Maybe simultaneously give it one or more other pitches that you consider just on the line of passing and then have it rank the pitches. If the evaluated pitch i

Maybe simultaneously give it one or more other pitches that you consider just on the line of passing and then have it rank the pitches. If the evaluated pitch is ranked above the others, it passes. Then in a clean context tell the LLM that this pitch failed and ask for actionable advice to improve it.