Mermaid to Unicode box art (grok-mermaid)
Simon Willison · Simon Willison · 2026-07-16
Simon Willison compiled a Rust-based Mermaid diagram renderer found inside xAI's open-sourced Grok CLI codebase into a browser-runnable WebAssembly tool.
Appears in
Extraction
Topics: webassemblymermaid-diagramsgrok-clirustdeveloper-tools
Claims
- The Grok CLI codebase contains a self-contained Rust terminal renderer for Mermaid diagrams that uses Unicode box-drawing characters.
- Willison compiled the Rust renderer to WebAssembly to make it runnable in a browser.
- The resulting tool was built using Claude Code for web (Fable 5).
Key quotes
xai-grok-markdown/src/mermaid.rs is a 'self-contained terminal renderer for Mermaid diagrams' written in Rust.
I figured it would be fun to try that out in a browser via WebAssembly.