diff --git a/nixos/modules/config/fonts/fontdir.nix b/nixos/modules/config/fonts/fontdir.nix
index cc70fbf8744d..a6aa84ae8224 100644
--- a/nixos/modules/config/fonts/fontdir.nix
+++ b/nixos/modules/config/fonts/fontdir.nix
@@ -25,6 +25,7 @@ in
     fonts = {
 
       enableFontDir = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Whether to create a directory with links to all fonts in
diff --git a/nixos/modules/config/fonts/ghostscript.nix b/nixos/modules/config/fonts/ghostscript.nix
index 1c62a525de94..b1dd81bf2d2e 100644
--- a/nixos/modules/config/fonts/ghostscript.nix
+++ b/nixos/modules/config/fonts/ghostscript.nix
@@ -9,6 +9,7 @@ with lib;
     fonts = {
 
       enableGhostscriptFonts = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Whether to add the fonts provided by Ghostscript (such as
diff --git a/nixos/modules/config/ldap.nix b/nixos/modules/config/ldap.nix
index b554f197dc4b..4c8b527676b2 100644
--- a/nixos/modules/config/ldap.nix
+++ b/nixos/modules/config/ldap.nix
@@ -88,6 +88,7 @@ in
       };
 
       useTLS = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           If enabled, use TLS (encryption) over an LDAP (port 389)
@@ -109,6 +110,7 @@ in
 
       daemon = {
         enable = mkOption {
+          type = types.bool;
           default = false;
           description = ''
             Whether to let the nslcd daemon (nss-pam-ldapd) handle the
diff --git a/nixos/modules/security/apparmor-suid.nix b/nixos/modules/security/apparmor-suid.nix
index 3c93f5440ab5..6c479e070e2b 100644
--- a/nixos/modules/security/apparmor-suid.nix
+++ b/nixos/modules/security/apparmor-suid.nix
@@ -9,6 +9,7 @@ with lib;
   ];
 
   options.security.apparmor.confineSUIDApplications = mkOption {
+    type = types.bool;
     default = true;
     description = ''
       Install AppArmor profiles for commonly-used SUID application
diff --git a/nixos/modules/security/pam.nix b/nixos/modules/security/pam.nix
index bfc2a881387f..aeb8629767bc 100644
--- a/nixos/modules/security/pam.nix
+++ b/nixos/modules/security/pam.nix
@@ -545,6 +545,7 @@ in
     };
 
     security.pam.enableSSHAgentAuth = mkOption {
+      type = types.bool;
       default = false;
       description =
         ''
@@ -555,12 +556,7 @@ in
         '';
     };
 
-    security.pam.enableOTPW = mkOption {
-      default = false;
-      description = ''
-        Enable the OTPW (one-time password) PAM module.
-      '';
-    };
+    security.pam.enableOTPW = mkEnableOption "the OTPW (one-time password) PAM module";
 
     security.pam.u2f = {
       enable = mkOption {
@@ -719,12 +715,7 @@ in
       };
     };
 
-    security.pam.enableEcryptfs = mkOption {
-      default = false;
-      description = ''
-        Enable eCryptfs PAM module (mounting ecryptfs home directory on login).
-      '';
-    };
+    security.pam.enableEcryptfs = mkEnableOption "eCryptfs PAM module (mounting ecryptfs home directory on login)";
 
     users.motd = mkOption {
       default = null;
diff --git a/nixos/modules/services/mail/postfix.nix b/nixos/modules/services/mail/postfix.nix
index 19e11b31d9ca..608f64a68fb0 100644
--- a/nixos/modules/services/mail/postfix.nix
+++ b/nixos/modules/services/mail/postfix.nix
@@ -269,6 +269,7 @@ in
       };
 
       enableSmtp = mkOption {
+        type = types.bool;
         default = true;
         description = "Whether to enable smtp in master.cf.";
       };
diff --git a/nixos/modules/services/mail/spamassassin.nix b/nixos/modules/services/mail/spamassassin.nix
index f6c0b9c794c9..4e642542ec66 100644
--- a/nixos/modules/services/mail/spamassassin.nix
+++ b/nixos/modules/services/mail/spamassassin.nix
@@ -15,6 +15,7 @@ in
       enable = mkEnableOption "the SpamAssassin daemon";
 
