Check the idea first

⏱ 20 min6 steps

This one runs in , in . If you'd rather stay in the , see Vet the idea in an hour.

At some point you'll want to chase every idea you have. Don't. Building is now so fast that the real risk is spending months on something nobody wants. Learning is never wasted, but your hours are worth more than "well, at least I learned something."

I learned this the expensive way. I started projects, bought domains and canceled them before they launched. The checks in this piece exist because I skipped them.

Pick one idea and check it. If Claude's search comes up empty, that's normal.

Claude Code Claude, working inside Terminal. It can make files and run things on your Mac, with a safety checker watching what it does. All wordsTerminal An app on your Mac where you type instructions instead of clicking on things. Claude Code works inside it. All wordsClaude app Claude on your phone or computer, where you chat with it by typing. claude.ai is the same thing in a web browser. All words

Before this, you'll want:

Your first real conversation with Claude

Steps

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Steps for

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Name who has the problem, as narrowly as you can
Your idea can be a side business, a tool, a website. Now name who has the problem it solves, as narrowly as you can: "restaurant owners with 2 to 5 locations," not "businesses." "Parents planning a kid's first birthday party," not "parents."
1. Write down who has the problem, in one line.
2. Check it: if you could find five of them this week, it's narrow enough.
That's not what I see
My idea is for everyone.
Everyone is nobody you can find. Pick the one kind of person who'd want it most, the one you could text today. You can widen it later.
Make a folder for your idea and go into it
Your idea gets its own in your , called my-idea. The next few pieces use it too.
1. Open Terminal (Cmd+SpaceWindows key, type Terminal, press Enter).
2. Make the folder. Type this and press Enter:
  mkdir ~/Backyard/my-idea
  mkdir ~\Backyard\my-idea
3. Go into it. Type this and press Enter:
  cd ~/Backyard/my-idea
  cd ~\Backyard\my-idea
folder A place on your computer that holds files and other folders, like a drawer in a filing cabinet. All wordsBackyard The folder right inside your home folder where everything you build in these lessons lives. All words
You should see:
The now says my-idea, right before the %>.
prompt line The line in Terminal that ends with a % sign. The word right before the % is the folder you're in. All words
That's not what I see
It says "cd: no such file or directoryCannot find path … because it does not exist".
The folder wasn't made, or the name was spelled differently. Type ~/Backyard/my-idea~\Backyard\my-idea and press Enter, then ~/Backyard/my-idea~\Backyard\my-idea and press Enter.mkdir The command that makes a new folder. Type mkdir, a space and the new folder's name. It's short for make directory. All wordscd The command that moves Terminal into a folder. Type cd, a space and the folder's name. It's short for change directory, an old word for folder. All words
Start Claude Code and let it into the folder
1. Type this and press Enter:
  claude
2. If Claude Code shows "Quick safety check", check that the folder under Accessing workspace ends in my-idea. It shows this the first time in a new folder.
3. Press the down arrow to Yes, I trust this folder, then press Enter.
You should see:
Claude Code's name and version at the top, a line starting with ❯ where you type, and ⏵⏵ on in the bar at the bottom.
auto mode Claude works without asking, and a separate safety checker blocks anything risky. All words
That's not what I see
It says "zsh: command not found: claudeThe term 'claude' is not recognized".
This Terminal window doesn't know about Claude Code. Close the window with Cmd+WCtrl+Shift+W, open a new one and try again. If it still says that, go back to Claude Code and .install Put a new program on your computer so you can use it. All wordssign in Tell Claude Code which Claude account is yours, so it knows you've paid for it. All words
The folder it asked me to trust doesn't end in my-idea.
Choose No, exit. Type cd ~/Backyard/my-idea~\Backyard\my-idea, press Enter, check the prompt line says my-idea, then type claude again.
Ask Claude to look for what would kill the idea
This asks Claude to look for the one thing that would sink your idea, find where your people gather and what they pay for now, and save it all in a . Your idea and your people go at the end.
1. Copy the prompt below.
```
Before I build anything, help me find out whether this problem is real. 1. Tell me, honestly, the single assumption that would kill this idea if it's wrong. 2. Find where these people already gather online: specific groups, subreddits, forums, associations. Link each one. 3. Find what they use or pay for today to solve this. Name real products and their prices, with links. Say plainly if you couldn't find any. 4. Write 5 questions I can ask real people about their life, not my idea. No "would you use this?" 5. Suggest the smallest test that answers whether this is worth building, and the result that means I stop. Label everything you looked up with its source, and mark your own opinions as "my take". Save all of it in a file called idea-check.txt in this folder. Don't build anything. Here's my idea in one sentence, and who has the problem:
```
1. Paste it into Claude Code with Cmd+VCtrl+V.
2. Type a space, then your idea in one sentence and who has the problem, like a meal-prep service, for nurses who work night shifts.
3. Press Enter.
Read the first answer most carefully: the one that would kill the idea. That's the thing to find out first.
prompt What you type to Claude. A good one says what you want, how to work and what never to do. All wordsfile One document on your computer, like a letter or a photo. Files live inside folders. All wordsassumption Something you're counting on being true without having checked it yet. All words
You should see:
Lines with while Claude looks things up. Then it saves idea-check.txt and tells you what it found.
web search Claude looking things up on the internet during a chat. Its answer comes with links to the pages it used. All words
That's not what I see
Claude says it can't search the web.
It may ask permission to look things up first. Read what it wants to do and choose Yes. If it still can't, do this step in the Claude app instead, and paste the answer into a file yourself.
A link Claude gave me doesn't work, or goes somewhere else.
Links can be wrong. Tell Claude which one didn't work and ask it to check again. Never count on a link you haven't opened yourself.
It found a product that already does my idea.
That's good news, not bad. It means people pay to fix this. Ask Claude: What do people complain about in that product? That's where you'd fit.
Plan your five conversations
"Would you use this?" gets a polite yes that means nothing. Ask about what they actually do:
- When did this last happen to you? What did you do about it?
- What does it cost you, in time, money or headaches?
- What have you already tried? Are you paying for anything now?
If nobody has tried to fix it or spent anything on it, it may not be a real problem.

