Lean4 Skills plugin for Codex
Lean 4 theorem proving skill and workflow pack for AI coding agents
How to install Lean4 Skills in Codex
1. Add the repo as a Codex plugin marketplace:
codex plugin marketplace add cameronfreer/lean4-skills2. Install the plugin from it:
codex plugin add lean4@lean4-skillsThis repo ships a Codex marketplace file (.agents/plugins/marketplace.json). The first command adds it as a marketplace (Codex CLI reference); the second installs the plugin 'lean4'. 'lean4-skills' is the marketplace name from that file. Check the repo README too. Command format: Codex CLI reference.
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What it contains
Plugins in this marketplace (1)
lean4— Unified Lean 4 plugin (draft, formalize, autoformalize, prove, autoprove, disprove, checkpoint, review, refactor, golf, learn, diagnose) — LSP-first, scripts fallback
About this listing
Lean4 Skills is a community plugin on GitHub by cameronfreer. Its README documents a Codex install and the repo ships a Codex plugin manifest. It passed the CodexStacks quality filter for repos found this way (at least 100 stars, pushed in the last 90 days, not a fork or a list). OpenAI hasn't reviewed it, but it passed our Codex install check on Oct 29, 2026 (an install and load check, not a code review). From its files we found 1 plugin. It's one of 441 listings in the Developer Tools category (category assigned by CodexStacks from the repo's topics and description).
Lean4 Skills FAQ
How do I install Lean4 Skills in Codex?
Add the repo as a Codex plugin marketplace with codex plugin marketplace add cameronfreer/lean4-skills, then install it with codex plugin add lean4@lean4-skills. Commands: the command format from the Codex CLI reference; check the repo README too.
Is Lean4 Skills an official Codex plugin?
No. Lean4 Skills is a community repo on GitHub by cameronfreer. It passed the CodexStacks quality filter, but OpenAI hasn't reviewed it, but it passed our Codex install check on Oct 29, 2026 (an install and load check, not a code review), so read the code before you install it.
What does Lean4 Skills include?
From its manifest and repo files, Lean4 Skills includes 1 plugin: lean4.
Details
- Type
- Plugin
- Category
- Developer Tools (assigned by us)
- Source
- Community
- Author
- cameronfreer
- License
- MIT
- GitHub stars
- 476 (at last sync)
- Last push
- 2026-10-28
- Manifest
.agents/plugins/marketplace.json- Source
- https://github.com/cameronfreer/lean4-skills
- Listed via
- GitHub search: README documents a Codex install
- Install check by CodexStacks
- Passed on Oct 29, 2026 with Codex CLI 0.163.0: Codex loaded its skills. proof · how we check
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For maintainers: badge and embeds
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Markdown
[](https://codexstacks.com/p/lean4-skills/)HTML
<a href="https://codexstacks.com/p/lean4-skills/"><img src="https://codexstacks.com/badge.svg" alt="Listed on CodexStacks" width="172" height="28"></a>Embed card (static HTML and inline CSS, no JavaScript). Preview:
<a href="https://codexstacks.com/p/lean4-skills/" style="display:block;max-width:380px;box-sizing:border-box;padding:14px 16px;border:1px solid #3a2c26;border-radius:12px;background:#0d0b0a;color:#f3ece6;font:14px/1.45 -apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;text-decoration:none"><span style="display:block;font-size:16px;font-weight:700;color:#f3ece6">Lean4 Skills</span><span style="display:block;margin:2px 0 8px;font-size:12px;color:#b5a9a1">Community Codex plugin · 1 plugin</span><span style="display:block;margin:0 0 10px;color:#ddd3cc">Lean 4 theorem proving skill and workflow pack for AI coding agents</span><span style="font-size:12px;font-weight:600;color:#ffb347">View on CodexStacks →</span></a>Markdown summary
**[Lean4 Skills on CodexStacks](https://codexstacks.com/p/lean4-skills/)**: Community Codex plugin with 1 plugin.More on badges, embeds and keeping your listing up to date: CodexStacks for plugin authors.
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