# Building a feedback app with the Microsoft 365 Copilot App Builder agent > What building an ideas app with Copilot's App Builder agent taught me about Lists back ends and prompting fixes, and where to build apps now it's being retired. - URL: https://www.danielanderson.io/articles/copilot-app-builder-feedback-app/ - Author: Daniel Anderson, Microsoft MVP (https://www.danielanderson.io/) - Published: 2025-10-29 - Updated: 2026-10-17 - Video: https://www.youtube.com/watch?v=SkrfvHmuAWE ## Key takeaways - The App Builder agent in Microsoft 365 Copilot built interactive apps from a prompt and stored their data in Microsoft Lists on a SharePoint site. - Microsoft is retiring the App Builder agent on 30 November 2026. New app creation stopped in mid-October 2026, and Copilot Cowork and Copilot Studio are where you build apps now. - In my build, the app looked finished before the voting worked. Upvotes weren't being written to the Votes list until I named that list in the prompt. - Open the lists behind an app after you test each action. In my build, the Votes list showed the problem before the screen did. The App Builder agent in Microsoft 365 Copilot let you describe an app in plain language and get back a working app with its data stored in Microsoft Lists. I used it to build an ideas and feedback app with categories, upvotes and an admin panel, and it took one long prompt and about half a dozen follow-ups to get the voting right. Since I recorded this, Microsoft has announced the App Builder agent's retirement. New app creation stopped in mid-October 2026 and the agent is retired on 30 November 2026, with apps you haven't migrated by then no longer accessible. Building apps from natural language now happens in Copilot Cowork and Copilot Studio. I've written up [building a SharePoint CRM with Copilot Cowork's App skill](https://www.danielanderson.io/articles/copilot-cowork-app-builder-sharepoint-crm/), and the lessons below carry across to it. ## What did the App Builder agent do? It arrived in October 2025 as a Frontier preview, for tenants in Microsoft's early access program with Microsoft 365 Copilot licences. You described the app in Copilot, the agent wrote itself a plan, and it worked through the build task by task. Each app got its own SharePoint site with the data in lists, and you shared the finished app like a document, by name, group or link. Compared with consumer vibe coding tools like Lovable or Bolt, an App Builder app ran inside Microsoft 365 under your permissions, and its data sat in lists you could open yourself. ## How I built the ideas app My prompt asked for an app where people could submit improvement ideas with a title, description and category, see each idea as a card, and upvote the ones they liked. The agent broke that into 13 tasks (data schema, the submission flow, the idea cards, sorting and filtering, an admin panel) and finished in a few minutes. Behind the app it created three lists in a new SharePoint site: Categories, Ideas and Votes, with some sample ideas already filled in. The category picker on the form read from the Categories list. It also added sorting and a status filter I hadn't asked for, and both worked. Adding an idea worked too, but nothing on screen told me so. I only knew because the new card appeared in the list underneath. One follow-up prompt asking for a success message after submitting fixed that, and I left it to the agent to decide how it looked. ## Where did it go wrong? Upvoting. The button animated and only let me vote once per idea, but every card showed zero votes and nothing persisted when I reloaded. When I opened the Votes list, only the sample votes were in it. Asking it to "show the number of upvotes" didn't fix it. Neither did adding "from the votes list". What worked was a prompt that described the data model plainly: we have a Votes list that holds the votes, use it to show the totals, and when someone clicks upvote, add a vote for that idea to the Votes list. After that pass, each vote landed in the list with the vote ID, the idea ID and the ID of the person who voted, and the cards showed the right counts after a reload. The rest was quicker. Styling changes like a new header and coloured status pills took a prompt each, and the admin panel saved status changes straight away without a save button. ## Design the lists before you design the app The voting bug is the lesson I'd take into Cowork or any other natural language app builder. I found it by opening the Votes list, and fixed it only once I talked to the agent about that list by name. So when I build these now, I start with the data. Decide what the lists are, what each column holds and how they relate, then give the agent that schema so it doesn't invent its own. My Cowork CRM build went that way: Copilot in SharePoint created the lists from a written definition, then Cowork built the app from an as-built description of them. Two more things I'd settle before anyone shares an app. First, who owns the site the data lives in. App Builder created a new site per app, so every person who built one added a site to your tenant that nobody had planned for. Second, who can edit the lists directly. Anyone with edit rights on the Votes list could add votes without going near the app, so check the list permissions as well as who the app is shared with. [Why your SharePoint needs an information architecture before AI](https://www.danielanderson.io/articles/sharepoint-information-architecture-before-ai/) covers how I'd think about where sites like these belong. ## Frequently asked questions **Is the Microsoft 365 Copilot App Builder agent still available?** No new apps can be created in it. New app creation stopped in mid-October 2026, and the agent and vibe.powerapps.com are retired on 30 November 2026. Existing apps can be opened to start an in-product migration, and anything not migrated by then is no longer accessible through those experiences. **What replaces the App Builder agent?** Copilot Cowork and Microsoft Copilot Studio. Apps in Copilot Cowork became available through the Frontier program on 8 September 2026, and a public preview of apps in Copilot Studio began in early October 2026. **Where did App Builder apps store their data?** In Microsoft Lists on a SharePoint site created for the app. Admins could find and audit the apps in the Power Platform admin center under Manage, Inventory, filtered to App Builder apps. **Could App Builder apps connect to external systems?** No. The preview didn't support external data connections or custom APIs, so apps worked from Microsoft 365 data and their own lists. **How do I check an app built by Copilot is saving data?** Test an action, then look for the new item in the list behind it. Once my voting worked, each vote appeared in the Votes list with a vote ID, the idea ID and the ID of the person who voted, which is enough to confirm the app is writing what you expect.