diff --git a/my/__main__.py b/my/__main__.py
index 6ac0aad..4c6ac87 100644
--- a/my/__main__.py
+++ b/my/__main__.py
@@ -1,5 +1,72 @@
+import os
+import sys
+from subprocess import check_call, run, PIPE
+import traceback
+
+from my.core import LazyLogger
+
+log = LazyLogger('HPI cli')
+
 class Modes:
-    HELLO = 'hello'
+    HELLO  = 'hello'
+    CONFIG = 'config'
+
+
+def config_check(args):
+    def eprint(x: str):
+        print(x, file=sys.stderr)
+
+    def indent(x: str) -> str:
+        return ''.join('   ' + l for l in x.splitlines(keepends=True))
+
+    def info(x: str):
+        eprint('✅ ' + x)
+
+    def error(x: str):
+        eprint('❌ ' + x)
+
+    def warning(x: str):
+        eprint('❗ ' + x) # todo yellow?
+
+    try:
+        import my.config as cfg
+    except Exception as e:
+        error("failed to import the config")
+        tb = ''.join(traceback.format_exception(Exception, e, e.__traceback__))
+        sys.stderr.write(indent(tb))
+        sys.exit(1)
+
+    info(f"config file: {cfg.__file__}")
+
+    try:
+        import mypy
+    except ImportError:
+        warning("mypy not found, can't check config with it")
+    else:
+        # todo dunno maybe use the same mypy config in repository?
+        # I'd need to install mypy.ini then??
+        # todo how to bring it into mypypath? cooperate with core, maybe?
+        mres = run([
+            'python3', '-m', 'mypy',
+            '--namespace-packages',
+            '--color-output', # not sure if works??
+            '--pretty',
+            '--show-error-codes',
+            '--show-error-context',
+            '--check-untyped-defs',
+            '-p', 'my.config'
+        ], stderr=PIPE, stdout=PIPE)
+        rc = mres.returncode
+        if rc == 0:
+            info('mypy check: success')
+        else:
+            error('mypy check: failed')
+            sys.stderr.write(indent(mres.stderr.decode('utf8')))
+        sys.stderr.write(indent(mres.stdout.decode('utf8')))
+
+
+def hello(args):
+    print('Hello')
 
 
 def parser():
@@ -10,21 +77,34 @@ Tool for HPI.
 Work in progress, will be used for config management, troubleshooting & introspection
 ''')
     sp = p.add_subparsers(dest='mode')
-    sp.add_parser(Modes.HELLO, help='TODO just a stub, remove later')
+    hp = sp.add_parser(Modes.HELLO , help='TODO just a stub, remove later')
+    hp.set_defaults(func=hello)
+
+    cp = sp.add_parser(Modes.CONFIG, help='Work with configuration')
+    scp = cp.add_subparsers(dest='mode')
+    if True:
+        ccp = scp.add_parser('check', help='Check config')
+        ccp.set_defaults(func=config_check)
+
     return p
 
 
 def main():
     p = parser()
     args = p.parse_args()
-    mode = args.mode
-    if mode == Modes.HELLO:
-        print('hi')
-    else:
-        import sys
+
+    func = args.func
+    if func is None:
+        # shouldn't happen.. but just in case
         p.print_usage()
         sys.exit(1)
 
+    import tempfile
+    with tempfile.TemporaryDirectory() as td:
+        # cd into tmp dir to prevent accidental imports..
+        os.chdir(str(td))
+        args.func(args)
+
 
 if __name__ == '__main__':
     main()
diff --git a/setup.py b/setup.py
index 4acce99..b68d77f 100644
--- a/setup.py
+++ b/setup.py
@@ -61,6 +61,7 @@ def main():
                 # TODO document these?
                 'logzero',
                 'cachew',
+                'mypy', # used for config checks
             ],
             ':python_version<"3.7"': [
                 # used for some modules... hopefully reasonable to have it as a default