CO-STAR Framework
Context · Objective · Style · Tone · Audience · Response
The Singapore GPT-4 competition winner. Maximum control over voice, audience, and output format.
- Definition
- The CO-STAR framework (Context · Objective · Style · Tone · Audience · Response) is a prompt engineering structure that breaks your AI request into 6 discrete fields. It is best suited for business communication and marketing copy.
The 6 Fields
Context
Background information the AI needs to understand the task and situation.
Objective
The specific goal or outcome you want the AI to achieve.
Style
The writing style — e.g., formal, conversational, journalistic, academic.
Tone
The emotional register — e.g., persuasive, empathetic, authoritative, friendly.
Audience
Who the output is for. Shapes vocabulary, depth, and assumptions.
Response
The exact output format — e.g., bullet list, 500-word article, JSON, table.
Real Example
Scenario: Writing a product launch email for a SaaS tool targeting CTOs
Context: PromptQuorum is a multi-model AI tool launching in July 2026. Objective: Write a product launch email that drives signups. Style: Clear and direct, no fluff. Tone: Confident and professional. Audience: CTOs at mid-size tech companies. Response: 200-word email with subject line.
When to Use CO-STAR
- ✓Business communication and marketing copy
- ✓Content where voice and tone matter (brand writing)
- ✓Professional writing for a specific audience
- ✓Any task where you need to control style separately from tone
- ✗Quick one-off queries where structure adds no value
- ✗Sequential multi-step tasks (use RISEN instead)
- ✗Technical tasks where examples matter more (use TRACE)
Frequently Asked Questions
What does CO-STAR stand for?
CO-STAR stands for Context, Objective, Style, Tone, Audience, and Response — six fields that give you precise control over AI output.
Why did CO-STAR win the Singapore GPT-4 competition?
CO-STAR won because it separates Style (presentation) from Tone (emotion), giving more precise control than frameworks that treat them as one field.
When should I use CO-STAR vs CRAFT?
Use CO-STAR when you need fine-grained control over voice and audience. Use CRAFT when you want a Role-based framing with a clear Target persona. Learn how to measure the effectiveness of your CO-STAR prompts at https://www.promptquorum.com/prompt-engineering/how-to-evaluate-prompt-quality.