Arbiter 0.1.0 Is Out: The First Public Pre-Release

Four weeks ago we wrote what a first pre-release owes the people who install it, and said the candidate would go out when its checks passed rather than on a date. They passed. Arbiter 0.1.0 is out: the first public pre-release, an early build for early adopters, where the rough edges you find shape the first full version.

Getting it

Downloads are on the public release channel. On Windows there is a setup program, an MSI installer and a zip. On Linux there is a Debian package, an AppImage and a tarball. Each platform also carries its software bill of materials.

Arbiter needs a license, and during the pre-release it is free: enter your email at arbitermcp.com and the key arrives by email. Enter it in the app’s first screen or with arbiter activate.

Check the download before you run it

These builds are not code-signed yet. On Windows that means SmartScreen will say “Windows protected your PC” the first time you run the setup program. Do not click through that on trust.

Every download is listed with its SHA256 in a checksum file, and that file is signed with the Code Reality Labs release key, which is published with the release. Its fingerprint is 0CF6 23D6 6975 AC42 EF02 A1EA 98F3 6798 1E68 D3E3. Check that the signature on the checksum file is good and that your download shows OK against it; the release notes give the exact commands. Only then, on Windows, choose More info and Run anyway.

What is in it

One program. arbiter is the engine that runs your work, the MCP server your coding agents connect to, and every command; arbiter <command> --help describes each one. A desktop app sits on top of it.
Sessions that outlive their window. Claude Code and Codex sessions keep running when their window closes and can be driven remotely, as described in Arbiter, Off the Machine It Was Built On.
Tickets. A work list joined to what your sessions provably did, covered in Tickets: A Work List Joined to What Your Sessions Actually Did.
Remote control, strict by default. Telegram, with Signal and WhatsApp in beta. Once a channel is configured, two-factor approval is on: anything that runs code or sends a prompt needs a code from your authenticator, and is refused until one is enrolled. See Remote Control, Stricter by Default and Nothing on Your Machine Can Stand In for Your Second Factor.
Starts with you. arbiter service install starts Arbiter at sign-in, as you, without administrator or root rights.
Bug reports without secrets. arbiter doctor checks the machine, and arbiter doctor --bundle packs versions, masked settings, recent logs and error references into one file. A crash report is sealed so that only Code Reality Labs support can read it.

What leaves your machine

Nothing is sent until Arbiter has shown you a notice saying what it sends. The default level sends counts, durations, error types and an abstract record of how work was handled. It never sends prompts, code, file names, paths, project names or keys. arbiter telemetry status lists every field, and arbiter telemetry off stops all of it. The license check is not telemetry and is listed separately. The README that ships with each download lists where Arbiter connects and why, and the bill of materials carries the complete list.

What it runs on

Windows 10 or 11 on 64-bit x86, or Linux on 64-bit x86 with glibc 2.34 or newer; the desktop app on Linux needs WebKitGTK 4.1. macOS is not supported yet. The local model runs on your graphics card and needs a driver with Vulkan support; it is not bundled, and the app downloads it when you ask. Claude Code and Codex are installed separately, with Codex 0.158 or newer.

This is a pre-release. The databases are versioned and migrate forward, and interfaces may still change before the first full version. Tell us what breaks.

Arbiter is a proprietary public pre-release for Windows and Linux. Follow the public release channel or RSS feed for updates.