system-prompt-engineering
Design effective system prompts for custom agents. Use when creating agent system prompts, defining agent identity and rules, or designing high-impact prompts that shape agent behavior.
npx skills add majiayu000/claude-skill-registry --skill system-prompt-engineering --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# System Prompt Engineering Skill Design effective system prompts for custom agents that establish identity, rules, and behavior. ## Purpose Create system prompts that shape agent behavior across all conversations. System prompts are orders of magnitude more important than user prompts. ## When to Use - Creating new custom agents - Establishing agent expertise - Defining persistent rules - Building specialized assistants ## System Prompt vs User Prompt | Aspect | System Prompt | User Prompt | | --- | --- | --- | | Scope | All conversations | Single task | | Persistence | Affects everything | Per-request | | Impact | Orders of magnitude higher | Lower blast radius | | Sections | Purpose, Instructions, Examples | All sections | ## Key Sections ### Purpose (Required) Define who the agent is and what it does. ```markdown ## Purpose You are a security expert specializing in code review. Your role is to identify vulnerabilities and suggest fixes. You focus on OWASP Top 10 and secure coding practices. ``` **Guidelines:** - Direct, clear identity statement - Specific expertise area - What the agent DOES ### Instructions (Recommended) Establish rules, constraints, and boundaries. ```markdow
- Purpose
- When to Use
- System Prompt vs User Prompt
- Key Sections
- Purpose (Required)
- Instructions (Recommended)
- Examples (Critical)
- Design Process
- Step 1: Define Agent Identity
- Step 2: Establish Boundaries
- Step 3: Create Examples
- Step 4: Validate Design
- What to Avoid
- System Prompt Architecture
What does the system-prompt-engineering skill do?
Design effective system prompts for custom agents. Use when creating agent system prompts, defining agent identity and rules, or designing high-impact prompts that shape agent behavior.
How do I install it?
Run `npx skills add majiayu000/claude-skill-registry --skill system-prompt-engineering --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From majiayu000/claude-skill-registry, a repository with 534 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.