       debug = mkOption {
+        type = types.bool;
         default = false;
         description = "Whether to run the SpamAssassin daemon in debug mode";
       };
diff --git a/nixos/modules/services/misc/autofs.nix b/nixos/modules/services/misc/autofs.nix
index 84f49f964b12..5e7c1e668288 100644
--- a/nixos/modules/services/misc/autofs.nix
+++ b/nixos/modules/services/misc/autofs.nix
@@ -57,6 +57,7 @@ in
       };
 
       debug = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Pass -d and -7 to automount and write log to the system journal.
diff --git a/nixos/modules/services/misc/disnix.nix b/nixos/modules/services/misc/disnix.nix
index 0776ac679088..69386cdbb381 100644
--- a/nixos/modules/services/misc/disnix.nix
+++ b/nixos/modules/services/misc/disnix.nix
@@ -25,10 +25,7 @@ in
         description = "Whether to support multi-user mode by enabling the Disnix D-Bus service";
       };
 
-      useWebServiceInterface = mkOption {
-        default = false;
-        description = "Whether to enable the DisnixWebService interface running on Apache Tomcat";
-      };
+      useWebServiceInterface = mkEnableOption "the DisnixWebService interface running on Apache Tomcat";
 
       package = mkOption {
         type = types.path;
diff --git a/nixos/modules/services/networking/gogoclient.nix b/nixos/modules/services/networking/gogoclient.nix
index c9b03bca7112..99455b183144 100644
--- a/nixos/modules/services/networking/gogoclient.nix
+++ b/nixos/modules/services/networking/gogoclient.nix
@@ -19,6 +19,7 @@ in
         '';
       };
       autorun = mkOption {
+        type = types.bool;
         default = true;
         description = ''
           Whether to automatically start the tunnel.
diff --git a/nixos/modules/services/networking/hostapd.nix b/nixos/modules/services/networking/hostapd.nix
index 12c0626a9414..6418ae699431 100644
--- a/nixos/modules/services/networking/hostapd.nix
+++ b/nixos/modules/services/networking/hostapd.nix
@@ -72,6 +72,7 @@ in
       };
 
       noScan = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Do not scan for overlapping BSSs in HT40+/- mode.
@@ -127,6 +128,7 @@ in
       };
 
       wpa = mkOption {
+        type = types.bool;
         default = true;
         description = ''
           Enable WPA (IEEE 802.11i/D3.0) to authenticate with the access point.
diff --git a/nixos/modules/services/networking/openfire.nix b/nixos/modules/services/networking/openfire.nix
index c74f3611f79e..fe0499d52323 100644
--- a/nixos/modules/services/networking/openfire.nix
+++ b/nixos/modules/services/networking/openfire.nix
@@ -12,6 +12,7 @@ with lib;
       enable = mkEnableOption "OpenFire XMPP server";
 
       usePostgreSQL = mkOption {
+        type = types.bool;
         default = true;
         description = "
           Whether you use PostgreSQL service for your storage back-end.
diff --git a/nixos/modules/services/networking/ssh/lshd.nix b/nixos/modules/services/networking/ssh/lshd.nix
index 892e59778c34..41d0584080e4 100644
--- a/nixos/modules/services/networking/ssh/lshd.nix
+++ b/nixos/modules/services/networking/ssh/lshd.nix
@@ -54,21 +54,25 @@ in
       };
 
       syslog = mkOption {
+        type = types.bool;
         default = true;
         description = ''Whether to enable syslog output.'';
       };
 
       passwordAuthentication = mkOption {
+        type = types.bool;
         default = true;
         description = ''Whether to enable password authentication.'';
       };
 
       publicKeyAuthentication = mkOption {
+        type = types.bool;
         default = true;
         description = ''Whether to enable public key authentication.'';
       };
 
       rootLogin = mkOption {
+        type = types.bool;
         default = false;
         description = ''Whether to enable remote root login.'';
       };
@@ -90,11 +94,13 @@ in
       };
 
       tcpForwarding = mkOption {
+        type = types.bool;
         default = true;
         description = ''Whether to enable TCP/IP forwarding.'';
       };
 
