Building your app
The chat panel is where you build. Every message you send is a turn: the agent reads your project, makes changes, and the live preview updates.
Writing good prompts
Be as specific as the thing you want. Small, incremental asks work well:
- “Add a search box above the table”
- “Sort habits by longest streak first”
- “Rename ‘Tasks’ to ‘Habits’ everywhere”
You don’t need to describe implementation details — just describe the behavior or look you want.
Attachments
You can attach images, PDFs, and text files to a message — for example, a screenshot of a layout you want to match, or a spec document. Bool also supports voice input: tap the mic in the composer to dictate your message instead of typing it.
Checkpoints and reverting
Every assistant turn that changes files gets a checkpoint marker in the chat. If a change didn’t go the way you wanted, use the checkpoint’s Restore to here action to roll your project’s files back to that point — your chat history stays intact, so you can see what led there and try a different instruction.
When something breaks
If the live preview hits a runtime error, or the dev server fails to build, Bool detects it automatically and shows an Issues found notice with a one-click Resolve with AI action — no need to paste the error back into chat yourself.
Working with others live
If a Bool is shared with collaborators, you’ll see their presence and typing indicators while you’re both in the workspace. Only one person can send a message at a time — if someone else is mid-turn, your message queues until theirs finishes. See Sharing and collaborators for how to invite people.
Upgrading an older app’s backend
Bools built before Bool’s current backend don’t get the newer built-in features — sign-in for your app’s users, Analytics, Logs, and using the app as a backend from the CLI or the API.
You don’t have to rebuild. If a Bool is eligible, an Upgrade this app’s backend offer appears above the chat box. Choosing it makes an upgraded copy of the Bool and opens it, then the agent’s first turn moves the app’s data code over to the new data API and keeps everything else — the same screens, the same behavior, the same design.
Because it’s a copy, nothing happens to the original: it stays exactly as it is, still published at the same address. If you don’t like the upgraded one, just go back to the original. The copy lands in whichever workspace you have selected, and inherits the original’s sharing.
The offer only shows for people with edit & publish rights on the Bool.
Version history
Every checkpoint is also a point-in-time version of your app. Open Version history to preview how the app looked and behaved at any past version, view its code, or restore or publish that specific version. See Files and code for more on browsing code.