@mrkt_frwd/reel

Drive a real browser from a declarative script and record it. Run it twice and get the same frames.

npx @mrkt_frwd/reel script.json --dry-run
npx @mrkt_frwd/reel script.json --deterministic

What it is for

Repeatable video of a web page — product demos, regression captures, marketing clips — without a human driving the mouse and without the output drifting between runs.

The claim, and the evidence for it

The script is data, not code:

{
  "name": "studio-tour",
  "viewport": { "width": 1440, "height": 900 },
  "fps": 24,
  "shots": [
    { "id": "land", "intent": "Open on the landing and let the hero settle.",
      "actions": [
        { "type": "goto", "url": "/" },
        { "type": "hold", "ms": 1100 },
        { "type": "scroll", "to": 620, "ms": 1500 }
      ] }
  ]
}

Because it is data, an agent can write one, diff one, and review one before anything runs. An imperative recording script has to be executed to be understood — and by then you have already paid for the capture.

--dry-run on a real 4-shot, 18-action script: 4.06 s. It loads the page, resolves all six selectors, and validates the whole script without recording a frame. A capture that dies four minutes in on a renamed selector is the expensive failure in this pipeline; this is the cheap thing that catches it.

--deterministic runs a fixed clock, so frame N is frame N regardless of how long a frame cost to draw on your machine.

What it refuses to do

• A shot without an intent is refused — the critic has nothing to judge against.
• A selector that does not resolve fails the dry run rather than the capture.

Flags

--dry-run          validate and resolve every selector; record nothing
--deterministic    fixed clock — the same frames every run
--formats          mp4, gif, vertical, from one capture pass
--live <origin>    record against a running server
--gate             fail the build when the recording does not hold

Requirements

Node 18+, Chromium and ffmpeg — both come in as dependencies. This is the one engine in the set that is not zero-dependency, because it drives a real browser and encodes real video.

MIT © Joe Asare. Built at Joe Asare Studio, where it records the work the other engines make.