Getting it into your agent
There is no command for this one: it runs only inside a plugin, and the catalogue could not identify which plugin ships it. The source is linked below.
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.
[](https://agentmods.dev/skills/oaustegard/claude-skills/creating-skill)<a href="https://agentmods.dev/skills/oaustegard/claude-skills/creating-skill"><img src="https://agentmods.dev/badge/skills/oaustegard/claude-skills/creating-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/oaustegard/claude-skills/creating-skill"><img src="https://agentmods.dev/badge/skills/oaustegard/claude-skills/creating-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 | $0.00164 | $0.04925 |
| Opus 5 | $0.00082 | $0.02462 |
| Sonnet 5 | $0.00033 | $0.00985 |
| Haiku 4.5 | $0.00016 | $0.00492 |
Grade A, and why
creating-skill 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 10d 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 — 488 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Creating Skills
Create portable, reusable expertise that extends Claude's capabilities across contexts.
What a skill is for — read before writing one
A skill is a procedural anchor. Measured across 528 paired executions, 65.7% of skill effects come from supplying a usable procedure — setup steps, tool sequence, intermediate checks, pitfalls — and 4.5% from supplying facts the agent lacked (Jiang et al. 2026, arXiv:2608.14036).
Three consequences shape every rule below:
- The procedure is the deliverable. A high-level plan of three to five steps measured at 47.7% success against a 50.0% no-skill baseline. The same experience written as a full SKILL.md measured 79.2%. Vagueness scores worse than silence.
- Abstraction costs something.
skill_guidance_misapplied_or_ignoredruns at 0.8% without a skill and 10.0% with one. A skill that never says when it does not apply has not paid for itself. - Facts are a reference, not a skill. Writing one is fine. Call it a reference and do not expect it to change behaviour.
Load references/skill-utility-evidence.md before authoring or reviewing a SKILL.md. It carries the failure-mode tables behind every requirement here, and reading it is what stops these rules from being followed as ritual.
When to Create Skills
Skills are appropriate when:
- Capability needed across multiple projects/conversations
- Procedural knowledge that applies broadly (not project-specific)
- Instructions should activate automatically on trigger patterns
- Want portable expertise that loads progressively on-demand
Not appropriate when:
- Context is project-specific (use Project instructions instead)
- One-off task (use standalone prompt instead)
- See crafting-instructions skill for detailed decision framework
Skill Structure
Every skill is a directory containing:
SKILL.md(required): Frontmatter + imperative instructionsscripts/(optional): Executable code for deterministic operationsreferences/(optional): Detailed docs loaded on-demandassets/(optional): Templates/files used in output
What ships with it
7 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.
- 10d ago First seen · 488 lines · 164 tokens per session scan A 14e35eb90f0f
creating-skill is a skill published in the GitHub repository oaustegard/claude-skills (148 stars, last pushed yesterday), licensed MIT. It adds 164 tokens to every session and 4,925 once invoked, about $0.0008 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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