Why might I get a "Service cannot initialize" error in my console when a plist file is run?
python3 is not in the path used by launchd which will be less that that in the terminal.

Try using the full path in the plist

e.g.

&lt;key&gt;ProgramArguments&lt;/key&gt;
&lt;array&gt;
    &lt;string&gt;/usr/local/bin/python3&lt;/string&gt;
    &lt;string&gt;/Users/me/workspace/Learning/src/kjuvbot.py&lt;/string&gt;
&lt;/array&gt;