I want to add AI processing to my app. Here's what it should do:

[Describe exactly what transformation the AI should perform on user input]

Set this up securely so that my API key stays protected.

The AI should:
- Take the user's input
- Process it with [OpenAI/Claude] 
- Return the improved version
- Handle errors gracefully if the AI service is down

Add a loading state so users know processing is happening.

First, walk me through the API integration step by step.