# Transcript: build-me-a-budget-tracker One conversation, session bcf27ec0-e66e-4719-abfb-7173580aacfb, model claude-sonnet-5-5, 2.1.287 (Claude Code), run with claude -p on 2026-10-02. Claude could only create, read and edit files in an empty folder (told that files it saves are offered to the user as downloads), the nearest headless equivalent of claude.ai with file creation switched on. No terminal, no web search, no connectors. Each step was sent with --resume so Claude saw everything before it. Replies are verbatim; lines in *[brackets]* mark where Claude saved a file, and the files themselves are published unedited. --- ## Prompt 1: you I'd like a simple budget tracker that I can open on my phone and my laptop. I'm Ellie, and my partner Sam and I want to keep an eye on what we spend each month. What I'd like it to do: - I set a monthly amount for each category. Ours are: Food shopping £420, Bills £260, Transport £140, Eating out £90, Fun £60 and Other £50. - When we spend something, I add it: the amount, which category, a short note (like "Tesco big shop") and the date. - It shows how much is left in each category this month, and in total, and makes it obvious when we've gone over. - Everything in pounds. Our numbers are private. I don't want accounts or passwords, I don't want to connect our bank, and I don't want our spending stored on anyone's server. I'm not technical, and I want it to be free to run. Before you make anything, ask me anything you need to know, and tell me in plain English what you're going to make and where our numbers would be kept. ### Claude Nothing is built yet. Here's what I'd make, where your numbers would live, and a few questions I need answered first. ## What I'd make A single web page that works on a phone screen and a laptop screen. You'd: - **Set up:** see your six categories with their monthly amounts (Food shopping £420, Bills £260, Transport £140, Eating out £90, Fun £60, Other £50, so £1,020 in total). You can change them any time. - **Add spending:** enter the amount, pick a category, type a short note and choose the date. The date defaults to today. - **See the month:** each category shows what's spent, what's left and a bar. It turns red and says "over by £X" when you've gone past the limit. There's a total for everything too. - **Fix mistakes:** edit or delete an entry, and flip back to previous months. Everything is in pounds. There are no accounts, no passwords and no bank connection. ## Where your numbers would be kept Your spending would be saved **inside the browser on the device you're using**. It never goes to a server, mine or anyone else's. The page itself would be hosted somewhere free so you can open it by link. That's just the empty tracker, with none of your numbers in it. ## The catch: phone and laptop won't automatically match Because the data stays on each device, **your phone and your laptop would each have their own separate copy.** Automatic syncing needs a server somewhere holding your data, which is exactly what you don't want. There are a few ways to handle that: 1. **One main device.** You or Sam enters everything on one device and the other just looks. This is the simplest option. 2. **Manual sync.** A "Save backup / Load backup" button moves your data between devices through a small file you send yourself (for example by AirDrop or email). It's free and private, but you have to remember to do it. 3. **Syncing through your own cloud account** (iCloud, Google Drive). This is more complicated and only partly private, so I'd avoid it unless you really want it. I'd recommend option 2, with a backup button either way. If you clear your browser data or lose your phone, the numbers go with it unless you have a backup. ## Questions 1. **Who adds spending?** Just you, or Sam too? If both, are you happy with the manual sync above, or would you rather pick one device to enter everything on? 2. **What phones do you use?** iPhone or Android? Which laptop browser? 3. **When does your month start?** The 1st, or payday (say the 25th)? 4. **Unspent money:** should leftover money in a category carry over to next month, or does each month start fresh? 5. **Hosting:** the easiest free option is a free GitHub or Netlify account to put the page online. I can write step-by-step instructions, or you can skip the hosting and I'll give you a file to open directly. The file route is more awkward on phones. Which do you prefer? 6. **Regular bills:** do you want recurring items (like rent) to be added automatically each month, or will you enter everything by hand? Once you've answered, I'll build it. --- ## Prompt 2: you Thanks, that sounds right. My answers: 1. Mostly me adding things, on my phone. Option 2 is fine: please add the backup button so I can copy it to the laptop now and then. 2. I have an iPhone and Sam has an Android. The laptop uses Chrome. 3. The 1st of the month. I'd like to be able to look back at last month. 4. Each month starts fresh. No carrying over. 5. I'd like it online so I can open it from a link. I've got free GitHub and Cloudflare accounts, so please make it so I can upload it there. Instructions can come later. 