Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/bcastelino/agent-skills-kitnpx agentmods add skills/bcastelino/agent-skills-kit/skill-creatorWrote 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/bcastelino/agent-skills-kit/skill-creator)<a href="https://agentmods.dev/skills/bcastelino/agent-skills-kit/skill-creator"><img src="https://agentmods.dev/badge/skills/bcastelino/agent-skills-kit/skill-creator/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/bcastelino/agent-skills-kit/skill-creator"><img src="https://agentmods.dev/badge/skills/bcastelino/agent-skills-kit/skill-creator.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 | $0.00052 | $0.02993 |
| Opus 5 | $0.00026 | $0.01496 |
| Sonnet 5 | $0.00010 | $0.00599 |
| Haiku 4.5 | $0.00005 | $0.00299 |
Grade A, and why
skill-creator 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.
How it starts
The opening of the file, as written. The whole thing — 296 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Skill Creator
About
A skill is a folder containing SKILL.md (required instructions with YAML frontmatter) and optional bundled resources. Skills teach Claude how to handle specific tasks or workflows, eliminating the need to re-explain preferences, processes, and domain expertise in every conversation.
Skills are powerful when you have repeatable workflows: generating consistent documents, conducting research with a standard methodology, orchestrating multi-step processes, or providing workflow guidance on top of MCP integrations.
Use Case Categories
Skills fall into three common categories:
Category 1: Document & Asset Creation: creating consistent, high-quality output (documents, presentations, code, designs).
- Key techniques: embedded style guides, template structures, quality checklists
- No external tools required; uses Claude's built-in capabilities
Category 2: Workflow Automation: multi-step processes that benefit from consistent methodology.
- Key techniques: step-by-step workflow with validation gates, iterative refinement loops
- This skill (skill-creator) is a Category 2 example
Category 3: MCP Enhancement: workflow guidance layered on top of an MCP server's tool access.
- Key techniques: multi-MCP call coordination, embedded domain expertise, error handling for MCP failures
Anatomy of a Skill
skill-name/
├── SKILL.md # Required - instructions + YAML frontmatter
├── scripts/ # Optional - executable code (Python, Bash, etc.)
├── references/ # Optional - documentation loaded into context as needed
└── assets/ # Optional - templates, fonts, icons used in output
SKILL.md (required)
The YAML frontmatter is how Claude decides whether to load your skill. Get it right.
Minimal required format:
---
name: your-skill-name
description: What it does. Use when user asks to [specific phrases].
---
Full example with optional fields:
---
name: pdf-rotator
description: Rotates and reorients PDF pages. Use when the user says "rotate PDF", uploads a .pdf and asks to fix page orientation, or needs portrait/landscape conversion.
license: MIT
compatibility: Requires Python 3.9+ and pypdf
metadata: {version: "1.0.0", author: YourName, tags: [pdf-processing, file-manipulation]}
---
What ships with it
3 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.
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.
- 9d ago First seen · 296 lines · 52 tokens per session scan A 98f685121558
skill-creator is a skill published in the GitHub repository bcastelino/agent-skills-kit (2 stars, last pushed 1mo ago), licensed MIT. It adds 52 tokens to every session and 2,993 once invoked, about $0.0003 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 2026-08-31.
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