applying-reasoning_skill

Overview

This skill applies structured mental models to solve complex technical and strategic problems. It guides decision-making for architecture choices, root cause analysis, prioritization, and strategic planning. The approach combines proven frameworks to produce evidence-backed recommendations and clear next steps.

How this skill works

The skill inspects codebases, logs, and system outputs to gather evidence, then maps findings to a library of mental models (First Principles, Inversion, Pareto, Second Order, 5 Whys). It synthesizes insights into a concise analysis artifact with an executive summary, framework-specific insights, and prioritized recommendations. The output emphasizes traceable claims and actionable items tied to the evidence found.

When to use it

• Making high-impact architectural or design decisions
• Investigating production incidents and performing root cause analysis
• Prioritizing technical debt and refactoring work using leverage-based criteria
• Evaluating planned changes for potential second-order effects
• Preparing strategic technical recommendations for leadership

Best practices

• Start from evidence: include file references, logs, or command output for every claim
• Choose the simplest model that explains the issue; escalate to combinations when needed
• Use First Principles to validate assumptions before designing solutions
• Apply Inversion to enumerate and defend against failure modes for critical changes
• Document findings in a short analysis artifact with clear, prioritized actions

Example use cases

• Compare two database migration strategies by listing assumptions, risks, and expected side effects
• Debug a recurring latency spike using 5 Whys and Inversion to find the root cause and failure modes
• Trim deployment complexity by applying Pareto to identify the 20% of modules causing 80% of slowdowns
• Assess a major refactor for second-order impacts on observability and rollback paths