6. By hand for now. Please also put in a few made-up spends for this month so I can see how it looks. I'll delete them. I've attached a screenshot of a website I like the look of. I like the off-white background, the big clean writing and the blue. Don't copy its words, just the feel. Please make it now. Keep it as simple as possible: just the files I'll need to upload, nothing I have to install. It must be easy to use on a phone. *[Attached: site-i-like.png]* ### Claude *[Claude saved the file `index.html`]* I've built it as a single file, **index.html**. That's the only file you need to upload. Nothing needs installing, and I haven't tested it in a browser yet, so please click through it once before you rely on it. **What's in it** - **Top of the page:** one big figure showing what's left across all categories this month, for example "£612.50 left in October". It turns red and says "over budget" if you've overspent. The off-white, large thin type and blue are my take on the feel of your screenshot, with none of its words. - **Add a spend:** amount, category, note and date (today by default). On your phone it's the first thing under the headline. - **Left this month:** a card for each category with a bar. A category turns amber when it's nearly used up and red with "£X over" when it's over, so it doesn't rely on colour alone. - **Spends list:** every spend for the month, each with Edit and Delete. - **Looking back:** the ‹ › buttons move between months, and each month starts fresh with no carry-over. Last month keeps the amounts it had, even if you change your budgets later. - **Settings:** change the monthly amounts. New amounts apply from this month onwards. - **Backup:** "Copy backup" copies your numbers as text. Send it to yourself, paste it into the box on the laptop and press "Restore from box". You can also download or load a file instead. **Sample spends:** I added 13 made-up spends for October, marked "sample". Eating out is deliberately over budget so you can see the red warning. One button, "Remove the made-up sample spends", clears them all. Anything you add yourself stays. **Privacy:** the page makes no requests to anything outside itself. It uses no external fonts, analytics or libraries, and it saves only in the browser you're using. **Things to know** - **iPhone:** if you later use "Add to Home Screen", that version keeps its own separate data from Safari. Choose one way to open it and stick with it before you enter real spends. - **Safari clears old data:** Safari can clear a website's saved data if you don't open it for a long time. Press "Copy backup" and paste it somewhere safe every so often. - **Sam's Android phone:** it would have its own separate copy. If Sam adds spends, you'd need to merge them into yours by hand. - **Restoring replaces everything** on that device with the backup, and it asks you to confirm first. When you're ready, I'll write the GitHub and Cloudflare upload instructions. --- ## Prompt 3: you I opened it by double-clicking it and it looks great. Before we rely on it, please check it carefully as if you were me on a small phone, and as if you were trying to break it: - I type an amount like 12.5, £12.50, 12,50 or leave it blank, or type a minus number - I add a spend, close the page and open it again tomorrow: is it still there? - I add something by mistake and want to fix or delete it - the totals: do they add up exactly, with pennies? - the month changes while I'm using it - I clear my browser history, or my phone breaks: what happens to our numbers, and how do I keep a backup? - writing that's too small or too faint, anything that spills off the side, and anything that would trouble someone who uses a screen reader or only a keyboard Tell me in plain English what you found, then fix it in the files. ### Claude I can't run a browser or hold a phone here, so I checked by reading every line of the code and working through each of your scenarios by hand. A few real problems turned up. I'll write the fixes first and then tell you what I found. *[Claude saved the file `index.html`]* I've fixed everything below in **index.html**, which is still the only file. I couldn't run it in a browser or on a phone, so I checked it by reading the code and working each scenario through by hand. Please click through it once on your iPhone and on the laptop before you trust it. ## What I found, and what I did **Typing amounts** - **`12.5` and `£12.50`:** these worked. - **`12,50` was a real bug.** It would have been read as £1,250 with no warning, so I fixed it. It now reads as £12.50, and `1,200` still means £1,200. - **Blank, minus, zero or letters:** all of these were rejected, but with a vague message. Each now says what's wrong, for example "Amounts can't be negative. For a refund, edit or delete the original spend". The box is highlighted and the cursor goes back into it. - **Silly dates:** a date like year 0002 could have shown up as 1902. Dates are now limited to 2000–2100. **Closing the page and coming back tomorrow** - Your spends are saved each time, so they'll still be there. - **One bug could have wiped them.