Short version up front: system prompts set the AI’s role and behavior. The way you prompt (zero-shot, few-shot, chain-of-thought, etc.) changes accuracy, tone, and usefulness. Below you’ll find clear explanations, quick examples, practical templates, and bite-size tips you can use immediately.

What is a system prompt? (1-line)

A system prompt is an instruction that tells the AI who to be and how to behave before you start asking questions.
Example: You are a friendly tech writer who explains things simply and gives short examples.

Why system prompts matter (small, important points)

Sets tone & expertise — answers match the role you gave (teacher, reviewer, lawyer, etc.).
Reduces back-and-forth — fewer edits and clarifying prompts.
Keeps consistency — useful for multi-part content or product docs.
Improves safety/limits — can instruct the model to avoid certain content.

Types of prompting — what they are, when to use them, and short examples

1) Zero-Shot

What: Ask without examples.
When: Clear, common tasks (summaries, definitions).
Example: Summarize this article in 3 sentences.

2) Few-Shot

What: Give 2–4 examples to show the pattern.
When: When you want a specific style or format.
Example:

Q: Define "DRY" in programming.
A: DRY = Don't Repeat Yourself - avoid duplicate code.

Q: Define "YAGNI" in programming.
A: YAGNI = You Aren't Gonna Need It - don't add features before they're needed.

Q: Define "KISS" in programming.
A:

3) Chain-of-Thought (CoT)

What: Ask the model to show its reasoning steps.
When: Complex reasoning, debugging, multi-step calculations.
Example: Explain step-by-step how you'd debug a failing API call.

4) Instruction Prompting

What: Direct, explicit instructions (length, tone, format).
When: Content creation, specific outputs.
Example: Write a 150-word explanation of OAuth2 for non-devs, friendly tone.

5) Role / Persona Prompting

What: Tell the model a role (e.g., “You are a startup mentor”).
When: Advice that needs perspective or authority.
Example: You are a product manager with 10 years of B2B SaaS experience.

What: Provide output, then ask for revisions.
When: Editing drafts, tuning code, improving clarity.
Example: Shorten this paragraph to 2 sentences and make it more active.

7) Retrieval-Augmented / Contextual Prompting

What: Provide external text or documents as context.
When: When answers must reflect provided content (policy, docs).
Example: Based on the following doc, list the three user-facing changes.

8) Prompt Chaining

What: Break a big task into smaller prompts and combine outputs.
When: Long workflows: research → outline → write → edit.
Example: Step 1: “List headlines.” Step 2: “Expand headline #2 into a 300-word post.”

Practical templates you can copy/paste

System prompt (general):

You are an expert [role]. Answer concisely, use bullets, and include one short example.

Content writer:

You are a senior technical writer. Produce a clear, 5-paragraph article with headings and one code snippet. Keep language simple for beginners.

Code assistant:

You are a helpful programmer. Explain issues step-by-step, show corrected code, and include tests if applicable.

Quick tips (one-liners — high impact)

Start with a clear system prompt for every session.
Use few-shot when format matters.
Use CoT for tricky logic or math.
Provide only the context needed — too much context can confuse.
Ask the model to show examples, not just tell.
Combine methods: system prompt + few-shot + iteration = strong results.

Two short, practical examples

Example — Blog outline (fast):
System prompt:

You are a friendly content strategist. Produce a 6-point blog outline about "Remote onboarding".

Follow up (instruction): Expand point 3 into a 200-word section with a checklist.

Example — Debugging (stepwise):
System prompt:

You are a pragmatic backend engineer. Explain root causes, tests to run, and exact commands to try.

User prompt: A Rails app throws "NoMethodError" in production; logs show nil from user.profile.name.
AI: gives step-by-step diagnostic checks, safe fixes, and a test snippet.

Common mistakes to avoid (short)

Vague system prompts: “Be better” → useless.
Overloading with irrelevant context.
Expecting creative structure without examples when you need consistency.
Not iterating—first output is rarely perfect.

Closing — use this now

Pick one system prompt from the templates, set it at the start of your next session, and try one of these:

Zero-shot for quick tasks.
Few-shot when format matters.
CoT for reasoning.

System Prompts & Types of Prompting — simple, useful, and ready to use