Getting empty context when using Python CDK library explicitly without CDK CLI

Hello,

In the documentation about Runtime Context it's clearly stated how the context is getting populated from the various sources, however it's unclear how this context is getting populated when I use a Python CDK library explicitly without the CDK CLI. It seems in this case the context is not following what was described in the documentation, that's why I am getting an empty context after tryGetContext calls (for example even ~/.cdk.json is ignored). Having this caveat in mind I'd like to understand what options I have to be able to enrich the context without the CDK CLI helpers? Is there a way to distinguish between a state when my code runs as a sub-process of the CDK CLI and I can rely lets say on existing cdk.json context, or as a standalone application and in this case I have to load it myself in the code?