It seems the results returned are not specifically related to configuring JSON formatter verbosity in Prefect logs. None of the excerpts provided an answer to how to limit the fields in the JSON logs generated by Prefect.
Since I could not find a predefined configuration option in Prefect's documentation for reducing the verbosity of JSON logs directly, another approach might involve custom logging handlers or intercepting log messages to filter or modify them as needed. However, this would require custom code on the user's part and is not documented as a feature of Prefect.
I would recommend checking the Prefect community resources or reaching out to the Prefect support or community for further assistance.
Here is the link to the Prefect documentation that might help you explore logging further:
Prefect Logging Guide. Unfortunately, the link does not contain the specific information about configuring the JSON formatter verbosity.