diff --git a/.github/workflows/pytest.yml b/.github/workflows/pytest.yml
index b3ad0fa..bd70239 100644
--- a/.github/workflows/pytest.yml
+++ b/.github/workflows/pytest.yml
@@ -33,4 +33,8 @@ jobs:
         COVERALLS_REPO_TOKEN: ${{ secrets.COVERALL_SECRET }}
       run: |
         pip install coveralls
-        coveralls
\ No newline at end of file
+        coveralls
+    - name: Static type checking
+      run: |
+        pip install mypy
+        mypy
\ No newline at end of file
diff --git a/localite/__init__.py b/localite/__init__.py
index de74a3d..94bfac3 100644
--- a/localite/__init__.py
+++ b/localite/__init__.py
@@ -1,2 +1,2 @@
-__path__ = __import__("pkgutil").extend_path(__path__, __name__)
+# __path__ = __import__("pkgutil").extend_path(__path__, __name__)
 
diff --git a/localite/coil.py b/localite/coil.py
index c28e3f8..d35c451 100644
--- a/localite/coil.py
+++ b/localite/coil.py
@@ -58,7 +58,7 @@ def __init__(self, coil: int = 0, address: Tuple[str, int] = ("127.0.0.1", 6667)
 
     def await_connection(self):
         print("[", end="")
-        while not self.connected:
+        while not self.connected:  # pragma no cover
             print(".", end="")
         print("]")
 
@@ -203,3 +203,18 @@ def mode(self) -> str:
             
         """
         return self.request("stimulator_mode")["name"]
+
+    def set_response(
+        self, mepmaxtime: float, mepamplitude: float, mepmin: float, mepmax: float
+    ):
+        key = f"coil_{self.id}_response"
+        msg = {
+            key: {
+                "mepmaxtime": mepmaxtime,
+                "mepamplitude": mepamplitude,
+                "mepmin": mepmin,
+                "mepmax": mepmax,
+            }
+        }
+        self._push_loc(msg=json.dumps(msg))
+
diff --git a/localite/flow/loc.py b/localite/flow/loc.py
index e3031ed..8cfc5e6 100644
--- a/localite/flow/loc.py
+++ b/localite/flow/loc.py
@@ -126,7 +126,6 @@ def close(self) -> None:
 
     def write(self, msg: str) -> None:
         self.socket.sendall(msg.encode("ascii"))
-        return self
 
     def read(self) -> Union[None, str]:
         "parse the message"
@@ -134,10 +133,10 @@ def read(self) -> Union[None, str]:
         while True:
             try:
                 prt = self.socket.recv(1)
-                bmsg += prt               
+                bmsg += prt
                 dec = bmsg.decode("ascii")
                 return json.dumps(json.loads(dec))
-            except json.JSONDecodeError:  # pragma no cover              
+            except json.JSONDecodeError:  # pragma no cover
                 pass
             except Exception as e:  # pragma no cover
                 print("LCL:EXC:", e)
@@ -161,7 +160,7 @@ def listen_and_queue(
     """listen to the localice stream and forward to queue
     """
     msg = client.listen()
-    if json.loads(msg) in ignore or None:
+    if msg is None or json.loads(msg) in ignore:
         return None
     else:
         print("LOC:MSG", msg)
@@ -175,12 +174,12 @@ class LastMessage(Payload):
 
     def __init__(self):
         self.reset()
-        
+
     def reset(self):
         self.expect = None
         self.counter = 0
         self.msg = ""
-        
+
     def update(self, payload: Payload):
         "update the expectation"
         if payload.fmt != "loc":  # pragma no cover
@@ -223,6 +222,7 @@ def expects(self, response: Union[Dict[str, Any], None]) -> int:
             print("LOC:FOUND", response)
             self.reset()
             return 0
+        return 0
 
 
 class LOC(threading.Thread):
@@ -255,23 +255,23 @@ def run(self):
         while self.is_running.is_set():
             try:
                 payload = get_from_queue(self.inbox)
-                if payload is None:           
+                if payload is None:
                     if "status" in lastmessage.msg:
                         response = listen_and_queue(
                             client, ignore=[], queue=self.outbox
                         )
-                    else:                         
+                    else:
                         response = listen_and_queue(
                             client, ignore=self.ignore, queue=self.outbox
                         )
                     flevel = lastmessage.expects(response)
-                    #print("LOC:FRUST", flevel, response)
-#                    if flevel:
-#                        print("LOC:FRUST", flevel, response)
-#                    if flevel >= 2:
-#                        print("LOC:RESEND", lastmessage.msg)
-#                        client.send(lastmessage.msg)
-#                        lastmessage.counter = 0
+                    # print("LOC:FRUST", flevel, response)
+                #                    if flevel:
+                #                        print("LOC:FRUST", flevel, response)
+                #                    if flevel >= 2:
+                #                        print("LOC:RESEND", lastmessage.msg)
+                #                        client.send(lastmessage.msg)
+                #                        lastmessage.counter = 0
                 else:
                     print("LOC:RECV", payload)
                 if payload.fmt == "cmd":
diff --git a/localite/flow/mock.py b/localite/flow/mock.py
index 0b3a5a0..4ca4eac 100644
--- a/localite/flow/mock.py
+++ b/localite/flow/mock.py
@@ -2,7 +2,7 @@
 import json
 import threading
 import time
-from typing import Dict, Union
+from typing import Dict, Union, Any
 from localite.flow.payload import Queue
 from localite.flow.loc import localiteClient
 
