Run Grok Build on Your Phone (iPhone + Android)

Grok Build is xAI's terminal coding agent, and its installer accepts three operating systems: macOS, Linux, and Windows via Git Bash. There is no iPhone or Android build. So to run Grok Build on your phone, you put it on a real Linux machine and reach it. The fastest way: install Cosyra for iOS or Cosyra for Android, run curl -fsSL https://x.ai/cli/install.sh | bash in the terminal, sign in with grok login --device-auth, and launch grok. Here is each path, what we tested, and one thing xAI's docs get wrong.

This guide was written by the Cosyra team. Grok Build is days old; the repository was created on 2026-07-14. So we checked everything against primary sources on 2026-07-17 rather than trusting anything written about it: the xai-org/grok-build repo and its in-repo authentication guide, xAI's Grok Build docs, and the installer script itself. Then, rather than assume the install works, we ran it in a clean Ubuntu 24.04 x86_64 container, the same base our containers run.

What is Grok Build?

Grok Build is xAI's terminal-based AI coding agent. You describe a task and it plans, edits files across a repo, runs commands, and iterates, inside a fullscreen mouse-interactive TUI. Its README calls it "SpaceXAI's coding agent harness and TUI." That is the same shape as Claude Code or Codex CLI, from xAI.

• Command: grok. Note that grok-build is the repository name, not a command. The installer also links a second command, agent, to the same binary.
• Platforms: the installer's own case statement accepts Darwin, Linux, and Windows via Git Bash, and exits with "Unsupported OS" on anything else. It builds for x86_64 and aarch64 only.
• Install: a curl script that drops a native binary. There is no npm package, which matters more than it sounds. See the Termux section.
• Licensing: the harness is Apache-2.0 and written in Rust. The model behind it is not open source, and usage is billed through xAI. Both halves of that sentence matter.
• Version as of 2026-07-17: 0.2.102. This project ships fast: it gained roughly 400 GitHub stars in the six hours we spent writing this, so we date every number here rather than pretending it is stable.

The Grok app on your phone is not the coding agent

This is the mix-up worth clearing up first, because the naming invites it. You may already have Grok installed on your phone. That is the chat app: a conversational assistant, and a mature one. Grok Build is a different product that happens to share a brand. It is a terminal program that reads your repo, writes to your files, and runs shell commands.

Installing the chat app does not give you the coding agent, and no amount of asking it will make it edit your repo. There is no mobile build of grok, no cloud-agent web surface from xAI, and no remote-control product like the ones some competitors ship. The only official way to run Grok Build is a real terminal on a real machine. The question is only which machine, and how your phone reaches it.

How can you run Grok Build from a phone?

Two paths work today, and one is unverified: a cloud Ubuntu container where grok actually runs, SSH to a machine you own and keep awake, and Termux on Android.

1. Cosyra: install Grok Build in a cloud container

Cosyra is a native iOS and Android terminal connected to a persistent Ubuntu 24.04 x86_64 container. That userland matches what the installer wants, so the curl script resolves the linux-x86_64 build and grok runs in the container. Nothing of yours has to stay awake. This is the path we captured above.

• Works when: you want Grok Build on demand from either platform with no home machine to maintain.
• Breaks when: you have no internet, or you need it to reach resources that only exist on your home network.
• Cost: 1 hour free on signup, no credit card. Extend with a 10-hour, 7-day trial when you want more. Then $29.99/month or $300/year. See pricing. xAI bills your Grok usage separately.

2. SSH to your own always-on machine

Install Grok Build on a desktop or VM you own, then reach it from a phone SSH client. This works, and xAI clearly expects it: their authentication guide describes device-code auth as being for "headless environments (SSH sessions, Docker containers, remote VMs) where no browser is available locally." It is also how a chunk of the Hacker News thread about Grok Build already uses it. One commenter's whole endorsement of the TUI was that "it works on anything you can get a terminal on, you can use it over SSH, and the UI will be the same no matter where you use it," and another said it was "easiest to use when sshing into a VM."

The cost is the machine. It has to stay awake, stay online, stay reachable from a phone network, and stay patched. If you already run one, this is a fine answer. If you do not, you are buying a maintenance job to solve a connectivity problem.

3. Termux on Android: the honest state

Most guides would tell you Grok Build cannot run on Termux, cite the usual libc argument, and move on. That argument does not hold here, and the real answer is more interesting.

Start with what is definitely true: there is no npm package. The workaround that gets Node-based CLIs onto Termux, letting npm resolve an arm64 build and run it under Node, simply does not exist for Grok Build. It is a native binary from a curl script.

