diagnosing-bugs

Diagnose hard bugs and performance regressions through a structured feedback-loop workflow.

1|Updated Mar 2, 2026
One-click install
npx skills add https://github.com/mst-software-vn/mst-checkscam --skill diagnosing-bugs-mst-software-vn
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: diagnosing-bugs
Source: https://github.com/mst-software-vn/mst-checkscam/tree/main/.claude/skills/diagnosing-bugs
Command: npx skills add https://github.com/mst-software-vn/mst-checkscam --skill diagnosing-bugs-mst-software-vn

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) components.

What problem does it solve? Hard bugs and performance regressions resist casual code reading; without a reproducible signal, debugging devolves into guessing. This Skill enforces a disciplined six-phase diagnosis loop that builds a tight, deterministic pass/fail signal before any hypothesis is tested. ## Core Features & Use Cases - Feedback Loop Construction: Ten ranked strategies for building a red-capable repro, from failing tests and curl scripts to headless browser runs, trace replay, fuzz loops, and git bisect harnesses. - Structured Hypothesis Testing: Generates 3-5 ranked, falsifiable hypotheses, then instruments with tagged debug logs or debugger breakpoints, changing one variable at a time. - Regression Lockdown: Writes the regression test before the fix at a correct seam, then runs cleanup with grep-based removal of tagged instrumentation and a post-mortem. - Use Case: A user reports intermittent checkout failures. The Skill guides building a loop that replays the failing request 100 times to raise the reproduction rate, minimises the scenario, tests ranked hypotheses, and lands a fix with a regression test. ## Quick Start Ask the AI to diagnose the bug where the export button throws an error, and have it build a failing reproduction loop before proposing any fix.

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 sometimes?▼

For non-deterministic bugs, raise the reproduction rate instead of chasing a clean repro: loop the trigger 100 times, parallelise, add stress, and narrow timing windows. A 50%-flake bug is debuggable; keep increasing the rate until your feedback loop reliably goes red.

How to diagnose a performance regression in code?▼

Establish a baseline measurement first using a timing harness, performance.now(), a profiler, or query plans, then bisect between known states. Logs are usually wrong for perf work; measure first, fix second, and diff old versus new versions when possible.

What should I do before forming a hypothesis about a bug?▼

Build a tight feedback loop first: one command that is red-capable, deterministic, fast, and agent-runnable, asserting the user's exact symptom. Jumping to hypotheses without a reproducible signal is the primary failure mode this workflow prevents.

Can I debug a bug I cannot reproduce locally?▼

Stop and say so explicitly rather than guessing. Ask for environment access, a captured artifact such as a HAR file, log dump, or screen recording, or permission to add temporary production instrumentation before proceeding.

When should a regression test be written for a bug fix?▼

Write the regression test before the fix, but only at a correct seam where the test exercises the real bug pattern as it occurs at the call site. If no correct seam exists, that architectural gap is itself a finding worth flagging.