Get Alpha Harness for your computer.
The app is built and tested. What is left is code signing and Apple notarisation, which is what stops your machine warning you about an unidentified developer. Leave your email below and you get the link the day it is done.
The windows installer is not published yet — that button had nothing to give you, so it brought you here instead of failing silently. Email me when it is ready.
macOS
Apple Silicon (M1 and later). Open the .dmg, drag to Applications.
Windows
Windows 10 and 11, 64-bit. Unzip and run, nothing to install. Tells you when a new version is out.
Linux
One x86_64 file. Make it executable and run it on Ubuntu, Debian, Fedora or Arch.
What happens when you open it:
What each tool gets
Verified against each vendor's docs.
Dangerous commands are stopped before they run, risky file writes are stopped before they land, and your rules are added to every session automatically.
Same protection as Claude Code. Commands and file writes are both checked before they happen, and your rules are sized so that every tool reading them gets all of them.
Cannot: Since June 2026 Google serves the Gemini CLI only to paid API keys and Gemini Code Assist Standard or Enterprise. Individual accounts moved to the Antigravity CLI.
Same protection as Claude Code. Codex can silently stop reading a rules file that is too long; Alpha Harness checks yours fits, so no rule is dropped without you knowing.
Every terminal command the agent tries to run is inspected first and the dangerous ones refused, with the reason handed back so the model corrects itself.
Cannot: Alpha Harness uses Cursor's command hook only, so far. Cursor now also has hooks before every tool call and at session start; until we use them, a bad file write is reported rather than prevented, and your rules are not added to a session.
Antigravity reads the same rules file as the Gemini CLI, so installing once covers both. One file, not two copies that drift apart.
Cannot: Antigravity now has its own hooks, in the IDE and the agy CLI. Alpha Harness does not install them yet, so here it adds your rules but blocks nothing.
Same protection as Claude Code. Hermes builds its own skills as it goes, so a guard that catches a bad command before it runs matters more here, not less.
Your conventions are added to Aider's own config so they load in every session. Existing settings in that file are merged, never replaced.
Cannot: Aider has no hook system, so nothing can be blocked.
Your rules are added to Droid's own instructions file, so they load in every session. What you wrote in that file stays exactly as it is.
Cannot: Droid has hooks that can stop a command. Alpha Harness does not install them yet, so here it adds your rules but blocks nothing.
Your rules are added to the instructions file Amp always includes, so they apply in every project without copying anything into each one.
Cannot: Amp can stop a command through a plugin. Alpha Harness does not install one yet, so here it adds your rules but blocks nothing.
Your rules are added to Pi's own instructions file. If you moved Pi's folder, they go where Pi looks; if another file there would be read instead, the installer tells you.
Cannot: Pi can stop a command through an extension. Alpha Harness does not install one yet, so here it adds your rules but blocks nothing.
No surprises
What it changes on your machine.
Three kinds of thing, nothing else. The installer shows you the exact list before it writes, and skips every tool you do not have.
See it before it happens, and undo it after.
The installer shows you every file it is about to touch and waits for your yes. Uninstall removes our block from each file and leaves everything else untouched. Your notes are yours and are never deleted.