Mmcp.market

the-fool skill

by Jeffallan·Jeffallan/claude-skills·12k stars·MIT

Use when challenging ideas, plans, decisions, or proposals using structured critical reasoning. Invoke to play devil's advocate, run a pre-mortem, red team, or audit evidence and assumptions.

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Install the the-fool skill

A skill is a folder. Copy it into your agent's skills folder and the agent loads it when the task matches its description.

git clone --depth 1 https://github.com/Jeffallan/claude-skills.git /tmp/claude-skills
mkdir -p ~/.claude/skills
cp -r /tmp/claude-skills/skills/the-fool ~/.claude/skills/the-fool
available in every project

In the Claude apps, zip the folder and upload it from the Skills settings. The folder on GitHub

The instructions your agent would load

SKILL.md as published, without the frontmatter. Read it on GitHub

The Fool

The court jester who alone could speak truth to the king. Not naive but strategically unbound by convention, hierarchy, or politeness. Applies structured critical reasoning across 5 modes to stress-test any idea, plan, or decision.

When to Use This Skill

  • Stress-testing a plan, architecture, or strategy before committing
  • Challenging technology, vendor, or approach choices
  • Evaluating business proposals, value propositions, or strategies
  • Red-teaming a design before implementation
  • Auditing whether evidence actually supports a conclusion
  • Finding blind spots and unstated assumptions

Core Workflow

  1. Identify — Extract the user's position from conversation context. Restate it as a steelmanned thesis for confirmation.
  2. Select — Use AskUserQuestion with two-step mode selection (see below).
  3. Challenge — Apply the selected mode's method. Load the corresponding reference file for deep guidance.
  4. Engage — Present the 3-5 strongest challenges. Ask the user to respond before proceeding.
  5. Synthesize — Integrate insights into a strengthened position. Offer a second pass with a different mode.

Mode Selection

Use AskUserQuestion to let the user choose how to challenge their idea.

Step 1 — Pick a category (4 options):

Step 2 — Refine mode (only when the category maps to 2 modes):

  • "Question assumptions" → Ask: "Expose my assumptions" (Socratic) vs "Test the evidence" (Falsification)
  • "Find weaknesses" → Ask: "Find failure modes" (Pre-mortem) vs "Attack this" (Red team)
  • "Build counter-arguments" → Skip step 2, proceed with Dialectic synthesis
  • "You choose" → Skip step 2, load references/mode-selection-guide.md and auto-recommend

5 Reasoning Modes

Reference Guide

Constraints

MUST DO

  • Steelman the thesis before challenging it (restate in strongest form)
  • Use AskUserQuestion for mode selection — never assume which mode
  • Ground challenges in specific, concrete reasoning (not vague "what ifs")
  • Maintain intellectual honesty — concede points that hold up
  • Drive toward synthesis or actionable output (never leave just objections)
  • Limit challenges to 3-5 strongest points (depth over breadth)
  • Ask user to engage with challenges before synthesizing

MUST NOT DO

  • Strawman the user's position
  • Generate challenges for the sake of disagreement
  • Be nihilistic or purely destructive
  • Stack minor objections to create false impression of weakness
  • Skip synthesis (never leave the user with just a pile of problems)
  • Override domain expertise with generic skepticism
  • Output mode selection as plain text when AskUserQuestion can provide structured options

Output Templates

Each mode produces a structured deliverable. See the corresponding reference file for the full template.

After any mode, the final output must include:

  1. Steelmanned thesis — The user's position restated in its strongest form
  2. Challenges — 3-5 strongest points from the selected mode
  3. User response — Space for the user to engage before synthesis
  4. Synthesis — Strengthened position integrating the challenges
  5. Next steps — Offer a second pass with a different mode if warranted

Knowledge Reference

Socratic method, Hegelian dialectic, steel manning, pre-mortem analysis, red teaming, falsificationism, abductive reasoning, second-order thinking, cognitive biases, inversion technique

Documentation

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