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Agent skill

Thinking First Principles

by tjboudreaux in tjboudreaux/cc-thinking-skills

When a constraint is treated as fixed, separate physics from convention, keep only independently supported primitives, and rebuild the simplest solution that satisfies real constraints.

MITAuto-check passed

Install Thinking First Principles

skills CLI
$ npx skills add tjboudreaux/cc-thinking-skills --skill thinking-first-principles -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install tjboudreaux/cc-thinking-skills thinking-first-principles --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/tjboudreaux/cc-thinking-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/thinking-first-principles .claude/skills/thinking-first-principles && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
thinking-first-principles
GitHub stars
1.6k
Token cost
~839 tokens
SKILL.md length
392 words
Files
1
Skills in repo
26
Repo updated
First seen
Licence
MIT

At a glance

When a constraint is treated as fixed, separate physics from convention, keep only independently supported primitives, and rebuild the simplest solution that satisfies real constraints.

  • Works in 6 steps: State the problem and claimed… → Classify each constraint. Tag as… → Decompose to primitives. Required… → …
  • SKILL.md covers When to Use, When NOT to Use, Procedure and Output, plus 1 more section
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Thinking First Principles is an agent skill from tjboudreaux/cc-thinking-skills. When a constraint is treated as fixed, separate physics from convention, keep only independently supported primitives, and rebuild the simplest solution that satisfies real constraints.

Its SKILL.md is about 840 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

The repository describes itself as: 28 eval-informed mental models and critical-thinking skills for Claude Code, GitHub Copilot, Codex, Cursor, and other Agent Skills-compatible tools. The licence is MIT.

Example prompts

  • “/thinking-first-principles”

Workflow steps

6 steps, taken from the first numbered list in SKILL.md.

  1. State the problem and claimed constraints. List every limit treated as fixed (cost, scale, stack, process, "must use X").
  2. Classify each constraint. Tag as physics/math, regulation/contract, measured fact, or convention/analogy/authority. Keep only the first…
  3. Decompose to primitives. Required inputs, conservation/complexity bounds, true non-negotiables. Demand independent support (measurement…
  4. Discard unsupported assumptions. For each convention tag, state a falsifier. Drop or renegotiate anything lacking support.
  5. Rebuild from remaining primitives only. Simplest solution that satisfies binding constraints and ignores artificial ones. Prefer commodity…
  6. Validate and stop. Check against real physics, contracts, and measured needs. Define the cheapest kill test. Stop when a coherent rebuild…

What it can do on your machine

Read from SKILL.md and the folder at commit 7b8fece. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md.

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Thinking First Principles loads about 839 tokens when it runs. Until then it costs about 53 tokens; SKILL.md has 392 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~53
When it runs · the whole SKILL.md, loaded when a task matches
~839

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from tjboudreaux/cc-thinking-skills at commit 7b8fece, republished under its MIT licence (© tjboudreaux). 392 words, ~839 tokens.

Download SKILL.mdSave it as .claude/skills/thinking-first-principles/SKILL.md (or your agent's skills folder).
name
thinking-first-principles
description
When a constraint is treated as fixed, separate physics from convention, keep only independently supported primitives, and rebuild the simplest solution that satisfies real constraints.
disable-model-invocation
true

First Principles

Strip assumed constraints to independently supported primitives, then rebuild. Escape analogy when convention fails or looks artificially expensive.

When to Use

  • A constraint is treated as fixed ("too expensive," "impossible," "always done this way") without independent support.
  • Convention or analogy has failed, stalled, or only yields weak incremental variants.
  • Greenfield design where industry defaults may smuggle false requirements.
  • Cost or feasibility claims rest on pricing, precedent, or authority rather than physics, math, or measured need.

When NOT to Use

  • The constraint is verified physics, hard regulation, or measured capacity → accept it and optimize within it.
  • A proven standard library, protocol, or known-good pattern already fits → use it; do not re-derive.
  • Time-critical incidents → act on the most likely cause first; reserve first-principles rebuild for post-incident redesign.
  • Incremental polish of a working system with no false-constraint signal → skip.

