I built a coding agent from scratch in 90 days.

Almost all useful agents today are coding agents. Instead of interacting with an application through the UI, agents are now writing code to make slides, excel sheets, or browse the internet. In the past 90 days, I built my first coding agent from scratch (chippy.build, an ai prototyping tool for ChatGPT apps).

Here's how mine works:

1) Plan Break down the user's request into tasks

2) Tool calls A simple loop with a set of ~20 tools, including create_tool, edit_file, get_app_config and more.

3) Verify Check the code compiles and run a verification skill to ensure the code hasn't made any mistakes with SDKs

4)Respond and Preview Bundle the React code into HTML to show in an IFrame for the user

Building the core loop of a coding agent is surprisingly simple. Making a coding agent good is a lot of work!