Hi EagerOtter28 , welcome 🙂 . a few comments:

agent.system_side_packages: true

 will make ClearML at least use the packages installed into the system-python in the docker container, right?

Correct. The agent will always install a venv (minimal), and this flag will cause it to use packages installed in the system python instead of installing them in the venv.

I know there is 

clearml-agent build

 (

) - could this be used to build a general purpose image, or just to build an image specific to one task?

It's meant as a way to build a self-contained image for a specific task

Running pre-built environments in an agent works with 

clearml-agent daemon --docker --standalone-mode

, right? Is there any documentation on the requirements for the standalone mode? I managed to reverse-engineer most of the requirements, but I am stuck at a point where the agent cannot find the git repo to use inside of the container.

Well, that's correct, although not mandatory. In standalone mode, the agent will basically not try to fetch anything, so no repo cloning, no requirements installation etc - it basically assumes everything (including the code) exists in the image.