Josh has it right, but, in more detail:

./pants run path/to/dir:target -- --port 3001 --no-access-log --proxy-headers swizzler:app

Where path/to/dir/BUILD has:

pex_binary(
    name="target",
    script="uvicorn",
    ...
)

What would be nice is to be able to seal in the

swizzler:app

argument to the PEX binary such that it always ran your

swizzler:app

via

uvicorn

without you having to type that. That feature idea is tracked here but it's had no one yet motivated to actually add the feature: https://github.com/pantsbuild/pex/issues/987