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Agent skill

Feynman

by LilMGenius in LilMGenius/paperthin

Press a decision you just made until you can explain it to a skeptic in your own words, or surface the gap where you can't.

MITAuto-check passedDevelopment

Install Feynman

skills CLI
$ npx skills add LilMGenius/paperthin --skill feynman -a claude-code

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

GitHub CLI
$ gh skill install LilMGenius/paperthin feynman --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/LilMGenius/paperthin.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/depth/feynman .claude/skills/feynman && 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
feynman
GitHub stars
1.1k
Token cost
~1k tokens
SKILL.md length
624 words
Files
1
Skills in repo
28
Repo updated
First seen
Licence
MIT

At a glance

Press a decision you just made until you can explain it to a skeptic in your own words, or surface the gap where you can't.

  • Works in 8 steps: Trigger: fire right after a decision is… → Restate, don't justify: state the… → Isolate the critic: hand the decision —… → …
  • Development work in your project
  • SKILL.md covers Goal, Workflow, Rules and Verification
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Feynman is an agent skill from LilMGenius/paperthin. Press a decision you just made until you can explain it to a skeptic in your own words, or surface the gap where you can't. The Feynman test aimed at a choice: understanding is cheapest to fake the moment after you decide, so a fresh critic presses for what you can't actually explain. Use right after picking an option, especially one an agent laid out without arguing for.

Its SKILL.md is about 1k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Development. The repository describes itself as: Low-level agentic design patterns. Turning old engineering wisdom into reflexes your agent reaches for on its own—on any agent. The licence is MIT.

When your agent uses it

  • Development work in your project

Example prompts

  • “/feynman”

Workflow steps

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

  1. Trigger: fire right after a decision is made — typically just after options were laid out with no argument for any, and one was picked.
  2. Restate, don't justify: state the decision neutrally. Do not supply the reasoning behind it, and do not let the user borrow reasoning that…
  3. Isolate the critic: hand the decision — not any reasoning — to a fresh, context-free sub-session that never watched the decision get made…
  4. Return one gap at a time: give the user the sharpest unresolved gap and ask them to explain it in their own words. Never batch gaps into a…
  5. Judge the explanation: if the answer actually resolves the gap, close it and move on. If it restates the question, deflects, or leans on…
  6. Narrow, don't repeat: on a shallow answer, don't ask the same question again — narrow to the exact part that stayed vague and ask that…
  7. Stop condition: after repeated rounds, either every gap is genuinely explained, or one isn't. Both are valid endings.
  8. On an unexplained gap: don't force a resolution or let the user paper over it. Name the unresolved point specifically and flag the…

What it can do on your machine

Read from SKILL.md and the folder at commit 7d5dc62. 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

Feynman loads about 1k tokens when it runs. Until then it costs about 96 tokens; SKILL.md has 624 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~96
When it runs · the whole SKILL.md, loaded when a task matches
~1k

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 LilMGenius/paperthin at commit 7d5dc62, republished under its MIT licence (© LilMGenius). 624 words, ~1,039 tokens.

Download SKILL.mdSave it as .claude/skills/feynman/SKILL.md (or your agent's skills folder).
name
feynman
description
Press a decision you just made until you can explain it to a skeptic in your own words, or surface the gap where you can't. The Feynman test aimed at a choice: understanding is cheapest to fake the moment after you decide, so a fresh critic presses for what you can't actually explain. Use right after picking an option, especially one an agent laid out without arguing for.
disable-model-invocation
true

Press a decision you just made until you can explain it, or the gap where you can't is named.

Goal

The moment after a choice is when understanding is cheapest to fake: you can restate an option fluently without having earned the reasons behind it, and by the time that gap matters the decision is load-bearing elsewhere. The Feynman test catches it — if you can't explain a thing plainly, you don't yet understand it. So no one hands you the rationale; a fresh critic that never made the decision presses for what you can't actually explain, and a shallow answer draws a narrower question instead of a pass. The result is a decision you can now explain under real pressure, or an honest flag that you can't yet.