@@ -49,8 +49,7 @@ def Messages():
 
 def kill(host: str = "127.0.0.1", port=6666):
     client = localiteClient(host, port)
-    msg = {"cmd": "poison-pill"}
-    msg = json.dumps(msg)
+    msg = json.dumps({"cmd": "poison-pill"})
     client.send(msg)
 
 
@@ -128,7 +127,7 @@ def kill(host: str = "127.0.0.1", port=6666):
 }
 
 
-def create_response(msg: Dict[str, Union[str, int]]) -> Dict:
+def create_response(msg: Any) -> Union[Dict, None]:
     if msg is None:
         return None
     key = list(msg.keys())[0]
@@ -143,10 +142,13 @@ def create_response(msg: Dict[str, Union[str, int]]) -> Dict:
         "coil_0_target_index",
         "coil_1_target_index",
     ]:  # set target index
-        if type(val) == int and val > 0:
+        if type(val) is int and val > 0:
             return msg
         else:
-            return {"error": msg}
+            return {
+                "request": {key: val},
+                "reason": f"Index value out of range. Value: {val}, Range: [0..0]",
+            }
     elif key == "single_pulse":  # trigger
         if val in ["COIL_0", "COIL_1"]:
             return {val.lower() + "_didt": 11}
@@ -199,7 +201,7 @@ def await_running(self):
             pass
 
     @staticmethod
-    def read_msg(client: socket.socket) -> dict:
+    def read_msg(client: socket.socket) -> Union[Dict, None]:
         "parse the message"
         client.settimeout(0.1)
         msg = b" "
@@ -207,8 +209,8 @@ def read_msg(client: socket.socket) -> dict:
             try:
                 prt = client.recv(1)
                 msg += prt
-                msg = json.loads(msg.decode("ascii"))
-                return msg
+                dmsg = json.loads(msg.decode("ascii"))
+                return dmsg
             except json.JSONDecodeError:  # pragma no cover
                 pass
             except socket.timeout:
diff --git a/localite/flow/mrk.py b/localite/flow/mrk.py
index f2d0885..723e490 100644
--- a/localite/flow/mrk.py
+++ b/localite/flow/mrk.py
@@ -38,12 +38,12 @@ def get_as_list(self) -> List[Any]:
 
 
 def expectation(msg: str) -> str:
-    msg = json.loads(msg)
-    key = list(msg.keys())[0]
+    dmsg = json.loads(msg)
+    key = list(dmsg.keys())[0]
     if key == "get":
-        return msg["get"]
+        return dmsg["get"]
     elif "single_pulse" in key:
-        return msg["single_pulse"].lower() + "_didt"
+        return dmsg["single_pulse"].lower() + "_didt"
     else:
         return key
 
diff --git a/mypy.ini b/mypy.ini
index 422ac89..8d41dc5 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -1,2 +1,6 @@
 [mypy]
 mypy_path=/media/rgugg/tools/python3/pyliesl, /media/rgugg/tools/python3/pyreiz
+ignore_missing_imports = True
+files = localite/**/*.py
+pretty = True
+error_summary = True
\ No newline at end of file
diff --git a/test/flow/test_mock.py b/test/flow/test_mock.py
index 08be44a..7c60e48 100644
--- a/test/flow/test_mock.py
+++ b/test/flow/test_mock.py
@@ -31,8 +31,8 @@ def test_create_response():
     assert "error" in cr({"current_instrument": "GARBAGE"}).keys()
     assert "NONE" in cr({"current_instrument": "NONE"}).values()
     assert 1 in cr({"coil_0_target_index": 1}).values()
-    assert "error" in cr({"coil_0_target_index": -1}).keys()
-    assert "error" in cr({"coil_0_target_index": "T"}).keys()
+    assert "reason" in cr({"coil_0_target_index": -1}).keys()
+    assert "reason" in cr({"coil_0_target_index": "T"}).keys()
     assert "coil_0_didt" in cr({"single_pulse": "COIL_0"}).keys()
     assert "error" in cr({"single_pulse": "COIL_2"}).keys()
     assert 1 in cr({"coil_0_amplitude": 1}).values()
diff --git a/test/test_coil.py b/test/test_coil.py
index 814597c..bdf9e43 100644
--- a/test/test_coil.py
+++ b/test/test_coil.py
@@ -50,9 +50,10 @@ def test_coil_static_properties(coil):
         assert coil.temperature == 35
         assert coil.didt == 99
         assert coil.visible
-        assert coil.connected == True
+        assert coil.connected is True
         with raises(AttributeError):
             coil.connected = False
+        assert coil.position_reached is True
         assert coil.model == "Mock0704 mock"
 
     def test_coil_setable_properties(coil):
@@ -80,6 +81,9 @@ def test_coil_setable_properties(coil):
         with raises(ValueError):
             coil.id = -1
 
+    def test_coil_response(coil):
+        coil.set_response(mepmaxtime=18, mepamplitude=40, mepmin=-20, mepmax=20)
+
     def test_coil_trigger(coil):
         coil.trigger()