An interactive teaching and exploration command for Lean 4 and mathlib. It can explain mathematical topics, inspect a project, or guide learning with different teaching styles.

Use it to study a topic, navigate mathlib, explore a repository, learn from a PDF, or create explanations and notes in a scratch file.

It helps people understand unfamiliar Lean code and formal mathematics by adapting explanations and exploring relevant library material.

learn — Command by cameronfreer

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods

npx agentmods add commands/cameronfreer/lean4-skills/learn

Clone the repo

git clone --depth 1 https://github.com/cameronfreer/lean4-skills

Or install lean4, the plugin that ships this one along with the rest of its 1 skill, 12 commands, 4 agents, 3 hooks.

Per session 8 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 4,090 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5	$0.00008	$0.04090
Opus 5	$0.00004	$0.02045
Sonnet 5	$0.00002	$0.00818
Haiku 4.5	$0.00001	$0.00409

Measured 3d ago against content hash ad2cff2e6f26, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

learn scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/lean4/commands/learn.md · 206 lines

How it starts

The opening of the file, as written. The whole thing — 206 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Lean4 Learn

Interactive teaching and mathlib exploration. Adapts to beginner, intermediate, and expert audiences.

Usage

/lean4:learn                                 # Start conversational discovery
/lean4:learn Finset.sum                      # Auto-detect mode from topic
/lean4:learn --mode=repo                     # Explore current project
/lean4:learn --mode=mathlib topology         # Navigate mathlib for a topic
/lean4:learn --style=socratic --interactive  # True Socratic method
/lean4:learn --style=game --track=nng-like   # Game-style natural numbers track
/lean4:learn --source ./paper.pdf            # Learn from a paper/PDF
/lean4:learn --presentation=informal "Bolzano-Weierstrass"  # Prose, Lean-backed
/lean4:learn --output=scratch                # Write results to scratch file
/lean4:learn --style=socratic --adaptive=off  # Socratic, no style/level drift

Invocation Contract

Interpret this command's inputs per the Command Invocation Contract.

Primary path (hook-validated): If a validated-invocation block for this command appears in context, treat it as the authoritative interpretation of parser-decidable inputs and do not re-parse the raw invocation text for those inputs. Start by reading all parser-decided fields from the block. Then, if this command has repo-dependent startup rules (the --mode=mathlib scope coercion depends on local-declaration resolution), apply them using runtime context (LSP, grep). Emit the final Resolved Inputs summary from the combined result. See Validated Invocation Block.

Fallback path (other hosts): If no validated-invocation block is present, parse the raw invocation text against this command's input table before discovery.

Startup requirements:

Emit a Resolved Inputs block with explicit values, defaults, coercions, ignored flags, and startup validation errors.
Refuse to start on startup validation errors.
Validate output paths and overwrite policy before writing anything.

Read the full file on GitHub · 206 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

3d ago First seen · 206 lines · 8 tokens per session scan A ad2cff2e6f26

Subscribe to this mod's changes

learn is a command published in the GitHub repository cameronfreer/lean4-skills (418 stars, last pushed 7d ago), licensed MIT. It adds 8 tokens to every session and 4,090 once invoked, about $0.0000 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Learning and teaching Scientific

learn

Getting it into your agent

What it costs to keep this loaded

Grade A, and why

Nothing flagged

How it starts

Lean4 Learn

Usage

Invocation Contract

What this file has done since we first saw it

Other commands, from other repositories

learn

formalize

autoformalize

derive

teach

afsim-learn