I've found that writing a very simple DSL that resembles human speech and an interpreter that can output JSON is very effective.

Human

4x1200 with 30 second rest

AI DSL output

Repeat 4 times:

- Run 1200 meters

- Rest 30 seconds

I hand wrote a recursive descent parser in Python to process DSL. Human speech to DSL is pretty effective with a simple prompt and some examples.

I created a tool that can program Garmin & Apple Watches for interval training based on what I wrote above.

https://speedystride.com

Looking for beta testers- please give it a try :)