Grok Build CLI from your phone or your desk

Grok Build carries the longest list of things Happier cannot do with it, and the list is specific rather than vague: no session listing, no forking, no rollback, no vendor-state handoff. Happier launches grok in an update-safe Agent Client Protocol mode — the CLI’s auto-update is switched off for the session, so a release landing mid-conversation cannot change the program you are talking to — and hands it MCP servers natively, though that path is marked experimental too.

The quirk that looks alarming and is not: Grok gives Happier no reliable non-interactive way to check a cached login, so the provider page shows “Unknown” for it. That is a missing signal, not a verdict — the protocol handshake validates the account for every session independently, so a session that starts is a session that authenticated. There is also a second way in for a computer you cannot open a browser on: alongside the ordinary login, the provider page can run the device-code flow, which is the difference between signing in to a headless box and giving up on it. An XAI_API_KEY in the environment is honoured too, and Happier keeps the value out of session metadata and logs.

Two more places the integration is deliberately literal. Models are only the ones the running session advertises: a reasoning-effort control appears for a model that says it has one, no fallback model id is invented when the CLI offers no inventory, and a switch the CLI rejects is reported as a rejection rather than shown as success. And Grok’s structured questions are drawn as questions — a prompt with no advertised choices takes free text, one with choices can still take an answer of your own, and commas and newlines survive the trip. Happier looks for the binary on your PATH and in ~/.grok/bin, which is where xAI’s installer puts it.

Grok Build is xAI’s coding CLI. happier grok runs the grok binary in your repository over the Agent Client Protocol, under whichever xAI credentials that computer already has.

This integration is experimental, and these are the limits: session listing, forking, rewind and vendor-state handoff are not supported for Grok today. The Happier docs page linked below is the one to read before you plan a workflow around it.

The iOS and Android apps, the desktop app for macOS, Windows and Linux, and app.happier.dev are all clients onto the Grok Build process running on your computer — not read-only mirrors. Answer a permission request, send the next instruction, browse the repository, read the diff. The transcript is end-to-end encrypted before it leaves your computer, so the server carrying it holds ciphertext.

Happier installs on the computer that already holds your repository, and happier grok starts Grok Build there as an ordinary subprocess, in the directory you point it at, signed in the way you signed it in. There is no gateway between the agent and xAI, and no copy of your source anywhere else.

Happier looks for grok on your PATH and runs the copy you installed. xAI distributes it with an install script rather than a package; Happier can show you that command, and it will not execute a vendor install script on its own — vendor recipes are refused unless you explicitly allow them.

xAI’s own install and sign-in guide is at x.ai/cli. Happier does not mirror it, because a copy of someone else’s install instructions is a copy that goes stale.

Configuration reference for the Happier side — Grok Build in the Happier docs.

Grok Build is one of 13 command-line coding agents Happier runs, and they share one session list, one permission inbox, one set of keyboard shortcuts and one MCP configuration.

You define an MCP server once and Grok Build receives it as native MCP inventory, next to whatever MCP servers it already had of its own.

That matters most on the days you are running more than one: sessions from different vendors side by side, and a notification tap opening the session that raised the request rather than the app’s front door. The full list is here.

Typing happier grok in a terminal starts the session right where you are standing, and the same session is in the app at the same time. What you read in that shell is Happier’s own display of the session — the transcript, the permission prompts, the tool output — rather than Grok Build’s interface. Nobody has to give up the terminal to get a phone client.

There is no hand-off to Grok Build’s own TUI. That exists for Claude Code, Codex and OpenCode, and for Grok Build the session stays Happier’s on both ends. happier attach <session-id> lists the sessions on that computer and marks the ones it cannot reattach, rather than failing after you pick one.

The attach guide lists the cases instead of promising all of them.

One command on the computer that holds your code, then happier grok in the repository you want to work in.

Walkthroughs are in the guides. All of it is MIT-licensed, and the relay is one you can run yourself.