This prompt has Claude draft a short message asking people for ten minutes.
1. Copy the prompt below.
```
Draft a short, friendly message I can send to people in the groups you found, asking for 10 minutes of their time to hear about how they deal with this problem today. Make it clear I'm not selling anything. Keep it under 60 words.
```
1. Paste it into Claude Code with Cmd+VCtrl+V and press Enter.
You should see:
Claude writes a short message you could send, under 60 words.
That's not what I see
I don't want to bother strangers.
Start with people you already know who have the problem. Most people like being asked about their own life. If nobody will talk to you about it, that tells you something too.
Decide the smallest test and when you'd stop
Pick one question you want answered, like "will 5 people pay $20 for this?" Then build the smallest thing that answers it. That could be a one-page website, a sign-up form or a spreadsheet you run by hand. Like a lemonade stand before you open a café.

Decide before you start what result means you stop. Then set a time and money budget for this idea. When you hit it, stop and decide on purpose whether to keep going.

This prompt has Claude write all of that at the bottom of idea-check.txt, in your words.
1. Copy the prompt below.
```
Add a section called My test to the bottom of idea-check.txt. Write down what I tell you, in my words: the question I want answered, the smallest test, the result that means I stop, and my time and money budget. Here they are:
```
1. Paste it into Claude Code with Cmd+VCtrl+V.
2. Type a space, then your question, your test, the result that means stop, and your budget, separated by commas.
3. Press Enter.
You should see:
Claude adds a My test section to the bottom of idea-check.txt and tells you it did.
That's not what I see
I don't know what result should mean stop.
Pick a number before you start, like "if fewer than 5 of 20 people sign up in a month, I stop." Writing it down first keeps you honest later.

Your challenge

Talk to five real people who have the problem before you build anything. Ask them the questions from Plan your five conversations, not "would you use this?" Write down what each one says in idea-check.txt.

Last checked 2026-10-17

Build something new › 2. Plan it, in Claude Code