Workflow

  1. Trigger: fire right after a decision is made — typically just after options were laid out with no argument for any, and one was picked.
  2. Restate, don't justify: state the decision neutrally. Do not supply the reasoning behind it, and do not let the user borrow reasoning that was never actually given.
  3. Isolate the critic: hand the decision — not any reasoning — to a fresh, context-free sub-session that never watched the decision get made. Have it press for gaps: what a skeptical outsider would ask, what is assumed but unstated, what would have to be true for the choice to hold.
  4. Return one gap at a time: give the user the sharpest unresolved gap and ask them to explain it in their own words. Never batch gaps into a checklist.
  5. Judge the explanation: if the answer actually resolves the gap, close it and move on. If it restates the question, deflects, or leans on authority ("the agent suggested it") instead of reasoning, do not accept it.
  6. Narrow, don't repeat: on a shallow answer, don't ask the same question again — narrow to the exact part that stayed vague and ask that. Keep narrowing each round; never widen back to a generic "are you sure?"
  7. Stop condition: after repeated rounds, either every gap is genuinely explained, or one isn't. Both are valid endings.
  8. On an unexplained gap: don't force a resolution or let the user paper over it. Name the unresolved point specifically and flag the decision for re-review — not a verdict that it was wrong, only that it isn't yet earned.
Show full SKILL.md (229 more words)Show less

Rules

  • Never supply the rationale before the user attempts one. Handing reasoning over first is the frame-injection failure this skill exists to avoid.
  • The pressing comes from an isolated sub-session, never self-assessed in the session that made the choice — a mind can't un-know the decision it just made, any more than an author can un-know their own draft.
  • Narrow, don't repeat. A second identical question teaches the user to restate louder; a narrower one tests whether the gap actually closed.
  • Never force a resolution. An honestly unexplained gap is a usable result — a signal the decision needs another look — not a failure of the skill.
  • User-invoked on purpose: a challenge-every-decision reflex always in reach would bias the user toward chronic self-doubt. It fires only when deliberately reached for.

Verification

  1. Compare the user's first answer to a gap against their answer after narrowing — the round-over-round change in what they can actually explain is the real signal, not merely that no more objections came up.
  2. Every closed gap traces to an explanation that resolved the actual question, not one that restated it.
  3. Any gap still open is named specifically — which assumption, not a vague "the user struggled" — and carried forward as a flag on the decision, never silently dropped.
  4. The rationale was never supplied by this skill; every reason that closed a gap came from the user.

© LilMGenius, 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/depth/feynman of LilMGenius/paperthin.

Open the folder on GitHubat commit 7d5dc62

Compare with similar skills

Feynman 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.

Feynman compared with similar skills
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Feynman this skillLilMGenius/paperthin1.1k—~1kAutomated safety check: PassMIT
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Typescript Advanced Typesrolling-scopes/rsschool-app10k25 repos~4.2kAutomated safety check: PassMPL-2.0
PR Babysitteropeninterpreter/openinterpreter69k3 repos~4.2kAutomated safety check: PassApache-2.0
Code Review ChecklistshareAI-lab/learn-claude-code78k5 repos~1.1kAutomated safety check: PassMIT

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Categories

Questions about Feynman

What does Feynman do?

Press a decision you just made until you can explain it to a skeptic in your own words, or surface the gap where you can't. Feynman is an agent skill from LilMGenius/paperthin. Press a decision you just made until you can explain it to a skeptic in your own words, or surface the gap where you can't.

When should I use Feynman?

Feynman fits situations like: development work in your project.

How do I install Feynman in Claude Code?

Run `npx skills add LilMGenius/paperthin --skill feynman -a claude-code`. Or copy the skill folder (skills/depth/feynman in LilMGenius/paperthin) into .claude/skills/feynman in your project. Claude Code loads it when a task matches its description.

How do I install Feynman in Codex?

Run `npx skills add LilMGenius/paperthin --skill feynman -a codex`. Or copy the skill folder (skills/depth/feynman in LilMGenius/paperthin) into .agents/skills/feynman in your project. Codex loads it when a task matches its description.

Can I use Feynman 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 LilMGenius/paperthin --skill feynman -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/feynman, .gemini/skills/feynman, .github/skills/feynman and .opencode/skills/feynman in your project.

What does Feynman need to run?

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

Does Feynman 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 Feynman 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 Feynman use?

Feynman 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 Feynman use?

About 1k tokens (SKILL.md is roughly 4.2k 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 Feynman?

Skills that share tags, products or a category with Feynman: Vercel Composition Patterns (supabase/supabase, 111k stars), Finishing a Development Branch (obra/superpowers, 296k stars), Typescript Advanced Types (rolling-scopes/rsschool-app, 10k stars) and PR Babysitter (openinterpreter/openinterpreter, 69k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Feynman?

LilMGenius (a GitHub user) maintains it in LilMGenius/paperthin, which has 1,130 GitHub stars. The repository holds 28 skills in this directory. The repository was last updated on October 1, 2026.

Source: LilMGenius/paperthin on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.