def classify_text(text): 

  # Layer 1 — clinical allowlist 
  if is_clinical_allowlisted(text): return {"is_phi": False,    "label": "CLINICAL"}

  # Layer 2 — clinical patterns (probe IDs, measurements)
  if matches_clinical_pattern(text):
    return {"is_phi": False, "label": "CLINICAL"}

  # Layer 3 — PHI heuristics
  if matches_phi_heuristic(text):
    return {"is_phi": True, "label": "PHI_HEURISTIC"}

  # Layer 4 — Stanford NER model
  if classify_with_ner(text):
    return {"is_phi": True, "label": "PHI_NER"}

return {"is_phi": False, "label": "SAFE"}

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