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Claude Mythos Just Cloned a $10B App in 2 Prompts (Fable 5)
⏱ 16 min video · 2 min read10 Jun 2026
TL;DR
The creator demos Claude claude-sonnet-4 (referred to in the video as 'Fable 5'/'Mythos') building a fully functional Notion clone as a macOS desktop Electron app using just two prompts in 45 minutes. The video argues that AI coding capability is now so advanced that the real competitive skill has shifted entirely to idea selection, design taste, and distribution.
Key points
1
Claude claude-sonnet-4 (called 'Fable 5' in the video, Anthropic's latest model) cloned Notion — a $10B app — in two prompts and 45 minutes using Claude Code inside the Claude desktop app
2
The resulting app includes rich text editing, emoji picker, database views (board, gallery, table), filtering, sorting, dark/light mode, favorites, trash, and a Convex backend — all without a spec or PRD
3
Free access to Claude claude-sonnet-4 on Claude subscriptions was ending June 22 (2026 context: this date has passed), after which usage would switch to more expensive API billing
4
The creator recommends using cheaper models like Claude Opus to draft a solid spec and validate your idea before spending heavily on Claude claude-sonnet-4 to build
5
The creator argues the hard part of software is now idea validation, distribution, and design — not building — and that demand for custom software will increase massively as a result
Actionable insights
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Use Claude Code inside the Claude desktop app with Claude claude-sonnet-4 Max for complex app builds — it thinks deeply before coding and produces production-quality results from minimal prompts
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Before burning expensive Claude claude-sonnet-4 credits, use a cheaper model like Claude Opus to fully spec out and validate your idea first, then hand the spec to Claude claude-sonnet-4 to build
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Shift your focus from 'can I build this' to 'should I build this' — use Convex for the database layer in desktop or web apps as Claude claude-sonnet-4 integrates it well out of the box
Notable quotes
“The difficult part now is choosing the right thing to build, choosing the right idea, and then finding people who want to use it. Distribution, taste, design, and the quality of your idea. These are the three things that are key.”
“Two prompts, 45 minutes. The difficult part now is choosing the right thing to build.”
“I don't want to overhype this, but this is like a big deal when it comes to AI models and the capability.”
Worth watching?
⏭️
Worth watching the full video?
Skip the video — the key demo details and strategic takeaways are fully captured here. Watch only if you want to see the live screen walkthrough of the Notion clone UI to judge the quality yourself.
Saved you some time? The creator still deserves a like.
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