rein

A deterministic control plane you drop into any project: a layer of machine checks that sits outside your coding agent rather than replacing it.

The agent does the work. rein decides whether it is done — by running the check the ticket was born with, in a fresh subprocess, and recording what happened. "I've finished" becomes a request rather than a conclusion.

npm install -g @rein-dev/rein
rein --help

This package is a small launcher. The binary for your platform arrives as an optional dependency that npm skips everywhere it does not apply, so there is no install script and nothing is downloaded after the fact.

rein self-update will notice it was installed this way and print the command for your package manager rather than replacing a file npm is tracking.

What rein does not do

rein runs the commands your project registered — the check on a ticket, the project checks, the scripts in .rein/checks.d. This is the same thing npm test does with the scripts in your package.json. There is no allow-list, because rein is not a new kind of exposure; it is one more member of a category every build tool is already in. Do not run it in a repository you would not run those in.

rein does not stop somebody who can already write your files. Anyone able to edit .rein/tickets.json can write passing into it. The promise is narrower and more useful: a forged green does not survive. The next full gate re-runs that check and marks it stale, and all of it is in git.

Links

• Releases, checksums and issues: https://github.com/rockychang7/rein-releases

The source is not public. The binaries are free to use and to redistribute unmodified; see LICENSE.