logging.yml options cannot be set with `prefect config set`

[jwalton3141]

Bug summary

The documentation on customising Prefect logging states:

Any value in Prefect’s logging configuration file can be overridden through a Prefect setting of the form PREFECT_LOGGING_[PATH]_[TO]_[KEY]=value corresponding to the nested address of the field you are configuring.

...

to change the default logging level for flow runs but not task runs, update your profile with:

prefect config set PREFECT_LOGGING_LOGGERS_PREFECT_FLOW_RUNS_LEVEL="ERROR"

However, I get an error when I try and set any of the values in that file via prefect config set.

For example, running prefect config set PREFECT_LOGGING_LOGGERS_PREFECT_FLOW_RUNS_LEVEL="ERROR" returns:

Unknown setting name 'PREFECT_LOGGING_LOGGERS_PREFECT_FLOW_RUNS_LEVEL'

MWE:

python3 -m venv prefect_mwe
source prefect_mwe/bin/activate
pip install prefect

prefect config set PREFECT_LOGGING_LOGGERS_PREFECT_FLOW_RUNS_LEVEL="ERROR"

Version info

Version:             3.4.11
API version:         0.8.4
Python version:      3.10.12
Git commit:          3c98aa7f
Built:               Thu, Jul 31, 2025 08:45 PM
OS/Arch:             linux/x86_64
Profile:             ephemeral
Server type:         cloud
Pydantic version:    2.11.7

Additional context

Some logging options can be set as expected with prefect config set, eg. prefect config set PREFECT_LOGGING_LEVEL="DEBUG" runs successfully.

Equivalent environment variables altering logging still look to be respected.