diff --git a/.gitignore b/.gitignore
index d4163725b2..d45f349939 100644
--- a/.gitignore
+++ b/.gitignore
@@ -46,3 +46,5 @@ docs/moduleguides
 .mypy_cache
 mypy
 types
+mypy.xml
+coverage
diff --git a/requirements.txt b/requirements.txt
index 8c4c919eaf..f7127ef38b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -21,5 +21,6 @@ sphinx-rtd-theme==0.4.2
 sphinx==1.8.1
 texttable==1.5.0
 tornado==4.5.3
+tox==3.5.3
 typing==3.6.6
 virtualenv==16.1.0
diff --git a/src/inmanta/agent/agent.py b/src/inmanta/agent/agent.py
index df3eaf101e..e1d726b61a 100644
--- a/src/inmanta/agent/agent.py
+++ b/src/inmanta/agent/agent.py
@@ -39,6 +39,7 @@
 from inmanta.agent import config as cfg
 from inmanta.agent.reporting import collect_report
 from inmanta.const import ResourceState
+from typing import Tuple
 
 LOGGER = logging.getLogger(__name__)
 GET_RESOURCE_BACKOFF = 5
@@ -90,7 +91,7 @@ def cancel(self):
             self.future.set_result(ResourceActionResult(False, False, True))
 
     @gen.coroutine
-    def _execute(self, ctx: handler.HandlerContext, events: dict, cache: AgentCache, event_only: bool=False) -> (bool, bool):
+    def _execute(self, ctx: handler.HandlerContext, events: dict, cache: AgentCache, event_only: bool=False) -> Tuple[bool, bool]:
         """
             :param ctx The context to use during execution of this deploy
             :param events Possible events that are available for this resource
@@ -362,7 +363,7 @@ def get_client(self):
 
 class AgentInstance(object):
 
-    def __init__(self, process, name: str, uri: str):
+    def __init__(self, process, name: str, uri: str) -> None:
         self.process = process
         self.name = name
         self._uri = uri
diff --git a/src/inmanta/agent/handler.py b/src/inmanta/agent/handler.py
index 24581d8e8c..75e2008a7c 100644
--- a/src/inmanta/agent/handler.py
+++ b/src/inmanta/agent/handler.py
@@ -45,7 +45,7 @@ class provider(object):  # noqa: H801
         :param name: A name to reference this provider.
     """
 
-    def __init__(self, resource_type: str, name: str):
+    def __init__(self, resource_type: str, name: str) -> None:
         self._resource_type = resource_type
         self._name = name
 
diff --git a/src/inmanta/agent/io/local.py b/src/inmanta/agent/io/local.py
index fa0b7b8a73..7f64afe1a0 100644
--- a/src/inmanta/agent/io/local.py
+++ b/src/inmanta/agent/io/local.py
@@ -569,7 +569,7 @@ def rmdir(self, path):
     global channel
 
     if os.getuid() == 0:
-        local_io = LocalIO(uri="local:", config={})
+        local_io = LocalIO(uri="local:", config={})  # type: IOBase
     else:
         local_io = BashIO(uri="local:", config={}, run_as="root")
 
diff --git a/src/inmanta/ast/__init__.py b/src/inmanta/ast/__init__.py
index 698c806f29..45455350d4 100644
--- a/src/inmanta/ast/__init__.py
+++ b/src/inmanta/ast/__init__.py
@@ -52,7 +52,7 @@ def __eq__(self, other: object) -> bool:
             return False
         return self.file == other.file and self.lnr == other.lnr
 
-    def merge(self, other):
+    def merge(self, other: "Location") -> "Location":
         if other is None:
             return self
 
@@ -70,7 +70,7 @@ def __init__(self, file: str, start_lnr: int, start_char: int, end_lnr: int, end
         self.end_lnr = end_lnr
         self.end_char = end_char
 
-    def merge(self, other):
+    def merge(self, other: Location) -> Location:
         if other is None:
             return self
 
@@ -107,10 +107,10 @@ def __str__(self) -> str:
 
 class Locatable(object):
 
-    def __init__(self):
-        self._location = None  # type: Location
+    def __init__(self) -> None:
+        self._location = None  # type: Optional[Location]
 
-    def set_location(self, location: Location):
+    def set_location(self, location: Location) -> None:
         assert location is not None and location.lnr > 0
         self._location = location
 
@@ -135,7 +135,7 @@ class LocatableString(object):
         2. in the constructors of other statements
     """
 
-    def __init__(self, value, location: Range, lexpos, namespace):
+    def __init__(self, value, location: Range, lexpos: "int", namespace: "Namespace") -> None:
         self.value = value
         self.location = location
 
@@ -159,7 +159,7 @@ def __str__(self):
 
 class Anchor(object):
 
-    def __init__(self, range: Range):
+    def __init__(self, range: Range) -> None:
         self.range = range
 
     def get_range(self) -> Range:
@@ -169,31 +169,31 @@ def get_location(self) -> Range:
         return self.range
 
     @abstractmethod
-    def resolve(self):
+    def resolve(self) -> Location:
         raise NotImplementedError()
 
 
 class TypeReferenceAnchor(Anchor):
 
-    def __init__(self, range: Range, namespace: "Namespace", type: str):
+    def __init__(self, range: Range, namespace: "Namespace", type: str) -> None:
         Anchor.__init__(self, range=range)
         self.namespace = namespace
         self.type = type
 
-    def resolve(self):
+    def resolve(self) -> Location:
         t = self.namespace.get_type(self.type)
         return t.get_location()
 
 
 class AttributeReferenceAnchor(Anchor):
 
