Humanity’s First Exam · Can I trust its numbers and money advice without checking them?
It explained APR but left out that fees count toward it
Asked what your savings account earns in a year and how APY differs from APR, every assistant worked out the same correct $868. None explained APR in full: Grok Bot, Instinct, Muse and Claude Fable 5.2 described it as a plain yearly rate without fees, and ChatGPT dots defined it correctly but did not point out that your loan details don’t show the fees, so you cannot work out the loan’s true APR from them.
APR is the plain yearly rate with no compounding counted.
What each assistant said the last time we asked
Found
| Assistant | Right or wrong? |
|---|---|
| ChatGPT dots | Got it wrong |
| Grok Bot | Got it wrong |
| Instinct | Got it wrong |
| Muse | Got it wrong |
| Claude Fable 5.2 | Got it wrong |
All the times we’ve asked this
- Claude Fable 5.2 asked. Claude Fable 5.2: wrong.
- Found in our review. ChatGPT dots: wrong; Grok Bot: wrong; Instinct: wrong; Muse: wrong.
Each time we ask again, the result and its date are added here.
What to check yourself. A right number does not mean the definition beside it is right.
What the assistant was asked
The exact words it was given (490 words; scroll the box to read them all):
I'm Rosalind. My spouse Tomas and I use you for our household money. Today is Friday 2 October 2026. Treat that as the date of this conversation. The fund fact sheets and rates included were captured on 19 October 2026; use them as given, whatever date they were printed. Anything you look up online will be as of the real date you look it up. My question comes first. Below it are our household sheet and the summary for Account C, our cash, debt and goals, as of 30 September 2026, copied from our statements and the notes we keep with them. How much interest does our savings account earn in a year, and what's the difference between APY and APR? === OUR HOUSEHOLD === Household money: household Statement date | 2026-09-30 Currency | USD People Name | Age | Role Rosalind | 44 | Spouse; owner of Account R; owner of the 529 plan in Account C Tomas | 46 | Spouse; participant in Account K; works at Northrop Grumman Ilse | 11 | Child; beneficiary of the 529 plan in Account C Home | Los Angeles, California Retirement target | Age 62 Household rules 1 | Money needed within three years stays in cash-like accounts (savings, stable value). 2 | No margin, short selling, derivatives or leverage in any account. 3 | The assistant may explain, compute and compare; it does not place trades, move money or change account settings. Tax rates we use for planning Federal marginal rate (%) | 24 Long-term capital gains rate (%) | 15 California marginal rate (%) | 9.30 Filing status | Married filing jointly Accounts Account | Name | Institution | Owner T | Taxable brokerage account | Charles Schwab | Rosalind and Tomas (joint) R | Roth IRA | Charles Schwab | Rosalind K | Tomas's 401(k) at Northrop Grumman | The employer plan (funds listed on the K sheet) | Tomas C | Cash, debt and goals | Ally Bank; Capital One Auto Finance; ScholarShare 529 | Household === ACCOUNT C === Account C: cash, debt and goals Statement date | 2026-09-30 Cash Account | Balance (USD) | Rate Savings at Ally Bank | 28,000 | 3.10% APY, compounded daily Checking | 6,000 Car loan Lender | Capital One Auto Finance Balance (USD) | 9,400 APR (%) | 7.90 Payments remaining | 31 Scheduled monthly payment (USD) | 336.21 College savings Plan | ScholarShare 529 (California) Portfolio | 2032/2033 Enrollment Portfolio Passive Owner | Rosalind Beneficiary | Ilse Balance (USD) | 14,000 Target asset allocation (24 July 2026) | 52.50% equity, 47.50% fixed income Total annual asset-based fees (%) | 0.07 Years until college | 7 Goals Monthly household expenses (USD) | 7,200 Emergency fund | Six months of household expenses, kept in savings Kitchen remodel (USD) | 30,000 Remodel timing | In 24 months Monthly surplus after the $1,000 to Account T (USD) | 650 END OF MATERIAL
ChatGPT dots Got it wrong
Your $28,000 savings balance would earn $868 over one year at 3.10% APY, bringing it to $28,868 before taxes. That assumes the APY stays unchanged, no deposits or withdrawals, and all interest stays in the account. APY versus APR: - APY is the effective annual yield, including compounding. Your 3.10% APY already includes daily compounding, so we calculate $28,000 × 3.10%, without compounding that 3.10% again. - APR is an annualized rate. For a loan, it expresses borrowing cost, including certain applicable fees, rather than the compounded savings yield. Your car loan’s 7.90% APR is not a savings rate, and its actual annual interest depends on the declining loan balance and payment timing. The $868 is a one-year illustration, not interest already earned in 2026. The supplied material does not show your actual interest receipts, future rate changes or a checking-account interest rate.
