Methodology

The pipeline

1. OCR pass. Your photos go through Claude Vision in OCR mode to extract any visible serial numbers, date codes, or identification stamps.
2. Brand detection. If you tell us the brand in the description, we use it. Otherwise the AI identifies the brand from logos, monograms, and labels.
3. Serial validation. The extracted serial is checked against brand-specific format rules (e.g., Louis Vuitton uses 2 letters + 4 digits; YSL uses 3 letters + 6 digits). Mismatches are flagged.
4. Visual analysis. Photos are evaluated against six authentication points — serial, stitching, hardware, logo, material, labels — with brand-specific hints fed into the prompt (e.g., "Goyard chevron is hand-painted, slight irregularity is normal — perfect symmetry is suspicious").
5. Verdict. The model returns one of three outcomes — likely original, likely fake, uncertain — with a 0–100 confidence score and a per-point breakdown.

What the confidence score means

• 90–100% — multiple authentic markers visible and consistent. Use as strong signal.
• 70–89% — most markers consistent, one or two unclear. Reasonable confidence; consider professional auth for high-value items.
• 50–69% — mixed signals. Get a second opinion before transacting.
• Below 50% — multiple red flags. Treat as likely counterfeit until proven otherwise.

Where we fall short

BrandCheck is intentionally conservative about its limits:

• Photo-only — we can't smell leather, feel weight, or hear hardware click. Some authentic markers are physical, not visual.
• Super-fakes — the top tier of counterfeits (often 1:1 factory replicas) can pass purely visual inspection. For 4-figure purchases, professional in-hand authentication is still the gold standard.
• Older / vintage items — pre-2000s pieces have less standardization; our brand rules skew toward modern production. Older items get more uncertain verdicts.
• Photo quality — blurry, low-light, or partial photos lower confidence. Five clear close-ups beat ten general-angle shots.
• AI limitations — Claude is a probabilistic model. Verdict is an opinion based on training data, not a legal guarantee.

What it's not

BrandCheck does not claim legal authority. We don't certify items. Our reports are intended as a pre-purchase or pre-sale informational signal — not a substitute for forensic, brand-issued, or accredited third-party authentication services for high-value transactions.