Build me anything: from idea to working app with Claude

Use this first, when the idea is still a few words in your head.

I want to build something but my idea is rough. Here it is: [YOUR IDEA IN A FEW SENTENCES]. My experience: [FOR EXAMPLE: I HAVE NEVER WRITTEN CODE, OR I HAVE MADE A SIMPLE WEBSITE BEFORE]. Help me shape it: 1. Ask me up to 8 questions, one at a time, about who will use it, what problem it solves, and what it must do on day one. 2. Then write a one paragraph description of the idea in plain English. 3. List the 3 to 5 things the first version must do. Keep this list small. 4. List the things to leave for later. 5. Tell me honestly if this is too big for a beginner's first build, and suggest a smaller starting point if it is.

Swap the highlighted parts for your own words.

Tip

• Start small. You can add more once the first version works.

Use this after prompt 1, before you write any code.

Using the description and the must do list above, recommend the simplest way for a beginner to build the first version. Tell me: 1. What kind of thing it is: a web page, a web app, a phone app, a spreadsheet tool, an automation or something else. 2. The tools and languages you recommend, and why they suit a beginner. 3. Anything that will cost money, with rough monthly costs. Say clearly if it can be done for free. 4. Accounts I would need to create. 5. The hardest part of the build, explained in plain words. If a no code tool would do the job better than writing code, tell me.

Tip

• Ask "what would change if I wanted this on my phone?" if that matters to you.

Use this as your first prompt in Claude Code, inside your new project folder.

I want to build [ONE SENTENCE DESCRIPTION OF YOUR IDEA]. I am a beginner, so explain any technical term the first time you use it. Interview me in detail before you write any code. Ask one question at a time. Ask about what it should do, what the screens look like, what happens when something goes wrong, and choices I might not have thought about. Skip obvious questions and focus on the hard parts. Keep interviewing until we have covered everything. Then write a complete spec to SPEC.md. The spec should list what the first version does, what is out of scope, and how we will check that it works from start to finish. Do not start building yet.

Swap the highlighted parts for your own words.

Tips

• A spec is a written description of exactly what you're building. With one, Claude doesn't have to guess.
• Paste in your description from prompt 1 to give Claude a head start.
• After the spec is written, type /clear to start fresh. Claude can read SPEC.md in the new session.

Use this after the spec exists. Switch Claude Code into plan mode first.

Read SPEC.md. Make a step by step plan to build it. Rules for the plan: 1. Break the work into small steps. Each step should add one thing I can see or test. 2. For each step, write how we will check it worked, such as a test that passes, a command that runs, or something I can see in the browser. 3. Put the steps in an order where the project works after every step. 4. Start with the simplest thing that runs, even if it does almost nothing. 5. Keep the solution simple. Do not add features or extra setup that the spec does not ask for. Save the plan to PLAN.md with a checkbox next to each step.

Tips

• Plan mode lets Claude research and write a plan without changing your files. Press Shift+Tab until the bottom of the screen says "plan mode on", or start your message with /plan.
• Read the plan. If a step confuses you, ask about it before you approve.

Use this for each step in the plan, one at a time.

Build the next unchecked step in PLAN.md. Only that step. When you finish: 1. Run the check written for that step and show me the result, such as the test output or the command and what it printed. 2. If the check fails, fix the cause and run it again. Keep going until it passes. 3. Tell me in two or three plain sentences what you changed and why. 4. Tick the step in PLAN.md. Then stop and wait for me before the next step.

Tips

• Stopping after each step gives you a chance to look and correct course early.
• To stop Claude in the middle of something, press Esc. Your chat is kept, so you can redirect it.

Use this whenever you want to try the thing yourself.

Show me how to run what we have built so far and see it working. Give me the exact steps, one at a time. Tell me what I should see at each step. If it needs a command, run it for me and tell me what to open, such as the address to type into my browser. Then give me 3 things to try that would show whether the latest step really works, including one mistake a user might make, where the app should show a clear message and keep working.

Tip

• If something looks wrong, take a screenshot and paste it into Claude Code. It can read images.

Use this when you see an error message or something breaks.

Something is broken. Here is what I did and what happened: <problem> [WHAT YOU DID, WHAT YOU EXPECTED, AND WHAT HAPPENED. PASTE THE FULL ERROR MESSAGE.] </problem> Find the root cause before you change anything. Tell me in plain words what is wrong. Then fix the cause. Do not just hide the error. Run the check again to prove it is fixed, and show me the result. If the fix needs a bigger change than you expected, tell me first and wait.

Swap the highlighted parts for your own words.

Tips

• Copy the whole error, even if it is long. The useful line is often near the bottom.
• To undo, press Esc twice or type /rewind. You can go back to an earlier point in the chat, the files, or both.
• If you have corrected Claude twice on the same problem and it is still wrong, type /clear and start again with a clearer prompt that includes what you learned.

Use this when you want to understand your own project.

Explain the project to me as if I have never seen code before. 1. List the main files and say in one sentence what each one does. 2. Walk me through what happens, step by step, when someone uses the main feature. 3. Point out the one or two parts that are most likely to break later, and why. Use plain words. Explain any technical term the first time you use it.

Tip

• Ask follow up questions such as "what would I change to make the button blue?". It is a good way to learn.

Use this when every step in the plan is ticked.

Use a subagent to review the whole project against SPEC.md in a fresh context. Check that: 1. Every item the spec says the first version must do actually works. 2. The checks in PLAN.md all still pass. Run them and show me the output. 3. Nothing obvious is unsafe, such as passwords or secret keys written into the code. Report only gaps that break the spec or are unsafe. Leave out style preferences. Then fix the gaps one at a time and show me the checks passing after each fix.

Tip

• A subagent is a second Claude that works separately and reports back. It checks the work without the first Claude's assumptions.

Use this when the project works on your computer and you want others to use it.

I want to put this project online so other people can use it. 1. Tell me the 2 or 3 most beginner friendly ways to do this for this kind of project. For each one, say what it costs, including the free tier if there is one, and what account I need. 2. Recommend one. 3. Walk me through it one step at a time. Wait for me to say "done" before the next step. 4. Before any step that costs money, makes something public, or cannot be undone, stop and tell me plainly. At the end, give me the address where people can find it and tell me how to update it later.

Tips

• Never paste passwords or secret keys into a public place. Ask Claude where they should go if you are unsure.
• Check the hosting company's own pricing page before you sign up for a paid plan.

Use this at the end of a session, and again at the start of the next one.

We are stopping for today. Write a short PROGRESS.md file with: 1. What works now. 2. What we were in the middle of. 3. The next 3 steps from PLAN.md. 4. Anything odd or broken you noticed that we have not fixed. Next time, I will start a new session and say "Read SPEC.md, PLAN.md and PROGRESS.md, then tell me where we are." Make sure those files have what you would need.

Tip

• Starting each day with a fresh session and these three files keeps Claude focused.