agent-development

Create and validate Codex plugin agents with frontmatter, system prompts, and triggering examples.

Updated Jul 10, 2026
One-click install
npx skills add https://github.com/AvaTar-ArTs/.Agent-skills --skill agent-development-avatar-arts
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: agent-development
Source: https://github.com/AvaTar-ArTs/.Agent-skills/tree/main/skills/agent-development
Command: npx skills add https://github.com/AvaTar-ArTs/.Agent-skills --skill agent-development-avatar-arts

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) and references (resource) components.

What problem does it solve? Writing Codex plugin agents requires precise frontmatter fields, triggering descriptions with examples, and well-structured system prompts, and mistakes in any of these cause agents to fail to trigger or behave unpredictably. ## Core Features & Use Cases - Agent File Authoring: Defines the complete Markdown agent format including name, description, model, color, and tools frontmatter fields with validation rules. - Triggering Design: Provides description patterns with 2-4 example blocks so agents activate under the right conditions. - System Prompt Templates: Supplies structured prompt templates covering responsibilities, process steps, output formats, and edge cases. - Use Case: When building a code-review plugin, use this Skill to generate a code-reviewer agent file with valid frontmatter, triggering examples, and a complete system prompt, then validate it with the included scripts. ## Quick Start Create a Codex plugin agent named code-reviewer with proper frontmatter, triggering examples, and a structured system prompt.

Frequently Asked Questions about agent-development

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I create an agent for a Codex plugin?▼

Create a Markdown file in the plugin's agents/ directory with YAML frontmatter containing name, description, model, and color fields, followed by a system prompt body. The description must include triggering conditions and 2-4 example blocks showing when the agent activates.

What frontmatter fields are required for a Codex agent?▼

Codex agents require name, description, model, and color fields, with tools as optional. The name must be 3-50 lowercase characters with hyphens, and the model field is typically set to inherit unless specific capabilities are needed.

How do I write a description that triggers an agent correctly?▼

Write triggering conditions starting with "Use this agent when" followed by 2-4 example blocks containing context, user request, assistant response, and commentary. Cover different phrasings of the same intent and explain why the agent triggers in each commentary.

What are the naming rules for Codex agent identifiers?▼

Agent identifiers must be 3-50 characters using only lowercase letters, numbers, and hyphens, starting and ending with an alphanumeric character. Underscores, spaces, and leading or trailing hyphens are invalid.

How do I restrict which tools an agent can access?▼

Add a tools array to the frontmatter listing only the required tool names, such as ["Read", "Grep"] for read-only analysis. Omitting the field grants access to all tools, so apply least privilege by limiting tools to the minimum needed.