dot-matrix and certain thermal-print fonts destroyed by the 160-threshold.
- Tests: 88 passing (test_net_fee_parking, test_vendor_prompt_does_not_contain_mcdonalds,
test_vendor_prompt_instructs_not_to_guess_absent_brand).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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