Grok Build Explained: What xAI's Coding Agent Actually Does

Grok Build is xAI's terminal-based coding agent. It reads your repository, plans a change, and edits files directly from the command line.

xAI opened it in early beta on May 25, 2026 to all SuperGrok and X Premium+ subscribers, after an earlier limited rollout. It now runs on Grok 4.6 by default and shipped with its own coding-specific model, Grok Build 0.1.

This guide covers what Grok Build does, how its subagent and Plan Mode system works, what model runs underneath it, and who it fits. For setup steps, see our how to use Grok Build guide.

What Is Grok Build?

Grok Build is a terminal-native AI coding agent built by xAI, the company behind Grok. It works as an interactive fullscreen terminal UI with mouse support, a headless mode for scripts and bots, and an Agent Client Protocol (ACP) integration for other apps.

The tool targets developers who want an agent to handle whole coding tasks instead of an autocomplete-style assistant. It reads a codebase, proposes a plan, then edits files, runs commands, and reports back.

It works with any codebase and any language, and it picks up a project's existing AGENTS.md file, plugins, hooks, skills, and MCP servers rather than requiring a new config format.

• Runs as a fullscreen terminal UI, in headless scripts, or via ACP inside other apps.
• Reads and edits files directly in your working repository.
• Reuses existing AGENTS.md, plugins, hooks, skills, and MCP server config.
• Works with any codebase or language.

How Grok Build's Subagents and Plan Mode Work

Grok Build can run up to eight parallel subagents on one task, each with its own context window and its own Git worktree. The process runs in three stages: plan, search, and build.

Plan Mode asks the agent to lay out its intended changes before it touches any files, and a developer approves the plan before execution starts. That approval step is what keeps a multi-file, multi-agent run reviewable instead of a black box.

Because each subagent works in its own worktree, several agents can research, build, and review different parts of a task at the same time without stepping on each other's file changes.

• Up to 8 parallel subagents per run, each in its own Git worktree.
• Three-stage loop: plan, search, build.
• Plan Mode requires approval before the agent starts editing files.
• Headless mode (-p flag) runs the same loop inside scripts and CI.

What Model Powers Grok Build?

Grok Build launched paired with a dedicated coding model, Grok Build 0.1, released on the xAI API on May 29, 2026 as a coding-focused model for agentic tasks like web development, debugging, and MCP-based tool calling.

xAI has since moved the CLI to run on Grok 4.6 by default, and the tool also supports custom models through a local config.toml file, checked with the grok inspect command.

Full pricing for the underlying API model, and how it compares to running the CLI on a SuperGrok subscription, is on our dedicated Grok Build pricing page.

Is Grok Build Open Source?

Yes. xAI open-sourced Grok Build on July 15, 2026, publishing the CLI's source on GitHub.

The release covers the agent loop, the file-editing tools, the terminal UI, and the extension system for skills, plugins, hooks, and MCP servers, so developers can see exactly how each piece is loaded and invoked.

Open-sourcing it also unlocked a fully local-first setup: developers can compile the CLI themselves, point it at their own local inference server, and configure everything through config.toml instead of xAI's hosted API.

Who Grok Build Is For

Grok Build fits developers already paying for SuperGrok or X Premium+ who want a terminal agent instead of switching to a separate paid tool. Its parallel-subagent model also suits larger repositories where several independent changes can run at once.

When we evaluate a new agentic coding tool for our own routine-automation portfolio, two things matter most: a reliable headless mode for unattended runs, and real workspace isolation so parallel agents cannot collide. Grok Build ships both from the beta, with the -p flag and per-subagent worktrees covering that bar.

It is a weaker fit for teams that need a polished GUI editor rather than a terminal-first workflow, or for anyone not already on a SuperGrok or X Premium+ plan and unwilling to add one. See our Grok Build vs Claude Code and Grok Build vs Cursor comparisons for the closest alternatives.

How to use Grok Build

You do not host Grok yourself — you use it through a tool, so "getting started" really means choosing the right one.

The fastest way to put Grok Build to work day to day is inside an AI IDE, and Cursor is the most popular — it supports it directly, so you can be working in minutes. Prefer a different editor? Windsurf, Zed, and GitHub Copilot drive these models too.