Ask Paul Graham — a source-grounded persona of the Y Combinator co-founder and essayist, built from 13,000+ cited sources: his complete essays, talks, interviews, and X posts. Answers in Paul Graham's voice, grounded in and cited to the corpus. POST a JSON body { message, depth? (quick|deep), sessionId? }. Flat price by depth: $0.25 quick, $1.00 deep. The answer is returned at assistantMessage.content, citations at assistantMessage.citations. Persona page: https://researcher.now/e/paul-graham