ChatGPT Can't Validate Your Startup Idea. This Can.
Stop guessing if your idea is good. Let 9,300 Reddit posts tell you.
NotebookLM was the tool to summarize documents and create podcasts.
Useful. But limited.
Then, before Christmas 2025, everything changed.
First, Google connected NotebookLM to Gemini. ([I wrote about it here.])
But what they did next changed everything.
They let you connect NotebookLM to Gemini Gems.
300 sources. One custom AI assistant. Permanent memory.
No re-uploading. No copy-pasting context. No explaining your business in every chat.
Your Gem just knows.
I built a Startup Idea Validator with this. Let me show you.
What We’re Building?
A custom Gemini Gem that validates startup ideas using real market data.
Not generic AI advice. Not “have you considered your target market?” fluff.
Real validation from:
Reddit threads where people complain about problems
Competitor product reviews (what’s missing?)
Industry reports and market research
Y Combinator videos on what works
You ask: “Is there a gap for an AI tool that helps freelancers track expenses?”
It answers based on 300 sources of real market evidence.
Fast-forward to what it looks like.
9,300 startup ideas.
Captured from real people complaining about real problems.
How many are already solved? How many are tar pits? How many are gold?
You don’t need to read them. Your AI already did.
Now you just ask:
“Is there a gap for an AI tool that helps freelancers track expenses?”
And it searches 9,300 posts to give you the verdict.
The backend = Gemini Gems + NotebookLM + Well Crafted Prompt.
That’s it.
What is Gemini Gems?
Custom AI assistants inside Google Gemini.
You give them:
A name (e.g., “Startup Validator”)
A role
Instruction
Knowledge
They remember their role in every conversation.
ChatGPT Custom GPTs, but with Google’s infrastructure.
To be able to create one of them:
Visit here.
Add “Name”, “Description” to it.
In the instructions, put the prompt you want.
Default tools:
A new Gem chat starts with its default tool, but you can change it anytime.
Knowledge
Now this has changed. Now you can add NotebookLM as a source.
What is NotebookLM?
NotebookLM is Google’s AI tool to learn anything.
You can upload up to 300 sources.
YT Videos, PDF’s, google docs are options of these sources.
Recently, you can even do a deep search and add your results as a source. Read this one for more information.
But at Christmas, the Google team announced a new feature, so now you can connect Gemini with NotebookLM and build apps with it.
Read this one for more information.
The Stack
NotebookLM: Your knowledge base
Gemini Gems: Your custom AI assistant
Reddit/Quora threads: Real user pain points
YouTube videos: Startup advice, market insights
Competitor reviews: What’s missing in existing solutions
You don’t need to code anything.
You don’t need API keys.
You just upload, connect, and use.
LearnAIWithMe Paid Perks
The standard subscription ($12/mo or $100/year) gives you full access to all my articles and posts on Substack
The Founding Member tier ($200/year) includes everything above PLUS access to The Vault, 700+ prompts, projects, AI tools, and AI labs.