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.
git clone --depth 1 https://github.com/JasonBoy/msw-mcpWrote 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/rules/jasonboy/msw-mcp/testing)<a href="https://agentmods.dev/rules/jasonboy/msw-mcp/testing"><img src="https://agentmods.dev/badge/rules/jasonboy/msw-mcp/testing/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/rules/jasonboy/msw-mcp/testing"><img src="https://agentmods.dev/badge/rules/jasonboy/msw-mcp/testing.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00221 | $0.00221 |
| Opus 5.5 | $0.00088 | $0.00088 |
| Sonnet 5.5 | $0.00044 | $0.00044 |
| Haiku 4.5 | $0.00022 | $0.00022 |
Grade A, and why
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 1mo 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.
What it actually says
Testing
When adding or changing features, add or update tests. See AGENTS.md for full conventions.
- Runner: Vitest v4 —
pnpm run testfrom repo root - Files: Co-locate as
src/**/*.test.ts(excluded fromtscbuild) - Environments: Node (
core,msw-cli,msw-mcp); jsdom (@msw-mcp/client) - Patterns: Unit tests with mocks; integration tests only for real WS/HTTP round-trips in
core - CLI: Test pure logic in
msw-cli/src/helpers.ts, notindex.ts - MCP tools: Inject a fake
wsServer.sendMessage— see existing tests inpackages/msw-mcp/src/tools/
Before finishing, run pnpm run test (and pnpm run build if types changed).
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.
- 1mo ago First seen · 18 lines · 221 tokens per session scan A ccd1f21f5c44
testing is a cursor rule published in the GitHub repository JasonBoy/msw-mcp (81 stars, last pushed 4mo ago), licensed MIT. It adds 221 tokens to every session, about $0.0009 per session on Opus 5.5. 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 2026-08-30.
Other cursor rules, from other repositories
pytest_unit_test_rules
Pytest Unit Test Rules for this repository.
spec-for-ut
Unit testing is essential to ensure the reliability and stability of code, especially for React components and functions. Adhering to best practices and ensuring high test coverage is critical to maintaining a robust codebase.
verify-scope
A guide for choosing how much testing to run after a code change, from one named test to the full release check. It covers pytest, Vitest, browser screenshots, type checks, linting, and the release gate.
testing
Vitest toolchain and testing discipline - two runtimes, no watch for agents, authoring gate, junk patterns.
unit-test-manners
When implementing unit tests, adhere to the following principles to ensure robust, maintainable, and fast tests.
android_unit_testing_bdd
Unit testing best practices with BDD style.