Count me among those who believe we are in an artificial-intelligence bubble.

I doubt that it's going to spur productivity gains or that Big Tech companies will recoup the hundreds of billions they are spending on AI or data centers. To protect my retirement kitty, I'm keeping roughly half my equity investments in foreign stocks and value stocks that should be less affected if the AI frenzy fizzles.

Given all that, I thought it might be interesting to recount how AI helped me stress-test my retirement plan. I was impressed.

There were a few mistakes that I'll discuss later, but in general AI quickly sized up my portfolio, understood the tax ramifications of my approach, and helped this 69-year-old test it in a variety of extreme situations.

AI also offered advice on everything from properly assigning retirement plan beneficiaries to how to draft a prenuptial agreement. A lot of it was stuff I knew as a personal finance reporter, but some it wasn't-including a potential risk if I remarry that was completely outside my understanding.

I didn't do anything special to prepare for all this, and I don't pretend to have any special insights on how to use AI most effectively. I simply began firing questions at Gemini, the Google large language model that is the default AI on my Chrome browser.

My first question was as basic as they come: "How much money can I spend each month in retirement?"

AI gave three answers to that question. It first used the 4% rule, spending down that percentage of my portfolio each year, adjusted annually for inflation. If I wanted to be more conservative early in retirement, I could withdraw only 3% annually. If I wanted more money, I could use a dynamic approach with a 5% annual withdrawal-but I'd have to be willing to reduce my draw in a down market

This is all good, sound retirement advice but consists of basic calculations you can do on the back of an envelope. I wanted more exact retirement spending and legacy estimates from AI. It asked me for a precise list of investments in my three main buckets: a brokerage account, a tax-deferred 401(k), and tax-free Roth accounts.

My brokerage account is all in cash because I hope to buy a townhouse in the next few months. My tax-deferred account is 20% in equities and the rest in bank certificates of deposit and Treasury inflation-adjusted securities (TIPS), including a TIPS ladder to generate income for 30 years And my Roth accounts are 100% in stocks.

AI understood immediately what I was trying to do: I hope to live off my Social Security check plus withdrawals from my tax-deferred account for the rest of my life. I want stable income-not maximum growth from my 401(k)-because every dime I take out will be taxed.

My Roths, by contrast, are invested aggressively because I don't expect to pull money out of them for decades-if ever. I want the rapid growth to take place in these accounts because the withdrawals won't be taxed. Roths are a great way to transfer wealth to heirs, who also pay no taxes on withdrawals. But you can always crack them open if you need the dough during your retirement.

I asked AI to calculate how much money I could spend each month if I change my mind and retire at age 70. It spit out a number.

I kept firing questions. What if I wait a year to retire? Or two? Or three? Or even five? How much will that increase the amount I can spend when I do hang it up. For each year I defer retirement, it calculated I would get an additional $300 to $500 a month for the rest of my life.

What about if equity markets have a subpar period like both Morningstar and Vanguard are predicting because of current high valuations? AI told me that it wouldn't change my retirement income dramatically because most of my income is coming from Social Security and conservative investments.

It would, however, result in a smaller inheritance for my children because the Roth accounts won't grow as much.

I kept using AI to stress-test my retirement plan. What about if we go through another period of high inflation and crummy markets like 1968-1982-which 4% rule creator William Bengen told Barron's was the worst period to retire in the last century? Once again, it wouldn't hit my retirement spending hard because the TIPS and other conservative investments should protect me from inflation, but it would slash my legacy.

How about if I need to help the kids with a down payment on a house or some sort of emergency? AI told me that should be doable because my planned spending should generates surpluses.

I found this whole exchange with AI useful. Sure, you'd get all this and more from a good financial advisor, but it will cost you several thousand dollars-or a fee on assets under management. This was free.

And I could estimates things like taxes in retirement by using free online worksheets. But it was a lot easier do it with AI, and I could keep firing more questions at it.

Was AI perfect? Nope. I write and edit personal finance stories, so I caught some-though likely not all-errors. When I asked AI for my annual taxes if I keep working after I hit 70 in December and get my first Social Security check, it took my entire annual Social Security benefit and added it to my salary.

"I think you're wrong," I told it. "Social Security is only 85% taxed at most."

AI congratulated me for a good catch, and lowered my tax bill within seconds.

It made another mistake when I asked it to calculate my taxes in retirement. This time AI took 85% of my Social Security benefit and added it to required minimum distributions from my 401(k). The tax number it predicted was almost twice as high as the one I got a few weeks from a free AARP online calculator from AARP.

I told AI that its calculation was off because my taxable income will be low enough in retirement so my Social Security will be taxed at less than 85%. AI immediately ran the provisional income test for Social Security taxation-it includes half your Social Security benefit, plus other income from salaries, pensions, plus interest from tax-free bonds-and discovered I was right.

It slashed my estimated retirement tax bill. Hot dog!

AI didn't just calculate numbers. When I told it that I might remarry in the future but wouldn't do it unless the bride signs a prenup, it told me all the things to put in a prenup. Most of them I knew, but AI warned the government could come after my assets in certain situations even with a prenup if my spouse ever went on Medicaid to pay for longterm care. That I didn't know.

The woman I'm dating has substantial assets of her own, so I don't see this as a big risk, but it was good to know about nonetheless.

I was impressed by AI. I assume that the mistakes-like botching Social Security taxation-will lessen over time. When I asked AI about this, it said the Social Security rules are complicated-they are-and artificial intelligence often gets taxation wrong. It described it as a "temporary engineering flaw" that will eventually go away.

Does my positive experience with AI change my opinion about its future? Not really. Fascinating technology but I'm still not sure how Big Tech gets back those many, many billions.

I remind you that I didn't spend a nickel to unleash AI on my retirement plan. Who knows how long that lasts?