creating-skills

creating-skills is a skill for Claude Code, Codex from mitodl/agent-kit. It costs 52 tokens per session (788 once invoked), scanned A, original, BSD-3-Clause.

A workflow for creating a new Agent Skill in a repository, including its instruction file, folder placement and catalogue entry. It follows the repository's naming and metadata conventions.

In plain words
What is it for?
Use it when turning a repeated process or project convention into a reusable skill, including choosing its category and updating the index.
Why use it?
It reduces setup mistakes that can stop a skill from being found or used correctly. It also makes repeated workflows easier to share with other agents.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/mitodl/agent-kit/creating-skills
Any agent
npx skills add mitodl/agent-kit --skill creating-skills
Clone the repo
git clone --depth 1 https://github.com/mitodl/agent-kit

Made for: Claude Code, Codex.

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-skills

README.md
[![agentmods](https://agentmods.dev/badge/skills/mitodl/agent-kit/creating-skills.svg)](https://agentmods.dev/skills/mitodl/agent-kit/creating-skills)
Your own site
<a href="https://agentmods.dev/skills/mitodl/agent-kit/creating-skills"><img src="https://agentmods.dev/badge/skills/mitodl/agent-kit/creating-skills.svg" alt="Measured on agentmods" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 788 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00052 $0.00788
Opus 5 $0.00026 $0.00394
Sonnet 5 $0.00010 $0.00158
Haiku 4.5 $0.00005 $0.00079

Measured 3d ago against content hash b107d3036011, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 3d 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.

skills/workflow/creating-skills/SKILL.md · 108 lines

How it starts

The opening of the file, as written. The whole thing — 108 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Creating a New Skill

Skills follow the Agent Skills open standard.

1. Choose a category

Place the skill under the most specific matching category in skills/:

Category When to use
python/ Python tooling, packaging, dependency management
dagster/ Dagster pipelines, code locations, dg usage
infrastructure/ Pulumi IaC, secrets, Vault, Kubernetes config
containers/ Docker builds, image conventions
workflow/ Cross-cutting process conventions; meta-skills

If no category fits, create a new one and add a README.md for it.

2. Create the skill directory

The directory name becomes the skill's name. Use lowercase letters and hyphens only.

skills/<category>/<skill-name>/
└── SKILL.md

The name in SKILL.md frontmatter must exactly match the directory name.

3. Write SKILL.md

---
name: <skill-name>           # must match directory name; max 64 chars
description: >               # what it does AND when to use it; max 1024 chars
  <one or two sentences describing the skill and the keywords/scenarios
  that should trigger it>
license: BSD-3-Clause
metadata:
  category: <category>
---

# Skill Title

...instructions...

Description guidelines (most important field)

The description is what the agent uses to decide whether to activate the skill. Make it trigger-friendly:

  • State both what the skill covers and when to use it.
  • Include the specific tool names, command names, or scenario keywords an agent would encounter when the skill is relevant.
  • Bad: "Conventions for X." — too vague, won't trigger reliably.
  • Good: "Apply X conventions. Use this skill when doing Y or Z — covers A, B, C."

4. Apply progressive disclosure

Keep SKILL.md under ~500 lines. If the skill has deep reference material (e.g., a detailed API reference, form templates, domain-specific lookup tables), move it to a references/ subdirectory and link to it from SKILL.md:

Read the full file on GitHub · 108 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. 3d ago First seen · 108 lines · 52 tokens per session scan A b107d3036011

Subscribe to this mod's changes

creating-skills is a skill published in the GitHub repository mitodl/agent-kit (2 stars, last pushed 5d ago), licensed BSD-3-Clause. It adds 52 tokens to every session and 788 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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