AI in App Development: Tell it. Test it. Fix it. · St. Ann's

You don't need to be a coder to ship. You need to be the person who can tell AI what to build, test what it built, and fix what broke.

Every week, make one small thing a stranger can open. AI builds it; AI marks it.

Before you start

Open Claude in your phone browser for the two builds. ChatGPT or Gemini is fine for Exercise 3 and 4. Pair with your neighbour if a tool hits its limit or shows only code.

Who are you today?

The Monday checklist below changes with your year. Nothing is stored on this page.

Build 1 · attendance calculator · Claude

1The attendance calculator

Every student in this room has done the 75% sum by hand. You know the right answer, so you can tell when AI is wrong.

Speaker builds (2 min). Then you build the same, or swap: fee-split, GST for Amma's Meesho shop, bus vs metro, marks to pass.

Build prompt · one send · Claude

Build a one-page, phone-friendly web tool: an attendance calculator for St. Ann's 75% attendance rule. Inputs: classes held, classes attended. Output: how many more classes I can skip and stay at 75%, or how many I must attend to reach 75%. One file, nothing to install.

Hunt the odd input (4 min). One send. Then you type the failing input into your own preview.

Hunt prompt · one send

Write five inputs a student would actually type that could break this calculator. Run each one. Show which fails and why.

Fix only that (3 min). Fill in what broke. Screenshot: working + failing input + the one-line fix.

Fix prompt · one send

It breaks when [what broke]. Fix only that. Show me the exact line you changed. Then list two more inputs I should test before sharing.

Paper fallback: write the six-line spec for the calculator and three odd inputs. Take a photo. A QA interviewer accepts that.

You didn't type code. You told it, tested it, fixed it.

Live demo · watch · Claude

DAI builds a login that isn't one

It looks right. That's the problem. The tester is the job.

Build a one-page login form for a college fee portal. Username and password. Show "Welcome" on a correct login and "Wrong password" on a wrong one. One file, nothing to install.

Test prompt · one send

Try to log in with a blank password, with only a username, and with any random password. Tell me which one gets in and why. Then show me where in the page the password is checked.

Fix prompt · make it tell the truth

This is not a safe login. In plain words, tell me why a one-file page cannot check a password safely, and what a real login needs that this page does not have. Then change the page so it says "demo only, not a real login" at the top.

It looks right. That's the problem. Test it.

Build 2 · home business page · Claude

2A page for a real home business

Amma's tiffin, Aunty's mehendi, sister's bakery. A neighbour tapping Order is a stranger opening what you made.

Build prompt · fill [number] with +91… · Claude

Build a one-page, phone-friendly website for a home tiffin service in Mehdipatnam: name, three menu items with prices, a line about delivery times, and a big "Order on WhatsApp" button that opens a chat with [number] and a pre-filled message "I'd like to order". One file, nothing to install.

Room builds: same prompt, swap the business. Use your WhatsApp number or your neighbour's, with +91.

Tap share link. WhatsApp it to the student next to you.

She opens it and taps Order on WhatsApp. Hand up if the chat opens with "I'd like to order".

Find what breaks it (2 min). Fix only that.

Fix prompt · one send

It breaks when [what broke]. Fix only that. Tell me in one line what you changed. Then list two more things a customer might do that I should test before sharing.

Paper fallback: six-line spec for the page + three things a customer might do that would break it. Photo.

A stranger opened it. That's a project. Marks are not.

One-page note · ChatGPT / Gemini / Claude

NThe note a recruiter reads in 60 seconds

Paste into a Google Doc. Set sharing to anyone with the link. Put the site link at the top. (Developers call this a README. Said once.)

Note prompt · one send

I built a one-page site for [the business] with a WhatsApp order button. Write the one-page note a recruiter reads in 60 seconds: who it's for, what it does, what broke and how I fixed it, what I'd add next. Under 120 words. Add three tests to run before sharing.

Recruiters don't read CVs. They click links.

Exercise 3 · spec before the build

3Six lines on paper. Then one send.

The job starts one step earlier than a prompt: someone has to say what to build. Here you mark AI, not the other way round.

Six-line spec template

Who uses it: ___
What she types in: ___
What she gets out: ___
What must never happen: ___
Three odd inputs: ___ / ___ / ___
How I'll know it works: ___

Ideas: fees-due reminder · lab-slot booking · canteen pre-order · bus-late alert · library seat finder.

Exercise 3 prompt · paste your six lines at ___

Here is my 6-line spec for an app my college needs: ___. Turn it into a build prompt under 80 words for a one-page phone tool. Then list three things my spec forgot to say that a builder would have to guess.

Then on paper: tick the gaps that are real. Cross the padding. Do not build it now — that is Sunday's Build 3.

Say exactly what you want. That is the half of the job AI can't do.

Exercise 4 · get marked

4Don't ask AI for the answer. Ask it to mark yours.

Write three sentences on paper first: what it was, what broke, what you changed. Then one send. Rewrite v2 yourself. No second send.

Interviewer prompt · one send

You are an interviewer at TCS or a Gachibowli startup hiring freshers for a QA or junior developer role in Hyderabad. My answer to "tell me about something you built": ___. Score it 1–10. Name the one biggest weakness and one fix. Do not rewrite it for me.

CS-row homework (handout, not in the 7 minutes): "Here is my function: ___. Write three inputs that break it. Do not fix it. After I paste my fix, tell me which of the three it still fails; I will run them myself."

Don't ask AI for the answer. Ask it to mark yours.

After class

The Monday link

On your phone today: calculator screenshot with failing input · Build 2 share link · Doc with the one-page note · spec photo with ticks and crosses · marked answer (v1 → v2).

Pick your year above to see your checklist

Or read both: final years send to placement by Monday 9 AM; first years start a Proof folder and send Build 2 to one person tonight.

Plain words

Words we use today

Something a stranger can open: A link anyone can tap. Proof of work.
The preview: The box below the chat where the page appears.
The share link: Turns the preview into a link anyone can open.
Odd inputs: Zero, blank, negative, decimal, bigger than allowed, tapping twice.
The spec: Six lines before anyone builds.
The tester: The person who tries to break it on purpose.
The one-page note: Who it's for, what it does, what broke, what you'd add. (README.)
One send: One message to the AI per exercise.

Optional

Stay in touch

My WhatsApp group: AI Marketing Lab. One useful thing a week on using AI at work. Only admins post. Members can see your number and photo — set profile photo to contacts only if you prefer. Leave any time.

Join AI Marketing Lab on WhatsApp

Same group as other masterclasses this week. The name says marketing because that is where it started. The habit is the same for app building.

Optional · 6 questions

Quick check

Tap an answer. No scores stored.

AI in App DevelopmentTell it. Test it. Fix it.