Custom Instructions for AI:
How to get the most out of ChatGPT and Claude
Why Custom Instructions?
Most people use ChatGPT and Claude like a stranger they have to re-introduce themselves to with every encounter. This takes time and leads to generic answers. Custom instructions fundamentally change this: you define once who you are and how your AI should respond, and these settings automatically apply to every new chat.
According to a study by the Boston Consulting Group, employees save an average of five hours per week through properly configured AI. The difference between a personalized and a standard AI is comparable to the difference between an assistant who knows your way of working and an intern on their first day.
If you are still unsure which AI tool is best for you, we recommend our article Which AI tool is right for me first.
Personalize ChatGPT
Where to find the settings
At OpenAI, you can find the settings as follows: Click on your profile picture in the top right corner, select “Settings”, then “Personalization” and finally “Configure ChatGPT individually”. The function is available to all users, even in the free plan.
The two core fields
ChatGPT offers two input fields with 1,500 characters each:
Field 1: “What should ChatGPT know about you?” Here you describe your context: profession, industry, typical tasks and target group.
Field 2: “How should ChatGPT respond?” Here you define the output format: tonality, length, preferred structures and phrases to avoid.
Practical example
Field 1: “I work as a content manager for a B2B software company. The target group is IT decision-makers. I create blog articles and LinkedIn posts. SEO is important.”
Field 2: “Use active language and short sentences. Avoid platitudes such as ‘in this day and age’. For blog article ideas, provide direct suggestions with H1 and meta description.”
Personalize Claude
Claude by Anthropic works with three levels instead of two fields:
Profile Preferences (account-wide): Settings under Initials → Settings → “What preferences should Claude consider?” These apply to all conversations.
Project Instructions: Claude enables projects with their own instructions and knowledge base. Ideal for recurring tasks such as blog articles or customer correspondence.
Custom Styles: Four preset styles (Normal, Concise, Formal, Explanatory) plus the option to create your own styles by uploading writing samples.
Claude has a context window of 200,000 tokens, while ChatGPT is limited to 128,000. This makes Claude a better choice for long documents and analyses.
Integrate advanced thinking methods
The quality of AI responses depends not only on what you ask, but also on how the AI thinks.
Tree of Thought
Tree of Thought was developed in 2023 by researchers at Princeton University and presented at the NeurIPS Conference. The method explores several lines of thought in parallel and evaluates each intermediate step. In the “Game of 24” task, the success rate improved from 4% to 74%.
How to integrate it: “For complex problems: First, develop three different solution approaches. Evaluate each one for feasibility and pros/cons. Execute the most promising one in detail.”
Graph of Thought
Graph of Thought was developed at ETH Zurich and presented in 2024. The method models thoughts as graphs whose nodes can be connected arbitrarily. Partial solutions can be combined in this way, resulting in 62% better quality at 31% lower costs.
How to integrate it: “For tasks with multiple sub-aspects: Process each aspect separately. Then combine the sub-results into an overall solution. Check whether the parts fit together consistently.”
Template for immediate use
You can insert and adapt this template directly into ChatGPT or Claude:
Context: “I am a [Position] at [Company] in the [Industry] industry. My target group is [Description]. I mainly create [Tasks/Formats]. Important terms in my industry are [Keywords].”
Response format: “Prioritize recommendations for action over theory. Start with the most important statement (BLUF principle). Keep paragraphs short. Avoid [annoying phrases]. For [Task type], deliver [desired format] directly. Ask for clarification if something is unclear, instead of making assumptions.”
Avoid common mistakes
Formulating too vaguely: “Answer well” doesn’t achieve anything. Better: “Keep answers under 200 words, unless I ask for more.”
Contradictory rules: “Be detailed” and “Keep it short” leads to chaos. Use context-dependent rules: “For how-to questions: detailed. For factual questions: short.”
Entering sensitive data: Never store passwords or confidential information in Custom Instructions.
Set it up once and forget it: Check your instructions every few months and adapt them to new tasks.
ChatGPT or Claude?
ChatGPT offers more functional diversity with Custom GPTs and integrated image generation. Claude scores with long documents and a more natural writing style. Many power users use both tools for different tasks.
Your action plan
- Open ChatGPT or Claude and navigate to the personalization settings
- Define your core context: profession, typical tasks, target group
- Formulate three concrete response rules
- Test with a typical task and refine
The investment of 15 minutes pays off with every further AI interaction. Instead of generic answers, you get results that match your context and style.
Would you like to understand how AI can specifically support your business?
In a free initial consultation, we will look together at which processes in your company are suitable for getting started with AI and which tools deliver real added value.
Frequently asked questions
Are custom instructions also available in the free ChatGPT? Yes, since August 2023, Custom Instructions have been available to all ChatGPT users, regardless of the plan.
How long can custom instructions be? For ChatGPT: 1,500 characters per field, a total of 3,000 characters. For Claude, Project Instructions are possible with significantly more.
What is the difference between Custom Instructions and the Memory function? Custom Instructions are basic rules set by you that take effect immediately. Memory automatically stores information from conversations and develops over time. Both complement each other.
Do the same instructions work for ChatGPT and Claude? The basic principles are transferable, but both tools react differently to formulations. Claude understands XML tags particularly well, ChatGPT works well with Markdown.
How often should I update my instructions? Every two to three months or when your tasks change significantly.
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Custom Instructions, Custom Instructions, ChatGPT Settings, Claude Personalization, AI Productivity, Prompt Engineering, Tree of Thought, Graph of Thought, AI Optimization, ChatGPT Tips