grok

name	grok
description	Delegate coding to xAI Grok Build CLI (features, PRs).
version	0.1.0
author	Matt Maximo (MattMaximo), Fabric
license	MIT
platforms	["linux","macos","windows"]
metadata	{"fabric":{"tags":["Coding-Agent","Grok","xAI","Code-Review","Refactoring","Automation"],"related_skills":["codex","claude-code","fabric-agent"]}}

Grok Build CLI — Fabric Orchestration Guide

Delegate coding tasks to Grok Build (xAI's autonomous coding agent CLI, the grok command) via the Fabric terminal. Grok can read files, write code, run shell commands, spawn subagents, and manage git workflows. It runs three ways: an interactive TUI, headless (-p), and as an ACP agent over JSON-RPC.

This is the third sibling to codex and claude-code. The orchestration pattern is nearly identical — prefer headless -p for one-shots, use a PTY for interactive sessions.

When to use

• Building features
• Refactoring
• PR reviews
• Batch issue fixing
• Any task where you'd otherwise reach for Codex / Claude Code but want Grok

Prerequisites

• Install (preferred): npm install -g @xai-official/grok
  • The official installer curl -fsSL https://x.ai/cli/install.sh | bash also works, but the x.ai host is Cloudflare-walled in some environments. The npm path avoids that dependency entirely.
• Auth — SuperGrok / X Premium+ subscription (primary path):
  • Run grok login once → opens a browser for OAuth → token cached in ~/.grok/auth.json. This uses your SuperGrok or X Premium+ subscription (no per-token API billing).
  • Check sign-in state by looking for ~/.grok/auth.json, or run a cheap headless smoke test: grok --no-auto-update -p "Say ok."
  • In the TUI, /logout signs out and /login (or relaunching) signs back in.
• No git repo required — unlike Codex, Grok runs fine outside a git directory (good for scratch/throwaway tasks).
• Claude Code / AGENTS.md compatible with zero config — Grok auto-reads CLAUDE.md, .claude/ (skills, agents, MCPs, hooks, rules), and the AGENTS.md family. Existing project context just works.

API-key fallback (not the default for this user): Grok also supports setting the XAI_API_KEY environment variable for pay-as-you-go billing via api.x.ai. Only use this if grok login / SuperGrok auth is unavailable. The subscription path (grok login) is the intended setup here.

Two Orchestration Modes

Mode 1: Headless (-p) — Non-Interactive (PREFERRED)

Runs a one-shot task, prints the result, and exits. No PTY, no interactive dialogs to navigate. This is the cleanest integration path — the analog of claude -p and codex exec.

terminal(command="grok --no-auto-update -p 'Add a dark mode toggle to settings'", workdir="/path/to/project", timeout=180)

Always pass --no-auto-update in automation to skip background update checks.

When to use headless:

• One-shot coding tasks (fix a bug, add a feature, refactor)
• CI/CD automation and scripting
• Structured output parsing with --output-format json
• Any task that doesn't need multi-turn conversation

Mode 2: Interactive PTY — Multi-Turn TUI Sessions

The TUI is a fullscreen, mouse-interactive app. Drive it with pty=true. For robust monitoring/input use tmux (same pattern as the claude-code skill).

# Launch in a tmux session for capture-pane monitoring
terminal(command="tmux new-session -d -s grok-work -x 140 -y 40")
terminal(command="tmux send-keys -t grok-work 'cd /path/to/project && grok' Enter")

# Wait for startup, then send a task
terminal(command="sleep 5 && tmux send-keys -t grok-work 'Refactor the auth module to use JWT' Enter")

# Monitor progress
terminal(command="sleep 15 && tmux capture-pane -t grok-work -p -S -50")

# Exit when done
terminal(command="tmux send-keys -t grok-work '/quit' Enter && sleep 1 && tmux kill-session -t grok-work")

Tip for headless-but-inline output: if you want TUI-style output without the fullscreen alt-screen takeover (e.g. for cleaner logs), add --no-alt-screen. For pure automation, headless -p is still cleaner than the TUI.

