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.
npx skills add gabrielmoreira/agent-skills-mirror --skill creating-skills-skillgit clone --depth 1 https://github.com/gabrielmoreira/agent-skills-mirrorWrote 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.
[](https://agentmods.dev/skills/gabrielmoreira/agent-skills-mirror/creating-skills-skill)<a href="https://agentmods.dev/skills/gabrielmoreira/agent-skills-mirror/creating-skills-skill"><img src="https://agentmods.dev/badge/skills/gabrielmoreira/agent-skills-mirror/creating-skills-skill/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.
<a href="https://agentmods.dev/skills/gabrielmoreira/agent-skills-mirror/creating-skills-skill"><img src="https://agentmods.dev/badge/skills/gabrielmoreira/agent-skills-mirror/creating-skills-skill.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00039 | $0.03350 |
| Opus 5 | $0.00019 | $0.01675 |
| Sonnet 5 | $0.00008 | $0.00670 |
| Haiku 4.5 | $0.00004 | $0.00335 |
Grade A, and why
creating-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.
This is a copy
100% identical to creating-skills — 0 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.
How it starts
The opening of the file, as written. The whole thing — 526 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Creating Skills
Overview
Skills are reference guides for proven techniques, patterns, or tools. Write them to help future Claude instances quickly find and apply effective approaches.
Skills must be discoverable (Claude can find them), scannable (quick to evaluate), and actionable (clear examples).
Core principle: Default assumption is Claude is already very smart. Only add context Claude doesn't already have.
When to Use
Create a skill when:
- Technique wasn't intuitively obvious
- Pattern applies broadly across projects
- You'd reference this again
- Others would benefit
Don't create for:
- One-off solutions specific to single project
- Standard practices well-documented elsewhere
- Project conventions (put those in
.claude/CLAUDE.md)
Required Structure
Frontmatter (YAML)
---
name: skill-name-with-hyphens
description: Use when [triggers/symptoms] - [what it does and how it helps]
tags: relevant-tags
---
Rules:
- Only
nameanddescriptionfields supported (max 1024 chars total) - Name: letters, numbers, hyphens only (max 64 chars). Use gerund form (verb + -ing)
- Avoid reserved words: "anthropic", "claude" in names
- Description: Third person, starts with "Use when..." (max 1024 chars)
- Include BOTH triggering conditions AND what skill does
- Match specificity to task complexity (degrees of freedom)
Document Structure
# Skill Name
## Overview
Core principle in 1-2 sentences. What is this?
## When to Use
- Bullet list with symptoms and use cases
- When NOT to use
## Quick Reference
Table or bullets for common operations
## Implementation
Inline code for simple patterns
Link to separate file for heavy reference (100+ lines)
## Common Mistakes
What goes wrong + how to fix
## Real-World Impact (optional)
Concrete results from using this technique
Degrees of Freedom
Match specificity to task complexity:
- High freedom: Flexible tasks requiring judgment
- Use broad guidance, principles, examples
- Let Claude adapt approach to context
- Example: "Use when designing APIs - provides REST principles and patterns"
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.
- 7d ago First seen · 526 lines · 39 tokens per session scan A c5daed46fa97
creating-skills is a skill published in the GitHub repository gabrielmoreira/agent-skills-mirror (17 stars, last pushed yesterday), licensed MIT. It adds 39 tokens to every session and 3,350 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to creating-skills, differing in 0 lines, and is treated as a copy.
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