Lean Knowledge Formalization

Q: What is a Claude Code skill and how does the Lean Knowledge Formalization skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Lean Knowledge Formalization is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Product category. Learn more at https://claudskills.com/learn/what-is-skill-md/.

Category: Product · Sub-category: product-misc · Last updated: 2026-05-30

USE FOR: Knowledge representation, ontology engineering, symbolic AI, commonsense reasoning, causal reasoning, legal reasoning, and abductive inference in Lean 4. Use when formalizing knowledge structures, reasoning systems, argumentation frameworks, deontic logic, defeasible reasoning, or any domain where structured knowledge and inference must be formally verified. Core skill for knowledge-lifecycle and provenance architectures. DO NOT USE FOR: KRR methodology not in Lean (use @ai-symbolic-neuro); commonsense reasoning methodology (use @ai-commonsense-reasoning); causal/deontic methodology (use @ai-causal-deontic). TRIGGERS: knowledge formalisation, ontology in Lean, symbolic AI Lean, abductive inference Lean, legal reasoning Lean.

Security AStatic scan found no risk patternsHow grading works ›

From the source SKILL.md

Guide to formalizing knowledge representation, reasoning systems, and domain-specific logic in Lean 4.

What this skill does

Lean Knowledge Formalization is a community-contributed Claude Code skill in the product-misc sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/lean-knowledge-formalization/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when formalizing knowledge structures, reasoning systems, argumentation frameworks, deontic logic, defeasible reasoning, or any domain where structured knowledge and inference must be formally verified. Core skill for knowledge-lifecycle and provenance architectures.

Who uses this skill

The Lean Knowledge Formalization Claude Code skill is built for product managers, product designers, and cross-functional teams planning, shipping, and measuring product features. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 211,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/lean-knowledge-formalization
curl -L https://claudskills.com/skills/lean-knowledge-formalization/SKILL.md \
  -o ~/.claude/skills/lean-knowledge-formalization/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/lean-knowledge-formalization/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/lean-knowledge-formalization/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\lean-knowledge-formalization\SKILL.md on Windows. See the full install guide for step-by-step instructions.

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the Lean Knowledge Formalization Claude Code skill?

Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/lean-knowledge-formalization/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.

What does the Lean Knowledge Formalization skill do?

Is this skill free to install?

Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.

When should I use the Lean Knowledge Formalization skill?

Use Lean Knowledge Formalization when your Claude Code task falls under the Product category — specifically in the product misc area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Lean Knowledge Formalization" or describe the task and let Claude pick). Browse related skills at /category/product/.

What is a Claude Code skill and how does the Lean Knowledge Formalization skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Lean Knowledge Formalization is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Product category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Source: https://github.com/r-irbe/proof-skills/blob/HEAD/skills/lean-knowledge-formalization/SKILL.md
License: Apache-2.0
Author: r-irbe
Website: https://github.com/r-irbe/proof-skills

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA

r-irbe. (2026). Lean Knowledge Formalization [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/lean-knowledge-formalization/

BibTeX

@misc{lean-knowledge-formalization-2026,
  author    = {r-irbe},
  title     = {Lean Knowledge Formalization [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/lean-knowledge-formalization/}
}

Embed this skill

Promote, attribute, or link this skill from your own README, blog post, or documentation. All three snippets are free to use — no sign-up, no API key. More distribution surfaces →

Badge

[![ClaudSkills](https://claudskills.com/badge/lean-knowledge-formalization.svg)](https://claudskills.com/skills/lean-knowledge-formalization/?utm_source=badge&utm_medium=readme&utm_campaign=skill_badge)

Security scan

Grade A · scanned 2026-10-25 — free static scan against the OWASP Agentic Skills Top 10.

The scan flagged 1 of 10 categories (filesystem), including lower-severity patterns. Patterns shown inside code fences are weighted as examples rather than instructions — read the grading methodology for what this does and does not guarantee.

✓ Prompt injection
✓ Data exfiltration
✓ Supply chain
✓ Reverse shell
✓ Credentials
✓ Execution
⚠ Filesystem
✓ Persistence
✓ Obfuscation
✓ Network

Show this grade on your repo (click to copy):

[![Security: A](https://img.shields.io/badge/Security-A-2e7d32)](https://claudskills.com/skills/lean-knowledge-formalization/#security)

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