I ran into this question when thinking about the approach for a recent project. Yes CLI coding tools are good agents for interactive use, but if you are building a product then you do need an agent abstraction.

You could package Claude Code into the product (via agents-sdk or Claude -p) and have it use the API key (with metered billing) but in my case I didn’t find it ergonomic enough for my needs, so I ended up using my own agent framework Langroid for this.

https://github.com/langroid/langroid

(No it’s not based on that similarly named other framework, it’s a clean, minimal, extensible framework with good dx)