oh-my-openagent/docs/category-skill-guide.md

Category & Skill System Guide

This document provides a comprehensive guide to the Category and Skill systems, which form the extensibility core of Oh-My-OpenCode.

1. Overview

Instead of delegating everything to a single AI agent, it's far more efficient to invoke specialists tailored to the nature of the task.

• Category: "What kind of work is this?" (determines model, temperature, prompt mindset)
• Skill: "What tools and knowledge are needed?" (injects specialized knowledge, MCP tools, workflows)

By combining these two concepts, you can generate optimal agents through delegate_task.

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2. Category System

A Category is an agent configuration preset optimized for specific domains.

Available Built-in Categories

Category	Default Model	Use Cases
visual-engineering	google/gemini-3-pro	Frontend, UI/UX, design, styling, animation
ultrabrain	openai/gpt-5.2-codex (xhigh)	Deep logical reasoning, complex architecture decisions requiring extensive analysis
artistry	google/gemini-3-pro (max)	Highly creative/artistic tasks, novel ideas
quick	anthropic/claude-haiku-4-5	Trivial tasks - single file changes, typo fixes, simple modifications
unspecified-low	anthropic/claude-sonnet-4-5	Tasks that don't fit other categories, low effort required
unspecified-high	anthropic/claude-opus-4-5 (max)	Tasks that don't fit other categories, high effort required
writing	google/gemini-3-flash	Documentation, prose, technical writing

Usage

Specify the category parameter when invoking the delegate_task tool.

delegate_task(
  category="visual-engineering",
  prompt="Add a responsive chart component to the dashboard page"
)

Sisyphus-Junior (Delegated Executor)

When you use a Category, a special agent called Sisyphus-Junior performs the work.

• Characteristic: Cannot re-delegate tasks to other agents.
• Purpose: Prevents infinite delegation loops and ensures focus on the assigned task.

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3. Skill System

A Skill is a mechanism that injects specialized knowledge (Context) and tools (MCP) for specific domains into agents.

Built-in Skills

1. git-master

   • Capabilities: Git expert. Detects commit styles, splits atomic commits, formulates rebase strategies.
   • MCP: None (uses Git commands)
   • Usage: Essential for commits, history searches, branch management.

2. playwright

   • Capabilities: Browser automation. Web page testing, screenshots, scraping.
   • MCP: @playwright/mcp (auto-executed)
   • Usage: For post-implementation UI verification, E2E test writing.

3. frontend-ui-ux

   • Capabilities: Injects designer mindset. Color, typography, motion guidelines.
   • Usage: For aesthetic UI work beyond simple implementation.

Usage

Add desired skill names to the load_skills array.

delegate_task(
  category="quick",
  load_skills=["git-master"],
  prompt="Commit current changes. Follow commit message style."
)

Skill Customization (SKILL.md)

You can add custom skills directly to .opencode/skills/ in your project root or ~/.claude/skills/ in your home directory.

Example: .opencode/skills/my-skill/SKILL.md

---
name: my-skill
description: My special custom skill
mcp:
  my-mcp:
    command: npx
    args: ["-y", "my-mcp-server"]
---

# My Skill Prompt

This content will be injected into the agent's system prompt.
...

---

4. Combination Strategies (Combos)

You can create powerful specialized agents by combining Categories and Skills.

🎨 The Designer (UI Implementation)

• Category: visual-engineering
• load_skills: ["frontend-ui-ux", "playwright"]
• Effect: Implements aesthetic UI and verifies rendering results directly in browser.

🏗️ The Architect (Design Review)

• Category: ultrabrain
• load_skills: [] (pure reasoning)
• Effect: Leverages GPT-5.2's logical reasoning for in-depth system architecture analysis.

⚡ The Maintainer (Quick Fixes)

• Category: quick
• load_skills: ["git-master"]
• Effect: Uses cost-effective models to quickly fix code and generate clean commits.

---

5. delegate_task Prompt Guide

When delegating, clear and specific prompts are essential. Include these 7 elements:

1. TASK: What needs to be done? (single objective)
2. EXPECTED OUTCOME: What is the deliverable?
3. REQUIRED SKILLS: Which skills should be loaded via load_skills?
4. REQUIRED TOOLS: Which tools must be used? (whitelist)
5. MUST DO: What must be done (constraints)
6. MUST NOT DO: What must never be done
7. CONTEXT: File paths, existing patterns, reference materials

Bad Example:

"Fix this"

Good Example:

TASK: Fix mobile layout breaking issue in LoginButton.tsx CONTEXT: src/components/LoginButton.tsx, using Tailwind CSS MUST DO: Change flex-direction at md: breakpoint MUST NOT DO: Modify existing desktop layout EXPECTED: Buttons align vertically on mobile

---

6. Configuration Guide (oh-my-opencode.json)

You can fine-tune categories in oh-my-opencode.json.

Category Configuration Schema (CategoryConfig)

Field	Type	Description
description	string	Human-readable description of the category's purpose. Shown in delegate_task prompt.
model	string	AI model ID to use (e.g., anthropic/claude-opus-4-5)
variant	string	Model variant (e.g., max, xhigh)
temperature	number	Creativity level (0.0 ~ 2.0). Lower is more deterministic.
top_p	number	Nucleus sampling parameter (0.0 ~ 1.0)
prompt_append	string	Content to append to system prompt when this category is selected
thinking	object	Thinking model configuration ({ type: "enabled", budgetTokens: 16000 })
reasoningEffort	string	Reasoning effort level (low, medium, high)
textVerbosity	string	Text verbosity level (low, medium, high)
tools	object	Tool usage control (disable with { "tool_name": false })
maxTokens	number	Maximum response token count
is_unstable_agent	boolean	Mark agent as unstable - forces background mode for monitoring

Example Configuration

{
  "categories": {
    // 1. Define new custom category
    "korean-writer": {
      "model": "google/gemini-3-flash",
      "temperature": 0.5,
      "prompt_append": "You are a Korean technical writer. Maintain a friendly and clear tone."
    },
    
    // 2. Override existing category (change model)
    "visual-engineering": {
      "model": "openai/gpt-5.2", // Can change model
      "temperature": 0.8
    },

    // 3. Configure thinking model and restrict tools
    "deep-reasoning": {
      "model": "anthropic/claude-opus-4-5",
      "thinking": {
        "type": "enabled",
        "budgetTokens": 32000
      },
      "tools": {
        "websearch_web_search_exa": false // Disable web search
      }
    }
  },
  
  // Disable skills
  "disabled_skills": ["playwright"]
}