A validation retry loop detects that the confidence field contains 1.8 (must be 0–1). The loop appends the error as a new user turn. Which error message produces the most reliable correction?
Answer: 'Field confidence has value 1.8, which exceeds the maximum allowed value of 1.0. Please return confidence between 0.0 and 1.0.'
A targeted error message names the specific field, states the actual value that failed, and specifies the constraint that was violated. The model can see exactly what to fix and fix only that. Generic messages (A, B, D) tell the model something failed but not what — the model must guess which field or constraint was violated, which may lead to fixing the wrong thing or introducing new failures. Specific feedback is a fundamental principle of effective retry loops.