With magentic you could do chain-of-thought in two or more steps: one function that generates a string output containing the chain-of-thought reasoning and answer, and a second that takes that output and converts it to the final answer object. I agree though that this is not encouraged or made obvious by the framework.

The approach I'm encouraging with this is to write many functions to achieve your goal. So in the case of your email writing example you might have some of the following prompt-functions - write key bullet points for email about xyz -> list[str] - write email based on bullet points -> str - generate feedback for email to meet criteria abc -> str - update email based on feedback -> str - does email meet all criteria abc -> bool And between these you could have regular python code check things like blacklist/whitelist of keywords, length of paragraphs, and even add hardcoded strings to the feedback based on these checks.