-    def __init__(self, range: Range, namespace: "Namespace", type: str, attribute: str):
+    def __init__(self, range: Range, namespace: "Namespace", type: str, attribute: str) -> None:
         Anchor.__init__(self, range=range)
         self.namespace = namespace
         self.type = type
         self.attribute = attribute
 
-    def resolve(self):
+    def resolve(self) -> Location:
         return self.namespace.get_type(self.type).get_attribute(self.attribute).get_location()
 
 
@@ -234,9 +234,10 @@ def __init__(self, name: str, parent: "Optional[Namespace]"=None) -> None:
             self.visible_namespaces = {self.get_full_name(): MockImport(self)}
             self.__parent.add_child(self)
         else:
+            # type: Dict[str,Union[DefineImport, MockImport]]
             self.visible_namespaces = {name: MockImport(self)}
-        self.primitives = None  # type: Dict[str,Type]
-        self.scope = None  # type: ExecutionContext
+        self.primitives = None  # type: Optional[Dict[str,Type]]
+        self.scope = None  # type:  Optional[ExecutionContext]
 
     def set_primitives(self, primitives: "Dict[str,Type]") -> None:
         self.primitives = primitives
diff --git a/src/inmanta/export.py b/src/inmanta/export.py
index 2baed1f23e..cfbf8cdc86 100644
--- a/src/inmanta/export.py
+++ b/src/inmanta/export.py
@@ -580,7 +580,7 @@ def convert_attribute(attr):
         def convert_relation(relation: RelationAttribute):
 
             return model.Relation(relation.type.get_full_name(),
-                                  [relation.low, relation.high],
+                                  (relation.low, relation.high),
                                   relation_name(relation.type, relation.end),
                                   convert_comment(relation.comment), location(relation),
                                   [convert_value_for_type(x.get_value()) for x in relation.source_annotations],
diff --git a/src/inmanta/model.py b/src/inmanta/model.py
index 1159579852..5787b7c292 100644
--- a/src/inmanta/model.py
+++ b/src/inmanta/model.py
@@ -69,7 +69,7 @@ class Attribute(object):
         :param Location location: source location where this attribute is defined
     """
 
-    def __init__(self, mytype: str, nullable: bool, multi: bool, comment: str, location: Location):
+    def __init__(self, mytype: str, nullable: bool, multi: bool, comment: str, location: Location) -> None:
         self.type = mytype
         self.nullable = nullable
         self.multi = multi
@@ -191,7 +191,7 @@ class Relation(object):
     """
 
     def __init__(self, mytype: str, multi: Tuple[int, int], reverse: str, comment: str, location: Location,
-                 source_annotations: List[Value], target_annotations: List[Value]):
+                 source_annotations: List[Value], target_annotations: List[Value]) -> None:
         self.type = mytype
         lower = multi[0]
         if lower is None:
@@ -259,7 +259,7 @@ class Entity(object):
     """
 
     def __init__(self, parents: List[str], attributes: Dict[str, Attribute],
-                 relations: Dict[str, Relation], location: Location):
+                 relations: Dict[str, Relation], location: Location) -> None:
         self.parents = parents
         self.attributes = attributes
         self.relations = relations
diff --git a/src/inmanta/module.py b/src/inmanta/module.py
index 8a2eb2e5bc..e55b0c416d 100644
--- a/src/inmanta/module.py
+++ b/src/inmanta/module.py
@@ -345,14 +345,14 @@ def _load_file(self, ns, file) -> Tuple[List[Statement], BasicBlock]:
                 block.add(s)
         return (statements, block)
 
-    def requires(self) -> dict:
+    def requires(self) -> "List[List[Requirement]]":
         """
             Get the requires for this module
         """
         # filter on import stmt
 
         if "requires" not in self._meta or self._meta["requires"] is None:
-            return {}
+            return []
 
         reqs = []
         for spec in self._meta["requires"]:
diff --git a/src/inmanta/moduletool.py b/src/inmanta/moduletool.py
index 1a92415361..bb7da74730 100644
--- a/src/inmanta/moduletool.py
+++ b/src/inmanta/moduletool.py
@@ -20,7 +20,7 @@
 import inspect
 import logging
 import os
-from os.path import sys
+import sys
 import shutil
 import subprocess
 import tempfile
diff --git a/src/inmanta/server/agentmanager.py b/src/inmanta/server/agentmanager.py
index 8964acc6d7..040f11546b 100644
--- a/src/inmanta/server/agentmanager.py
+++ b/src/inmanta/server/agentmanager.py
@@ -437,8 +437,8 @@ def _ensure_agents(self, env: data.Environment, agents: list, restart: bool=Fals
             LOGGER.info("%s matches agents managed by server, ensuring it is started.", agents)
             for agent in agents:
                 with (yield self.session_lock.acquire()):
-                    agent = self.get_agent_client(env.id, agent)
-                    if agent is None:
+                    myagent = self.get_agent_client(env.id, agent)
+                    if myagent is None:
                         needsstart = True
 
             if needsstart:
diff --git a/tox.ini b/tox.ini
index e77ac4ac78..d7eca83b35 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py34,py35,py36,pep8
+envlist = py34,py35,py36,pep8,mypy
 skip_missing_interpreters=True
 
 [pep8]
@@ -53,3 +53,15 @@ changedir=docs
 deps=pytest
     -rrequirements.txt
 commands=py.test -v check_sphinx.py
+
+
+[testenv:mypy]
+deps=
+    mypy
+    lxml
+commands_pre = mkdir -p coverage
+whitelist_externals = */mkdir
+commands = 
+    python -m mypy src --ignore-missing-imports --junit-xml mypy.xml --cobertura-xml-report coverage
+basepython = python3
+ignore_outcome = true