Procedure

  1. State the problem and claimed constraints. List every limit treated as fixed (cost, scale, stack, process, "must use X").
  2. Classify each constraint. Tag as physics/math, regulation/contract, measured fact, or convention/analogy/authority. Keep only the first three as binding unless evidence upgrades a convention.
  3. Decompose to primitives. Required inputs, conservation/complexity bounds, true non-negotiables. Demand independent support (measurement, derivation, primary requirement)—not vendor pricing or competitor precedent.
  4. Discard unsupported assumptions. For each convention tag, state a falsifier. Drop or renegotiate anything lacking support.
  5. Rebuild from remaining primitives only. Simplest solution that satisfies binding constraints and ignores artificial ones. Prefer commodity inputs and fewer moving parts over analogy.
  6. Validate and stop. Check against real physics, contracts, and measured needs. Define the cheapest kill test. Stop when a coherent rebuild plus discriminating validation exists, or when only verified hard constraints remain.
Show full SKILL.md (112 more words)Show less

Output

Emit a first-principles rebuild:

  • claimed_constraints: list with classification tags
  • primitives: independently supported truths only
  • discarded_assumptions: conventions dropped and why
  • rebuild: solution derived only from primitives
  • binding_residuals: real limits that remain
  • kill_test: cheapest check that would falsify the rebuild

Verification

  • Independence check: every primitive must cite measurement, derivation, or primary requirement—not precedent alone.
  • No smuggled analogy: if the rebuild still depends on "how others do it" without a primitive, strip it.
  • Constraint honesty: verified physics/regulation must remain; do not wish them away.
  • Over-application guard: if a standard solution is already optimal under verified constraints, do not rebuild for novelty.
  • Stop: one decompose → classify → rebuild → kill-test pass; do not recurse without new evidence.

© tjboudreaux, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in skills/thinking-first-principles of tjboudreaux/cc-thinking-skills.

Open the folder on GitHubat commit 7b8fece

Compare with similar skills

Thinking First Principles next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Thinking First Principles compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Thinking First Principles this skilltjboudreaux/cc-thinking-skills1.6k—~839Automated safety check: PassMIT
First Principles Thinkingmindfold-ai/Trellis15k—~4.1kAutomated safety check: PassMIT
Fixalirezarezvani/claude-skills28k1 repos~765Automated safety check: PassMIT
Principle Foundational Thinkingcursor/plugins10k8 repos~383Automated safety check: PassNone
Principle Fix Root Causescursor/plugins10k9 repos~312Automated safety check: PassNone
Constraint Physicalhashgraph-online/awesome-codex-plugins1.3k—~1.2kAutomated safety check: PassApache-2.0

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Questions about Thinking First Principles

What does Thinking First Principles do?

When a constraint is treated as fixed, separate physics from convention, keep only independently supported primitives, and rebuild the simplest solution that satisfies real constraints. Thinking First Principles is an agent skill from tjboudreaux/cc-thinking-skills. When a constraint is treated as fixed, separate physics from convention, keep only independently supported primitives, and rebuild the simplest solution that satisfies real constraints.

How do I install Thinking First Principles in Claude Code?

Run `npx skills add tjboudreaux/cc-thinking-skills --skill thinking-first-principles -a claude-code`. Or copy the skill folder (skills/thinking-first-principles in tjboudreaux/cc-thinking-skills) into .claude/skills/thinking-first-principles in your project. Claude Code loads it when a task matches its description.

How do I install Thinking First Principles in Codex?

Run `npx skills add tjboudreaux/cc-thinking-skills --skill thinking-first-principles -a codex`. Or copy the skill folder (skills/thinking-first-principles in tjboudreaux/cc-thinking-skills) into .agents/skills/thinking-first-principles in your project. Codex loads it when a task matches its description.

Can I use Thinking First Principles in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add tjboudreaux/cc-thinking-skills --skill thinking-first-principles -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/thinking-first-principles, .gemini/skills/thinking-first-principles, .github/skills/thinking-first-principles and .opencode/skills/thinking-first-principles in your project.

What does Thinking First Principles need to run?

SKILL.md names no scripts, command-line tools or credentials: Thinking First Principles is instructions for the agent only.

Does Thinking First Principles access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Thinking First Principles safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Thinking First Principles use?

Thinking First Principles is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Thinking First Principles use?

About 839 tokens (SKILL.md is roughly 3.4k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Thinking First Principles?

Skills that share tags, products or a category with Thinking First Principles: First Principles Thinking (mindfold-ai/Trellis, 15k stars), Fix (alirezarezvani/claude-skills, 28k stars), Principle Foundational Thinking (cursor/plugins, 10k stars) and Principle Fix Root Causes (cursor/plugins, 10k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Thinking First Principles?

tjboudreaux (a GitHub user) maintains it in tjboudreaux/cc-thinking-skills, which has 1,612 GitHub stars. The repository holds 26 skills in this directory. The repository was last updated on August 7, 2026.

Source: tjboudreaux/cc-thinking-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.