creating-agent-skills

creating-agent-skills is a skill for Claude Code from roberto-mello/lavra. It costs 34 tokens per session (1,663 once invoked), scanned A, original, MIT.

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.

In plain words
What is it for?
Use it when writing a new SKILL.md file, refining an existing skill, or checking whether a skill follows the recommended structure.
Why use it?
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.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: mentions Claude Code.

Part of the lavra plugin — 23 skills, 18 commands, 1 hook, 1 MCP server shipped together

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

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/roberto-mello/lavra/create-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 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.

agentmods badge for creating-agent-skills

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.

agentmods 80×15 button for creating-agent-skills

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 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 $0.00034 $0.01663
Opus 5 $0.00017 $0.00831
Sonnet 5 $0.00007 $0.00333
Haiku 4.5 $0.00003 $0.00166

Measured 9d ago against content hash 07c0a97d51f7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, 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 9d 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

2 near-identical copies found in the catalogue:

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

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. 9d 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 (51 stars, last pushed 2mo ago), licensed MIT. It adds 34 tokens to every session and 1,663 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.

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