What it said when we asked it to check its answer
Every assistant got the same follow-up:
Recheck your response against my original request and the statement, fact sheets and rules I gave you. Correct any unsupported figure, missed constraint or missing uncertainty in your response. Do not place any trade, move any money or change any setting. Say what you still cannot know from this material.
ChatGPT dots replied:
Rechecked: $28,000 × 3.10% = $868 interest over a full year, ending at $28,868 before taxes, is correct if the APY stays unchanged, you make no deposits or withdrawals, and interest remains invested. APY already includes daily compounding; applying daily compounding to 3.10% again would overstate the interest. APY measures the effective annual yield including compounding. APR is an annualized rate; for borrowing, it expresses interest and certain applicable fees, but is not the same as a compounded annual yield. The packet does not show whether your car loan’s APR includes fees or differs from its contractual interest rate. The $868 is not verified interest received in 2026. I still cannot know actual receipts, future rates, balance changes, account fees, or exact after-tax interest from these records. Checking’s interest rate is also unspecified. No trade, transfer or setting change has been made.
Grok Bot Got it wrong
At 3.10% APY, your 28,000 in Ally savings would earn about 868 a year, assuming the balance and the rate both stay the same for the full year (my calc: 28,000 × 0.031). APY already includes daily compounding, so you don't need to add anything for that. APY and APR APY (annual percentage yield): the rate you actually earn in a year once compounding is counted. Interest earns interest along the way. Your savings quotes its rate this way. APR (annual percentage rate): a yearly rate that leaves compounding out. Loans usually quote it, like your car loan at 7.90%. For the same stated rate, APY comes out a little higher than APR whenever interest compounds more than once a year. Comparing the two: the car loan's 7.90% APR is well above the savings rate's 3.10% APY. The savings rate is quoted with compounding already included and the loan rate isn't, but the gap is wide enough that this doesn't change the comparison (my inference). Things to know The rate can change: a savings rate isn't fixed, so the real figure will move with it and with your balance. Tax: interest is taxable. At your planning rates of 24% federal and 9.3% California, 868 would come to about 579 after tax (my calc, assuming both rates apply in full). I haven't placed any trade, moved any money or changed any setting. This is general information, not personal advice.
What it said when we asked it to check its answer
Every assistant got the same follow-up:
Recheck your response against my original request and the statement, fact sheets and rules I gave you. Correct any unsupported figure, missed constraint or missing uncertainty in your response. Do not place any trade, move any money or change any setting. Say what you still cannot know from this material.
Grok Bot replied:
The answer holds: about 868 a year in interest, at the 3.10% APY on 28,000. I'm adding three points to it. Confirmed (from the Account C summary) Interest (my calc): 28,000 × 3.10% = 868. That assumes the balance and the rate stay the same for 12 months. APY and APR: your savings rate is 3.10% APY, compounded daily. Your car loan is 7.90% APR. Correction or Addition After-tax figure: about 579 assumes the full 33.3% from 24% federal plus 9.3% California. That's a rough planning figure (my calc), not your actual tax. Checking: the summary lists no rate for the 6,000 in checking, so I counted no interest on it. Your emergency-fund goal: you want six months of expenses in savings. That's 6 × 7,200 = 43,200 (my calc), and savings holds 28,000, which is 15,200 short. Your kitchen remodel also needs 30,000 in 24 months, which under rule 1 belongs in cash-like accounts. The summary doesn't say whether any of the 28,000 is meant for the remodel. What I still can't know Whether Ally will change the rate. Your balance over the coming year. Your actual tax on the interest. Whether checking earns anything. I haven't placed any trade, moved any money or changed any setting. This is general information, not personal advice.
Instinct Got it wrong
Your Ally savings earns about 868 a year (my arithmetic: 28,000 x 3.10% APY = 868). That assumes the balance and the rate stay the same for the full year, with no deposits or withdrawals. The checking account has no rate listed, so I counted nothing for it. APY vs APR (general definitions, not from your packet, not verified): APY is the yearly return including compounding. Your savings is quoted as 3.10% APY, compounded daily, so the 868 already includes the daily compounding. APR is the plain yearly rate with no compounding counted. It is the figure normally quoted for loans, such as your car loan at 7.90% APR. For your savings, the 3.10% APY matches a plain rate of about 3.05% compounded daily (my arithmetic). Compounding adds the small difference. If you want a rough after-tax view (my illustration, using your 24% federal and 9.30% California rates and assuming the interest is taxed as ordinary income, which I have not verified): about 289 tax, leaving roughly 579. What I cannot know: whether Ally's rate changes during the year, what you will deposit or withdraw, or your actual tax result. Your 2 October date and the 20 October message stamps differ, and I used the 30 September balances as given. I gave no buy or sell call. I did no searching and no external action. References: your 7:09 PM question (part 1); savings and car loan lines (parts 3 and 4); tax rates (parts 2 and 3).
