Video Proof

Record video proof of implemented features after coding tasks complete. Use when a coding agent finishes work and needs to visually verify and demonstrate th...

Record video demos of implemented features using Playwright's built-in screen recording. After a coding task completes, this skill starts your app, runs a scripted walkthrough, and captures video + screenshots + console logs as proof artifacts.

Works with any stack — Next.js, Vite, Django, Rails, Go, Docker, static files, or an already-running server. You provide the start command; the skill handles the rest.

Prerequisites

Run once per machine:

bash scripts/setup.sh

Installs Playwright (Chromium), ffmpeg, and the yaml npm package.

Quick Start

Option A: YAML Proof Spec (recommended)

Create a proof-spec.yaml:

proof:
  start_command: "npm run dev"       # any shell command that starts your app
  start_port: 3000                   # port to poll before recording begins
  base_url: "http://localhost:3000"
  steps:
    - goto: "/dashboard"
    - wait: 2000
    - screenshot: "dashboard-loaded"
    - click: "text=Create New"
    - wait: 1000
    - assert_visible: "text=New Item"
    - screenshot: "item-created"

Run it:

node scripts/record-proof.js --spec proof-spec.yaml --output ./proof-artifacts

Option B: Inline CLI (simple cases)

node scripts/record-proof.js \
  --start "python3 -m http.server 8080" \
  --port 8080 \
  --url http://localhost:8080 \
  --goto "/" \
  --screenshot "home" \
  --output ./proof-artifacts

Option C: Already-running server (no start_command)

Omit start_command — the script skips server startup and goes straight to recording:

proof:
  base_url: "https://staging.myapp.com"
  steps:
    - goto: "/login"
    - screenshot: "login-page"

Artifacts Produced

proof-artifacts/
├── video.webm            # Full screen recording
├── video.mp4             # Chat-friendly version (auto-converted via ffmpeg)
├── screenshots/          # Named screenshots from steps
│   ├── dashboard-loaded.png
│   └── item-created.png
├── console.log           # Browser console output (errors, warnings, logs)
└── proof-summary.md      # Markdown report with pass/fail status per step

Exit code: 0 if all steps pass, 1 if any step fails. On failure, a FAILURE.png full-page screenshot is captured automatically.

Start Command Examples

The start_command field accepts any shell command. Examples:

Stack	start_command	start_port
Next.js	npm run dev	3000
Vite / React	npm run dev	5173
Django	python manage.py runserver 0.0.0.0:8000	8000
Flask	flask run --port 5000	5000
Rails	bin/rails server -p 3000	3000
Go	go run . -addr :8080	8080
Rust (Actix/Axum)	cargo run	8080
Docker Compose	docker compose up	3000
Static files	python3 -m http.server 8080	8080
Already running	(omit field)	—

Step Actions

Action	Value	Description
goto	"/path" or full URL	Navigate to a page
click	Playwright selector	Click an element (text=Submit, #btn, .class)
fill	{selector, value}	Clear and fill an input field
type	{selector, text}	Type into an element keystroke by keystroke
wait	milliseconds	Pause (let animations/data load)
screenshot	"name"	Save screenshots/<name>.png
scroll	"down" or "up"	Scroll 500px in direction
assert_visible	Playwright selector	Fail the proof if element isn't visible
assert_url	string	Fail if current URL doesn't contain string

API-Only Proof (No Browser)

For backend/API changes with no UI, use api-proof.js:

node scripts/api-proof.js --spec api-spec.yaml --output ./proof-artifacts

proof:
  start_command: "npm start"
  start_port: 3000
  base_url: "http://localhost:3000"
  requests:
    - method: GET
      path: /api/health
      assert_status: 200
      assert_body_contains: "ok"
    - method: POST
      path: /api/users
      headers:
        Content-Type: application/json
      body: '{"name": "test"}'
      assert_status: 201

Produces api-proof.md and api-results.json instead of video.

Integration with Coding Agents

Append to any coding task prompt:

After completing the implementation, create a proof-spec.yaml that:
1. Starts the app with the appropriate command for this project
2. Navigates to the relevant pages
3. Demonstrates the feature with clicks/fills as needed
4. Asserts the expected outcome is visible
5. Takes before/after screenshots

Then run:
  node <skill-path>/scripts/record-proof.js --spec proof-spec.yaml --output ./proof-artifacts

Commit proof-artifacts/ with your changes.

The agent writes the proof spec based on what it built, runs it, and the video becomes part of the deliverable.

Spec Reference

See references/proof-spec.md for the full YAML schema, API proof schema, and a copy-paste PRD template.

Tips

• Use assert_visible to make proofs fail when the feature doesn't work — video of a broken page isn't useful proof
• Keep specs focused on the specific feature, not the whole app
• wait steps between actions let data load and animations settle — 1-2s is usually enough
• The video captures real load times — doubles as a basic performance check
• If ffmpeg isn't available, the script still produces .webm (just skips mp4 conversion)