First Principles Reasoning
Rebuilds problems from fundamental truths by separating hard constraints from assumptions
- Repository
- danielmiessler/LifeOS
- Stars
- 19,682
- Licence
- MIT
- Files
- 4 files
What it does
Once installed, the agent stops copying how things are usually done and instead breaks a problem into its basic parts, labels each limit as a physical law, a policy or choice, or an unproven belief, and then designs a solution using only the parts that truly can't change. It works in three steps (Deconstruct, Challenge, Reconstruct) that can run together or separately, and returns a parts breakdown, a constraint table and a rebuilt solution. It is for analysis, not for making the fix itself.
Great for
- Engineers or architects who suspect inherited conventions are limiting a design
- Someone stuck on a problem who wants to question assumptions before accepting 'we can't do that'
- Teams planning a redesign or looking for a fresh approach instead of incremental patches
Skip it if
- Simple implementation or bug-fix tasks, which the skill says should be done directly rather than through this framework; the reasoning adds overhead without value
- Structural feedback-loop analysis, which the description says belongs to a different skill (SystemsThinking)
- Decisions where real evidence of constraints matters and the output could be treated as authoritative without expert review, since the 'hard' vs 'assumption' labels are the agent's judgement and can be wrong
Try asking
- “Challenge whether our database choice is a real constraint or just what we've always used”
- “Deconstruct what our onboarding flow is actually for and rebuild it from that function”
- “Start over on this caching design and tell me which assumption is limiting us”
- “Is 'hosting costs $10K a month' a fundamental fact or convention? Break it down”
Install in 3 steps
- 1
Download the skill
The ZIP contains the 4 original files, the MIT licence and an attribution note.
FirstPrinciples.zip - 2
Add it to your agent
Claude Code (all projects)
mkdir -p ~/.claude/skills && unzip FirstPrinciples.zip -d ~/.claude/skills/Claude Code / Agent SDK (this project only)
mkdir -p .claude/skills && unzip FirstPrinciples.zip -d .claude/skills/Claude apps (web/desktop): Settings → Capabilities → Skills → Upload skill, and choose the ZIP.
- 3
Ask for the task
No special command needed — the agent reads the skill's description and loads it when your request matches. Try one of the prompts above.
Get better results
- Give the problem, its context and any hard requirements you already know, so the agent can separate real limits from inherited ones.
- Ask for a brief pass when you only need the key insight; the full three-part template is meant for thorough runs.
- Check the constraint table yourself, especially items marked as hard, since the classification is a judgement call.
What's inside
- Intents/Challenge.md
- Intents/Deconstruct.md
- Intents/Reconstruct.md
- SKILL.md
Redistributed unmodified from danielmiessler/LifeOS under the MIT licence. The assessment was drafted with AI from the skill's files on 2026-10-29. Skills can instruct your agent to run code — read SKILL.md and any scripts before installing.