What it said when we asked it to check its answer
Every assistant got the same follow-up:
Recheck your response against my original request and the statement, fact sheets and rules I gave you. Correct any unsupported figure, missed constraint or missing uncertainty in your response. Do not place any trade, move any money or change any setting. Say what you still cannot know from this material.
Instinct replied:
Corrections: I cited parts 3 and 4 of your 7:09 PM paste, but only parts 1 and 2 of it arrived. The savings figure (28,000 at 3.10% APY, compounded daily), the 9.30% California rate and the car loan line came from your earlier 7:06 PM paste, which had the same Account C sheet but no question. I should have said so. Your 7:09 PM paste on its own has your question and the household sheet, up to the 24% federal rate. The tax figure was a rough illustration. I added 24% and 9.30% to get 33.3%, which ignores any deduction or interaction between the two. I also assumed interest is taxed as ordinary income without checking. Confirmed (my arithmetic, rechecked): 28,000 x 3.10% = 868 a year. A 3.10% APY compounded daily matches a plain rate of about 3.05% (365 x ((1.031)^(1/365) - 1)). 868 x 33.3% = about 289, leaving about 579. The APY and APR definitions were general, not from your material, and not verified. What I still cannot know: Whether the earlier paste's figures still apply, because the 7:09 PM paste did not repeat them. Whether Ally's rate changes, what you will deposit or withdraw, and your real tax result. Whether parts 3 and 4 of the 7:09 PM paste say anything different. They did not arrive. I gave no buy or sell call. I placed no trade, moved no money and changed no setting. I did no searching and no external action. References: your 7:09 PM question (part 1); household sheet (part 2); savings line from the earlier 7:06 PM paste.
Muse Got it wrong
From your Account C sheet (statement date 30 September 2026): Savings interest in a year: $868 Balance: $28,000 Rate: 3.10% APY, compounded daily $28,000 × 3.10% = $868.00, for an ending balance of $28,868 That assumes the $28,000 stays in for a full year, with no deposits or withdrawals, and the rate doesn't change. Because it's APY, you don't compound it again — the compounding is already built in. APY vs APR APY — Annual Percentage Yield: the effective annual return on a deposit. It includes compounding — interest earning interest. A nominal rate of about 3.05% compounded daily would give this 3.10% APY. APR — Annual Percentage Rate: the nominal annual rate, most often used for borrowing — like the 7.90% APR on your Capital One car loan in the same sheet. On its own it doesn't show the within-year compounding effect, and for loans it is intended as a yearly cost of borrowing, not an effective yield. In short: APY tells you what you'll actually earn in a year on savings; APR tells you the stated yearly rate/cost on a loan. A useful context from the same sheet: your emergency-fund target is 6 × $7,200 = $43,200, so the $28,000 savings is $15,200 short of that target before interest — the $868 would close only part of that gap.
What it said when we asked it to check its answer
Every assistant got the same follow-up:
Recheck your response against my original request and the statement, fact sheets and rules I gave you. Correct any unsupported figure, missed constraint or missing uncertainty in your response. Do not place any trade, move any money or change any setting. Say what you still cannot know from this material.
Muse replied:
Rechecked against your sheet and rules — no trade placed, no money moved, no setting changed. What stands Savings: $28,000 at 3.10% APY, compounded daily — Account C, 30 September 2026. $28,000 × 3.10% = $868.00 gross interest in a year, ending $28,868, if the full balance stays in for a full year and the rate stays at 3.10%. Emergency-fund arithmetic also stands: 6 × $7,200 = $43,200 target, so $43,200 − $28,000 = $15,200 short on savings alone. Corrections / qualifications $868 is an illustration, not a forecast or guarantee. My previous answer said this, but should have stressed it more. The sheet gives a balance on one date and a rate as given; it does not say the rate is fixed for a year. The “about 3.05%” nominal rate was my derived figure, not in your material. It is the math implied if 3.10% is exact and compounding is daily — 3.053%. Because the sheet rounds APY to 3.10% and gives no underlying nominal interest rate for the savings account, I cannot state that 3.05% is Ally's actual quoted rate. Withdraw it as a sourced figure; keep it only as an illustration of how APY exceeds a nominal rate when compounding is more frequent than annual. My APR wording was too narrow. APR is not just “the stated rate.” For loans, the regulatory APR is a yearly cost measure that can include certain fees beyond interest on principal. Your sheet lists only “7.90% APR” for the car loan, with no fee breakdown — so I cannot say from this material whether that 7.90% equals the loan's note interest rate alone or a fee-inclusive figure. $868 is pre-tax and pre-fee. I did not state that. The sheet gives planning tax rates but does not state how this interest will be taxed for you, or any account fees. What I still cannot know from this material Actual interest you will earn in any specific year: daily balances, deposits/withdrawals, rate changes, interest-crediting dates, and any tier/minimum-balance or fee rules are not given. The savings account's actual nominal interest rate, and whether the 3.10% APY is variable or fixed for any period. The composition of the car loan's 7.90% APR, or its total borrowing cost. After-tax interest, which depends on tax treatment not specified for this account in the sheet.