Headless Deep Dive

Common Flags

Flag	Effect
-p, --single <PROMPT>	Send one prompt, run headless, exit
-m, --model <MODEL>	Choose a model
-s, --session-id <ID>	Create or resume a named headless session
-r, --resume <ID>	Resume an existing session
-c, --continue	Continue the most recent session in the current directory
--cwd <PATH>	Set the working directory
--output-format <FMT>	plain (default), json, or streaming-json
--always-approve	Auto-approve all tool executions (the --full-auto / --yolo equivalent)
--no-alt-screen	Run inline, no fullscreen TUI takeover
--no-auto-update	Skip background update checks (use in all automation)

Output Formats

• plain — human-readable text (default)
• json — one JSON object at the end of the run (parse the result cleanly)
• streaming-json — newline-delimited JSON events as they arrive

# Structured result for parsing
terminal(command="grok --no-auto-update -p 'List all TODO comments in src/' --output-format json", workdir="/project", timeout=120)

# Auto-approve for autonomous building
terminal(command="grok --no-auto-update --always-approve -p 'Refactor the database layer and run the tests'", workdir="/project", timeout=300)

Background Mode (Long Tasks)

# Start headless in background
terminal(command="grok --no-auto-update --always-approve -p 'Refactor the auth module'", workdir="/project", background=true, notify_on_complete=true)
# Returns session_id

# Monitor
process(action="poll", session_id="<id>")
process(action="log", session_id="<id>")

# Kill if needed
process(action="kill", session_id="<id>")

For an interactive (TUI) background session, use pty=true + tmux and monitor with tmux capture-pane, exactly like the claude-code / codex skills.

Session Continuation

# Start a named session
terminal(command="grok --no-auto-update -s refactor-db -p 'Start refactoring the database layer' --always-approve", workdir="/project", timeout=240)

# Resume it later
terminal(command="grok --no-auto-update -r refactor-db -p 'Now add connection pooling' --always-approve", workdir="/project", timeout=180)

# Or continue the most recent session in this directory
terminal(command="grok --no-auto-update -c -p 'What did you change last time?'", workdir="/project", timeout=60)

Read-Only Audit → Markdown Note Pattern

To have Grok review local artifacts and return a clean markdown note (for Obsidian or a repo) without mutating anything:

1. Prepare stable input files first with Fabric tools (read_file, write_file). Snapshot only the relevant context into a temp file rather than dumping raw paths.
2. Run Grok headless without --always-approve so it cannot auto-write, and demand markdown only, no preamble.
3. Save Grok's stdout straight into the destination note with write_file().

grok --no-auto-update -p "Read /tmp/current.md and /tmp/inventory.md. Produce markdown only, no preamble. Output a clean note titled 'Cleanup Review'." --output-format plain

Pitfall (same as Claude Code): for document rewrites, a loose "rewrite this" prompt may return a change summary instead of the full file. Instead: pipe the file in, and demand Return ONLY the full revised markdown document. No intro, no explanation, no code fences. Start immediately with '# Title'. Verify the first lines with read_file() before overwriting the destination.

PR Review Patterns

Quick Review (Headless)

terminal(command="cd /path/to/repo && git diff main...feature-branch | grok --no-auto-update -p 'Review this diff for bugs, security issues, and style problems. Be thorough.'", timeout=120)

Clone-to-temp Review (safe, no repo mutation)

terminal(command="REVIEW=$(mktemp -d) && git clone https://github.com/user/repo.git $REVIEW && cd $REVIEW && gh pr checkout 42 && grok --no-auto-update -p 'Review the changes vs origin/main. Check bugs, security, race conditions, missing tests.'", pty=true, timeout=300)

Post the review

terminal(command="gh pr comment 42 --body '<review text>'", workdir="/path/to/repo")

Parallel Issue Fixing with Worktrees

# Create worktrees
terminal(command="git worktree add -b fix/issue-78 /tmp/issue-78 main", workdir="~/project")
terminal(command="git worktree add -b fix/issue-99 /tmp/issue-99 main", workdir="~/project")