The usual next argument is that prebuilt binaries are glibc-linked while Termux uses Android's Bionic libc, so the binary cannot run. So we checked instead of assuming, and pulled both published binaries apart:

Both binaries are statically linked with zero NEEDED entries, and the linux-aarch64 build genuinely ships. That URL returns HTTP 200, and it is a 119 MiB file. So the glibc-versus-Bionic dynamic-link mismatch, the thing that blocks other prebuilt agent CLIs on Termux, is absent here. A statically linked binary brings its own libc.

That removes one blocker. It does not prove the thing runs. Android imposes its own constraints on executing binaries, the aarch64 build is non-PIE where the x86_64 one is PIE, and we have not run it on a handset. So our answer is: unverified, with the usual reason for "no" ruled out. If you test it on-device, we would genuinely like to know. The broader set of Termux trade-offs, including process lifetime and Android killing background sessions, is in Cosyra vs Termux. A cloud x86_64 container, where we did verify it, avoids the question entirely.

How do you run Grok Build on iPhone or Android with Cosyra?

Four steps: install the app, run the install script, sign in with a device code, and run grok in a repo.

Step 1: Install Cosyra and sign in

Download from the App Store or Google Play. The container is Ubuntu 24.04 x86_64, which is exactly the target the installer looks for.

Step 2: Install Grok Build

Grok Build is not one of the four agents we pre-install, we ship Claude Code, Codex CLI, OpenCode, and Gemini CLI, but it is one command away. This is the real output from our capture, trimmed.

The binary lands in ~/.grok/bin and the installer appends that to your PATH. Two notes from reading the script: you can pin a version by passing it (| bash -s 0.1.42), and the download is a 146 MiB file on x86_64, which is worth knowing if you are watching a metered connection. Because the container is persistent, you pay that download once, not every session.

One thing to check before you run the installer: a second, unrelated coding agent also drops a binary named grok into ~/.grok/bin, and neither installer looks for the other, so the second one you install silently replaces the first. If a grok is already on this machine, grok --version settles it. xAI's build prints a version plus a commit hash (0.2.102 (ab5ebf69ac)), the community CLI prints a plain npm version (1.1.7). We probed both release channels on 2026-07-20 and wrote up which grok is which, and why their Linux ARM64 support runs backwards between them.

Step 3: Sign in with a device code

Here is where xAI's own docs and xAI's own binary disagree, and the binary is right. The docs page says that in non-browser environments you should use an API key. But run grok with no credentials and it tells you something better:

Use grok login --device-auth (the --device-code alias is what the error message suggests). It prints a URL and a code; you approve it on any other device, and the container never needs a browser. Tokens cache in ~/.grok/auth.json and refresh in the background, so this is a one-time step, not a per-session ritual.

We think the docs are giving the wrong advice here, and xAI would probably defend it. Recommending XAI_API_KEY for non-browser environments means pasting a long-lived credential into a shell on a phone keyboard, and leaving it in the environment afterwards. The device-code flow gets you a refreshing session token you approved on a device you were already holding. It is less typing and a better credential. The API key is a fine fallback; it should not be the headline instruction.

Step 4: Clone a repo and run Grok

Grok Build opens its fullscreen TUI, plans the change, and shows you the edits. Reviewing a proposed diff while standing on a platform waiting for a train is exactly the kind of small, bounded task a phone is good at. You are reading and approving, not typing paragraphs. If you want it non-interactive instead, -p takes a prompt directly and --output-format streaming-json makes the output machine-readable.

What are the real limits of running Grok Build on a phone?

• No offline mode. The container is in the cloud; no internet, no terminal. A local Android terminal wins here and we are not going to pretend otherwise.
• Two meters, not one. The container has its own cost and xAI bills your Grok usage separately.
• Nowhere to report bugs. Issues and Discussions are both turned off on the repository, so when something breaks there is no public tracker to search or file against. For a tool this young, that is a real cost.
• Check what it uploads before pointing it at secrets. A wire-level analysis published 2026-07-12, mitmproxy against v0.2.93, and widely discussed on Hacker News, reported that Grok Build uploads whole repository snapshots to a Google Cloud Storage bucket named grok-code-session-traces, including files the agent never read, and that a .env file's contents were transmitted verbatim and unredacted. The researcher recovered a never-read file from an uploaded git bundle to prove it. We have not reproduced this, and it may have changed since. But it is a reason to think about which repo you clone.
• Phone keyboards slow long prompts. Voice dictation and a Bluetooth keyboard help on longer instructions.

Cosyra vs SSH vs Termux for Grok Build

Cosyra runs grok for real with nothing left awake; SSH works if you already own an always-on machine; Termux is unverified. Verified 2026-07-17.

Prefer one of the agents that is pre-installed, or a setup where you bring your own key and pick the model? See Claude Code on phone, OpenCode on phone, and Gemini CLI on phone, or the pillar on AI coding agents on mobile, which maps which agents run on the phone versus remote-control something else.

Frequently asked questions