software-development-karpathy-guidelines

software-development-karpathy-guidelines is a skill for Claude Code, Codex from xiaohei-info/oh-my-multica. It costs 48 tokens per session (1,249 once invoked), scanned A, original, MIT.

Behavior guidelines for coding agents based on observations about common mistakes made by language models. They encourage small, careful changes, explicit assumptions, and checks that confirm the result.

In plain words
What is it for?
Use them when writing, reviewing, or refactoring code, especially when deciding scope, stating assumptions, choosing a surgical change, and defining how success will be verified.
Why use it?
They reduce unnecessary rewrites, guessed requirements, and overcomplicated solutions. They also help keep answers focused on what was actually requested.

Skill for Claude CodeCodex

Which agent this was written for is unclear — built for hermes-agent. Also seen: built for hermes-agent.

Good fit Use them when writing, reviewing, or refactoring code, especially when deciding scope, stating assumptions, choosing a surgical change, and defining how success will be verified.

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Install with agentmods
npx agentmods add skills/xiaohei-info/oh-my-multica/software-development-karpathy-guidelines
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.

Any agent
npx skills add xiaohei-info/oh-my-multica --skill software-development-karpathy-guidelines
Clone the repo
git clone --depth 1 https://github.com/xiaohei-info/oh-my-multica

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for software-development-karpathy-guidelines

README.md
[![agentmods](https://agentmods.dev/badge/skills/xiaohei-info/oh-my-multica/software-development-karpathy-guidelines/github.svg)](https://agentmods.dev/skills/xiaohei-info/oh-my-multica/software-development-karpathy-guidelines)
Your own site
<a href="https://agentmods.dev/skills/xiaohei-info/oh-my-multica/software-development-karpathy-guidelines"><img src="https://agentmods.dev/badge/skills/xiaohei-info/oh-my-multica/software-development-karpathy-guidelines/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for software-development-karpathy-guidelines

Your own site · 80×15
<a href="https://agentmods.dev/skills/xiaohei-info/oh-my-multica/software-development-karpathy-guidelines"><img src="https://agentmods.dev/badge/skills/xiaohei-info/oh-my-multica/software-development-karpathy-guidelines.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,249 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
SkillSpector: 1 finding, up to low

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • low Excessive Agency · line 24
    Skill's behavior or capabilities extend beyond its stated purpose. Scope creep allows an agent to perform actions unrelated to its documented functionality, increasing the attack surface.
    Fix: Limit the skill's scope to its documented purpose. Remove instructions that enable the agent to perform actions outside its stated functionality.
How audits are shown
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00048 $0.01249
Opus 5 $0.00024 $0.00624
Sonnet 5 $0.00010 $0.00250
Haiku 4.5 $0.00005 $0.00125

Measured 11d ago against content hash 00724d8fe1c7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

software-development-karpathy-guidelines 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 11d 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.

src/omac/agents/backend-eng/skills/software-development-karpathy-guidelines/SKILL.md · 101 lines

How it starts

The opening of the file, as written. The whole thing — 101 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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.

5. Answer the Question, Not the Implied Next Step

Research questions are not implementation mandates. When the user asks "does X", "will Y", "is Z", "how does", or "what would happen if" — that is not a request to change anything.

Common failure pattern:

  • User: "Will these 40 tools waste my tokens?" → Agent: answers + modifies config
  • User: "How does this repo work?" → Agent: clones and installs it
  • User: "Clarify the mapping between current repo paths and design-doc terms" → Agent: starts bulk-renaming design docs instead of adding the requested bridge note

Special case for docs and repo-structure work:

  • When the user asks for a README, orientation note, or terminology mapping, prefer the smallest bridging artifact that explains the relationship.
  • Do NOT silently expand the scope into sweeping doc rewrites, mass renames, or terminology cleanup unless the user explicitly asked for that broader change.
  • Preserve the distinction between design-layer terms (architecture roles like Agent Service / Agent Runtime) and physical filesystem names (e.g. app/ and hermes-agent/) when the user wants both to coexist.

Correct pattern:

  • Answer the question with data.
  • If there's a natural "would you like me to..." follow-up, offer it SEPARATELY after answering.
  • Do not bundle the answer and the action in one turn unless explicitly asked.

Messaging/file-delivery pitfall:

  • If the user asks you to send a file (e.g. "把文档发给我", "send me the markdown file"), they want an actual attachment or outbound file delivery — not the file contents pasted into chat.
  • In that case, use the messaging/file-delivery path first. Do not substitute with an inline dump unless the user explicitly asks for the content.
  • If your first attempt used a file marker/path but the user says they did not receive a file, switch to an explicit send step to the concrete channel/target and confirm delivery with the returned handle.

Read the full file on GitHub · 101 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.

  1. 11d ago First seen · 101 lines · 48 tokens per session scan A 00724d8fe1c7

Subscribe to this mod's changes

software-development-karpathy-guidelines is a skill published in the GitHub repository xiaohei-info/oh-my-multica (26 stars, last pushed 4d ago), licensed MIT. It adds 48 tokens to every session and 1,249 once invoked, about $0.0002 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.