The Fact & Gap Checker evaluates discoveries from the Grounded Memory research engine against a property's recalled claims, categorizing each finding based on whether it confirms, contradicts, or reveals an unprompted blind spot. When a finding aligns with or refutes recalled knowledge, the checker labels the claim as correct or incorrect while attaching source URLs as evidence, and any newly discovered facts that models failed to recall are added to the ledger as gaps without falsely validating them, preventing the system from grading its own homework.