For years, Ive had a secret ambition tucked away somewhere near the back of my brain. It was to write a simple note-taking appone that wouldnt be overwhelmed with features and that would reflect my own mental filing system. In part, this yen stemmed from my dissatisfaction with existing notetakers. But I also saw the project as an adventure in software development that could only make me a smarter technology user.Just one thing stopped me: The formidable technical knowledge required even just to get started. Im not an utter programming neophyte, but my skills largely atrophied after I graduated from high school and never extended much beyond writing buggy games. Almost everything Id need to know about modern coding Id have to learn from scratch.Or so it seemed.Recently, however, a new wave of AI-infused tools with names such as Replit, Bolt, and Lovable has enabled a phenomenon that OpenAI cofounder Andrej Karpathy has dubbed vibecoding. It doesnt involve coding an app yourself. Instead, you use a chatbot-like interface to tell an AI collaborator what you envision, and let it do the heavy lifting. Youre more product manager than programmer, and while a certain aptitude for technical matters is helpful, the barrier to building something is dramatically lower than in the past.Using a Replit feature called Agent, I put together my dream notes app in a week, finding the process so addictive that I often tinkered into the wee hours. I gave my brainchild a name (Doolee, as in duly noted) and used ChatGPT to design a logomark (a pencil twisted into a lowercase d). Mostly, though, I simply told the Agent what I wanted, including features that occurred to me as I was overseeing the project. The web-based result runs on my iPhone, iPad, and Mac, and doesnt feel much different than a native-app version might have. It requires a little more fit and finish before I can declare it complete, but Im already smitten with it.As a product team of one building an app with an intended user base of one, I aimed only to please myself. Ive always loved sticky notes as a metaphor for note managementtheyre informal, quick, and flexible. So I asked Replits Agent to make my app look like a searchable wall of them. It took just a few minutes to rough out a minimum-viable-product version. From there, I just kept tweaking and adding more capabilities, drawing inspiration from my favorite features in other notetakers Ive used over the decades, from a 1990s DOS program called Info Select to Evernote to the one Ive been using recently, Bear.I had the Agent program features such as a search bar right at the top, a hashtag browser, and lists for task management and other purposes. I made it turn URLs into little cards that display page titles and source sites. I got it to sync notes back and forth between devices, including in scenarios where the app might not have access to the internet and would need to sync later. Even a week ago, I wouldnt have guessed I could will something so professional-looking into existence.Whats it like collaborating with a software engineer that happens to be a piece of software itself? Throughout the development effort, the Replit Agent almost always grasped my requests without me having to spell out every detail. Its first drafts of new featureswritten using web technologies, such as TypeScript and React, that are far beyond my kenwere often solid. When they werent, I provided feedback to nudge it in the right direction. It came off as calm and persistent, and often heaped praise on my feature requests (Thats a fantastic idea!) in a manner that was somehow synthetic and charming.But as our collaboration progressed, it became clearer that the Agent doesnt really think like a human. It couldnt use the app it was constructing; verifying that everything worked was part of my job. At every step, the AI appeared to be puzzling out the project, as if it hadnt been involved all along. Fortunately, it was a quick study.I also learned not to trust the Agent too much. Whenever it finished debugging a problem area, it declared that work to have been a success, which it often wasnt, especially at first. Weirder still, at one point, the Agent helpfully proposed adding a feature that would turn audio recordings into text. When I took it up on the offer, I saw no evidence that it followed through.A snippet of my conversation with Replits AgentEven if the Agent proved overconfident and obtuse at times, the end result is an app I could never have produced on my own. Even if Id hired a competent human programmer, I doubt that Id have ended up with something that made me so happy so quickly.Speaking of paying programmers: The basic free Replit plan might whet your appetite to the services possibilities, but youll probably need to spring for one of the paid tiers to tackle serious projects. I maxed out the $20-per-month one I signed up for pretty quickly and ended up investing almost $300 in producing Doolee. I will also be paying Replit fees to host my app, though they shouldnt add up to a fortune as long as Im the only user. Given how long Ive craved building something like this, I dont find the cost unreasonable.Along with learning something about the highs and lows of AI-centric product development, I came away from this venture even more attuned to the ways productivity software in its conventional form can bog us down. With off-the-shelf apps, were at the mercy of design decisions we had nothing to do with. Most products are trying to please everybody, which leads to feature bloat. Anything with much historyMicrosoft Word turns 42 this yearis likely to be particularly cluttered with cruft.The tech industrys conventional wisdom says that users typically ignore a huge percentage of the features in the software they use. (The exact figure cited varies, but Microsoft CEO Satya Nadella told me that Office users tend to utilize just 5% of its features.) The only way around this conundrum would be to create your own apps, built with only the features you want, implemented as you see fit. Until tools such as Replit came along, that would have been a pipe dream for most of us. Now its an everyday reality, albeit one thats still slightly mind-bending. I cant wait to see where it goesand I hope to use my Doolee app for years to come.Youve been reading Plugged In, Fast Companys weekly tech newsletter from me, global technology editor Harry McCracken. 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