Debugging & runtime diagnostics — Master Hub
Use to debug runtime issues: crashes, port conflicts, profiling, and diagnostics.
How to use this hub
This single skill bundles all 8 debugging skills. Each bundled skill's full instructions live in skills/<name>/GUIDE.md (plus any scripts/, data/, references/ next to it).
Workflow:
- Match the user's request to one or more skills in the list below.
- Read that skill's
skills/<name>/GUIDE.md for full instructions before acting.
- Combine multiple bundled skills when a task spans several areas.
Bundled skills
- detecting-port-conflicts — Detect EADDRINUSE and port conflicts, find what's using the port, and resolve it by killing the process or suggesting an alternative port.
→ skills/detecting-port-conflicts/GUIDE.md
- finding-dev-server-url — Scan running terminals for dev server URLs (localhost ports), report them, and optionally open the app in Cursor's built-in browser.
→ skills/finding-dev-server-url/GUIDE.md
- grinding-until-pass — Keep iterating on code changes until the tests pass, the build succeeds, or linting is clean. Runs in a tight loop of fix → run → check → repeat. Use when you want the agent to autonomously grind t...
→ skills/grinding-until-pass/GUIDE.md
- mattpocock-diagnose — Disciplined diagnosis loop for hard bugs and performance regressions. Reproduce → minimise → hypothesise → instrument → fix → regression-test. Use when user says "diagnose this" / "debug this", rep...
→ skills/mattpocock-diagnose/GUIDE.md
- monitoring-terminal-errors — Watch running terminal processes for crashes and stack traces. When an error appears, navigate to the failing file and line, diagnose, and fix it automatically.
→ skills/monitoring-terminal-errors/GUIDE.md
- profiling-performance — Profile a running web application's CPU performance using Cursor's built-in browser profiler. Captures call stacks, identifies slow functions, and suggests optimizations. Use when a page feels slow...
→ skills/profiling-performance/GUIDE.md
- systematic-debugging — Structured debugging methodology — reproduce, isolate, hypothesize, verify. Covers git bisect, binary search, logging, and minimal reproduction.
→ skills/systematic-debugging/GUIDE.md
- tailing-build-output — Monitor a build process (webpack, turbo, docker) for warnings and errors as they stream. Summarize issues and fix them before the build finishes.
→ skills/tailing-build-output/GUIDE.md
Note
These bundled skills are intentionally not registered as separate Cursor skills (their files are GUIDE.md, not SKILL.md) so only this master appears in the skills list. Read the relevant GUIDE.md on demand.
1---2name: debugging-master3description: Debugging & runtime diagnostics — Master Hub4---56# Debugging & runtime diagnostics — Master Hub78Use to debug runtime issues: crashes, port conflicts, profiling, and diagnostics.910## How to use this hub1112This single skill bundles **all 8 debugging skills**. Each bundled skill's full instructions live in `skills/<name>/GUIDE.md` (plus any `scripts/`, `data/`, `references/` next to it).1314**Workflow:**151. Match the user's request to one or more skills in the list below.162. Read that skill's `skills/<name>/GUIDE.md` for full instructions before acting.173. Combine multiple bundled skills when a task spans several areas.1819## Bundled skills2021- **detecting-port-conflicts** — Detect EADDRINUSE and port conflicts, find what's using the port, and resolve it by killing the process or suggesting an alternative port. 22 → `skills/detecting-port-conflicts/GUIDE.md`23- **finding-dev-server-url** — Scan running terminals for dev server URLs (localhost ports), report them, and optionally open the app in Cursor's built-in browser. 24 → `skills/finding-dev-server-url/GUIDE.md`25- **grinding-until-pass** — Keep iterating on code changes until the tests pass, the build succeeds, or linting is clean. Runs in a tight loop of fix → run → check → repeat. Use when you want the agent to autonomously grind t... 26 → `skills/grinding-until-pass/GUIDE.md`27- **mattpocock-diagnose** — Disciplined diagnosis loop for hard bugs and performance regressions. Reproduce → minimise → hypothesise → instrument → fix → regression-test. Use when user says "diagnose this" / "debug this", rep... 28 → `skills/mattpocock-diagnose/GUIDE.md`29- **monitoring-terminal-errors** — Watch running terminal processes for crashes and stack traces. When an error appears, navigate to the failing file and line, diagnose, and fix it automatically. 30 → `skills/monitoring-terminal-errors/GUIDE.md`31- **profiling-performance** — Profile a running web application's CPU performance using Cursor's built-in browser profiler. Captures call stacks, identifies slow functions, and suggests optimizations. Use when a page feels slow... 32 → `skills/profiling-performance/GUIDE.md`33- **systematic-debugging** — Structured debugging methodology — reproduce, isolate, hypothesize, verify. Covers git bisect, binary search, logging, and minimal reproduction. 34 → `skills/systematic-debugging/GUIDE.md`35- **tailing-build-output** — Monitor a build process (webpack, turbo, docker) for warnings and errors as they stream. Summarize issues and fix them before the build finishes. 36 → `skills/tailing-build-output/GUIDE.md`3738## Note3940These bundled skills are intentionally not registered as separate Cursor skills (their files are `GUIDE.md`, not `SKILL.md`) so only this master appears in the skills list. Read the relevant `GUIDE.md` on demand.
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