karpathy-guidelines

name	Karpathy Guidelines
description	Behavioral guidelines to reduce common LLM coding mistakes — overcomplication, sloppy refactors, hidden assumptions, weak goals. Use when writing, reviewing, or refactoring code. Auto-applies; invoke explicitly via /karpathy-guidelines or 'follow karpathy discipline'.
version	1.0.0
category	core
author	Andrej Karpathy (originator) / forrestchang (skill packaging) / Rulebook (Rulebook adaptation)
tags	["core","discipline","quality"]
dependencies	[]
conflicts	[]
license	MIT
upstream	https://github.com/forrestchang/andrej-karpathy-skills
source	https://x.com/karpathy/status/2015883857489522876

Karpathy Guidelines

Behavioral guidelines to reduce common LLM coding mistakes, derived from Andrej Karpathy's observations on LLM coding pitfalls.

Tradeoff: these guidelines bias toward caution over speed. For trivial tasks, use judgment.

1. Think Before Coding

Don't assume. Don't hide confusion. Surface tradeoffs.

Before implementing:

• State your assumptions explicitly. If uncertain, ask.
• If multiple interpretations exist, present them — don't pick silently.
• If a simpler approach exists, say so. Push back when warranted.
• If something is unclear, stop. Name what's confusing. Ask.

2. Simplicity First

Minimum code that solves the problem. Nothing speculative.

• No features beyond what was asked.
• No abstractions for single-use code.
• No "flexibility" or "configurability" that wasn't requested.
• No error handling for impossible scenarios.
• If you write 200 lines and it could be 50, rewrite it.

Ask yourself: "would a senior engineer say this is overcomplicated?" If yes, simplify.

3. Surgical Changes

Touch only what you must. Clean up only your own mess.

When editing existing code:

• Don't "improve" adjacent code, comments, or formatting.
• Don't refactor things that aren't broken.
• Match existing style, even if you'd do it differently.
• If you notice unrelated dead code, mention it — don't delete it.

When your changes create orphans:

• Remove imports/variables/functions that YOUR changes made unused.
• Don't remove pre-existing dead code unless asked.

The test: every changed line should trace directly to the user's request.

4. Goal-Driven Execution

Define success criteria. Loop until verified.

Transform tasks into verifiable goals:

• "Add validation" → "write tests for invalid inputs, then make them pass."
• "Fix the bug" → "write a test that reproduces it, then make it pass."
• "Refactor X" → "ensure tests pass before and after."

For multi-step tasks, state a brief plan:

1. [Step] → verify: [check]
2. [Step] → verify: [check]
3. [Step] → verify: [check]

Strong success criteria let you loop independently. Weak criteria ("make it work") require constant clarification.

Interaction with Rulebook

This skill complements existing Rulebook rules:

• no-shortcuts.md forbids stubs/TODOs; Simplicity First forbids the opposite — bloat.
• research-first.md requires investigating unknowns; Think Before Coding adds surfacing what was investigated.
• incremental-implementation.md tests each step; Goal-Driven Execution adds defining the test up front.
• Surgical Changes has no Rulebook counterpart and fills a real gap: no rule today forbids opportunistic refactor of adjacent code.

Skill body is deliberately small (≤80 lines) so it adds < 1KB to the context budget per session.