Sounds like something very similar, I'll try to use it,

You can set it per container with -e CLEARML_AGENT_SKIP_PIP_VENV_INSTALL=1

Or add it here:
https://github.com/allegroai/clearml-agent/blob/51eb0a713cc78bd35ca15ed9440ddc92ffe7f37c/docs/clearml.conf#L149
extra_docker_arguments: ["-e", "CLEARML_AGENT_SKIP_PIP_VENV_INSTALL=1"]

we run in containers without venv, in the main section, and then delete it or use it for similar experiments Sounds like something very similar, I'll try to use it, thanks a lot! Can this be configured in the UI by simply adding a docker image to the launch options?

we run in containers without venv, in the main section, and then delete it or use it for similar experimentsIf this is the case then the idea is the venv creation is actually cached, you can turn it on here (unmark the line)
https://github.com/allegroai/clearml-agent/blob/51eb0a713cc78bd35ca15ed9440ddc92ffe7f37c/docs/clearml.conf#L116

tell me please, does the agent always create a virtual environment?

Yes, but it inherits from the container preinstalled system environment

is it possible to make the agent run the script in an already prepared docker container without creating a virtual environment in the container?

You can set the CLEARML_AGENT_SKIP_PIP_VENV_INSTALL=1 environment variable