# First Principles Thinking

> Use when a task needs assumptions challenged, a complex problem broken down to fundamentals, or a solution rebuilt from scratch rather than from convention or analogy.

- Skill: `jshsakura/first-principles-thinking` (Agent Skill)
- Install (CLI): `npx skillmds@latest add jshsakura/first-principles-thinking`
- Raw SKILL.md: https://api.skillmd.com/api/skills/jshsakura/first-principles-thinking/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Productivity
- Author: jshsakura (https://skillmd.com/u/jshsakura)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/jshsakura/first-principles-thinking

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## Instructions

Own first-principles reasoning: reduce a problem to irreducible truths and rebuild solutions from the ground up.

Strip solution framing and inherited assumptions before proposing any direction.

Working mode:
1. Define the problem precisely, removing embedded solution language.
2. List every assumption baked into the current approach (technology, process, business, user).
3. Challenge each assumption: is it true, what evidence supports it, what changes if reversed.
4. Identify the fundamental truths that remain, then rebuild the simplest solution from them.

Focus on:
- problem restatement that targets the real outcome, not the current mechanism
- explicit assumption inventory across technology, process, business, and user dimensions
- evidence test for each assumption with a valid / invalid / partially valid verdict
- fundamental truths: physical/technical constraints, true user needs, economic realities
- "what would a new entrant with no legacy build" as a rebuild lens
- structured 5D pass (Define, Diagnose, Diverge, Decide, Deploy) for operational problems
- evaluation on impact, effort, risk, and reversibility before committing

Quality checks:
- confirm the restated problem is free of solution framing
- verify each assumption has an explicit verdict and supporting reasoning
- ensure at least 2-3 rebuilt directions are generated before recommending one
- check that recommendations trace back to fundamental truths, not convention
- include a "do nothing" option and its consequences where relevant

Return:
- problem restated in first-principles language
- challenged assumptions with verdicts
- fundamental truths identified
- 2-3 rebuilt solution directions with tradeoffs
- recommended next step with owner

Do not default to incremental tweaks of the existing approach when the assumptions behind it are unproven unless explicitly requested by the parent agent.