What an AI Should Do With Your Finances

This article is general information, not financial advice.

An AI can explain your numbers and help you enter them. It should not calculate them, invent them, or tell you what to do with your money. Most of the risk in using AI for finances comes from letting it do one of those three.

How a Chatbot Gets Money Wrong

• Confident wrong arithmetic. A language model writes the most likely next words. It does not run a calculation unless a separate tool does it, so a total can look right, be wrong, and carry no warning. Ten years of compounding, tax bands and a mortgage are exactly where this shows.
• Invented figures. Asked for your cash in a particular month, it can produce a number that was never computed from anything you gave it. It may give one rather than say it cannot.
• Figures you cannot trace. If you cannot find the input behind a number, you cannot tell a good one from a bad one.
• Advice dressed as information. "Should I overpay my mortgage?" has no answer without knowing your whole situation, and a personal recommendation is regulated activity in the UK. CrestCast is not authorised to give one.
• Changes made for you. An assistant that edits your records turns an error into a corrupted plan, and you may not notice until later.
• Where your data goes. What you type is sent somewhere. You are entitled to know where, for how long, and who keeps it.

How CrestCast Splits the Job

The forecast is calculated by CrestCast, from the figures you entered. The assistant does not calculate it. Its job is to explain what the forecast shows and to help you enter details.

• Questions use only the forecast's own figures. On the forecast, tap Ask or try a what-if and ask about any figure, on any tab, in any year. Every figure in the answer has to match one the forecast already shows, and an answer that fails that check is not shown to you.
• You can follow an answer back. Show me opens the chart and period the answer is talking about, so the figure sits beside the screen it came from.
• Setup drafts and you decide. Describe your pay, accounts, bills and debts in plain English and each answer becomes a draft input on screen. Nothing goes into your plan until you tap Add, and you can edit or remove a draft first. A debt or savings pot opens its own form, so the details a chat should not guess, such as a promotional rate, are yours to enter.
• A what-if is a copy, not an edit. Describe a change, such as overpaying the mortgage by £200 a month, and it drafts the change. Save and compare puts it in a separate version beside your plan. Your plan does not change.
• It will not tell you what to do. It explains what your forecast shows and helps you enter your details. It will not tell you what to buy or where to put your money.
• It is off until you switch it on. In Settings, one tap. While it is off, the features are hidden and the server refuses them for your account.

What Leaves Your Account

When you send a message, it goes to an AI provider (Anthropic), which can process it in the United States, with what is needed to answer it: your messages, and for a question, figures from your plan. It does not send your email address, password or account id, and the names of the people in your household are replaced with roles such as Partner before the figures leave your device. What you type yourself, including the labels on your bills, is sent as you typed it. The provider does not train its models on it and deletes it within 30 days, unless its usage policy or the law requires it to keep it longer. CrestCast stores no copy of the conversation, only a record of how much was used.

The provider, exactly what is sent for each feature and what CrestCast keeps are on the privacy page, with a shorter version in where your data lives.

Five Questions for Any AI That Touches Your Money

• Can it show where a figure came from? A number you cannot trace is an opinion.
• Does it calculate, or hand the calculation to something that does? Ask which.
• Does it change anything without you pressing a button? It should not.
• What leaves your device, who keeps it, and for how long? The answer should be written down somewhere you can read.
• Does it tell you what to do, or what your numbers show? The second is information. The first is advice and needs an authorised adviser.

Where the Answer Changes

• A question the forecast cannot answer. If your plan has no figure for it, the assistant declines and says what it can answer instead, such as one month, one item or one debt. It does not estimate.
• A what-if it cannot run. It names the nearest thing it can model and the input it is missing, rather than a bare refusal.
• Wrong inputs. The assistant explains what you typed. If an input is wrong, the answer will be wrong with it, which is why drafts are checked before they are added.
• A figure the chat misheard. A draft is a draft: read the card before you tap Add.
• Your bank balance. CrestCast never connects to your bank, so the assistant knows what you tell it and nothing else.
• A daily limit. When you reach it, the assistant says so and is available again the next day.
• No AI at all. Everything else in CrestCast works without it, and nothing is sent anywhere until you open it and send a message.

Information, Advice and Where the Line Sits

Asking when your cash is at its lowest, or what a £200 overpayment does to the next ten years, is a question about your numbers. Whether to overpay is a decision, and it depends on things a forecast does not hold: your risk appetite, your plans and the products open to you. CrestCast can run both versions of the plan. It will not pick one for you.

When a decision does need regulated advice, planning before, between or alongside an adviser sets out where the line falls.

The feature itself, with screenshots of both the setup chat and a question being answered, is on the AI assistant page.

The same test applies to a person with a following. There Is No Main Character in Your Money is about the difference between a story that moves you and a number that tells you whether your household can afford the move.