Specification Filter Prompt Specification Filter Vague: "Write a Python Bernoulli function" + Clause: Return exact fractions.Fraction + Clause: First Bernoulli convention B1 = -1/2 + Clause: Modern indexing for n >= 0 + Clause: Return Fraction(0) for odd n > 1 5 Failure Modes: [not-fraction] [b1-sign] [ada-indexing], [off-by-one] [odd-terms] Testable Candidate Independent Checks Pass or Diagnostic Failure