The COSTAR Method: A Complete Guide

What is COSTAR?

COSTAR is an acronym for six prompt elements that together create comprehensive AI instructions. Each letter represents a component that shapes the AI output:

You do not need all six elements in every prompt. But knowing what each does helps you decide which to include based on your specific task.

C - Context

Context is the background information AI needs to understand your situation. Without context, AI makes assumptions that may be wrong for your specific case.

Good context answers: What is the situation? What has happened before? What constraints exist? What does the AI need to know to help you effectively?

CONTEXT:
I'm the marketing manager at a B2B SaaS startup (50 employees) that sells project management software. We're launching a new feature next week that allows teams to visualize dependencies between tasks. Our target customers are tech companies with 20-200 employees. Previous feature launches had email open rates of 15-20%.

O - Objective

The objective is what you want AI to accomplish. This is the core of your prompt. A vague objective leads to vague outputs. A specific objective leads to useful results.

Good objectives use strong action verbs and specify the exact deliverable: Write, Create, Analyze, Compare, List, Summarize, Design, Evaluate.

Help me with my email marketing.

OBJECTIVE:
Write a 3-email launch sequence announcing our new task dependency visualization feature. Each email should:
- Have a compelling subject line under 50 characters
- Be 150-200 words in the body
- Include one clear call-to-action
- Build on the previous email in the sequence

S - Style

Style defines the writing approach or communication method. It is about structure and formality, not emotion (that is tone). Think of style as the “how” of presentation.

Common styles include: formal, casual, academic, journalistic, technical, conversational, persuasive, instructional, storytelling.

STYLE:
Write in a conversational, direct style. Use short sentences and paragraphs. Avoid corporate jargon and buzzwords like "leverage," "synergy," or "game-changing." Write like you're explaining this to a smart friend over coffee, not presenting to a boardroom.

T - Tone

Tone is the emotional quality of the writing. It shapes how readers feel when they read the content. The right tone builds connection and trust with your audience.

Common tones include: friendly, authoritative, empathetic, enthusiastic, confident, reassuring, urgent, playful, serious, inspirational.

TONE:
Be enthusiastic but not over-the-top. Show genuine excitement about the feature benefits without resorting to hype language. Be confident in our solution while acknowledging the real challenges our customers face. Aim for "helpful expert who's excited to share a solution" rather than "aggressive salesperson."

A - Audience

Audience defines who will read or use the output. This shapes vocabulary, complexity level, assumed knowledge, and what examples resonate. The same topic requires completely different treatment for different audiences.

Consider: What do they already know? What do they care about? What problems do they face? What language do they use?

AUDIENCE:
The readers are engineering managers and technical project leads at mid-size tech companies (20-200 employees). They:
- Have used project management tools before (Asana, Jira, Monday)
- Understand software development workflows
- Care about team productivity and reducing coordination overhead
- Make or influence software purchasing decisions
- Are skeptical of marketing claims and prefer concrete examples

R - Response Format

Response format tells AI how to structure the output. Without format instructions, you get whatever format AI thinks is best. With format instructions, you get output you can use immediately without reformatting.

Format options include: bullet points, numbered lists, paragraphs, tables, JSON, code blocks, headers and sections, Q&A format, scripts, templates.

RESPONSE FORMAT:
For each email in the sequence, provide:

1. **Subject Line** (under 50 characters)
2. **Preview Text** (under 90 characters)
3. **Email Body**
   - Opening hook (1-2 sentences)
   - Main message (2-3 short paragraphs)
   - Call-to-action (clear, single action)
4. **Send Timing** (days after signup)

Use markdown formatting. Separate each email with a horizontal rule (---).

COSTAR in Action

See the dramatic difference between a prompt without COSTAR and one that uses the full framework.

Write an email about our new feature.

CONTEXT:
I'm the marketing manager at TaskFlow, a B2B project management SaaS for tech companies (20-200 employees). We're launching a task dependency visualization feature next week. Previous feature launch emails had 18% open rates and 3% click rates.

OBJECTIVE:
Write the first email in a 3-part launch sequence. This email should introduce the feature and create curiosity for the full announcement. Include subject line, preview text, and body copy.

STYLE:
Conversational and direct. Short paragraphs (2-3 sentences max). No corporate jargon. Write like explaining to a smart friend.

TONE:
Enthusiastic but grounded. Show genuine excitement without hype language. Confident in our solution while acknowledging real customer challenges.

AUDIENCE:
Engineering managers and technical leads who:
- Have used tools like Asana, Jira, Monday
- Care about reducing coordination overhead
- Are skeptical of marketing claims
- Prefer concrete examples over abstract benefits

RESPONSE FORMAT:
- Subject Line (under 50 chars)
- Preview Text (under 90 chars)
- Email Body (150-200 words)
- Single clear CTA

Quick Reference Cheatsheet

Use this cheatsheet when building your next prompt. Not every prompt needs all six elements, but check each one to decide what to include.

COSTAR Template - Copy and Fill In:

CONTEXT:
[Background information about your situation, company, project, or constraints]

OBJECTIVE:
[Specific task with action verb and clear deliverable]

STYLE:
[Writing style: formal, casual, technical, conversational, etc.]

TONE:
[Emotional quality: friendly, authoritative, urgent, empathetic, etc.]

AUDIENCE:
[Who will read this: their role, knowledge level, goals, pain points]

RESPONSE FORMAT:
[How to structure the output: headers, lists, length, specific sections]

Next Steps

You now have the COSTAR framework. But remembering to use it and filling in each section can be tedious. That is exactly what AskSmarter.ai solves.

Our prompt builder asks you smart questions that map to each COSTAR element. You answer naturally, and we construct the optimized prompt automatically. No memorizing frameworks. No blank-page paralysis.