create-skill

create-skill is a skill for Claude Code, Codex from siviter-xyz/dot-agent. It costs 24 tokens per session (648 once invoked), scanned A, original, MIT.

A guide for creating skills, which are self-contained instruction packages that extend an AI coding agent with workflows, knowledge, tools, or supporting files.

In plain words
What is it for?
It explains how to structure skill instructions, use progressive loading, keep the main file short, and add references or bundled resources.
Why use it?
It helps authors keep skills focused, maintainable, and easy for the agent to load when needed.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

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 skills/siviter-xyz/dot-agent/create-skill
Any agent
npx skills add siviter-xyz/dot-agent --skill create-skill
Clone the repo
git clone --depth 1 https://github.com/siviter-xyz/dot-agent

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 create-skill

README.md
[![agentmods](https://agentmods.dev/badge/skills/siviter-xyz/dot-agent/create-skill.svg)](https://agentmods.dev/skills/siviter-xyz/dot-agent/create-skill)
Your own site
<a href="https://agentmods.dev/skills/siviter-xyz/dot-agent/create-skill"><img src="https://agentmods.dev/badge/skills/siviter-xyz/dot-agent/create-skill.svg" alt="Measured on agentmods" height="20"></a>
Per session 24 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 648 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00024 $0.00648
Opus 5 $0.00012 $0.00324
Sonnet 5 $0.00005 $0.00130
Haiku 4.5 $0.00002 $0.00065

Measured 6d ago against content hash a88f91120ab8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

create-skill 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 6d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

skills/create-skill/SKILL.md · 79 lines

How it starts

The opening of the file, as written. The whole thing — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Create Skill

Guide for creating effective skills that extend agent capabilities with specialized knowledge, workflows, and tool integrations.

About Skills

Skills are modular, self-contained packages that extend agent capabilities by providing specialized knowledge, workflows, and tools. Think of them as "onboarding guides" for specific domains or tasks.

What Skills Provide

  1. Specialized workflows - Multi-step procedures for specific domains
  2. Tool integrations - Instructions for working with specific file formats or APIs
  3. Domain expertise - Company-specific knowledge, schemas, business logic
  4. Bundled resources - Scripts, references, and assets for complex and repetitive tasks

Progressive Disclosure Principle

The 200-line rule is critical. SKILL.md must be under 200 lines. If you need more, split content into references/ files.

Three-Level Loading System

  1. Metadata (name + description) - Always in context (~100 words)
  2. SKILL.md body - When skill triggers (<200 lines, ideally <500 lines for optimal performance)
  3. Bundled resources - As needed by agent (unlimited)

Why Progressive Disclosure Matters

  • 85% reduction in initial context load
  • Activation times drop from 500ms+ to under 100ms
  • Agent loads only what's needed, when it's needed
  • Skills remain maintainable and focused

Skill Structure

skill-name/
├── SKILL.md (required, <200 lines)
│   ├── YAML frontmatter metadata (required)
│   │   ├── name: (required)
│   │   └── description: (required)
│   └── Markdown instructions (required)
└── Bundled Resources (optional)
    ├── scripts/          - Executable code
    ├── references/       - Documentation loaded as needed
    └── assets/           - Files used in output

Core Principles

Concise is Key

The context window is a shared resource. Your skill shares it with everything else the agent needs. Be concise and challenge each piece of information:

  • Does the agent really need this explanation?
  • Can I assume the agent knows this?
  • Does this paragraph justify its token cost?

Read the full file on GitHub · 79 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 6d ago First seen · 79 lines · 24 tokens per session scan A a88f91120ab8

Subscribe to this mod's changes

create-skill is a skill published in the GitHub repository siviter-xyz/dot-agent (21 stars, last pushed 5mo ago), licensed MIT. It adds 24 tokens to every session and 648 once invoked, about $0.0001 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.

Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

local-ai-agents

Build local-first AI agents that run entirely on a developer workstation with Microsoft Foundry Local and Qwen function-calling models. Covers Small Language Models (SLMs), the OpenAI-compatible local endpoint, sandboxed local tools, local RAG with Chroma, local MCP servers, hybrid cloud/local routing, and the…

microsoft/ai-agents-for-beginners · 200 tokens

next-cache-components-adoption

Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…

vercel/next.js · 95 tokens

chat-pet-sprite-creation

Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.

microsoft/vscode · 53 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens

insight-error-page

Write or audit an insight-kind error page for the Next.js dev overlay. Use when creating a new errors/ .mdx page, auditing an existing one, or checking that a page matches the framework fix cards. Covers page structure, title alignment, FixCard cards with Copy prompt button, code snippets, terminology verification…

vercel/next.js · 83 tokens