I just tried this with ChatGPT 5.4 Thinking, not expecting it to work (doesn't really work in Opus 4.6...and 3-6 months ago, LLMs couldn't really even read a big Excel file) Step 1: Upload an existing financial model Step 2: "Analyze this model like an analyst. Explain what's been happening and what the key assumptions are saying about the future" Step 3: "What assumptions would you push back on?" I found it really, really good. Shockingly good, actually.