brevity

Rules and frameworks for writing high-quality LLM system prompts. Apply when authoring, reviewing, or optimizing a system prompt, system message, or LLM instructions.

Core discipline for unit tests across frameworks: Arrange-Act-Assert structure, behaviour-focused naming, isolation, mocking discipline, and meaningful coverage. Use when writing, reviewing, or maintaining unit tests.

Core principles for writing deterministic, reliable, and maintainable automated tests across frameworks. Use when writing, reviewing, or maintaining automated tests.

k6-specific best practices for performance tests, including load, stress, spike, and soak testing. Use when writing or reviewing k6 performance tests.

Bruno-specific best practices for API tests: .bru files, collections, environments, assertions, and scripting. Use when writing or reviewing Bruno API tests.

Playwright-specific best practices for reliable, parallel-safe end-to-end tests. Use when writing or reviewing Playwright tests.

Vitest-specific conventions for unit tests: test doubles, fake timers, async assertions, parametrisation, and config. Use when writing or reviewing Vitest tests.

Assess security advisories against a Git repository by creating an isolated worktree, building a PoC exploit, and validating whether the described vulnerability is real and exploitable. Use when given a CVE, GitHub Security Advisory, or vulnerability description to verify.

Framework-agnostic best practices for testing HTTP/REST APIs: request design, assertions, auth, data setup, and environment handling. Use when writing or reviewing API tests, or as the shared base for tool-specific API testing skills (Bruno, Postman).

Compact the current conversation into a handoff document so a fresh agent can continue the work in a new session. Use when splitting scope across sessions, spawning prototype or side tasks, or passing context between agents.