Measure OCR visibility ceilings before tuning candidate selection

Before tuning deterministic field selection, compute two oracle visibility ceilings per split: whether the exact normalized label appears in one OCR node, and whether its alphanumeric form appears after punctuation removal. Compare resolver agreement with both. A low exact ceiling means association rules alone cannot reach the target; the gap to the alphanumeric ceiling quantifies punctuation-assembly headroom, while the remaining gap reflects candidate selection or OCR disagreement. Freeze the resolver before validation and report each ceiling by split. These are silver-label diagnostics, not accuracy and not permission to invent missing characters.

Applies when: deterministic candidate ranking is layered over OCR for structured identifiers. Keywords: OCR visibility ceiling strict agreement alphanumeric punctuation candidate ranking validation