Summary
Brian Casel, a product developer with 20 years of experience, introduces Flywrite — a markdown-first writing application he built to solve a specific gap in the AI writing workflow. As Casel explains it, terminal-based AI agents like Claude Code and Codex CLI live inside coding environments like VS Code and Cursor, which are feature-rich for code but hostile to prose writing. Meanwhile, dedicated writing apps like Obsidian, Bear, and Notion offer comfortable markdown environments but have no real agent integration. Flywrite bridges the two: a full-featured markdown editor with a built-in terminal, purpose-built for the human-AI writing loop.
The demo walks through the core editing experience — rendered markdown with inline formatting, a source-only mode, customizable fonts and colors per-project, and a command palette — alongside the integrated terminal where Claude Code or any other CLI agent can be invoked against the current file. Version control is handled via automatic git-backed checkpoints with optional GitHub sync, making cross-device project management straightforward without requiring git knowledge.
Casel positions Flywrite around a specific workflow rhythm: write a draft by hand, hand it to Claude Code to restructure or extend, return to hand-edit, repeat. He notes that for him the markdown file is the deliverable — the thinking itself — not just an implementation artifact, which is why a coding IDE feels wrong as a writing environment. The app is available with a discount for YouTube subscribers, and Casel uses it weekly to produce his Builder Briefing newsletter at buildermethods.com.
📺 Source: Brian Casel · Published July 23, 2026
🏷️ Format: Showcase
