diff --git a/setup.cfg b/setup.cfg
index beaa51d75..d4b936967 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -71,6 +71,21 @@ test =
     Sphinx
     pytest-subtests
 
+mypy =
+    mypy>=0.902
+    mypy-zope
+    typing-extensions
+    ; Libraries which include type annotations:
+    hypothesis
+    pytest>=6.0.0
+    sphinx>=3.4.0
+    twisted @ git+https://github.com/twisted/twisted.git
+    types-requests
+    ; FIXME: https://github.com/twisted/pydoctor/issues/504
+    ; This is pinned for now as newer versions are breaking our static checks.
+    types-docutils==0.17.5
+    types-toml
+
 [options.entry_points]
 console_scripts =
     pydoctor = pydoctor.driver:main
diff --git a/tox.ini b/tox.ini
index 706c60f15..4f402705b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -64,7 +64,8 @@ commands =
 [testenv:pyflakes]
 description = Run pyflakes over the pydoctor code
 
-deps: pyflakes
+deps =
+    pyflakes
 
 commands =
     ; Custom pyflakes run to exlcude some files. The demo packages are trigerring some unused imports warnings. But pydoctor uses those imports to resolve links. So we skip pyflakes for the demo sites. But not the test files. 
@@ -182,20 +183,8 @@ commands =
 [testenv:mypy]
 description = run mypy (static type checker)
 
-deps =
-    mypy>=0.902
-    mypy-zope
-    typing-extensions
-    ; Libraries which include type annotations:
-    hypothesis
-    pytest>=6.0.0
-    sphinx>=3.4.0
-    git+https://github.com/twisted/twisted.git
-    types-requests
-    # FIXME: https://github.com/twisted/pydoctor/issues/504
-    # This is pinned for now as newer versions are breaking our static checks.
-    types-docutils==0.17.5
-    types-toml
+extras =
+    mypy
 
 commands =
     mypy                                       \