agent-creation

agent-creation is a skill for Claude Code, Codex from majiayu000/claude-skill-registry. It costs 77 tokens per session (2,989 once invoked), scanned A, original, MIT.

A guide for writing standards-compliant agent definitions in Markdown files with YAML metadata, a format for structured configuration.

In plain words
What is it for?
Use it to create project-specific agents, document their responsibilities, and check their metadata against a schema.
Why use it?
It requires gathering enough context before creation and includes validation steps to prevent incomplete definitions.

Skill for Claude CodeCodex

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

Good fit Use it to create project-specific agents, document their responsibilities, and check their metadata against a schema.

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Install with agentmods
npx agentmods add skills/majiayu000/claude-skill-registry/agent-creation
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.

Any agent
npx skills add majiayu000/claude-skill-registry --skill agent-creation
Clone the repo
git clone --depth 1 https://github.com/majiayu000/claude-skill-registry

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 agent-creation

README.md
[![agentmods](https://agentmods.dev/badge/skills/majiayu000/claude-skill-registry/agent-creation/github.svg)](https://agentmods.dev/skills/majiayu000/claude-skill-registry/agent-creation)
Your own site
<a href="https://agentmods.dev/skills/majiayu000/claude-skill-registry/agent-creation"><img src="https://agentmods.dev/badge/skills/majiayu000/claude-skill-registry/agent-creation/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 agent-creation

Your own site · 80×15
<a href="https://agentmods.dev/skills/majiayu000/claude-skill-registry/agent-creation"><img src="https://agentmods.dev/badge/skills/majiayu000/claude-skill-registry/agent-creation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 77 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,989 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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: 7 findings, 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 Memory Poisoning · line 121
    Skill manipulates agent memory, state, or stored context. Memory corruption can alter personality, override safety rules, or cause unpredictable behavior.
    Fix: Protect agent memory and state from modification by untrusted content. Use read-only memory for critical instructions and validate all state changes.
  • medium Agent Snooping · line 244
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
  • medium Agent Snooping · line 245
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
  • medium Agent Snooping · line 246
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
  • medium Agent Snooping · line 247
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
  • medium Agent Snooping · line 248
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
  • medium Agent Snooping · line 249
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
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 $0.00077 $0.02989
Opus 5 $0.00039 $0.01494
Sonnet 5 $0.00015 $0.00598
Haiku 4.5 $0.00008 $0.00299

Measured 9d ago against content hash 419cbb891d87, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

agent-creation 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.

skills/agent/agent-creation/SKILL.md · 319 lines

How it starts

The opening of the file, as written. The whole thing — 319 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Creation Skill

Overview

Provides actionable instructions for creating standards-compliant agent definitions using templates. Agents are defined in markdown files (AGENTS.md) with YAML frontmatter specifying metadata and a clear, readable structure. This skill enforces context gathering before agent creation to ensure robust and well-defined agents.

Objective

Enable agents and users to generate agent definitions that strictly follow the required structure and conventions using the provided template. Ensure sufficient context is gathered through clarifying questions before proceeding with agent creation. Validate each agent against the JSON schema and provide a compliance checklist to ensure all requirements are met.


When to Use

Use this skill when:

  • Creating a new agent definition from scratch
  • Setting up project-specific agents
  • Documenting agent workflows and responsibilities
  • Defining agent context and skill requirements

Don't use this skill for:

  • Creating individual skills (use skill-creation instead)
  • Creating context prompts (use prompt-creation instead)
  • Modifying existing agents without full context

References


Instructions

Step 1: Gather Context (CRITICAL - DO NOT SKIP)

Before creating an agent definition, you MUST ask clarifying questions when context is missing. Do not proceed until you have sufficient information.

Required context to gather:

  • What is the primary purpose of this agent?
  • What type of input will the agent receive? (e.g., files, text, objects, user queries)
  • What is the expected output format? (e.g., markdown, JSON, text, files)
  • Which skills does the agent need to accomplish its tasks?
  • Are there any specific workflows, policies, or constraints the agent must follow?
  • Who is the target audience for this agent? (e.g., developers, end-users, AI assistants)
  • What technologies, frameworks, or tools will the agent interact with?
  • What is the project context where this agent will operate?
  • Are there any tone or communication style requirements? (e.g., formal, casual, technical)

Read the full file on GitHub · 319 lines

Files

What ships with it

1 file 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.

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. 9d ago First seen · 319 lines · 77 tokens per session scan A 419cbb891d87

Subscribe to this mod's changes

agent-creation is a skill published in the GitHub repository majiayu000/claude-skill-registry (606 stars, last pushed today), licensed MIT. It adds 77 tokens to every session and 2,989 once invoked, about $0.0004 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 2026-09-03.