creating-agent-skills

creating-agent-skills is a skill for Claude Code, Codex from pr-pm/prpm. It costs 47 tokens per session (1,403 once invoked), scanned A, original, MIT.

A guide for creating Agent Skills packages: folders containing a SKILL.md file and optional scripts, references, or assets. Agent Skills are portable instructions that can give coding agents a repeatable capability.

In plain words
What is it for?
Use it to create or update skills and check that their names, descriptions, directories, and front matter follow the specification.
Why use it?
It removes uncertainty about the required file format, naming rules, folder layout, and metadata. The same package can be prepared for Codex CLI, GitHub Copilot, or Amp.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents); mentions Codex.

Good fit Use it to create or update skills and check that their names…

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Install with agentmods
npx agentmods add skills/pr-pm/prpm/creating-agent-skills
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 pr-pm/prpm --skill creating-agent-skills
Clone the repo
git clone --depth 1 https://github.com/pr-pm/prpm

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 creating-agent-skills

README.md
[![agentmods](https://agentmods.dev/badge/skills/pr-pm/prpm/creating-agent-skills.svg)](https://agentmods.dev/skills/pr-pm/prpm/creating-agent-skills)
Your own site
<a href="https://agentmods.dev/skills/pr-pm/prpm/creating-agent-skills"><img src="https://agentmods.dev/badge/skills/pr-pm/prpm/creating-agent-skills.svg" alt="Measured on agentmods" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,403 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.
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 $0.00047 $0.01403
Opus 5 $0.00023 $0.00701
Sonnet 5 $0.00009 $0.00281
Haiku 4.5 $0.00005 $0.00140

Measured 7d ago against content hash f059549a2eb6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

creating-agent-skills 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 7d 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.

.agents/skills/creating-agent-skills/SKILL.md · 239 lines

How it starts

The opening of the file, as written. The whole thing — 239 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Creating Agent Skills

Overview

Agent Skills is an open standard for portable AI agent capabilities. One SKILL.md file works across Codex CLI, GitHub Copilot, and Amp.

Official Spec: https://agentskills.io/specification

Installation Directories

Tool Location
Codex CLI .agents/skills/{skill-name}/SKILL.md
GitHub Copilot .github/skills/{skill-name}/SKILL.md
Amp .agents/skills/{skill-name}/SKILL.md

Directory Structure

my-skill/                 # Must match frontmatter `name`
├── SKILL.md              # Required - main definition
├── scripts/              # Optional - executable code
├── references/           # Optional - additional docs
└── assets/               # Optional - static resources

Frontmatter Specification

Required Fields

---
name: skill-name
description: What it does and when to use it
---
Field Constraints
name 1-64 chars, lowercase alphanumeric + hyphens, no leading/trailing/consecutive hyphens, must match parent directory
description 1-1024 chars, explains functionality AND use cases

Optional Fields

---
name: pdf-processing
description: Extracts and processes PDF content. Use for document analysis and text extraction.
license: MIT
compatibility: Requires pdftotext, poppler-utils
allowed-tools: Bash(pdftotext:*) Read Write
metadata:
  category: document-processing
  version: 1.0.0
---
Field Constraints
license Short reference (e.g., MIT, Apache-2.0)
compatibility 1-500 chars, environment requirements
allowed-tools Space-delimited pre-approved tools (experimental)
metadata Arbitrary string key-value pairs

Name Validation

✅ Valid: pdf-processing, code-review, data-analysis
❌ Invalid: PDF-Processing (uppercase), -pdf (leading hyphen), pdf--processing (consecutive hyphens)

Pattern: ^[a-z0-9]+(-[a-z0-9]+)*$

Read the full file on GitHub · 239 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. 7d ago First seen · 239 lines · 47 tokens per session scan A f059549a2eb6

Subscribe to this mod's changes

creating-agent-skills is a skill published in the GitHub repository pr-pm/prpm (120 stars, last pushed 2mo ago), licensed MIT. It adds 47 tokens to every session and 1,403 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.