Guided build · ~15 min
Savings-goal tracker
Set a goal, log deposits, watch a bar fill toward it.
You will build this by describing what you want in plain words, in your own language. Claude writes the code; your job is to describe the result well and check it. Here is the whole path, start to finish.
Set a goal, log deposits, watch a bar fill toward it.
First, how to actually talk to the agent
- 1Describe the RESULT, not the tech: what's on screen, what each button does, what gets saved. The agent handles the 'how'.
- 2Be concrete about screens and fields — 'a form with amount, category and date' beats 'let me add expenses'.
- 3Ask for the smallest working version first. You grow it by talking afterwards — that's Step 2, not the first message.
- 4Decide what's YOURS, not the agent's: name the categories, colours, rules. Don't make it guess what only you know.
Step 1 — Build it live
Prompting for this kind of tool
- 1For a savings-goal tracker, spell out the setup card (goal name, target amount, target date) and the ONE big visual: a progress bar showing saved-versus-target with the percentage AND the amount still left — don't just say 'show progress', name both numbers.
- 2Describe the status line in plain words: 'tell me the monthly amount I still need to put away to hit the date, and whether I'm ahead of or behind pace.' That on-pace math is the heart of it; decide the rule yourself rather than hoping Claude infers it.
- 3Add 'everything stays on my device, nothing is sent anywhere' — your goal and balance are nobody's business but yours.
- 4End with: 'build the whole thing, check that it works, and tell me exactly how to open it.'
claude
Open the terminal and run this (if Claude is already running, type /exit first). Then ask it to make a folder for this project and work inside it.
Say it in YOUR language — Russian, Spanish, anything. Claude understands.
Build it now — tick as you go
0/6Step 2 — It's built. Now make it yours
Don't panic at the techy link. Claude tells you one of two things. Either a file like index.html — find it in your project folder and double-click it; it opens in your browser. Or a web address starting with http://localhost — copy it into your browser's address bar and press Enter. 'localhost' just means 'this is running on your own computer right now'. That's your tool. It's real.
Now tweak it until YOU like it — just talk
This is the part that makes it YOURS. Don't accept the first version — change it by saying what you want, right there in the same chat. Claude rebuilds and you refresh. Keep going until it fits how you actually work. For this tool, try things like:
I don't type long messages. I open voice-to-text (the mic in ChatGPT, or your phone keyboard), and just TALK through everything I think about what it built — what's wrong, what I want next — then select-all, copy, and paste the whole brain-dump into Claude Code. Messy spoken thoughts work fine; the agent sorts them out. It's several times faster than writing.
Step 2.5 — Test it like a real thing (it won't be perfect first try)
The truth no one tells beginners: the first build is a DRAFT. The agent makes something, you run it, you find what's off, you tell it — and THAT loop is the actual work. Don't read the code. Use the tool like a stranger would and watch where it lets you down. For this tool, check exactly this:
- 1Open it (Claude gives a localhost link or an index file — see Step 2), set a goal like '2000 by December', then log two deposits with dates.
- 2Watch the progress bar: does it fill to the right percentage (your deposits divided by the target) and does 'amount left' equal target minus what you've saved? If not, the math is your first fix.
- 3Read the status line — given your target date, is the 'monthly amount still needed' a sensible number, and does it correctly say whether you're ahead or behind?
- 4Refresh the page (F5 / Cmd-R). Are your goal and both deposits still there? If they vanish, 'saves on my device' isn't wired up — fix that next.
- 5Log a big deposit that pushes you past 100%. The bar should cap nicely at full and the tool should clearly say you've hit the goal — not show 137% in a broken bar.
Found something wrong? Say it like this
You fix nothing yourself — you DESCRIBE what's wrong in plain words and the agent fixes it. Be specific: what you saw vs. what you expected. Real examples for this tool:
Don't stop at v1 — grow it
A tool you built in ten minutes is a starting point, not the finish line. The people who get hooked keep saying 'now also…'. Each line below is one sentence you paste into the same chat to level this tool up:
Step 3 — Connect it to the world (optional)
Free data & APIs for this one
An API is just how your tool pulls in outside data or sends things out — many are free. You rarely need to research them yourself; the move that works for ANY idea is to ask the agent to find them:
- 1To start you need NO external API — the goal, deposits, percentage and pace math all run locally on your device.
- 2Saving toward something in another currency (a trip, a foreign purchase)? A free rates API like exchangerate.host or Frankfurter (no key) can show your target in both currencies — ask Claude to wire one in only if you need it.
- 3Reusable move for ANY idea: ask Claude — 'look up free or open APIs that fit a savings-goal tracker and tell me which actually need a key.' It will list them; you pick.
About paying for the AI parts
- 1Building the tool with Claude Code is covered by your Claude plan (Pro, Max, Team or Enterprise) within its usage limits.
- 2If the finished tool itself should call Claude (for example to write texts for you), it needs its own API key from the Claude Console, and that use is paid separately, per use.
- 3Prices change; check claude.com/pricing before you plan anything that runs often.
A tool gets superpowers when it can talk to other services — send you a message, read a sheet, pull live data. Each service hands out an 'API key' (a long password that says 'this is me'). For THIS tool, the useful ones are:
Which keys this tool can use
- 1Telegram — nudge you on payday to log this month's deposit
Getting a key works the same almost everywhere: log into the service → Settings → 'API' or 'Developers' → 'Create key' → copy it. Then ask Claude: 'create a .env file with an empty spot for this key and check that .env is in .gitignore', and paste the key into that file yourself. Do not type the key into the chat.
Step 4 — Put it online (only if someone else needs it)
Just for you, on your computer? You're already done — skip this step with a clear conscience. Put it online only if someone ELSE should open it, or you want to reach it from your phone away from home.
Step 6 — Stay safe (two easy habits)
- 1Back up anything you'd hate to lose. If the tool holds real data (your budget, health log, client list), ask Claude early: 'add an export/backup button' — one click saves your data to a file. Do it before you ever rebuild from scratch or move the folder.
- 2Don't hand Claude the keys to dangerous rooms. Keep it pointed at this project's own folder. Never connect a learning project to your bank, your crypto, or anything irreversible. Receipts and calendars — yes. Savings — no.
- 3Think before you ask. Claude does what you say in the folder you're in. 'Optimize my photos' optimizes them; it won't delete them — unless you ask for something reckless. Sane requests, clean workspace, and there's simply nothing scary left.
The mistakes that stop most people
- 1Asking for something vague ('make me an app') and getting something vague back. Name the screens, the buttons, what gets saved.
- 2Cramming in ten features at once. Ask for the tiniest working version first — then grow it with follow-up requests.
- 3Stopping at the first error. An error isn't failure — paste it to Claude or describe what you see, and it fixes it. That loop IS the work.
- 4Deciding you need to 'learn programming first'. You don't need to understand the code Claude writes. You need to describe the result.
- 5Not saying what 'done' means. End the request with how you will check it, for example 'done when I can add an item and it is still there after I reload the page'.
- 6Building for an imaginary audience. Build the version YOU will open tomorrow. Polish never; use immediately.
Normal. Tell Claude what's wrong in plain words ('the button does nothing', 'the page is blank') or paste the red error text. It finds and fixes it. You check. Repeat until it works.
That's it. You built a real tool.
You described the tool in words, Claude built it, and you checked it yourself. That is the whole loop, and it works the same for bigger tools.
More to build