creating-agent-skill

A skill for creating and reviewing Agent Skills, which are folders of instructions that extend an AI agent for specialized work.

In plain words
What is it for?
Creating a new `SKILL.md`, reviewing an existing skill, and improving its organization or compliance.
Why use it?
It helps keep skills compatible with the open Agent Skills specification and easier for agents to follow. It also provides guidance on names, descriptions, structure, and instructions.

Skill for Claude CodeCodex

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/willvelida/code-minions/creating-agent-skill
Any agent
npx skills add willvelida/code-minions --skill creating-agent-skill
Clone the repo
git clone --depth 1 https://github.com/willvelida/code-minions

Made for: Claude Code, Codex.

Per session 77 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 757 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 $0.00077 $0.00757
Opus 5 $0.00039 $0.00378
Sonnet 5 $0.00015 $0.00151
Haiku 4.5 $0.00008 $0.00076

Measured 3d ago against content hash 103bfc56c52b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

creating-agent-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 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.

packages/creating-agent-skill/skills/creating-agent-skill/SKILL.md · 75 lines

How it starts

The opening of the file, as written. The whole thing — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Creating Agent Skills

Overview

This skill provides capabilities for creating and reviewing Agent Skills that comply with the Agent Skills specification and follow authoring best practices.

Agent Skills are a lightweight, open format for extending AI agent capabilities with specialized knowledge and workflows. A skill is a folder containing a SKILL.md file with metadata and instructions, optionally bundled with scripts, references, and assets.

Capabilities

Capability Action Description
Create actions/create.md Generate a new, specification-compliant Agent Skill
Review actions/review.md Analyse an existing skill for compliance and improvements

Standards

This skill bundles the following standards in standards/:

Standard File Description
Specification specification.md Core Agent Skills format specification
Naming naming.md Naming conventions for skills and files
Descriptions descriptions.md Writing effective skill descriptions
Structure structure.md Directory structure and progressive disclosure
Instructions instructions.md Writing effective skill instructions
Clarifying Questions clarifying-questions.md Questioning framework for gathering skill requirements
Checklist checklist.md Consolidated compliance and quality checklist

Principles

1. Concise is Key

The context window is a shared resource. Only add context the agent doesn't already have. Challenge each piece of information: "Does the agent really need this explanation?"

2. Progressive Disclosure

Structure skills for efficient context use:

  • Metadata (~100 tokens): name and description loaded at startup
  • Instructions (<5000 tokens recommended): Full SKILL.md body loaded when activated
  • Resources (as needed): Additional files loaded only when required

Read the full file on GitHub · 75 lines

Files

What ships with it

9 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. 3d ago First seen · 75 lines · 77 tokens per session scan A 103bfc56c52b

Subscribe to this mod's changes

creating-agent-skill is a skill published in the GitHub repository willvelida/code-minions (23 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 77 tokens to every session and 757 once invoked, about $0.0004 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.

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