** If the saved data was ever unreadable, the tracker would have quietly replaced it with fresh samples. It now keeps a copy and shows a warning instead. - **A page that wouldn't open:** if a browser refuses to save at all (private browsing, for example), the page could have come up blank. It now loads and shows a red warning that nothing will be kept. - **Two tabs open at once:** they now stay in step instead of overwriting each other. **Fixing or deleting a mistake** - Each spend now has one **Edit** button, which fills the form in. Delete is inside that screen, so you're less likely to hit it by accident. After deleting, an **Undo** button appears. - Before, deleting the spend you were in the middle of editing could have left the form in a confusing state. That's fixed. **Totals** - Money is held in whole pence, so there's no rounding drift. - Amounts now always show two decimals (£30.00, not £30), so you can check them by eye. - I added up the sample data by hand: **£561.93 spent, £458.07 left**, with Eating out over by **£29.00**. If your screen shows the same, the sums are right. - The total can look healthy while one category is red, because spare money in one category offsets overspending in another. The line under the big number says how many categories are over. - I told you there were 13 sample spends. There are 14. **The month changing while you use it** - Before, a page left open over midnight would still show the old month, and the form would still default to yesterday's date. That's a real risk on a phone, where tabs stay open for days. It now catches up when you come back to it and when the clock rolls over. **Clearing history or losing the phone** - Clearing website data on your phone or laptop deletes your numbers. A broken or lost phone does too, because nothing is stored anywhere else. - To protect you, the page now shows a banner with a "Back up now" button if you have real spends and no backup for 14 days. It doesn't appear for the sample data. - Restoring now puts your previous numbers into the box afterwards, so a wrong restore can be undone. - I suggest backing up once a month when you start the new month. - **Your test data won't move to the hosted version.** The page you opened by double-clicking has its own separate storage. That's fine for the samples. For real numbers, start fresh at the online address, or move them with the backup. **Readability and accessibility** - **Small or faint text:** I raised the smallest text from 11–13px to 12–15px and darkened the grey, amber and red so they're easier to read. - **iPhone zoom:** the backup box used 13px text, which makes iPhones zoom in when you tap it. It's now 16px. - **Fitting small screens:** the form stacks into one column on narrow phones, and long notes wrap instead of spilling off the side. - **Touch and keyboard:** buttons are at least 44–48px tall. "Restore from file" was a label that keyboard users couldn't reach, so it's now a proper button. - **Screen readers:** the page has a proper main heading, labelled fields, a list of spends, "Edit" buttons that say which spend they're for, and messages that are read out. Nothing relies on colour alone, because "£29.00 over" is written out. **Not done:** Sam's Android phone still keeps its own separate copy, and there's no automatic sync. That's the privacy trade-off we agreed on. If you're happy with this, I'll write the GitHub and Cloudflare upload steps next. --- ## Prompt 4: you We've been using it for a bit and want one change. Please add a new category called "Presents" with £35 a month, and change Eating out from £90 to £70. Then tell me which files you changed, so I know which ones to upload again, and whether the spends I've already added will still be there after I upload the new version. ### Claude *[Claude edited the file `index.html`]* *[Claude edited the file `index.html`]* *[Claude edited the file `index.html`]* *[Claude edited the file `index.html`]* *[Claude edited the file `index.html`]* *[Claude edited the file `index.html`]* *[Claude edited the file `index.html`]* I've added **Presents** at £35 a month and changed **Eating out** to £70. I couldn't run it in a browser, so I checked the change by reading the code. **Files to upload again:** just **index.html**. It's the only file, so upload it over the old one in GitHub and Cloudflare. **Your spends will still be there.** They're saved in your browser, not in the uploaded file, so uploading a new version doesn't touch them. The same goes for your monthly amounts, which are saved the same way, and for the backup reminder. When you first open the new version, it updates your saved amounts once: - **From the month you first open it:** Eating out becomes £70 and Presents becomes £35. If you open it in October, that applies from October. The other categories keep whatever amounts you currently have. - **Earlier months** keep the amounts they had, so September still shows Eating out at £90 and no Presents. The Presents card is hidden in months where it has no budget and no spend. - **Your made-up October spends** are included in the update, so Eating out will now show about £49 over. - **Monthly total:** the total budget goes from £1,020 to £1,035 (the £20 saving on Eating out, plus the £35 for Presents). **If you restore an old backup** (made before this change), the same update is applied to it, so you won't lose the new