What is a GPT-4o system prompt?

A system prompt in ChatGPT and the OpenAI API is a special message that sets the AI's behavior before the conversation starts. It typically defines the role, constraints, and output format.

How should I format a ChatGPT system prompt?

Markdown headers work well with GPT models. Separate role, task context, and output format into distinct sections so GPT can follow each instruction independently.

What is the GPT-4o system prompt token limit?

GPT-4o supports up to 128,000 context window tokens shared between the system prompt, conversation history, and the response.

OpenAI Prompt Builder

Build structured system prompts for ChatGPT and GPT-4o.

Role / Persona

Task / Instruction

Context / Background

Constraints / Rules

Output Format

Examples

Assembled Prompt

0 tokens · 0 chars

Fill in the fields on the left to build your prompt...

Format: Markdown headers

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FAQ

What is a GPT-4o system prompt?: A system prompt in ChatGPT and the OpenAI API is a special message that sets the AI's behavior before the conversation starts. It typically defines the role, constraints, and output format.
How should I format a ChatGPT system prompt?: Markdown headers work well with GPT models. Separate role, task context, and output format into distinct sections so GPT can follow each instruction independently.
What is the GPT-4o system prompt token limit?: GPT-4o supports up to 128,000 context window tokens shared between the system prompt, conversation history, and the response.

Build well-structured prompts optimized for OpenAI GPT models. Fill in role, task, context, constraints, output format, and examples. Assembled prompt uses markdown headers — the standard format for GPT-4o and ChatGPT system prompts.