andrej-karpathy

name	andrej-karpathy
description	Behavioral guidelines to reduce common LLM coding mistakes. Use when writing, reviewing, or refactoring code to avoid overcomplication, make surgical changes, surface assumptions, and define verifiable success criteria.
risk	safe
source	community
source_repo	multica-ai/andrej-karpathy-skills
source_type	community
license	MIT
license_source	https://github.com/multica-ai/andrej-karpathy-skills/blob/main/skills/karpathy-guidelines/SKILL.md
date_added	2026-03-06
author	renat
tags	["coding-guidelines","code-review","llm-coding","simplicity"]
tools	["claude-code","antigravity","cursor","gemini-cli","codex-cli"]

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.

When to Use This Skill

• Use when writing, reviewing, or refactoring code with an LLM.
• Use when a change needs to stay surgical and avoid speculative abstractions.
• Use when assumptions, tradeoffs, and verification criteria should be made explicit.
• Use when code has become overcomplicated and needs to be simplified.

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 such as "make it work" require constant clarification.

Examples

User request: "Add validation to this form."

Better response:
1. Assumption: validation should run before submit and show inline errors.
2. Plan: add a small validator, add tests for invalid inputs, then verify existing submit behavior.
3. Scope: only touch the form component and its test file.

User request: "Refactor this service."

Better response:
1. Ask what behavior must remain unchanged.
2. Identify a concrete smell, such as duplicated parsing logic.
3. Make the smallest refactor and run the existing service tests.

Limitations

• These guidelines are behavioral guardrails, not a replacement for project-specific architecture or style rules.
• For emergency fixes, prioritize the smallest verified correction over extensive planning.
• For exploratory prototypes, some caution can be relaxed, but assumptions and verification should still be explicit.