Simon Willison (@simonwillison.net): I poked around in the just open sourced Grok Build CLI tool - 844,000 lines of Rust code! - and dug up a few interesting highlights, including a "self-contained terminal renderer for Mermaid diagrams"
Provides deep technical insight into xAI's coding agent architecture and implementation details for developers building similar tools.
AI Summary
xAI has open-sourced their Grok Build CLI tool after facing backlash over privacy concerns, revealing 844,000 lines of Rust code including interesting components like a terminal-based Mermaid diagram renderer and various coding agent tool implementations. The release appears to be an attempt to regain user trust following data upload issues. The codebase includes system prompts and tool implementations similar to other coding agents.
Excerpt
I poked around in the just open sourced Grok Build CLI tool - 844,000 lines of Rust code! - and dug up a few interesting highlights, including a "self-contained terminal renderer for Mermaid diagrams" that renders them using Unicode box-art! simonwillison.net/2026/Jul/15/...
