What an AI-Powered Tool Does
An AI-powered tool takes input from a user, sends it to an AI API along with a system prompt that defines what the AI should do with it, receives the AI-generated response, and displays or uses that response. The AI API does the intelligence work. Your Replit app is the interface that connects the user to the AI.
Examples: a tool that takes a meeting transcript and returns action items, a tool that takes a job description and generates tailored interview prep, a tool that takes a product description and generates a sales page, a tool that takes a URL and returns a summary.
The key design decision: what is your system prompt? The system prompt defines what the AI does with the user's input. A well-designed system prompt produces consistent, useful output. A vague system prompt produces variable results. Spend more time on the system prompt than on any other part of the tool.
The Build Prompt for Claude
"Build an AI-powered tool in my Replit Express app. The tool should: show a form at / with a text input called [input_name] and a submit button. When submitted, POST to /api/generate. The /api/generate route should call the Anthropic API using my API key stored in process.env.ANTHROPIC_API_KEY with this system prompt: [your system prompt]. Pass the user's input as the user message. Return the AI response as JSON. Display the response on a /result page."