Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/int2t05/engineering-skills/e2e-testingnpx skills add int2t05/engineering-skills --skill e2e-testinggit clone --depth 1 https://github.com/int2t05/engineering-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/int2t05/engineering-skills/e2e-testing)<a href="https://agentmods.dev/skills/int2t05/engineering-skills/e2e-testing"><img src="https://agentmods.dev/badge/skills/int2t05/engineering-skills/e2e-testing.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00075 | $0.01607 |
| Opus 5 | $0.00037 | $0.00804 |
| Sonnet 5 | $0.00015 | $0.00321 |
| Haiku 4.5 | $0.00007 | $0.00161 |
Grade A, and why
e2e-testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.
End-to-End Testing
E2E tests verify real user flows through the browser. Unit tests don't catch CSS, layout, or rendering bugs — runtime verification does. Playwright is the default automation tool (adapt if your project uses Cypress or another); pair it with a browser-inspection tool like Chrome DevTools MCP for visual and network inspection when available.
When to use
- Writing or reviewing E2E tests (Playwright by default, or your framework's equivalent)
- Testing form submissions, authentication flows, user journeys
- Debugging flaky browser tests
- Verifying UI changes render correctly at runtime
Not for: backend-only changes, CLI tools, code that doesn't run in a browser. API contract testing (use api-testing); generating test scaffolds for existing code (use test-generation).
Steps
1. Detect the stack
Check package.json for @playwright/test. Detect the frontend framework
(React, Vue, Next.js) — it affects waiting strategy and form input handling.
Detect auth pattern (session vs token) and rate limiting (throttle middleware
in dev causes 429s after ~5 login attempts).
2. Choose locators by priority
Role-based locators mirror how users and assistive technology interact with the page. They survive refactoring; CSS selectors and test IDs don't. Priority order and code examples — see references/playwright-rules.md.
Handle strict mode violations with { exact: true }, scoped locators, or
.first() — never disable strict mode.
3. Reuse authentication with storage state
Log in once per role in a setup project, save browser state to JSON, and reuse
via storageState in all tests. Never log in per-test — it wastes 1-2s per
test and hits rate limits after ~5 attempts. Setup-project and storage-state
code examples — see references/playwright-rules.md.
4. Use web-first assertions
expect(locator) auto-retries until the condition is met or timeout. Never use
page.$() + manual checks, waitForTimeout, or isVisible() snapshots. Assertion
examples — see references/playwright-rules.md.
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago First seen · 132 lines · 75 tokens per session scan A 9c76717148d9
e2e-testing is a skill published in the GitHub repository int2t05/engineering-skills (3 stars, last pushed 3d ago), licensed MIT. It adds 75 tokens to every session and 1,607 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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