What is creating-agent-skills?

A guide to creating and improving Claude Code Skills, which are instruction files that teach a coding agent how to handle particular tasks. It covers their format, descriptions, organisation, and examples.

Use it when writing a new SKILL.md file, refining an existing skill, or checking whether a skill follows the recommended structure.

It helps make skills easier for an agent to discover and follow. It also helps keep instructions focused and move detailed material into supporting files.

creating-agent-skills — Skill for Claude Code by roberto-mello/lavra

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 roberto-mello/lavra --skill create-agent-skills

Clone the repo

git clone --depth 1 https://github.com/roberto-mello/lavra

Made for: Claude Code.

Or install lavra, the plugin that ships this one along with the rest of its 23 skills, 18 commands, 1 hook, 1 MCP server.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/roberto-mello/lavra/create-agent-skills/github.svg)](https://agentmods.dev/skills/roberto-mello/lavra/create-agent-skills)

Your own site

<a href="https://agentmods.dev/skills/roberto-mello/lavra/create-agent-skills"><img src="https://agentmods.dev/badge/skills/roberto-mello/lavra/create-agent-skills/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/roberto-mello/lavra/create-agent-skills"><img src="https://agentmods.dev/badge/skills/roberto-mello/lavra/create-agent-skills.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,663 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 84% copy Near-identical to another mod 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.

Model	Per session	Once invoked
Fable 5.1	$0.00034	$0.01663
Opus 5.5	$0.00014	$0.00665
Sonnet 5.5	$0.00007	$0.00333
Haiku 4.5	$0.00003	$0.00166

Measured 2mo ago against content hash 07c0a97d51f7, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, 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 2mo 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

This is a copy

84% identical to creating-agent-skills — 11 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/lavra/skills/create-agent-skills/SKILL.md · 309 lines

How it starts

The opening of the file, as written. The whole thing — 309 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Creating Agent Skills

This skill teaches how to create effective Claude Code Skills following Anthropic's official specification.

Core Principles

1. Skills Are Prompts

All prompting best practices apply. Be clear, be direct. Assume Claude is smart - only add context Claude doesn't have.

2. Standard Markdown Format

Use YAML frontmatter + markdown body. No XML tags - use standard markdown headings.

---
name: my-skill-name
description: What it does and when to use it
---

# My Skill Name

## Quick Start
Immediate actionable guidance...

## Instructions
Step-by-step procedures...

## Examples
Concrete usage examples...

3. Progressive Disclosure

Keep SKILL.md under 500 lines. Split detailed content into reference files. Load only what's needed.

my-skill/
├── SKILL.md              # Entry point (required)
├── reference.md          # Detailed docs (loaded when needed)
├── examples.md           # Usage examples
└── scripts/              # Utility scripts (executed, not loaded)

4. Effective Descriptions

The description field enables skill discovery. Include both what the skill does AND when to use it. Write in third person.

Good:

description: Extracts text and tables from PDF files, fills forms, merges documents. Use when working with PDF files or when the user mentions PDFs, forms, or document extraction.

Bad:

description: Helps with documents

Skill Structure

Required Frontmatter

Field	Required	Max Length	Description
`name`	Yes	64 chars	Lowercase letters, numbers, hyphens only
`description`	Yes	1024 chars	What it does AND when to use it
`allowed-tools`	No	-	Tools Claude can use without asking
`model`	No	-	Specific model to use

Naming Conventions

Use gerund form (verb + -ing) for skill names:

processing-pdfs
analyzing-spreadsheets
generating-commit-messages
reviewing-code

Read the full file on GitHub · 309 lines

Files

What ships with it

25 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.

2mo ago First seen · 309 lines · 34 tokens per session scan A 07c0a97d51f7

Subscribe to this mod's changes

creating-agent-skills is a skill published in the GitHub repository roberto-mello/lavra (53 stars, last pushed 21d ago), licensed MIT. It adds 34 tokens to every session and 1,663 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 84% identical to creating-agent-skills, differing in 11 lines, and is treated as a copy.

Building agents Claude Code Multi-Agent agents ai beads coding

creating-agent-skills next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
creating-agent-skillsroberto-mello/lavra	Skill	53	21d ago	MIT	A	34	Claude Code
agent-framework-py-releasemicrosoft/agent-framework	Skill	15k	today	MIT	A	102	Claude Code, Codex
python-package-managementmicrosoft/agent-framework	Skill	15k	today	MIT	A	43	Claude Code, Codex
foundry-hosted-agent-validationmicrosoft/agent-framework	Skill	15k	today	MIT	A	82	Claude Code, Codex
agent-framework-builder-dotnetmicrosoft/agent-framework	Skill	15k	today	MIT	A	82	Claude Code, Codex
build-and-testmicrosoft/agent-framework	Skill	15k	today	MIT	A	26	Claude Code, Codex
python-feature-lifecyclemicrosoft/agent-framework	Skill	15k	today	MIT	A	43	Claude Code, Codex