diagnosing-bugs

Diagnoses hard bugs and performance regressions through a six-phase feedback-loop workflow.

9|Updated Jul 17, 2026
One-click install
npx skills add https://github.com/Yassimba/loom --skill diagnosing-bugs-yassimba
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: diagnosing-bugs
Source: https://github.com/Yassimba/loom/tree/main/skills/diagnosing-bugs
Command: npx skills add https://github.com/Yassimba/loom --skill diagnosing-bugs-yassimba

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) components.

What problem does it solve? Hard bugs and flaky failures resist casual code reading; without a reproducible signal, debugging devolves into guessing. This Skill enforces a disciplined diagnosis loop that builds a tight, red-capable feedback command before any hypothesis is tested. ## Core Features & Use Cases - Feedback Loop Construction: Builds a deterministic pass/fail signal via failing tests, curl scripts, CLI fixtures, headless browser runs, trace replays, fuzz loops, or git bisect harnesses. - Structured Six-Phase Process: Guides reproduction and minimization, ranked falsifiable hypotheses, single-variable instrumentation with tagged debug logs, regression-test-first fixes, and verified cleanup. - Human-in-the-Loop Fallback: Ships a bash template (scripts/hitl-loop.template.sh) that drives a human through manual reproduction steps and captures observations for the agent. - Use Case: A user reports that CSV export intermittently throws in production. The Skill builds a replay harness from a captured request, minimizes the failing input, tests ranked hypotheses one variable at a time, and lands a fix with a regression test. ## Quick Start Use the diagnosing-bugs skill to diagnose why the export endpoint intermittently returns a 500 error.

Frequently Asked Questions about diagnosing-bugs

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I debug a bug that only happens intermittently?

Intermittent bugs require raising the reproduction rate rather than finding a clean repro. Loop the trigger 100 times, parallelize execution, add stress, narrow timing windows, or inject sleeps until the failure rate is high enough to debug against.

How to diagnose a performance regression in code?

Performance regressions need measurement before fixing: establish a baseline with a timing harness, performance.now(), a profiler, or a query plan, then bisect between known states. Logs are usually the wrong tool for perf diagnosis.

What should I do when I cannot reproduce a bug locally?

Stop and say so explicitly instead of hypothesizing without a loop. Ask the user for environment access, a redacted captured artifact such as a HAR file or log dump, or permission to add temporary production instrumentation.

Why write a regression test before fixing a bug?

Writing the regression test first proves the test actually catches the bug by watching it fail before the fix and pass after. If no correct seam exists for the test, that absence itself signals an architecture problem worth flagging.

Can this debugging workflow handle bugs that need manual UI steps?

Yes, as a last resort it uses a human-in-the-loop bash template that prompts the user through manual steps and captures their observations as structured output. The agent then parses the captured values to continue the diagnosis loop.