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Original: Lenny Rachitsky · 09/02/2026

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Summary

CJ demonstrates his custom-built tool, Flowy, that transforms Claude’s ASCII diagrams into interactive visual mockups and flowcharts. 1. How CJ built Flowy, a custom visual planning tool that converts JSON files into interactive mockups and flowcharts 2. Why visual planning tools are more effective than ASCII diagrams for complex UI and animation workflows 3. How to create and use Claude Code skills to extend your development envi

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Key Insights

“CJ demonstrates his custom-built tool, Flowy, that transforms Claude’s ASCII diagrams into interactive visual mockups and flowcharts.” — Introduction to Flowy, a tool for converting ASCII diagrams to visual formats.
“Using model-to-model comparison (Claude + Codex) to improve code quality.” — Discussing the process of enhancing code quality through AI model comparisons.

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Topics

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Full Article

CJ Hess is a software engineer at Tenex who has built some of the most useful tools and workflows for being a “real AI engineer.” In this episode, CJ demonstrates his custom-built tool, Flowy, that transforms Claude’s ASCII diagrams into interactive visual mockups and flowcharts. He also shares his process for using model-to-model comparison to ensure that his AI-generated code is high-quality, and why he believes we’re just at the beginning of a revolution in how developers interact with AI. Listen or watch on YouTube, Spotify, or Apple Podcasts

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What you’ll learn:

  1. How CJ built Flowy, a custom visual planning tool that converts JSON files into interactive mockups and flowcharts
  2. Why visual planning tools are more effective than ASCII diagrams for complex UI and animation workflows
  3. How to create and use Claude Code skills to extend your development environment
  4. Using model-to-model comparison (Claude + Codex) to improve code quality
  5. How to build your own ecosystem of tools around Claude Code
  6. The value of bypassing permissions in controlled environments to speed up development

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Brought to you by:

[![](https://substackcdn.com/image/fetch/$s_!ZZHS!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F651feca4-c1c3-40cd-8def-e96fb69444d8_1028x210.png)](https://substackcdn.com/image/fetch/$s_!ZZHS!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F651feca4-c1c3-40cd-8def-e96fb69444d8_1028x210.png)
Orkes—The enterprise platform for reliable applications and agentic workflows Rovo—AI that knows your business

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In this episode, we cover:

(00:00) Introduction to CJ Hess (02:48) Why CJ prefers Claude Code for development (04:46) The evolution of developer environments with AI (06:50) Planning workflows and the limitations of ASCII diagrams (08:23) Introduction to Flowy, CJ’s custom visualization tool (11:54) How Flowy compares to mermaid diagrams (15:25) Demo: Using Flowy (19:30) Examining Flowy’s skill structure (23:27) Reviewing the generated flowcharts and diagrams (28:34) The cognitive benefits of visual planning vs. text-based planning (31:38) Generating UI mockups with Flowy (33:30) Building the feature directly from flowcharts and mockups (35:40) Quick recap (36:51) Using model-to-model review with Codex (Carl) (41:52) The benefits of using AI for code review (45:13) Lightning round and final thoughts

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Tools referenced:

• Claude Code: • Claude Opus 4.5: • Cursor: • Obsidian: • GPT-5.2 Codex: • Google’s Project Genie:

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Other references:

• Mermaid diagrams: • Figma: • Excalidraw: • TypeScript:

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Where to find CJ Hess:

LinkedIn: 

X:

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Where to find Claire Vo:

ChatPRD: 

Website: 

LinkedIn: 

X:
Production and marketing by . For inquiries about sponsoring the podcast, email jordan@penname.co.

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Originally published at https://www.lennysnewsletter.com/p/how-to-build-your-own-ai-developer.