Personal edition

Download Valhalla …

Read this before the first launch on a Mac

Valhalla is not notarised by Apple yet, so macOS will say it "could not verify that Valhalla is free of malware". That is Apple's notice for an app it has not checked, not a finding about this one. Open System Settings › Privacy & Security, scroll to Security, and press Open Anyway beside Valhalla. Once. The full steps.

Read this before you run it on Windows

The installer is not code-signed yet, so SmartScreen may say "Windows protected your PC", its notice for a new publisher. Press More info, then Run anyway. The full steps.

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If this does not change, the release list could not be read. The changelog lists every version.

Not sure which Mac you have? How to tell. Every file's SHA-256 is printed beside it, so you can check what you downloaded.

By downloading you accept the terms: personal, noncommercial use under the PolyForm Noncommercial License 1.0.0. For work, see the commercial edition.

Before you install

Valhalla ships no AI model and runs none of ours. It needs one of these, and the app tells you which it found:

Claude Code, signed in with a Claude subscription. The default engine, and the one that can read and edit files and run commands for you. Install it from Anthropic, run claude once in a terminal to sign in, and Valhalla finds it.
An Anthropic API key, set as ANTHROPIC_API_KEY. Answers only; no tools.
An OpenAI-compatible endpoint: OpenAI with a key, or a local server such as Ollama with no key at all.

For working in a repository you also want git, which macOS offers to install the first time it is asked for, and Windows gets from git-scm.com.

macOS	macOS 11 Big Sur or newer. Apple silicon and Intel builds. About 110 MB on disk.
Windows	Windows 10 (version 1809 or later) or Windows 11, 64-bit. The installer adds Microsoft's WebView2 runtime if the machine lacks it (Windows 11 already has it). About 120 MB on disk. No administrator rights needed.

Installing on a Mac

Open the disk image and drag Valhalla into Applications.
Open it from Applications or Spotlight. The first time, macOS says it "could not verify that Valhalla is free of malware". Open System Settings › Privacy & Security, scroll to the Security section, and press Open Anyway beside Valhalla. Once.
The window opens on Home. If no engine is ready it says so and names what to install; otherwise, type.

Prefer the terminal? The command lives inside the app: /Applications/Valhalla.app/Contents/Resources/python/bin/valhalla. Link it onto your PATH as mimir and run mimir doctor first. The terminal guide.

Installing on Windows

Run the installer. It installs for your user only, under %LOCALAPPDATA%\Programs\Valhalla, and asks for no administrator password.
If SmartScreen says "Windows protected your PC", press More info, then Run anyway.
Valhalla opens when the installer finishes, and is in the Start menu after that. Tick "Add the mimir command to your PATH" in the installer if you want it in a terminal.

Updating

Once a day the app asks this website which version is newest and says so in Settings › Advanced › Window › About, with a button that downloads the new installer, checks it against its published checksum and opens it. Nothing is downloaded until you press it, and the request carries the version and the platform and nothing else. Switch it off in the same place.

Uninstalling

On a Mac, drag Valhalla out of Applications. On Windows, use Add or remove programs. Everything the app wrote for you (conversations, settings, your knowledge) is in ~/.valhalla (%USERPROFILE%\.valhalla on Windows), and is yours to keep or delete.