# Launch Grok headless in each (background)
terminal(command="grok --no-auto-update --always-approve -p 'Fix issue #78: <description>. Commit when done.'", workdir="/tmp/issue-78", background=true, notify_on_complete=true)
terminal(command="grok --no-auto-update --always-approve -p 'Fix issue #99: <description>. Commit when done.'", workdir="/tmp/issue-99", background=true, notify_on_complete=true)

# Monitor
process(action="list")

# After completion: push and open PRs
terminal(command="cd /tmp/issue-78 && git push -u origin fix/issue-78")
terminal(command="gh pr create --repo user/repo --head fix/issue-78 --title 'fix: ...' --body '...'")

# Cleanup
terminal(command="git worktree remove /tmp/issue-78", workdir="~/project")

Useful Subcommands & TUI Commands

Command	Purpose
grok	Start the interactive TUI
grok -p "query"	Headless one-shot
grok login / grok logout	Sign in / out (SuperGrok / X Premium+ OAuth)
grok inspect	Show what Grok discovered in cwd: config sources, instructions, skills, plugins, hooks, MCP servers
grok agent stdio	Run as an ACP agent over JSON-RPC (for IDE/tool integration)
grok update	Update the CLI (needs the x.ai host; skip in automation)

TUI slash commands (interactive only): /model <name>, /always-approve, /plan, /context, /compact, /resume, /sessions, /fork, /usage, /quit. Shift+Tab cycles session modes (including Plan mode, which blocks write tools except the session plan file).

Config (~/.grok/config.toml)

[cli]
auto_update = false          # skip background update checks persistently

[ui]
permission_mode = "ask"      # or "always-approve" to skip tool prompts by default

[models]
default = "grok-build-0.1"

Put global preferences in ~/.grok/config.toml (not project-scoped .grok/config.toml). permission_mode supersedes the legacy approval_mode / yolo = true keys.

Pitfalls & Gotchas

1. Auth is subscription-gated. grok login requires a SuperGrok or X Premium+ subscription. If login fails or there's no ~/.grok/auth.json, confirm the subscription is active before falling back to XAI_API_KEY.
2. Don't conflate Fabric' xAI auth with the grok CLI's auth. Fabric' x_search runs on its own xAI OAuth; the standalone grok CLI has a separate token in ~/.grok/auth.json. A working x_search does NOT mean grok is logged in.
3. Always pass --no-auto-update in automation — otherwise Grok phones home for update checks (and x.ai/storage.googleapis.com may be unreachable).
4. Prefer npm install over the curl installer — npm install -g @xai-official/grok avoids the Cloudflare-walled x.ai host.
5. --always-approve is the autonomous-build switch. Without it, headless runs may stall waiting on tool-approval prompts. Omit it deliberately for read-only review/audit work so Grok can't mutate files.
6. Headless -p skips TUI dialogs; the TUI needs pty=true (+ tmux for monitoring), just like Claude Code.
7. Use --no-alt-screen if you run the TUI inline and the fullscreen alt-screen takeover garbles captured output.
8. No git repo needed, but for PR/commit workflows you still want one — use mktemp -d && git init for scratch commit tasks.
9. Clean up tmux sessions with tmux kill-session -t <name> when done.

Rules for Fabrics

1. Prefer headless -p for single tasks — cleanest integration, structured output via --output-format json.
2. Always set workdir (or --cwd) so Grok targets the right project.
3. Pass --no-auto-update in every automated invocation.
4. Use --always-approve only when Grok should write autonomously; omit it for read-only reviews and audits.
5. Background long tasks with background=true, notify_on_complete=true and monitor via the process tool.
6. Use tmux for multi-turn interactive work and monitor with tmux capture-pane -t <session> -p -S -50.
7. Verify auth before relying on it — check ~/.grok/auth.json or run a cheap grok -p "Say ok." smoke test; don't assume Fabric' xAI auth carries over.
8. Report results to the user — summarize what Grok changed and what's left.