HomeCasa Lean Canvas for your idea with the riskiest assumptions ranked
Fill in all 9 Lean Canvas boxes while separating facts from assumptions, rank the 5 riskiest assumptions and design the cheapest experiment to test each one. Designed for ChatGPT, Claude, Gemini and Microsoft Copilot. It includes 4 customizable variables and you can copy it for free in one click.
Intermediate · Text · Pending editorial review
Prompt
Act as a startup mentor who knows Lean Startup and the Lean Canvas inside out. Your job is to separate what I know from what I am assuming.
My idea:
- Idea or product: {{idea}}
- Customer segment: {{segment}}
- How they solve the problem today (alternatives): {{alternatives}}
- Stage: {{stage}}
If a box cannot be filled from what I gave you, ask me first instead of guessing.
Deliverables:
1. A complete Lean Canvas in a table with the 9 boxes: problem (top 3), customer segments and early adopters, unique value proposition, solution, channels, revenue streams, cost structure, key metrics and unfair advantage. Keep each box to 1-3 lines.
2. Tag every statement as [FACT] (checked with customers or data) or [ASSUMPTION]. If I have no unfair advantage yet, say so; do not invent one.
3. A one-sentence high-level concept (an "X for Y" line).
4. The 5 riskiest assumptions, ranked by impact × uncertainty, explaining why each would sink the business if false.
5. For each assumption: the cheapest, fastest experiment (interviews, waitlist landing page, pre-sale, manual "Wizard of Oz" test), the metric and the success threshold set in advance, and the timeframe.
6. Which canvas box you would change first if the experiment fails.
Constraints:
- Do not invent market data or results. Use [FILL IN] where information is missing.
- Concrete language: no "innovative solutions" or "synergies".
Format: a table for the canvas and a table for the assumptions (assumption, risk, experiment, metric, threshold, timeframe).How to use it
- Describe the idea and how your customers solve the problem today. 2. Check which statements get tagged [ASSUMPTION]. 3. Run the experiment for assumption number 1 first, then update the canvas with what you learn.
Usage example
Idea: app for families at the same school to share trusted babysitters · Segment: parents of kids aged 3-10 · Alternatives: group chats and grandparents · Stage: idea.
Sample output
Lean Canvas (excerpt)
| Box | Content |
|---|---|
| Problem | 1. Buying a tool to use it once [ASSUMPTION] 2. Borrowing creates awkward favors [ASSUMPTION] 3. Hardware store rentals are limited and far away [ASSUMPTION] |
| Customer segments | Homeowners doing occasional DIY; early adopters: people who just moved in [ASSUMPTION] |
| Unique value proposition | The tool you need, two doors down, by the hour [ASSUMPTION] |
| Revenue streams | Commission per rental: [FILL IN]% |
| Unfair advantage | None yet. |
High-level concept: "Airbnb for power drills, for your block."
Riskiest assumptions
| Assumption | Risk | Experiment | Metric | Threshold | Timeframe |
|---|---|---|---|---|---|
| Neighbors want to rent out their tools | No supply, no platform | 15 interviews with tool owners | % willing to list | ≥ 40% | 2 weeks |
| People will pay for a one-off rental | No revenue | Waitlist landing page with prices | Sign-ups with price shown | ≥ 50 in one neighborhood | 3 weeks |
| Trust between strangers is enough | Nobody hands over a tool | Wizard of Oz: 5 rentals handled manually | Rentals completed with no issues | 4 of 5 | 4 weeks |
If the first experiment fails: revisit Customer segments before touching the Solution…
Key facts
- Category
- Business & entrepreneurship · Business models
- Output type
- Text
- Level
- Intermediate
- Designed for
- ChatGPT, Claude, Gemini and Microsoft Copilot
- Verified in
- Pending editorial verification
- Variables
- Idea or product, Customer segment, Current alternatives and Stage
- Language
- English
- Price
- Free, no sign-up
- Updated
- Nov 7, 2026
Frequently asked questions
How is a Lean Canvas different from a Business Model Canvas?
The Lean Canvas swaps boxes such as key partners for problem, solution, key metrics and unfair advantage. It is built for new ideas with high uncertainty, while the Business Model Canvas suits businesses that already work.
Why set the success threshold before the experiment?
If you decide afterwards what counts as success, you will tend to justify any result. A threshold set in advance, such as "10 of 50 visitors leave their email", keeps you honest.
What is this prompt for?
Fill in all 9 Lean Canvas boxes while separating facts from assumptions, rank the 5 riskiest assumptions and design the cheapest experiment to test each one.
Which AI tools does it work with?
It is designed for ChatGPT, Claude, Gemini and Microsoft Copilot. We have not verified it in these tools yet, so results may vary between them.
How do I customize the prompt?
Click “Customize” and fill in the variables (Idea or product, Customer segment, Current alternatives and Stage). The text updates instantly and you can then copy it in one click. Values are stored only in your browser.
Do I need experience to use it?
It is intermediate: it helps to know the topic so you can provide good context and review the result critically.
Is this prompt free?
Yes. Every HomeCasa Prompts prompt is free, with no sign-up or subscription. You can also use them in professional projects.
Can I trust the AI output?
Treat it as a high-quality draft: always check data, figures and important claims before publishing or making decisions.