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 rules/nerds-odd-e/doughnut/frontend-testinggit clone --depth 1 https://github.com/nerds-odd-e/doughnutWhat 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 | $0.00000 | $0.01519 |
| Opus 5 | $0.00000 | $0.00759 |
| Sonnet 5 | $0.00000 | $0.00304 |
| Haiku 4.5 | $0.00000 | $0.00152 |
Grade A, and why
frontend-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 2d 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 — 188 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Frontend Testing Rules
Style ("small test" practice — stable boundary, data over mocks, focused assertions, concise makeMe): always-applied unit-testing.mdc — follow that first.
Test Commands
From the repo root:
CURSOR_DEV=true nix develop -c pnpm frontend:test
Run tests with browser rendering UI:
CURSOR_DEV=true nix develop -c pnpm frontend:test:ui
Run tests in browser-rendered watch mode:
CURSOR_DEV=true nix develop -c pnpm frontend:test:watch
Run a single test file from the repo root:
CURSOR_DEV=true nix develop -c pnpm frontend:test tests/path/to/TestFile.spec.ts
Or only the frontend package:
CURSOR_DEV=true nix develop -c pnpm -C frontend test tests/path/to/TestFile.spec.ts
Run a specific test case:
CURSOR_DEV=true nix develop -c pnpm -C frontend test -t "test name pattern"
The test file path is relative to frontend/. Do not use pnpm ... test -- tests/...; the -- is forwarded to Vitest and file filtering is skipped.
In most situations, run all unit tests instead of a selected file only. Use a single test file when actively debugging or iterating on a specific component.
Component Behavior
- Drive the mounted component / page ("small test" style per
unit-testing.mdc); cover lower layers with realisticmakeMeprops/state, not by testing internal helpers in isolation. - Test through user interactions; assert observable DOM outcomes.
- Use
data-testidfor test selectors. - Use Vitest browser mode and prefer real browser rendering over mocking sibling components or internal modules; stop using jsdom.
Routing assertions
Navigation assertions use named locations (or helpers that return them).
Rendered-href assertions use noteShowHref. Path strings belong only in
routes.spec.ts (matching / redirects) and inbound URL classifiers. Test
routers that resolve named screen locations use production routes or
dummyRouteRecordsFromMetadata (the routeMetadata table with dummy
components; no page imports). Catch-all / or /:pathMatch(.*)* routers
and useRoute stubs with path: "/" are not a second screen dialect
(Proposed ADR 0005).
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.
- 2d ago First seen · 188 lines · 0 tokens per session scan A 8d45f423bd9c
frontend-testing is a cursor rule published in the GitHub repository nerds-odd-e/doughnut (49 stars, last pushed 2d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,519 tokens. 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 2026-08-30.
Other cursor rules, from other repositories
webkit-browser
Cursor rule "webkit-browser" from duckduckgo/apple-browsers, covering webkit & browser development guidelines, webview configuration, basic webview setup, user scripts management and tab management.
cypress-e2e-testing-cursorrules-prompt-file
Cursor rules for Cypress development with E2E testing.
vasu-playwright-utils
../../templates/cursor-rules/vasu-playwright-utils.mdc.
dev-browser
Fallback browser automation with persistent Chrome state. Use only when Browser Use is unavailable or blocked.
node-dependencies
Enforce Node.js versioning and package management best practices.
security-standards
Cursor rule "security-standards" from wjgogogo/cursor-rules, covering 安全规范, 核心原则 [p0], 输入验证, xss 防护 and csrf 防护.