MrVPlusOne/playwright-e2e-tester

Playwright E2E Tester

Use this skill to run browser-based E2E verification for UI changes, bug fixes, and user workflows.

When To Use

• Visual verification of new or updated UI components
• Regression checks after frontend/backend refactors
• End-to-end workflow validation from a user perspective
• Bug reproduction and post-fix verification in-browser

Prerequisites

• Ensure the target application is running and reachable in a browser.
• Read repository-level agent instructions (AGENTS.md or equivalent) for project-specific URLs, ports, and setup commands.
• Ensure node/npx are available.

Run Learnings Log (Mandatory)

• Before starting, read LEARNINGS.md in this same skill directory and reuse relevant tips.
• After each E2E run, reflect on what could have been easier and update LEARNINGS.md with any useful takeaways.
• Add practical notes when they improve future runs, for example:
  • run context (URL/env/scope) when it matters
  • what worked well
  • blockers/flaky behavior and safe fallbacks
  • quest-specific verification notes that can help future runs
• Keep the file concise and practical:
  • keep evergreen guidance near the top
  • remove or update stale, inaccurate, or misleading guidance when the UI/workflow changes
• Never add secrets or destructive instructions.

Quick Start (Mandatory)

Before any browser action:

1. Start Playwright MCP:
   • npx -y mcp-cmd start playwright npx -y @playwright/mcp@latest
2. Navigate to the target URL:
   • npx -y mcp-cmd call playwright browser_navigate --url="<target-url>"
3. Snapshot (preferred for interactions):
   • npx -y mcp-cmd call playwright browser_snapshot
4. Interact using refs from snapshot:
   • npx -y mcp-cmd call playwright browser_click --element="Submit button" --ref="A1"
5. Screenshot:
   • npx -y mcp-cmd call playwright browser_take_screenshot --filename="step1.png"
6. Stop MCP server when done:
   • npx -y mcp-cmd stop playwright

Browser Automation (via mcp-cmd)

This workflow uses Playwright MCP through shell commands, not direct Playwright scripts.

• Start MCP server once at the beginning and keep it running through the test flow.
• Use: npx -y mcp-cmd tools playwright to discover all available operations and parameter schemas.

Testing Workflow

1. Read LEARNINGS.md and plan test cases with expected outcomes.
2. Execute each flow step-by-step.
3. Capture screenshots at each significant state change.
4. If behavior is wrong: diagnose, fix, and re-run until passing.
5. Continue until all requested checks are complete.
6. Update LEARNINGS.md with useful new learnings and clean up outdated guidance.

Best Practices

• Prefer browser_snapshot for interaction planning.
• Use browser_wait_for instead of fixed sleeps.
• Organize screenshots by test case and step name.
• Capture key steps as proof for reviewers.

Evidence Requirements

• Every important claim should be backed by screenshots.
• Include both successful and failure/fix verification states.
• Use descriptive screenshot names that map to test steps.

Screenshot Storage

• Raw MCP screenshots are typically written under /tmp/playwright-mcp-output/
• Copy relevant screenshots to a repo-local evidence directory with descriptive filenames.

Required Output

When done, report:

1. Pass/fail/fixed summary
2. What was tested and outcomes
3. Issues found and fixes applied
4. Screenshot inventory
5. Exact absolute screenshot directory path (required)

Cleanup (Mandatory)

Run these in order after tests complete:

• npx -y mcp-cmd stop playwright
• rm -f .mcp-cmd.json

If mcp-cmd stop fails, explicitly warn that manual cleanup may be needed.