       x11Forwarding = mkOption {
+        type = types.bool;
         default = true;
         description = ''Whether to enable X11 forwarding.'';
       };
diff --git a/nixos/modules/services/networking/tcpcrypt.nix b/nixos/modules/services/networking/tcpcrypt.nix
index 18f2e135124b..5a91054e1668 100644
--- a/nixos/modules/services/networking/tcpcrypt.nix
+++ b/nixos/modules/services/networking/tcpcrypt.nix
@@ -15,6 +15,7 @@ in
   options = {
 
     networking.tcpcrypt.enable = mkOption {
+      type = types.bool;
       default = false;
       description = ''
         Whether to enable opportunistic TCP encryption. If the other end
diff --git a/nixos/modules/services/networking/wicd.nix b/nixos/modules/services/networking/wicd.nix
index 03c6bd28aaba..aa10a50f876a 100644
--- a/nixos/modules/services/networking/wicd.nix
+++ b/nixos/modules/services/networking/wicd.nix
@@ -9,6 +9,7 @@ with lib;
   options = {
 
     networking.wicd.enable = mkOption {
+      type = types.bool;
       default = false;
       description = ''
         Whether to start <command>wicd</command>. Wired and
diff --git a/nixos/modules/services/web-servers/jboss/default.nix b/nixos/modules/services/web-servers/jboss/default.nix
index 3a125982831b..ca5b8635fc00 100644
--- a/nixos/modules/services/web-servers/jboss/default.nix
+++ b/nixos/modules/services/web-servers/jboss/default.nix
@@ -60,6 +60,7 @@ in
       };
 
       useJK = mkOption {
+        type = types.bool;
         default = false;
         description = "Whether to use to connector to the Apache HTTP server";
       };
diff --git a/nixos/modules/services/x11/display-managers/gdm.nix b/nixos/modules/services/x11/display-managers/gdm.nix
index d7bef68e5bcb..622ea62f3a91 100644
--- a/nixos/modules/services/x11/display-managers/gdm.nix
+++ b/nixos/modules/services/x11/display-managers/gdm.nix
@@ -93,16 +93,17 @@ in
       };
 
       wayland = mkOption {
+        type = types.bool;
         default = true;
         description = ''
           Allow GDM to run on Wayland instead of Xserver.
           Note to enable Wayland with Nvidia you need to
           enable the <option>nvidiaWayland</option>.
         '';
-        type = types.bool;
       };
 
       nvidiaWayland = mkOption {
+        type = types.bool;
         default = false;
         description = ''
           Whether to allow wayland to be used with the proprietary
diff --git a/nixos/modules/services/x11/hardware/digimend.nix b/nixos/modules/services/x11/hardware/digimend.nix
index a9f5640905aa..b1b1682f00b2 100644
--- a/nixos/modules/services/x11/hardware/digimend.nix
+++ b/nixos/modules/services/x11/hardware/digimend.nix
@@ -16,12 +16,7 @@ in
 
     services.xserver.digimend = {
 
-      enable = mkOption {
-        default = false;
-        description = ''
-          Whether to enable the digimend drivers for Huion/XP-Pen/etc. tablets.
-        '';
-      };
+      enable = mkEnableOption "the digimend drivers for Huion/XP-Pen/etc. tablets";
 
     };
 
diff --git a/nixos/modules/virtualisation/xen-dom0.nix b/nixos/modules/virtualisation/xen-dom0.nix
index 7f0af9901b9b..7b2a66c43489 100644
--- a/nixos/modules/virtualisation/xen-dom0.nix
+++ b/nixos/modules/virtualisation/xen-dom0.nix
@@ -103,6 +103,7 @@ in
         };
 
         forwardDns = mkOption {
+          type = types.bool;
           default = false;
           description = ''
             If set to <literal>true</literal>, the DNS queries from the
@@ -135,14 +136,8 @@ in
           };
       };
 
-    virtualisation.xen.trace =
-      mkOption {
-        default = false;
-        description =
-          ''
-            Enable Xen tracing.
-          '';
-      };
+    virtualisation.xen.trace = mkEnableOption "Xen tracing";
+
   };