No coding tools installed? FirstThree scopes a tiny v1 and writes three copy-paste prompts that make ChatGPT build it as a single index.html file you open with a double-click.
Before the prompts you get the plan: 3 to 5 things v1 must do, what to skip (with a reason for each), the simplest stack for ChatGPT, and the main screens. Every prompt says what not to build yet and ends with a “Done when…” check.
Unedited FirstThree output for two one-sentence ideas.
Real example 1
CampCheck: “a packing checklist generator for weekend camping trips based on the weather”
A simple checklist generator that creates a custom weekend camping packing list based on the weather forecast.
v1 includes
- Weather input selector (Sunny, Rainy, Cold, Hot)
- Generated packing list with checkboxes
- Ability to add custom items to the list
- Saves your checklist automatically using browser storage
Skip for now
- User accounts · Not needed for a personal packing checklist.
- Live weather API · Manual weather selection keeps things working without API keys.
- PDF export · Checking items off on the screen is enough for v1.
- Mobile app stores · A web page works great on mobile browsers.
Stack: HTML, Tailwind CSS, and Vanilla JavaScript · None · Browser localStorage · Browser local file or Vercel
1Build core layout and listYou will have a complete working single-file app with the user interface and sample packing data.
We are building CampCheck, a web app that generates a weekend camping packing list based on the weather. Please write the complete code for a single index.html file using Tailwind CSS via CDN and vanilla JavaScript.
- Create a clean, modern mobile-friendly interface with a title and brief description.
- Add a weather selector section with buttons or a dropdown for Sunny, Rainy, Cold, and Hot.
- Add a generate button that displays a categorized packing list (Gear, Clothing, Food) based on the chosen weather.
- Include working checkboxes next to each item so users can check things off.
- Provide clear step-by-step instructions on how to save this code into an index.html file and open it in a web browser.
Do not include backend servers, user logins, or live API calls.
Done when: I can open the HTML file in my browser, select a weather type, and see a tailored checklist with working checkboxes.
2Add local storage and custom itemsYou will be able to save your checked items and add new custom items to the list.
We are continuing work on CampCheck, our single-file HTML camping packing list generator using Tailwind CSS and JavaScript. Please review the current app logic and update the index.html file with complete code.
- Add an input field and an 'Add Item' button so users can add their own custom items to any category.
- Implement browser localStorage so that checked items and custom items stay saved even if the page is refreshed.
- Add a 'Reset List' button to uncheck all items and clear custom additions.
- Ensure the UI feels responsive and gives subtle visual feedback when items are checked off.
- Provide the complete updated index.html file so I can replace my old code entirely.
Do not add external databases or user accounts.
Done when: I can check items, add a custom item, refresh the page, and see that my changes were saved.
3Polish styles and empty statesYou will have a polished, finished v1 ready to use for your next camping trip.
We are finalizing v1 of CampCheck, our single-file camping packing list generator. Please review the complete index.html file and provide the final polished version with all previous features intact.
- Add a progress bar at the top that fills up as you check off items on your list.
- Improve the visual design with better spacing, friendly camping icons or emojis, and a clean color palette using Tailwind CSS.
- Add a nice empty state or instruction banner when the page first loads before a weather type is selected.
- Include clear instructions on how to use the app and test all features.
- Output the entire index.html file in one complete code block without truncation.
Do not add complex animations, multi-language support, or external JavaScript libraries.
Done when: The app looks polished, the progress bar moves as I check items, and I can use it smoothly from top to bottom.
Generate a fresh plan for this idea →
Real example 2
BandSet Builder: “a setlist builder for my band that sorts songs by key and tempo”
A simple web app for musicians to organize, sort, and filter band setlists by key and tempo.
v1 includes
- Song library with title, key, tempo, and duration
- Interactive setlist builder with drag or add functionality
- Automatic calculation of total setlist duration
- Sorting and filtering by musical key and tempo
Skip for now
- User accounts · Local storage is enough for a single musician.
- Cloud syncing · Not needed for a quick afternoon build.
- PDF export · Printing via browser is good enough for v1.
- Spotify integration · Manual entry keeps the first version simple.
Stack: HTML, Tailwind CSS via CDN, and vanilla JavaScript · None · Browser localStorage · Local file openable by double click
1Build the Song LibraryYou will have a working single-page app displaying a song library stored in local storage.
We are building BandSet Builder, a simple web app to manage band songs and setlists. We are using a single index.html file with Tailwind CSS via CDN and vanilla JavaScript, storing data in localStorage.
- Create a complete, single index.html file that includes all HTML, Tailwind styling, and JavaScript logic.
- Design a clean, modern interface with two main sections: a Song Library and a Active Setlist.
- Include a form in the Song Library to add new songs with Title, Artist, Key, Tempo (BPM), and Duration.
- Pre-populate the library with 5 sample songs so the app is not empty on first load.
- Enable deleting songs from the library.
Do not add multi-user support, backend servers, or PDF export features.
Done when: You can open index.html in your browser, see the sample songs, and add a new song to the list.
2Add Setlist Building and SortingYou will be able to build setlists and sort them by key and tempo.
We are continuing BandSet Builder in our single index.html file using Tailwind CSS and vanilla JavaScript. If you need context, the app manages songs and setlists using localStorage.
- Add a button to each song in the library to add it to the Active Setlist.
- Display the Active Setlist with its items, allowing users to remove songs or reorder them up and down.
- Calculate and display the total running time of the active setlist at the top.
- Add sorting controls to sort the song library and setlist by key or by tempo.
- Ensure all changes save automatically to localStorage so they persist on refresh.
Do not add user accounts, drag-and-drop libraries, or cloud sync.
Done when: You can add songs from the library to the setlist, see the total duration update, and sort by tempo or key.
3Polish and Print ReadyYou will have a polished, responsive app ready for band practice with a print-friendly view.
We are finishing v1 of BandSet Builder in our single index.html file. Please review the complete code for polish and ease of use.
- Add clear empty states when the song library or setlist has no items.
- Style the app to look great on both mobile screens and desktop monitors.
- Add a Print Setlist button that formats the active setlist cleanly for printing or saving as a PDF.
- Add confirmation prompts when clearing the entire setlist or deleting a song.
- Output the entire, working index.html file in one complete code block with no missing parts.
Do not add external backend databases or complex animations.
Done when: You can print the setlist cleanly, use it on your phone, and have a zero-error experience.
Generate a fresh plan for this idea →