System Prompt
Instructions that define an AI's behavior, personality, and constraints before it responds to user queries.
What is System Prompt?
A system prompt is the initial instruction set that tells an AI how to behave before it sees any user input.
Think of it as the AI's job description. It defines the role ("You're a helpful coding assistant"), sets the tone (formal vs casual), and establishes guardrails (what it should and shouldn't do).
Builders use system prompts to customize AI behavior for specific tasks. You might create one system prompt for customer support (friendly, patient) and another for code review (technical, critical). Claude and ChatGPT both let you set custom system prompts through their APIs.
The difference from user prompts: system prompts persist across the entire conversation, while user prompts are your individual questions. System prompts shape HOW the AI thinks, user prompts shape WHAT it thinks about.
Good to Know
How Vibe Coders Use System Prompt
Frequently Asked Questions
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Related Terms
The text instruction you give an AI model to tell it what you want it to do, like asking ChatGPT to write code or explain a concept.
The practice of crafting specific instructions to get better outputs from AI models like ChatGPT, Claude, or Gemini.
The amount of text an AI model can remember and process at once, measured in tokens. Bigger windows mean longer conversations and documents.
A custom interface built on top of existing AI models like GPT-4 or Claude that adds specific features, workflows, or constraints for a particular use case.
The bite-sized chunks of text that AI models read and generate, like words or word fragments. They're how AI counts and processes language.
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