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diagnose

Diagnose bugs and performance regressions through a phased feedback loop.

1|Updated Mar 9, 2026

Search Tags:#performance #debugging #instrumentation #quality-assurance #reproduction #hypothesis-testing #bug-diagnosis

Ready to run

npx skills add https://github.com/danievanzyl/code-skills --skill diagnose-danievanzyl

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: diagnose
Source: https://github.com/danievanzyl/code-skills/tree/main/skills/diagnose
Command: npx skills add https://github.com/danievanzyl/code-skills --skill diagnose-danievanzyl

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) components.

What problem does it solve?

This skill helps teams diagnose hard bugs and performance regressions through a disciplined, phased workflow that guides reproduction, hypothesis testing, instrumentation, and verification.

Core Features & Use Cases

Disciplined phases: Build a repeatable loop from reproduction to verification, including planning, experimentation, instrumentation, and regression testing.
Structured approach: Provides a clear, sequential process to isolate root causes and prevent scope creep.
Use Case: When a bug is reported or performance regresses, follow the defined phases to reproduce, hypothesise, instrument, fix, and validate.

Quick Start

Begin by reproducing the bug, then follow the six phases to identify and fix the root cause.

Frequently Asked Questions about diagnose

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

FAQPage Schema

What is a structured workflow for diagnosing hard bugs and performance regressions?▼

A structured bug diagnosis workflow guides engineers through disciplined phases of reproduction, hypothesis testing, instrumentation, and verification to isolate root causes. It prevents scope creep by enforcing a sequential process from bug report to validated fix.

How do I reproduce a performance regression before testing a fix?▼

To reproduce a performance regression, establish a fast and repeatable feedback loop that consistently triggers the issue. This reproducible baseline serves as the starting point for the planning, experimentation, and instrumentation phases of the diagnosis workflow.

What is the best way to isolate the root cause of a reported bug?▼

The best way to isolate a bug's root cause is applying hypothesis testing within a disciplined feedback loop. By systematically instrumenting the reproducible issue and verifying constraints, engineers can pinpoint the source without scope creep.

Can I use a disciplined diagnosis approach for both broken functionality and performance issues?▼

Yes, a disciplined diagnosis approach can be applied when users report both broken functionality and performance regressions. The same structured phases of reproduction, hypothesis testing, and verification guide engineers to the root cause in either scenario.

Why does my bug diagnosis process result in scope creep?▼

Bug diagnosis often results in scope creep when lacking a structured, sequential process with defined phases and constraints. Implementing a disciplined workflow from reproduction to regression testing isolates the root cause and maintains investigation focus.