If you have files in this structure:

project
   |- sub-package
        |- pyproject.toml
        |- something.py       

say that pyproject.toml configures for profile black.

Then, this works (picks up the profile black):

C:\project> python -m isort C:\project\sub-package\something.py

but this does not:

C:\project> type C:\project\sub-package\something.py | python -m isort - --filename C:\project\sub-package\something.py

but this does (notice the CWD)

C:\project\sub-package> type C:\project\sub-package\something.py | python -m isort - --filename C:\project\sub-package\something.py

In VS Code extension for isort we are using the stdin way to perform sorting. This is need to support the organize import on save capability. I was able to simulate the same problem using type (on windows) and cat (on linux).

reference issue: microsoft/vscode-isort#138