Custom Instructions
Set up persistent preferences that shape every AI conversation automatically.
Custom instructions (called "Memory" in ChatGPT, "Profile" in some other tools) let you set persistent preferences that apply to every conversation. Instead of repeating "I'm a senior developer" or "Keep responses concise" in every prompt, you write it once and the model remembers. This is one of the highest-ROI prompt engineering techniques — a few minutes of setup saves hours of repetitive prompting.
- Who you are: Your role, expertise level, and industry. "I'm a senior product manager at a B2B SaaS company."
- How you work: Your preferred tools, frameworks, and methodologies. "I use React with TypeScript and prefer functional components."
- Communication preferences: How you want the AI to respond. "Be direct. No preamble. Use bullet points over paragraphs."
- What to avoid: Common AI behaviors that annoy you. "Don't apologize. Don't add disclaimers about being an AI. Don't repeat my question back to me."
- Output defaults: Your standard format preferences. "Use markdown formatting. Include code examples in TypeScript."
Developer Custom Instructions
Custom instructions for a senior TypeScript developer.
About me: - Senior full-stack developer, 8+ years experience - Stack: TypeScript, React, Next.js, Node.js, PostgreSQL - I prefer functional programming patterns and composition over inheritance - I use ESLint, Prettier, and strict TypeScript config How to respond: - Show code first, explain after (only if needed) - Use TypeScript with proper types — never use `any` - Follow my existing code patterns when I share code - If I ask for a fix, show only the changed lines, not the full file - No basic explanations unless I ask — assume I know the fundamentals - When suggesting libraries, prefer well-maintained ones with good TypeScript support
Marketer Custom Instructions
Custom instructions for a marketing leader at a small company.
About me: - Head of Marketing at a DTC e-commerce brand ($5M ARR) - Focus on email, social media, and paid acquisition - Our audience is 25-40 year old professionals - Brand voice: confident, friendly, slightly irreverent How to respond: - Always consider our specific audience, not generic marketing advice - Include specific metrics or benchmarks when possible - Give me the strategy AND the execution — not just theory - When I ask for copy, give me 3 variations with different approaches - Suggest A/B test ideas proactively - Don't recommend strategies that require a team of 10 — we're a team of 3
- Too long: Keep it under 500 words. Models struggle when custom instructions are essays. Prioritize.
- Too vague: "Be helpful" tells the model nothing. "Give me actionable next steps, not general advice" tells it exactly what to do.
- Contradictory: "Be concise" and "explain your reasoning in detail" conflict. Resolve contradictions or make them conditional.
- Task-specific instructions in global settings: "Always write Python code" in your custom instructions will interfere when you want JavaScript. Keep instructions general enough to apply across conversations.
Prompt Templates
Custom Instructions Generator
Generates personalized custom instructions through a structured interview.
Help me create custom instructions for my AI assistant. Interview me: 1. What is your role and expertise level? 2. What tools/technologies/frameworks do you use daily? 3. How do you prefer information presented? (concise vs. detailed, bullets vs. prose, etc.) 4. What AI behaviors annoy you? (what should it NEVER do?) 5. What default output format do you prefer? My answers: [ANSWER EACH] Now write optimized custom instructions under 500 words that capture these preferences.
Custom Instructions Auditor
Reviews and improves existing custom instructions.
Review my current custom instructions for issues: [PASTE YOUR CUSTOM INSTRUCTIONS] Check for: 1. Contradictions between different instructions 2. Instructions too vague to be actionable 3. Task-specific instructions that should be conversation-specific 4. Missing high-impact preferences 5. Overall length and priority issues Suggest a revised version that fixes any problems found.
Test Your Knowledge
Knowledge Check
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What is the ideal length for custom instructions?
Key Takeaways
- ✓Custom instructions are the highest-ROI prompt engineering technique — set up once, benefit always
- ✓Include: who you are, how you work, communication preferences, things to avoid, and output defaults
- ✓Keep them under 500 words and free of contradictions
- ✓Avoid task-specific instructions in global settings
- ✓Review and update monthly as your needs evolve
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