Installation

Needs Node 22.18+ (or 23.6+). Install it one of two ways:

Global: one decisium command for every project on the machine.

npm install -g decisium
decisium install

Per project: the version is pinned in package.json, so teammates and CI replay cassettes with the version that recorded them. Needed for raw cucumber-js. Run the commands through npx:

npm install --save-dev decisium
npx decisium install

These docs write decisium …; with a per-project install, type npx decisium ….

decisium install downloads the Chromium build Decisium's Playwright drives; on Linux, decisium install --with-deps also installs the system libraries it needs.

Live runs call Jev, TypeSafe's decision model, through the TypeSafe API: you need a TypeSafe API key. Decisium's code is MIT; Jev is TypeSafe's hosted service under its own terms. Set the key in the environment or in a .env file in the directory you run from:

echo 'TYPESAFE_API_KEY=...' >> .env

A replay (--record none) makes no model calls and does not need the key.

Check the setup

decisium doctor features/checkout.feature

doctor checks Node, Chromium and the key (one tiny Jev call). Given features, it also opens every start URL. Each check prints [OK] or [FAIL]; the exit code is 2 when one fails.

What is sent to Jev

On a live run, per Turn: the Step's text and a text snapshot of the page (Playwright's accessibility tree: roles, names, visible text, link URLs), plus the message of an open browser dialog. No screenshots, no cookies, no network traffic.

• "$NAME" secrets are sent as the token only; the value never leaves your machine, and is masked back wherever the page shows it.
• A value written literally in a Step is sent to Jev, recorded in the cassette and written to log.txt.
• Replays (--record none) send nothing.