create-skill

create-skill is a skill for Claude Code, Codex from aeonfun/aeon. It costs 20 tokens per session (4,051 once invoked), scanned A, original, MIT.

A skill that creates a new coding-agent skill from a one-line description and submits the result as a GitHub pull request, a proposed change for review.

In plain words
What is it for?
Use it to request skills that monitor sources, fetch data, generate files, analyze information, track changes, or send alerts. The request can specify the action, data source, output, and schedule.
Why use it?
It turns a rough automation idea into a structured, reviewable skill and checks for similar existing skills before creating it.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions CLAUDE.md.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is DRYRUN_VERDICT="output/.dry-run/$name.json" bash scripts/dry-run.sh run "$name" || true.

Good fit Use it to request skills that monitor sources, fetch data, generate files, analyze information, track changes, or send alerts. The request can specify the action, data source, output, and schedule.

Compare 6 skills from other repositories ↓
Install

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.

Clone the repo
git clone --depth 1 https://github.com/aeonfun/aeon
agentmods
npx agentmods add skills/aeonfun/aeon/create-skill

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 create-skill

README.md
[![agentmods](https://agentmods.dev/badge/skills/aeonfun/aeon/create-skill/github.svg)](https://agentmods.dev/skills/aeonfun/aeon/create-skill)
Your own site
<a href="https://agentmods.dev/skills/aeonfun/aeon/create-skill"><img src="https://agentmods.dev/badge/skills/aeonfun/aeon/create-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.

agentmods 80×15 button for create-skill

Your own site · 80×15
<a href="https://agentmods.dev/skills/aeonfun/aeon/create-skill"><img src="https://agentmods.dev/badge/skills/aeonfun/aeon/create-skill.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 20 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,051 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Rogue Agent · line 234
    Skill modifies its own code, configuration, or behavior at runtime. Self-modification enables an agent to escalate privileges, disable safety constraints, or install persistent backdoors.
    Fix: Prevent the skill from modifying its own code, SKILL.md, or configuration files. Treat skill files as read-only at runtime.
How audits are shown
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 $0.00020 $0.04051
Opus 5.5 $0.00008 $0.01620
Sonnet 5.5 $0.00004 $0.00810
Haiku 4.5 $0.00002 $0.00405

Measured 12d ago against content hash a428cc9c850a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

create-skill scanned grade A with 1 finding 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 12d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

2. **{Step title}.** {More instructions. Code blocks for curl/bash when relevant.}
Origin

Copies of this mod

1 near-identical copy found in the catalogue:

skills/create-skill/SKILL.md · 268 lines

How it starts

The opening of the file, as written. The whole thing — 268 lines — stays where its author put it; the contents beside it link to each section on GitHub.

${var} — A natural-language description of the skill to create. Required. Example: "monitor Hacker News for AI papers and send a summary" or "track gas prices on Ethereum and alert when below 10 gwei".

If ${var} is empty, exit CREATE_SKILL_NO_VAR:

./notify "create-skill aborted: var empty — pass a description e.g. \"monitor X for Y\""

Then stop.

Today is ${today}. Your task is to generate a complete, production-ready skill from ${var}, score it against a quality bar, and ship it as a PR — never commit directly to main.

Steps

  1. Parse the request. Extract from ${var}:

    • Core action verb (monitor, fetch, generate, analyze, alert, track, scan, etc.)
    • Data source(s) — APIs, websites, RSS, on-chain, GitHub, etc.
    • Output format — notification, article, file, PR, dashboard, etc.
    • Configurable parameter(s) the new skill will accept via its own ${var}
    • Suggested cadence (daily, hourly, weekly, on-demand)

    Save a one-paragraph structured request summary; you'll use it in the PR body.

  2. Duplicate detection (deep — not just ls). Find functional overlap, not just name collision.

    keywords=$(echo "${var}" | tr '[:upper:]' '[:lower:]' | grep -oE '[a-z]{4,}' \
      | grep -vE '^(send|with|from|that|this|when|each|into|over|some|like|just|than|then|also|will|have|been|using|monitor|track|fetch|alert)$' \
      | sort -u)
    for kw in $keywords; do
      grep -liE "$kw" skills/*/SKILL.md | head -5
    done
    

    Read the top 3 candidates fully. For each, judge: does it already do this? Could the request be solved by running an existing skill with a different var=?

    • Near-duplicate exists → exit CREATE_SKILL_DUPLICATE. Notify with the existing skill name and a one-line suggestion ("use existing {skill} with var={...} instead"). Stop.
    • Functionally adjacent → design the new skill to complement (different angle/cadence/output). Document the boundary in the PR body.
  3. Research the data sources. For every API or data source the new skill needs:

    • WebSearch for the current API documentation. Cross-check against a secondary source when feasible (a recent GitHub repo using it, an official changelog, or a Stack Overflow answer dated ≥2026) to confirm the endpoint isn't deprecated.
    • WebFetch the canonical docs URL — record it as a comment in the SKILL.md and in the PR body's "Sources researched" section.
    • Identify exact endpoints, required headers, auth scheme, response schema, and rate limits.
    • Note every required environment variable / API key.
    • Determine fallback strategy when an optional API key isn't set (WebSearch / WebFetch / cached data / public endpoint).

    Research bar (soft): at least one confirmed source URL or exemplar (a working docs page or a public repo using the API). If none, do not hard-abort — log CREATE_SKILL_INSUFFICIENT_RESEARCH, ask the operator via ./notify with what was tried and why each source failed, and stop. The operator can re-dispatch with a clearer prompt or a source hint.

  4. New-secret guard. Secrets values are never inspectable from the workflow — only names are listed. Use gh api repos/:owner/:repo/actions/secrets --jq '.secrets[].name' to read the names of secrets already configured (this endpoint returns names only, never values). Cross-reference with env-var usage in aeon.yml and existing workflows. For each env var the new skill needs:

    • Name present → continue.
    • Name missing → record as NEW_SECRET_REQUIRED. The generated skill must gracefully degrade or skip when the secret is absent (no hard crash). Add a ### Required secrets section to the PR body listing what the operator must add to GitHub Actions secrets before enabling.

    If the secret has no graceful fallback, the generated skill's step 1 must do:

    if [ -z "$VAR" ]; then ./notify "{skill} skipped: VAR not set"; exit 0; fi
    

Read the full file on GitHub · 268 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. 12d ago Changed a428cc9c850a
  2. 18d ago Changed · +8 lines 817deb2f4a31
  3. 1mo ago First seen · 260 lines · 20 tokens per session scan A 312b970cc904

Subscribe to this mod's changes

create-skill is a skill published in the GitHub repository aeonfun/aeon (778 stars, last pushed today), licensed MIT. It adds 20 tokens to every session and 4,051 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.