Lean4 Skills plugin for Grok Build

Name: Lean4 Skills
Author: cameronfreer

Community Claude Code plugin, installs in GrokPluginAutomation

Lean 4 theorem proving skill and workflow pack for AI coding agents

How to install Lean4 Skills in Grok Build

1. Add this repo as a plugin marketplace in Grok Build (once per computer):

grok plugin marketplace add cameronfreer/lean4-skills

2. Install the plugin:

grok plugin install lean4@cameronfreer/lean4-skills --trust

✓ Install-checked in Grok Buildchecked Oct 18, 2026

Review before you trust it. --trust lets this plugin's hooks, MCP servers and scripts run code on your computer. It's a community repo that neither xAI nor GrokStacks has reviewed, so read its code first.

This repo's marketplace has 2 plugins; we checked lean4, lean4-contribute. Install another the same way: grok plugin install <name>@cameronfreer/lean4-skills --trust (names under 'What it contains'). Then start a new Grok session, or press r in /plugins, to load it.

Inside Grok Build: type /plugins, open the Marketplace tab, press a and add cameronfreer/lean4-skills, then select lean4 and press i.

Command format: Grok Build's plugin guide

What we checked: on Oct 18, 2026 it installed with grok 1.0.62 and Grok found 16 skills, 15 slash commands, 1 subagent. That's an install check only: we haven't run it in a live Grok session.

What it contains

Skills (16)

lean4 — Use when editing .lean files, debugging Lean 4 builds (type mismatch, sorry, failed to synthesize instance, axiom warnings, lake build errors), searching mathlib for lemmas, formalizing mathematics in Lean, finding a counterexample to, refu
autoformalize — Autonomous end-to-end formalization from informal sources
autoprove — Autonomous multi-cycle theorem proving with explicit stop budgets
checkpoint — Save progress with a safe commit checkpoint
diagnose — Diagnostics, cleanup, and migration help
disprove — Guided counterexample search with certified refutation
draft — Draft Lean declaration skeletons from informal claims
formalize — Interactive formalization — drafting plus guided proving
golf — Improve Lean proofs for directness, clarity, performance, and brevity
learn — Interactive teaching and mathlib exploration
prove — Guided cycle-by-cycle theorem proving with explicit checkpoints
refactor — Leverage mathlib, extract helpers, simplify proof strategies
review — Read-only code review of Lean proofs
bug-report — Draft a bug report issue for lean4-skills
feature-request — Draft a feature request issue for lean4-skills
share-insight — Draft a shareable insight from your session as a GitHub issue

Subagents (4)

lean4:axiom-eliminator — Remove nonconstructive axioms by refactoring proofs to structure (kernels, measurability, etc.). Use after checking axiom hygiene to systematically eliminate custom axioms.
lean4:proof-golfer — Golf Lean 4 proofs after they compile; improve proofs for directness, clarity, performance, and brevity without changing semantics. Use after successful compilation to achieve 30-40% size reduction.
lean4:proof-repair — Compiler-guided iterative proof repair with two-stage repair escalation (fast → strong). Use for error-driven proof fixing with small sampling budgets (K=1).
lean4:sorry-filler-deep — Strategic resolution of stubborn sorries; may refactor across files within the header fence. Use when fast pass fails or for complex proofs.

Hooks (1)

hooks — PreToolUse, SessionStart, UserPromptSubmit

Plugins in this marketplace (2)

lean4 — Unified Lean 4 plugin (draft, formalize, autoformalize, prove, autoprove, disprove, checkpoint, review, refactor, golf, learn, diagnose) — LSP-first, scripts fallback
lean4-contribute — Draft and submit bug reports, feature requests, and insights as GitHub issues. Commands may share Lean code snippets with GitHub — review every draft before confirming.

About this listing

Lean4 Skills is a community plugin on GitHub by cameronfreer, written as a Claude Code plugin that Grok Build installs. We install-checked it in Grok; we haven't run it in a live session or reviewed its code. When we installed it, Grok found 16 skills, 4 subagents, 1 hook, 2 plugins in this marketplaces. Its license is MIT. We checked commit b6243b85b9b0. It's one of 82 listings in the Automation category on GrokStacks.

Lean4 Skills FAQ

How do I install Lean4 Skills in Grok Build?

Add the repo as a marketplace with grok plugin marketplace add cameronfreer/lean4-skills, then run grok plugin install lean4@cameronfreer/lean4-skills --trust. This repo's marketplace has 2 plugins; we checked lean4, lean4-contribute. Install another the same way: grok plugin install <name>@cameronfreer/lean4-skills --trust (names under 'What it contains'). Then start a new Grok session, or press r in /plugins, to load it.

Is Lean4 Skills an official Grok Build plugin?

No. Lean4 Skills is a community plugin on GitHub by cameronfreer, not in xAI's official Grok Build marketplace. We checked that it installs and what Grok loads from it, but haven't run it in a live Grok session or reviewed its code.

What does Lean4 Skills include?

According to what Grok loaded in our install check, Lean4 Skills includes 16 skills, 4 subagents, 1 hook, 2 plugins in this marketplaces: lean4, autoformalize, autoprove, checkpoint, diagnose, disprove….

Details

Type: Plugin
Category: Automation
Source: Community Claude Code plugin, installs in Grok
License: MIT
Author: cameronfreer
Source repo: https://github.com/cameronfreer/lean4-skills
Checked commit: b6243b85b9b0
Checked by GrokStacks: Install-checked in Grok Build on Oct 18, 2026; not run in a live session

Something wrong or missing? Submit or improve this listing. Marketplace listings also refresh automatically every night.

For maintainers: badge and embeds

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Markdown

[![Listed on GrokStacks](https://grokstacks.com/badge.svg)](https://grokstacks.com/p/lean4-skills/)

HTML

<a href="https://grokstacks.com/p/lean4-skills/"><img src="https://grokstacks.com/badge.svg" alt="Listed on GrokStacks" width="164" height="28"></a>

Embed card (static HTML and inline CSS, no JavaScript). Preview:

Lean4 SkillsCommunity plugin for Grok Build · 16 skills, 4 subagents, 1 hook, 2 plugins in this marketplacesLean 4 theorem proving skill and workflow pack for AI coding agentsView on GrokStacks →

<a href="https://grokstacks.com/p/lean4-skills/" style="display:block;max-width:380px;box-sizing:border-box;padding:14px 16px;border:1px solid #2a2e3c;border-radius:12px;background:#0a0b0f;color:#e8eaf0;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:#e8eaf0">Lean4 Skills</span><span style="display:block;margin:2px 0 8px;font-size:12px;color:#9aa0b1">Community plugin for Grok Build · 16 skills, 4 subagents, 1 hook, 2 plugins in this marketplaces</span><span style="display:block;margin:0 0 10px;color:#c9cdd8">Lean 4 theorem proving skill and workflow pack for AI coding agents</span><span style="font-size:12px;font-weight:600;color:#7c9cff">View on GrokStacks →</span></a>

Markdown summary

**[Lean4 Skills on GrokStacks](https://grokstacks.com/p/lean4-skills/)**: Community plugin for Grok Build with 16 skills, 4 subagents, 1 hook, 2 plugins in this marketplaces. Install: `grok plugin install lean4@cameronfreer/lean4-skills --trust` (after `grok plugin marketplace add cameronfreer/lean4-skills`)

More on badges, embeds and keeping your listing up to date: GrokStacks for plugin authors.

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