Create a tool that simulates and previews custom GPT configurations before you build them
Free tier works fine
We'll use AI to build the simulator interface and logic. Either tool works great for this project.
VS Code, Notepad, anything
You'll save HTML and JavaScript files. A simple text editor is all you need to run this locally.
First, we'll build the main interface where users can configure their Custom GPT settings. This combines the structured approach from prompt journaling with the configuration concepts from ChatGPT memory and custom instructions.
Create an HTML page for a Custom GPT Builder Simulator. I need: 1. A clean, modern interface with these configuration sections: - GPT Name and Description fields - Category dropdown (Writing, Coding, Business, Education, Creative, Other) - Conversation starters (4 text inputs) - System prompt textarea (large, with character count) - Capabilities checkboxes (Web Browsing, DALL-E, Code Interpreter) - Knowledge files upload simulation (just UI, not functional) 2. Use a dark theme with professional styling 3. Make it responsive and user-friendly 4. Add a "Preview Configuration" button at the bottom 5. Include helpful placeholder text in all fields Make the HTML complete and self-contained with CSS and basic JavaScript for interactivity.
What to look for: The AI should generate a complete HTML page with form fields for all major Custom GPT configuration options. You should see a professional-looking interface that resembles the actual ChatGPT Custom GPT builder, with proper styling and placeholder text to guide users.
Now we'll add the preview functionality that shows users how their Custom GPT will behave. This uses the feedback concepts from prompt journaling to give immediate results.
Add a live preview section to the Custom GPT Builder. When users fill in the configuration form, I want: 1. A preview panel that shows: - GPT name and description as they'll appear to users - The conversation starters as clickable buttons - A preview of the system prompt (first 200 characters with "...") - Selected capabilities as badges - Category tag 2. Real-time updates as the user types in the form fields 3. A mock chat interface showing what a conversation might look like 4. JavaScript to connect form inputs to the preview display 5. Make the preview visually distinct with a card-like design Update the existing HTML to include this preview functionality alongside the configuration form.
What to look for: The AI should add a preview panel that updates in real-time as you type in the form fields. You should see JavaScript code that listens for input changes and updates the preview display accordingly. The preview should look like how a Custom GPT actually appears to users.
We'll enhance the system prompt section with advanced editing features, drawing from the structured instruction concepts you learned in the CLAUDE.md and custom instructions tutorials.
Enhance the system prompt section of the Custom GPT Builder with advanced features: 1. A larger, more prominent system prompt textarea with: - Live character count (with color coding: green under 500, yellow 500-1000, red over 1000) - Line numbers - Syntax highlighting for common prompt patterns - Auto-resize as user types 2. Add a "Prompt Assistant" sidebar with: - Common prompt templates (Personal Assistant, Code Helper, Creative Writer, etc.) - Best practice tips that appear as user types - Validation warnings for common mistakes 3. Include prompt structure suggestions: - Role definition section - Task instructions section - Output format guidelines - Constraint examples 4. A "Test Prompt" button that simulates how the GPT would respond Make this feel like a professional prompt engineering tool.
What to look for: The AI should create an enhanced editor with helpful features like character counting, template suggestions, and structure guidance. You should see a more sophisticated interface that helps users write better system prompts, similar to how CLAUDE.md files provide project-level structure.
Now we'll add a library of pre-built templates, applying the organization and reusability concepts from your prompt journaling practice.
Add a template library to the Custom GPT Builder with these features: 1. A template gallery with pre-built configurations for: - Personal Writing Assistant (blog posts, emails, creative writing) - Code Review Helper (code analysis, bug finding, optimization tips) - Business Consultant (strategy, planning, analysis) - Learning Tutor (explanations, quizzes, study guides) - Creative Director (brainstorming, concept development) - Data Analyst (data interpretation, visualization suggestions) 2. Each template should include: - Complete system prompt - 4 conversation starters - Appropriate capabilities selected - Category and description 3. Template cards with: - Preview thumbnail or icon - Template name and brief description - "Use This Template" button - Tags for easy filtering 4. When a template is selected, populate all form fields automatically 5. Add a "Save as Template" feature for custom configurations Make the templates feel professional and immediately useful.
What to look for: The AI should create a library section with several professionally crafted Custom GPT templates. Each template should have realistic, useful system prompts and conversation starters. When you click "Use This Template," it should automatically fill in all the configuration fields.
Finally, we'll add the ability to export configurations and test them, completing the workflow from design to implementation that ties together all the concepts you've learned.
Add final features to complete the Custom GPT Builder Simulator: 1. Export functionality: - "Export Configuration" button that generates a downloadable JSON file - "Copy System Prompt" button for easy pasting into ChatGPT - "Generate Setup Instructions" that creates step-by-step directions - "Share Configuration" feature that creates a shareable URL/code 2. Testing interface: - Mock chat window where users can test their GPT configuration - Sample conversation that demonstrates the system prompt in action - "Send Test Message" feature with realistic AI responses - Response analysis that shows how well the system prompt is working 3. Configuration validation: - Check for required fields - Warn about overly long system prompts - Suggest improvements for conversation starters - Score the configuration quality (1-100) 4. Save/load functionality: - Save configurations to localStorage - Load previous configurations - Configuration history Make this feel like a complete, professional tool.
What to look for: The AI should add export buttons, a testing chat interface, and validation features. You should be able to download your configuration as a file, copy the system prompt directly, and test how your Custom GPT would behave in a simulated chat environment.
If the preview panel isn't updating as you type, check that the JavaScript event listeners are properly connected to the form inputs.
Ask your AI: "The preview isn't updating when I type in the form fields. Can you check the JavaScript event listeners and fix the real-time updates?"
If template buttons don't populate the form fields, the template data structure might not match the form field names.
Ask your AI: "When I click 'Use This Template', the form fields aren't getting filled. Can you check that the template data matches the form input names?"
If the export buttons don't download files or copy text, there might be browser security restrictions or JavaScript errors.
Ask your AI: "The export and copy buttons aren't working. Can you add proper error handling and ensure the download/copy functions work in modern browsers?"
Applied CLAUDE.md principles to create organized, hierarchical configuration interfaces that guide users through complex setup processes.
Built live feedback mechanisms that show immediate results, combining prompt journaling concepts with interactive user interfaces.
Created reusable configuration templates that embody ChatGPT memory and custom instruction best practices for different use cases.
Implemented export and sharing features that bridge the gap between design and implementation, making configurations portable and actionable.
Add version control: Create a system to save multiple versions of configurations and track changes over time, similar to how you'd version control code.
Build a community feature: Add the ability to share configurations publicly and rate/review other users' Custom GPT templates.
Create an API integration: Connect to OpenAI's API to actually create Custom GPTs directly from your simulator (requires API access).
Add analytics: Track which templates are most popular, what system prompt patterns work best, and provide data-driven suggestions.
Build prompt optimization: Create an AI-powered system that analyzes and suggests improvements to system prompts based on best practices.