ChatGPT Custom Instructions let you set persistent context and rules that apply to every new conversation. Instead of repeating "I'm a marketing manager" and "keep it concise" in every chat, you set it once and ChatGPT remembers.
There are two fields: "What would you like ChatGPT to know about you?" (your context) and "How would you like ChatGPT to respond?" (your rules). Most people leave both empty or write something generic. This guide gives you exact text to paste into each field, customized for your role. If you're also hunting an old thread where ChatGPT finally gave you a useful answer, our guide on how to search your ChatGPT history covers that separately.
| Field | Purpose | Character Limit | Example |
|---|---|---|---|
| About you | Who you are + what you do | ~1,500 | "PM at B2B SaaS…" |
| How to respond | Rules for output (tone/format) | ~1,500 | "Lead with answer…" |
The Two Fields Explained
"What would you like ChatGPT to know about you?"
This is your context. Tell ChatGPT who you are, what you do, and what you're working on. The AI reads this before processing every message, so it shapes every response without you mentioning it.
What to include:
Your role and seniority level. "Senior product manager at a B2B SaaS company (50 employees, $5M ARR)."
Your domain. "I work in fintech. Our product is a payments API for small businesses."
Your current focus. "Currently working on: launching a new pricing tier, preparing for Series A fundraising, and hiring two engineers."
Your knowledge level. "I'm technical enough to read code but don't write it. I understand SQL. I'm not a designer."
What NOT to include: Personal information you wouldn't share with a coworker. Anything sensitive or confidential about clients, financials, or internal strategies. This data goes to OpenAI's servers.
"How would you like ChatGPT to respond?"
This is your rulebook. Define the output style, format, and behaviors you want. Be specific and use negative instructions (what NOT to do) — they're often more useful than positive ones.
What to include:
Tone: "Direct and concise. No filler phrases like 'Great question!' or 'Absolutely!'"
Format: "Use bullet points for lists. Use tables for comparisons. Keep responses under 300 words unless I ask for more."
Behavior: "When uncertain, say so directly instead of hedging with caveats. Give your best assessment, then note the uncertainty."
Negatives: "Don't add disclaimers about consulting professionals. Don't repeat my question back to me. Don't use the word 'leverage.'"
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Subscribe free →Templates by Role
📋 TEMPLATE: Marketing Manager
Know about me: "I'm a marketing manager at a B2B SaaS company (200 employees). Our ICP is mid-market engineering teams. I manage content, email campaigns, and paid ads. I report to the VP of Marketing. Budget: $50K/quarter."
Response style: "Write in a conversational, direct tone. For content drafts, match our brand voice: confident but not arrogant, specific over vague. Default to bullet points. When I ask for strategy, give me 2-3 options ranked by expected ROI with tradeoffs. Don't use: leverage, synergy, best-in-class, or ideate."
📋 TEMPLATE: Software Developer
Know about me: "I'm a full-stack developer. Stack: TypeScript, React/Next.js, Node.js, PostgreSQL, AWS. I have 5 years of experience. I understand design patterns and system architecture. Currently building a real-time collaboration feature."
Response style: "Show code first, then explain. Use TypeScript for all code examples. Follow these conventions: functional components, named exports, async/await over .then(). Don't explain basic concepts. When debugging, give the most likely cause first, not a comprehensive list. Include error handling in all code. Be opinionated — tell me what you'd do, not just options."
📋 TEMPLATE: Data Analyst
Know about me: "I'm a data analyst at an e-commerce company. I use SQL daily, Python occasionally, and Excel for presentations. Our main metrics: conversion rate, AOV, CAC, LTV. I present to non-technical stakeholders weekly."
Response style: "When I share data, lead with the most surprising finding. Use tables over paragraphs for comparisons. When I ask for SQL, write for PostgreSQL and include comments. For presentations, suggest 3-5 talking points with specific numbers. Don't explain statistical concepts I already know (regression, significance, correlation). Challenge my assumptions when you see weak reasoning."
📋 TEMPLATE: Writer/Content Creator
Know about me: "I'm a freelance writer specializing in technology and business topics. My clients include SaaS companies and tech publications. I write blog posts, white papers, and case studies. My style: conversational but informed, uses specific examples, avoids jargon."
Response style: "When editing my work, suggest improvements but preserve my voice. When drafting, use short paragraphs (2-3 sentences max). Lead every section with the most important point. Use active voice. No filler: 'it's worth noting,' 'in this article,' 'let's dive in.' When I say 'make it shorter,' cut aggressively — remove 30%+ without losing substance."
Testing Your Instructions (Checklist)
- Role awareness: Ask "What do you know about my work?"
- Format compliance: Ask for a list; verify bullets/tables/length.
- Negative rules: Trigger a situation where it would use banned words/disclaimers.
If a test fails, move the most important rules to the top of each field.
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Subscribe free →Frequently Asked Questions
Do Custom Instructions work on ChatGPT Free?
Yes. Custom Instructions are available on both Free and Plus plans.
Can I turn off Custom Instructions for one conversation?
Yes. Click the Custom Instructions icon in any conversation and toggle them off temporarily. They'll re-enable for the next conversation.
Is there a character limit?
Each field has a 1,500-character limit (roughly 250 words). Prioritize the most impactful rules. If you need more space, consider switching to Claude Projects which supports much longer instructions plus file uploads.
What’s the best way to write these fast?
Draft your two fields, then run them through the Prompt Optimizer to tighten tone, constraints, and format.
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