diagnose

Reproduce failures, rank falsifiable hypotheses, and verify fixes with regression tests.

1|Updated May 22, 2026
One-click install
npx skills add https://github.com/spontus-reach/spontus --skill diagnose-spontus-reach
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: diagnose
Source: https://github.com/spontus-reach/spontus/tree/main/.agents/skills/diagnose
Command: npx skills add https://github.com/spontus-reach/spontus --skill diagnose-spontus-reach

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

This Skill helps you reliably find the root cause of hard bugs and performance regressions by turning a vague failure into a repeatable, falsifiable debugging process.

Core Features & Use Cases

  • Disciplined feedback loop: Build an aggressive repro signal so you can iterate quickly (from failing tests to replayed traces).
  • Structured investigation: Reproduce, then generate 3–5 ranked, falsifiable hypotheses before testing any of them.
  • Targeted instrumentation and regression safety: Add the minimum probes needed to distinguish hypotheses, then fix and lock in a regression test where a correct seam exists.
  • Performance-focused measurement: Establish a baseline measurement and prefer bisecting over noisy logging when speed is the issue.

Quick Start

Ask the AI to diagnose the bug and drive a loop that reproduces the failure, ranks falsifiable hypotheses, instruments the code with targeted probes, then implements the fix and verifies it with regression testing.

Frequently Asked Questions about diagnose

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

FAQPage Schema
How do I find the root cause of a hard bug or performance regression?▼

To find the root cause of a hard bug or performance regression, construct a fast, deterministic feedback loop that reproduces the exact failure, then generate ranked, falsifiable hypotheses before testing them.

What is the best way to structure a debugging workflow for failing tests?▼

The best way to structure debugging for failing tests is applying disciplined phases: reproduce the failure, rank 3–5 falsifiable hypotheses, add targeted instrumentation to distinguish them, and verify the fix with regression testing.

How do I isolate a performance regression without relying on noisy logging?▼

To isolate a performance regression without noisy logging, establish a baseline measurement and prefer bisection to narrow down the exact cause rather than relying on scattered logs.

When do I need hypothesis testing during software debugging?▼

You need hypothesis testing during software debugging when a vague failure requires root-cause isolation, allowing you to generate 3–5 ranked, falsifiable predictions and add targeted probes before changing code.

How does trace replay help reproduce broken behavior?▼

Trace replay helps reproduce broken behavior by creating an aggressive, deterministic repro signal that allows you to iterate quickly through a tight feedback loop until the exact failure is consistently replicated.

Can I use bisection to fix measurable performance regressions?▼

Yes, you can use bisection to fix measurable performance regressions by establishing a baseline measurement and progressively narrowing the search space to isolate the exact cause of the speed issue.