amounts. **Sam's Android phone** has its own separate copy, and it gets the same update the first time he opens the new version. Before you rely on it, I'd press **Copy backup** on your phone first as a safety net. Then upload the file and open the page, check that the Presents card shows £35.00 and that your spends are still listed. --- ## Prompt 5: you I've made free GitHub and Cloudflare accounts. On GitHub I made a new repository called ellie-budget (I switched on "Add README"), and in Cloudflare I went to Workers & Pages, Create application, Pages, Connect to Git, and picked that repository, so it should go live by itself whenever the files on GitHub change. I don't want to use the terminal or install anything. Please tell me, step by step, how to get the budget tracker into my repository using the GitHub website, what I should see at each step, how I find the address where it's live, and how I put a change live later (like the new category). Also: if it's on a public address, can other people who open it see our numbers? And if I add spends on my phone, will they show up on my laptop? ### Claude Nothing in the tracker needed changing for this. Your Cloudflare setup is the right one: it watches your GitHub repository and republishes whenever the files change. GitHub and Cloudflare change their screens now and then, so a button label may differ slightly from what I've written. ## Part 1: Put the tracker into GitHub 1. Make sure the file is saved on your computer and is named exactly **index.html**. 2. Go to github.com, sign in, and open your **ellie-budget** repository. You should see a list of files with just **README.md** in it. 3. Click **Add file** (above the file list, on the right), then **Upload files**. You'll see a big box saying "Drag files here to add them to your repository". 4. Drag **index.html** into the box, or click "choose your files". The file name appears underneath. 5. Scroll down. Leave "Commit directly to the main branch" selected and click the green **Commit changes** button. 6. You're taken back to the repository page. You should now see **index.html** listed next to README.md. ## Part 2: Check Cloudflare and find your address 1. In Cloudflare, go to **Workers & Pages** and click your **ellie-budget** project. 2. If it's still asking you to set up the build, use these settings: - Production branch: `main` - Framework preset: **None** - Build command: leave empty - Build output directory: leave empty (type `/` if it won't let you) - Then click **Save and Deploy**. 3. Open the **Deployments** tab. The top item should say **Production** and show a green **Success**. While it's working it says "In progress". That takes a minute or two after any change on GitHub. 4. Your address is on the project page, under **Domains** or beside a **Visit site** button. It looks like `ellie-budget.pages.dev` (it may have extra letters if that name was taken). Click it and you should see the "Ellie & Sam" page. 5. Bookmark that address on your phone and laptop. **Always use that same main address.** Your numbers are stored against the exact address you open. Cloudflare also makes long one-off addresses with random letters for each upload, and those would look like an empty tracker. On the iPhone, I'd avoid "Add to Home Screen". Choose Safari or the home-screen icon and stick with it, because they don't share numbers. **If you've been entering real spends in the file you double-clicked,** the live address starts fresh with sample spends. To bring your numbers across, open the old copy, go to *Backup & move to another device* and tap **Copy backup**. Then open the live address, paste it into the box and tap **Restore from box**. You can also tap **Remove the made-up sample spends** to clear the samples. ## Part 3: Putting a change live later 1. I'll give you a new **index.html**. Save it on your computer with exactly that name. 2. Do steps 2–6 of Part 1 again. Uploading a file with the same name replaces the old one. 3. Wait a minute or two. Cloudflare's Deployments tab will show a new Success. 4. Reload the page on your phone and laptop. If you still see the old version, close the tab and open it again. Your numbers stay put, because the saved numbers live in your browser and the upload only replaces the page. ## Can other people see our numbers? No. Anyone with the link can open the page, but they only see an empty tracker with sample spends. Your numbers are in your own browser on your own device. GitHub and Cloudflare only hold the page itself, and they can see that someone loaded it, as any website can. Your numbers are never sent to them. The one real risk is someone using your unlocked phone or laptop in the same browser, who could open the page and see your numbers. ## Will spends I add on my phone show up on my laptop? No. Each device keeps its own copy, and the same goes for Sam's Android phone. To move your numbers, press **Copy backup** on your phone, send the text to yourself, then on the laptop paste it in and tap **Restore from box**. Restoring replaces what's on that device and doesn't merge. So treat the phone as the place where you enter spends and the laptop as a place to look, and do the copy across when you want to see the latest.