Record a demo video of a web app feature or flow on a real desktop (Docker, Xvfb, XFCE, real X cursor), producing an mp4 plus a click/hover/scroll/type telemetry file. Takes a flow description, an existing demo name or path, or init. Use when the user says "record a demo of the checkout", "gravar um demo dessa feature", "make a screencast of this flow", "video for the changelog", "re-record the checkout demo", "refresh the demo video", or "demo init". Do NOT use for general browser testing or automation that needs no video (use playwright-skill), page debugging or network inspection (use chrome-devtools), or static screenshots.
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IMPORTANT - Path Resolution:
This skill can be installed in different locations (plugin system, manual installation, global, or project-specific). Before executing any commands, determine the skill directory based on where you loaded this SKILL.md file, and use that path in all commands below. Replace $SKILL_DIR with the actual discovered path.
Records a scripted flow of the local app as video.mp4 (1440x900, 30fps, full X display with XFCE panel, Chromium window, and system cursor) plus events.json.
The first word decides the form: init is a command; anything else is a demo name, path, or flow description.
/demo record the checkout paying by card logged in as a customer. Pick a name, write .demos/<name>/script.mjs, record./demo checkout-card-as-customer, /demo .demos/checkout-card-as-customer, or /demo .demos/checkout-card-as-customer/script.mjs. Skip authoring and re-record as-is. If it fails loudly (the UI changed), fix the demo script, retry, and tell the user what changed in it.init, i.e. /demo init: follow references/init.md.One directory per demo, fixed file names, plus one optional config for all demos:
.demos/demo.config.mjs settings for every demo (see Config)
.demos/checkout-card-as-customer/
script.mjs demo script
video.mp4 last good recording
events.json telemetry of that recording
failed.png only after a failed run that reached the desktop
failed.json only after a failed runA successful run replaces video.mp4 and events.json and removes failed.*. A failed run leaves the previous good video untouched. .demos/ is gitignored.
Names are descriptive kebab-case slugs of the specific flow, not the area: <area>-<flow>[-<variant>], e.g. checkout-card-as-customer, checkout-coupon-applied, admin-user-invite. Before creating one, ls .demos/ and reuse the existing name for the same flow instead of adding a near-duplicate.
/demo init sets that up). Then write the demo script (template below).$SKILL_DIR/scripts/record <name>. The first run builds the Docker image (tag hashed from the assets, so edits rebuild automatically). Before launching the browser the recorder checks that app.url (unset, http://localhost:$PORT from the environment or .env, else 3000) answers; if failed.json says app not reachable at <url>, start the app the way the project's AGENTS.md or README says, re-run, and stop what you started when done. If the app runs elsewhere, set app.url in the config.t in events.json is seconds into the video.
ffmpeg -loglevel error -y -ss 6.5 -i .demos/<name>/video.mp4 -frames:v 1 /tmp/frame.pngvideo.mp4 and events.json paths.Runs inside the container next to lib.mjs, so always import ./lib.mjs.
Framing rules:
record(). Set the scene before it: browser open, logged in, starting page loaded. The video never shows the browser launching or an empty desktop.record(), not the animated helpers. Start on the page where the user's intent begins (e.g. /admin/users for "invite a user"), not on the home page.Pacing: timings come from the pace config, so call helpers without timing arguments. Don't hover right before humanClick on the same target (the click already approaches it). Keep extra sleeps short: 300-500ms between steps, ~400ms after a new page loads.
import { launch, record, hover, humanClick, type, wheel, sleep, finish, APP_URL } from './lib.mjs'
const { page } = await launch()
await page.goto(`${APP_URL}/<sign-in-path>`, { waitUntil: 'networkidle' })
await page.getByLabel('<email-label>').fill('<test-account-email>')
await page.getByLabel('<password-label>').fill('<test-account-password>')
await Promise.all([
page.waitForURL((url) => !url.pathname.startsWith('/<sign-in-path>')),
page.getByRole('button', { name: '<submit-label>' }).click(),
])
await page.goto(`${APP_URL}/cart`, { waitUntil: 'networkidle' })
await record()
await hover(page, page.getByRole('link', { name: /Order summary/ }).last())
await humanClick(page, page.getByRole('link', { name: 'Checkout' }).first())
await wheel(page, 400)
await type(page, page.getByLabel('Coupon'), 'SAVE10')
await finish()lib.mjs API: launch(), record({ lead }) (starts capture and the event clock; required, a demo script that never calls it fails), hover, humanClick, type (click then key by key), wheel(page, pixels), moveTo(x, y, ms) in screen coordinates, settle(page), mark(type, box) for custom telemetry, sleep, finish(ms).
Test accounts are project-specific: take them from the project's docs (AGENTS.md, README) or seed data, never guess.
.demos/demo.config.mjs is optional and applies to every demo. Leave it out unless the user wants something different: the defaults are the house style. Keys are deep-merged over the defaults; unknown keys, wrong types, or out-of-range values fail the run before recording.
Create it with every default documented in place with /demo init ($SKILL_DIR/scripts/config), then edit or delete lines. It never overwrites an existing file. The file's comments are the reference for each key; defaults and pace presets live in $SKILL_DIR/assets/config.mjs. The top-level keys are app.url (where the app is served; unset, http://localhost:$PORT from the environment or .env, else 3000; localhost is the host's localhost: shared host network on Linux, forwarded to host.docker.internal on macOS), pace (normal or slow, or single timing overrides), theme (system follows GNOME or macOS appearance, light, dark), browser.locale, browser.window (width and height as screen fractions, window centered), desktop.dockAutohide, timeouts, and video.
button.btn-cta can match a header copy first (off-screen, negative y). Prefer getByRole with a name, and .first()/.last() deliberately.moveTo code must do the same.wheel(). Never xdotool click 4/5: an event escaping the window switches the xfwm4 workspace and blacks out the rest of the video.finish(), never browser.close(), or the last seconds show an empty desktop.Promise.all with page.waitForURL(...), then wait for the result (toast, row) before finish().<dialog> top layer and (hover: hover) CSS just work.launch(). If a new one shows up in failed.png, add its pref there.Any error (missing locator, timeout) fails fast (5s action timeout) and the run exits non-zero with no new video. Read .demos/<name>/failed.json (error, stack, page URL, t, events so far), look at failed.png (the display at failure time; not written when the config is invalid or the app is unreachable, since those fail before the display starts), fix the demo script, and re-run. Never hand over a video from a failed run.
{
"video": "video.mp4",
"fps": 30,
"width": 1440,
"height": 900,
"events": [{ "t": 6.504, "type": "click", "rect": { "x": 12, "y": 346, "w": 195, "h": 36 } }]
}type is hover, click, type, or scroll. rect is in screen (video) pixels, measured when the pointer starts moving toward the target, so t leads the visible action by about 0.7s. scroll has rect: null.
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