Manifest
File, title, description, audience, visibility, and optional wall-clock target are explicit inputs.
Interactive demo · zero uploads
Schedule logic,
without the upload.
Replay validation, audience, visibility, scheduling, verification, and resume state against synthetic fixtures. YouTube Studio is never opened.
60-second deterministic replay
Inspect each scheduling decision.
The mock adapter preserves the live manifest contract and produces evidence for every item without loading a browser client.
Problem
A successful upload is not proof of a correct schedule.
Studio changes the number of wizard steps by channel, disables controls during processing, and accepts wall-clock dates in the channel timezone. A premature click can leave a private draft; an unchecked field can schedule the wrong moment.
The scheduler models the batch independently from Studio, makes audience and visibility explicit, reads date and time back before finalization, and persists completed keys for safe resume.
Architecture
Deterministic orchestration around a volatile UI.
Only the injected live adapter knows selectors or CDP. Validation, sequencing, failure behavior, and reporting stay testable without YouTube.
manifest.json→validation→batch core→demo / Studio adapter→readback verification→resume state
Batch core
Stable keys drive order, deduplication, pacing, stop-on-error behavior, and event evidence.
Studio adapter
Owns CDP file injection, variable wizard steps, enabled-state waits, and native controls.
Verification
Requested date and time are compared with Studio readback before the final button is allowed.
Workflow
Seven stages guard the terminal click.
The adapter moves forward only when the previous platform state is observable.
- 01ValidateMedia, title, values, and stable key.
- 02UploadInject media through CDP.
- 03DetailsTitle and description.
- 04AudienceMade-for-kids choice is explicit.
- 05VisibilitySchedule or public/private/unlisted.
- 06VerifyRead date and time back.
- 07PersistFinalize, save key, then pace.
aria-disabled is polled before Next or Done. This prevents a silent private draft while processing is incomplete.
The manifest carries a wall-clock value interpreted in the configured channel timezone; the adapter does not silently convert it.
A readback mismatch throws before Done, directly preventing publication at an unintended time.
Real, linked code
The critical guards are small and reviewable.
These excerpts are taken from the public implementation.
while (Date.now() - start < timeoutMs) {
if (await el.count()) {
const aria = await el.getAttribute('aria-disabled');
if (aria !== 'true') {
await el.click();
return;
}
}
await sleep(1000);
}The automation waits for Studio's real control state instead of assuming that a visible button is actionable.
const rb = await page.evaluate(() => ({
date: document.querySelector('#datepicker-trigger')
?.innerText.trim(),
time: document.querySelector(
'tp-yt-paper-input#textbox input'
)?.value
}));
if (rb.date !== dateLabel || rb.time !== timeLabel) {
throw new Error('schedule mismatch');
}Finalization is impossible when the platform does not echo the exact requested wall-clock target.
if (doneSet.has(key)) {
results.push({ key, status: 'skipped', steps: [] });
onEvent({ type: 'skipped', key, done: [...doneSet] });
continue;
}A completed item never reaches the upload adapter on a resumed run.
Execution boundary
The public path has no upload capability.
Demo mode is a separate import graph, backed by a local mock and static evidence.
npm run demo
- Synthetic fixture
- Deterministic adapter
- No media bytes transmitted
- No Playwright, CDP, login, or Studio
npm run batch
- Operator-owned media and channel
- Attached Chrome profile
- Native upload and schedule UI
- Explicit consequential command
Quality and limitations
Evidence for the core; caution for the platform edge.
- Unit tests cover the batch core, report contract, deterministic output, dependency boundary, and injection sinks.
- Pages tests cover desktop/mobile rendering, keyboard navigation, reduced motion, report parity, console errors, and unexpected network requests.
- Studio selectors, wizard steps, and labels can change and require adapter maintenance.
- Wall-clock semantics depend on the channel timezone configured in YouTube Studio.
- Live runs should remain supervised and the resulting Studio queue should be reviewed.
Run locally
Generate the offline evidence.
No login or API key is required for demo mode.
npm install
npm run demo
npm test
npm run test:site
# equivalent explicit CLI
node src/demo.mjs \
--fixture manifest.example.json \
--output site