Traditional financial planning has two settings: a spreadsheet that demands you already speak finance, or an advisor who charges a percentage of your assets. Mentat's bet is a third: you describe the fork you're weighing in ordinary words — "I'm thinking about leaving consulting to retrain as a nurse" — and the app drafts the branches, the segments, the rough cashflows, and the questions worth asking, so you start from a working model instead of a blank page.
AI for the setup, math for the answers
The AI's job is to get you to a model quickly: turn a sentence into a structured tree of decisions and chance outcomes, suggest sensible starting numbers, and surface the trade-offs you might not have named. From there, the answers come from arithmetic, not a language model's opinion. Net worth is computed by the same deterministic projection engine that powers the whole app; wellbeing is integrated from scores you author. Nothing important is a black box.
Grounded in facts, not invented heuristics
Mentat's defaults reference real external facts — IRS contribution limits, statutory tax brackets, FICA, state rates — rather than made-up rules of thumb. It reports things that are provable from your inputs ("at this savings rate, this branch crosses financial independence around here") and deliberately stays out of comparative advice ("you should pick this one"). The line is clean on purpose: math the app can show its work for, yes; judgments about how you should live, no.
You stay in control
Every number the AI proposes is yours to edit, and a full manual editor sits alongside the conversational one. The AI accelerates the boring part — building and updating the tree — while the decision, the assumptions, and especially the wellbeing scores stay firmly in your hands.