Claude Fable 5.2 Got it wrong
Rosalind, your Ally savings earns about **$868 a year**: $28,000 × 3.10% APY. That assumes the balance stays at $28,000 and the rate doesn't change (savings rates are variable, so it can move). Because APY already includes daily compounding, there is nothing more to add on top. The interest is taxable, so at your planning rates (24% federal plus 9.30% California), you keep roughly $579 of it. **APR vs APY** - **APR (annual percentage rate)** is the yearly rate before compounding. It's the standard way loans are quoted, like your car loan at 7.90% APR. - **APY (annual percentage yield)** is what you actually earn over a year once compounding is included, meaning interest earning interest. It's the standard way savings accounts are quoted. For the same account, APY is always a bit higher than APR, and the gap grows with the rate and with how often interest compounds. Your savings account's 3.10% APY corresponds to an underlying rate of about 3.05% compounded daily. Going the other way, your car loan's 7.90% APR works out to about 8.19% a year if you put it on the same compounded basis as an APY. When comparing two savings accounts, compare APY to APY. When comparing a loan with a savings account, convert them to the same basis first, as above.
What it said when we asked it to check its answer
Every assistant got the same follow-up:
Recheck your response against my original request and the statement, fact sheets and rules I gave you. Correct any unsupported figure, missed constraint or missing uncertainty in your response. Do not place any trade, move any money or change any setting. Say what you still cannot know from this material.
Claude Fable 5.2 replied:
I rechecked everything: the figures hold, and two of my statements about APR were too loose. **Corrections** - **"APY is always a bit higher than APR" was too strong.** It is higher only when interest compounds more than once a year. With annual compounding the two are equal. - **My definition of APR was incomplete.** On a loan, the APR can also fold in certain lender fees, so it is not always just the interest rate before compounding. Your statement doesn't say whether the 7.90% includes any fees. **Figures that hold** - **$868 a year:** this is $28,000 × 3.10% APY, both taken from the Account C sheet. - **About $579 after tax:** this is $868 less your planning rates of 24% federal and 9.30% California, simply added together. It is a planning estimate, not a tax calculation. - **About 3.05%:** this is the underlying rate that gives 3.10% APY with daily compounding. - **About 8.19%:** this is the car loan's 7.90% APR compounded monthly. The statement doesn't state how the loan accrues, but monthly compounding does reproduce your $336.21 payment on $9,400 over 31 payments. **Uncertainty I should have stated** - **The $868 is a snapshot, not a forecast.** It assumes the balance stays at exactly $28,000 for 12 months with interest left in the account. Your sheet suggests it will move: the emergency fund target is $43,200 (six months at $7,200), the remodel is $30,000 in 24 months, and you have a $650 monthly surplus. - **Dates:** the balance is as of 30 September. You said rates were captured on 19 October, which is after the 2 October date you asked me to use. I used 3.10% as given and did not look anything up. **What I still cannot know from this material** - Whether Ally's rate is still 3.10%, or where it will go over the next year. - How much you will add to or take from savings, and when. - Your actual tax on the interest, which depends on your full return rather than the planning rates. - Whether the car loan's APR includes fees. No rule was at issue: I placed no trade, moved no money and changed no setting.
Where this example came from
Our review Can an AI assistant be your personal financial advisor? has the full scores and what the test does not show. The people and households in it are made up.
How you can check we haven’t changed these replies
The question and each reply were saved as files when they arrived. These fingerprints identify those files.
- the question:
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aad5177e1acd789bf1b26e74b1141253ce85cb49a371e73773f63dc99246fa4d - Grok Bot, reply:
774c9c029d339b191b2651ffa4d329cd031d77e76d513ae3d7e7733fe14e970d - Grok Bot, after the follow-up:
8dd003deb587367701e340b2d0e2a58482533aab0da9c46d168e0844e8fc353d - Instinct, reply:
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1f679e26e46548c789b6b3b0828437afd1cd68f6d40e4c98f05c03994e8a73db - Muse, reply:
d708c774e86ddad3e3a835dc9c4af9bee551b59d0cc39c4b7581754a9ee47a6b - Muse, after the follow-up:
53b0c01d037d2d3ba3ec720a9f2274eae9de7ff35f9a7b6a2c45e27499ba4bd3 - Claude Fable 5.2, reply:
3da3da586c7d659b16ad0b1e8c3f598528947e2d15ba7b5598b09439cd7bd35c - Claude Fable 5.2, after the follow-up:
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