first-principles-thinking · diff
v2026.5.17 to v2026.10.5
39 added, 52 removed. Audit A to A.
---
name: first-principles-thinking
description: >
- Use this skill when the user asks for first-principles thinking or first
- principles (including naming them or directing use/apply/run with obvious
- misspellings; decisive) or wants to reason from bedrock—stripping borrowed
- analogies and convention, surfacing fundamentals, then rebuilding the reasoning
- chain and implications. Use when they want to reason from scratch, challenge
- industry defaults, want physics-style business breakdowns, or sanity-check
- whether copying incumbents still makes sense, even if they never say first
- principles. Skip when they want a quick convention-following checklist with no
- rebuild of assumptions, or purely social coordination with no modeling ask.
+ Use for first principles thinking, or when the user questions an inherited default: "why do we do it this way?", "is this cost really necessary?", "should we copy what competitors do?". Strips analogies and rebuilds from fundamentals. Skip for convention-following checklists.
license: MIT
metadata:
author: ysskrishna
- version: "2026.5.17"
+ version: "2026.10.5"
---
# First Principles Thinking
Question inherited baggage. Rebuild only from **bedrock** you can defend.
- **How to run it with this skill:** one clearly headed section per step in this order: Surface → Question → Bedrock → Rebuild → Implications.
-
- ---
-
- ## Setup (run before starting)
-
- In one short block:
-
- 1. **Reconstruction target** — belief, cost, design, or strategy to ground
- 2. **Default pass** — Surface → Question → Bedrock → Rebuild → Implications (state this line)
-
- If immutable constraints (physics, law, budget) are unclear, ask at most 3 questions in one message, then proceed. Note unknowns or working guesses in plain language (no bracket tags in Setup).
-
- ---
-
- ## The Steps
-
- ### Surface
+ ## When to use
- State the **conventional answer** or analogy people rely on. List **loaded words** or hidden comparisons ("like Uber for…").
+ - "Why do we do it this way?", "is this really required?", "what would this cost if we started from scratch?"
+ - A strategy or design copied from an incumbent ("like Uber for X") that nobody has checked.
+ - Cost, architecture or process choices that exist only because they always have.
- ### Question
+ Skip: quick convention-following checklists with no wish to revisit assumptions, or purely social coordination with nothing to model.
- For each major assumption: **Assumption:** … — **Why believed?** (authority, analogy, experience) — **What if false?**
+ ## Before you start
- ### Bedrock
+ 1. State in one block: **Reconstruction target** (belief, cost, design or strategy to ground) and **Pass** (Surface, Question, Bedrock, Rebuild, Implications).
+ 2. **Gather first.** Read the code, contracts, specs or data that show what is actually required (a regulation, an SLA, a measured limit) before tagging anything fundamental. Ask up to 3 questions only for immutable constraints that tools cannot answer.
+ 3. **Light path.** Small ask: 3 assumptions, 3 bedrock items, a 3-step rebuild, 2 implications.
- List **fundamental truths** that survive scrutiny — physics, logic identities, legal musts, documented preferences of real users, arithmetic. Label each `[FUNDAMENTAL]` vs `[STILL ASSUMPTION]`.
+ ## Steps
- Prefer three or more honest bedrock items when that is credible; if fewer are honest, say why in one line.
+ ### 1. Surface
+ State the conventional answer or the analogy people rely on. List loaded words and hidden comparisons.
- ### Rebuild
+ ### 2. Question
+ For each major assumption: **Assumption:** ... - **Why believed?** (authority, analogy, experience) - **What if false?**
- From **only** `[FUNDAMENTAL]` items, derive conclusions in numbered steps. No smuggled analogies; if you need a new premise, add it to **Bedrock** first with a tag.
+ ### 3. Bedrock
+ List truths that survive scrutiny: physics, logic, arithmetic, legal musts, documented needs of real users. Tag each `[FUNDAMENTAL]` or `[ASSUMPTION]`.
- ### Implications
+ Aim for three or more honest bedrock items. If fewer exist, say why in one line.
- **So what** for decisions: what changes vs the conventional path? **Cost of being wrong** if a tagged assumption fails.
+ ### 4. Rebuild
+ Derive conclusions in numbered steps using only `[FUNDAMENTAL]` items. "Industry standard" is not a premise unless translated into a fundamental (for example "buyers require SLA X because regulation Y"). A new premise goes into Bedrock first, with a tag.
- Add a short **vs convention** contrast (a few bullets or a two-column mini-summary) if it clarifies the decision.
+ ### 5. Implications
+ - **So what:** what changes versus the conventional path.
+ - **Cost of being wrong** if a tagged assumption fails.
+ - A short **vs convention** contrast when it helps the decision.
- ---
+ If bedrock is too thin to rebuild, write **insufficient grounding** and list the evidence that would fix it.
- ## Execution Rules
+ ## Pitfalls
- 1. **Rebuild** cannot cite "industry standard" as a premise unless translated into a fundamental (e.g. "buyers require SLA X because regulation Y").
- 2. If bedrock is too thin to rebuild, say **insufficient grounding** and list what evidence would fix it.
- 3. Avoid faux profundity; keep steps short and checkable.
+ - Calling a preference or a habit "fundamental".
+ - Rebuilding from first principles and arriving exactly at the old answer. That is fine if each step is defended; say so.
+ - Faux profundity. Keep every step short and checkable.
+ - Ignoring switching cost. A better design from scratch may not beat the current one after migration.
- ---
+ Worked example: [references/example.md](references/example.md).
- ## Checklist (verify before responding)
+ ## Checklist
- - [ ] Setup: reconstruction target + default pass
- - [ ] Surface names convention or analogy explicitly
- - [ ] Question step ties assumptions to why held
- - [ ] Bedrock uses `[FUNDAMENTAL]` / `[STILL ASSUMPTION]`
- - [ ] Rebuild chain only uses fundamentals
- - [ ] Implications name what changes vs convention (and vs-contrast if helpful)
+ - [ ] Target and Pass stated
+ - [ ] Surface names the convention or analogy
+ - [ ] Question ties each assumption to why it is held
+ - [ ] Bedrock tagged `[FUNDAMENTAL]` or `[ASSUMPTION]`
+ - [ ] Rebuild uses only fundamentals
+ - [ ] Implications name what changes and the cost of being wrong