xAI Open-Sources Grok Build: Full Harness of Terminal-Native Coding Agent Exposed

On July 15, 2026, xAI open-sourced the CLI, full-screen TUI and Rust agent runtime of Grok Build coding Agent under the Apache 2.0 license, and disclosed the complete harness implementations including context assembly, tool calling, Skills/Plugins/MCP extensions and so on. This article sorts out the repository architecture layering, extension system and local construction method, and explains the reasons why it has attracted attention as one of the GitHub AI trending repos in July, as well as how developers can make use of this source code.