$npx -y skills add tronghieu/agent-skills --skill system-prompt-creatorCreate high-quality, model-aware system prompts for any LLM (Claude, GPT, Gemini, open-source, etc.). Use this skill whenever the user wants to create, write, build, design, draft, or improve a system prompt, system instructions, or custom instructions for any AI model. Also trig
| 1 | # System Prompt Creator |
| 2 | |
| 3 | Build effective system prompts for any LLM using a structured, research-backed process derived from the official prompting guides of Claude (Anthropic), GPT-5 (OpenAI), and Gemini (Google). |
| 4 | |
| 5 | This skill guides you through interview, analysis, structuring, drafting, and optimization — producing system prompts that are clear, well-structured, and tailored to the target model. |
| 6 | |
| 7 | ## Workflow |
| 8 | |
| 9 | Follow these 5 steps in order. Each step builds on the previous. |
| 10 | |
| 11 | ### Step 1: Interview — Gather Requirements |
| 12 | |
| 13 | Before writing anything, collect these essentials from the user: |
| 14 | |
| 15 | 1. **Target model** — Which LLM? (Claude, GPT, Gemini, open-source, or model-agnostic) |
| 16 | 2. **Use case** — What will the AI do? (chatbot, agent, content generator, data extractor, code assistant, etc.) |
| 17 | 3. **Persona** — Who should the AI be? (role, expertise level, personality traits) |
| 18 | 4. **Audience** — Who interacts with it? (developers, end users, internal team, customers) |
| 19 | 5. **Input types** — What will users send? (free text, code, documents, images, structured data) |
| 20 | 6. **Output format** — What should responses look like? (prose, JSON, markdown, code, tables) |
| 21 | 7. **Tone & style** — Formal, casual, technical, friendly? Concise or detailed? |
| 22 | 8. **Constraints** — What must it NOT do? (safety rules, topic limits, action restrictions) |
| 23 | 9. **Tools & capabilities** — Does it have tool access? (APIs, file system, web search, code execution) |
| 24 | 10. **Examples** — Can the user provide examples of good/bad responses? |
| 25 | |
| 26 | If the user is vague on some points, suggest reasonable defaults and confirm before proceeding. |
| 27 | |
| 28 | **Push for completeness:** After gathering basics, ask "What *else* might users ask about?" Many prompts fail not because they handle their core task poorly, but because they don't anticipate adjacent scenarios. A billing chatbot also gets account access questions, product questions, and complaints. A coding agent needs to handle not just building features but also debugging, refactoring, and project setup. Map the full territory before writing. |
| 29 | |
| 30 | ### Step 2: Analyze — Determine Complexity & Scope |
| 31 | |
| 32 | Based on the interview, classify the prompt complexity: |
| 33 | |
| 34 | | Complexity | Characteristics | Typical Length | |
| 35 | |-----------|----------------|---------------| |
| 36 | | **Simple** | Single task, no tools, fixed format | 50-200 words | |
| 37 | | **Moderate** | Multiple behaviors, some tools, varied outputs | 200-800 words | |
| 38 | | **Complex** | Agentic, multi-tool, long-running, safety-critical | 800-2000+ words | |
| 39 | |
| 40 | Then determine which sections are needed: |
| 41 | |
| 42 | - **Role/Persona** — Almost always needed |
| 43 | - **Context/Knowledge** — When domain expertise or background is required |
| 44 | - **Instructions/Rules** — Always needed |
| 45 | - **Domain Playbooks** — When the system handles multiple distinct operational scenarios (see below) |
| 46 | - **Output Format** — When response structure matters |
| 47 | - **Examples** — When accuracy and consistency matter (3-5 diverse examples) |
| 48 | - **Tool Usage** — When the model has access to tools or APIs |
| 49 | - **Safety/Guardrails** — When actions have real-world consequences |
| 50 | - **Agentic Behavior** — When the model operates autonomously |
| 51 | |
| 52 | **Domain Playbooks:** For systems that handle multiple distinct workflows (a coding agent that builds, debugs, refactors, and reviews; a support bot that handles billing, accounts, and technical issues), include named playbooks — concise step-by-step patterns for each operational scenario. These give the model a reliable decision tree for common situations rather than forcing it to derive the approach from general instructions every time. Place playbooks inside the `<instructions>` section, organized by scenario name. |
| 53 | |
| 54 | ### Step 3: Structure — Apply the Layered Architecture |
| 55 | |
| 56 | Organize the prompt using this universal architecture. Include only the sections relevant to the use case. |
| 57 | |
| 58 | **XML structure** (preferred for complex prompts): |
| 59 | |
| 60 | ```xml |
| 61 | <role> |
| 62 | Who the AI is, expertise, personality |
| 63 | </role> |
| 64 | |
| 65 | <context> |
| 66 | Domain knowledge, background information, constraints |
| 67 | </context> |
| 68 | |
| 69 | <instructions> |
| 70 | Core behavior rules, workflow steps, decision criteria |
| 71 | </instructions> |
| 72 | |
| 73 | <output_format> |
| 74 | Response structure, formatting rules, verbosity guidelines |
| 75 | </output_format> |
| 76 | |
| 77 | <examples> |
| 78 | 3-5 diverse input/output pairs covering normal cases and edge cases |
| 79 | </ex |