AI prompt engineering formula: the RTFC framework

There are dozens of prompt engineering frameworks floating around. CRISP, RISEN, APE, CREATE, CO-STAR. Most of them add complexity without adding value. The one that actually sticks is the simplest: RTFC.

RTFC stands for Role, Task, Format, Constraints. Four parts. That is all you need for 90% of AI interactions, whether you are using ChatGPT, Claude, Gemini, or any other model.

R is for Role

Tell the AI who to be. This is the single most underused part of prompting.

"You are a senior copywriter with 10 years of SaaS experience" produces completely different output than "You are a college freshman learning about marketing." Same question, different depth, vocabulary, and assumptions.

Good roles are specific. Not just "You are a writer" but "You are a technical writer who writes documentation for developer tools." The more specific the role, the more the AI adjusts its vocabulary, depth, and perspective.

Roles you can try:

• "You are a CFO reviewing a budget proposal"
• "You are a pediatrician explaining vaccines to a nervous parent"
• "You are a Python developer who prefers readable code over clever one-liners"
• "You are a hiring manager reviewing resumes for a senior data analyst position"

T is for Task

What should the AI actually do? This is where most people are too vague.

Vague: "Help me with my resume."

Specific: "Rewrite the work experience section of my resume. I am applying for a senior product manager role at a fintech startup. Focus on metrics and outcomes. Each bullet point should start with an action verb."

The specific version gives the AI enough context to produce something usable on the first attempt. The vague version leads to back-and-forth that wastes time.

When writing the task, answer these questions:

• What is the deliverable? (an email, a list, a code function, a summary)
• Who is the audience? (customers, your boss, a 5-year-old, developers)
• What is the context? (product launch, performance review, bug report)

F is for Format

Tell the AI how to structure its response. If you skip this, the AI picks a format on its own, and it usually picks long paragraphs.

Format options:

• Bullet points - Best for lists, features, quick summaries
• Numbered steps - Best for how-to guides and processes
• Table - Best for comparisons and structured data
• JSON - Best for developers who need structured output
• Code block - Best for programming tasks
• Paragraph - Best for essays, emails, long-form content
• Markdown - Best for documentation and formatted text

You can also combine formats: "Start with a 2-sentence summary, then use a numbered list for the steps, then end with a paragraph about common mistakes."

C is for Constraints

Constraints are the guardrails. Without them, AI output tends to be long, generic, and full of hedging language.

Types of constraints:

• Length: "Keep it under 200 words" or "No more than 5 bullet points"
• Avoidance: "Do not use jargon" or "Do not start sentences with 'In today's world'"
• Requirements: "Include a call-to-action" or "Mention the pricing tier"
• Tone: "Professional but not stiff" or "Casual, like texting a coworker"
• Audience awareness: "The reader has no technical background" or "Assume the reader knows SQL"

The best constraints come from knowing what bad output looks like. If the AI keeps using the word "leverage," add a constraint: "Do not use buzzwords." If it keeps writing 500-word responses when you need 100, add a word limit.

Putting it together

Here is a complete RTFC prompt:

Role: You are a customer success manager at a project management SaaS company.

Task: Write a reply to a customer who is frustrated that the Gantt chart feature was removed in the latest update. Acknowledge their frustration, explain that the feature is being rebuilt with better performance, and give a timeline (Q3 2026).

Format: Email format. Subject line, greeting, 2-3 short paragraphs, sign-off.

Constraints: Keep it under 150 words. Do not apologize more than once. Do not use the phrase "we understand your frustration." Sound genuine, not corporate.

When you only need two parts

Not every prompt needs all four. For simple requests, Task + Format is enough:

List 10 blog post ideas about remote work productivity. Bullet points, one sentence each.

That works because the task is straightforward and the format is clear. Add Role and Constraints when the task is complex, the audience matters, or you have had trouble getting good output.

RTFC vs other frameworks

• CRISP (Context, Role, Instructions, Style, Parameters) - More granular but harder to remember. RTFC covers the same ground in fewer pieces.
• RISEN (Role, Instructions, Steps, End Goal, Narrowing) - Good for multi-step tasks but overkill for everyday prompting.
• APE (Action, Purpose, Expectation) - Too vague. Misses format and constraints entirely.
• CO-STAR (Context, Objective, Style, Tone, Audience, Response) - Six parts. Works well but RTFC gets you 90% of the way with four.

Start with RTFC. If you hit a situation where four parts are not enough, add context or examples. But most of the time, four parts is plenty.

Related tools and guides

• Prompt Builder - Auto-build RTFC prompts
• System Prompt Generator - For API-level system instructions
• Token Counter - Check prompt size before sending