diff --git a/lib/types.nix b/lib/types.nix
index e57ceafcbaa4e..dbbf0848d3474 100644
--- a/lib/types.nix
+++ b/lib/types.nix
@@ -1439,6 +1439,9 @@ let
       # Either value of type `t1` or `t2`.
       either =
         t1: t2:
+        let
+          isEitherOrSubmodule = t: t.name == "either" || t.name == "submodule";
+        in
         mkOptionType rec {
           name = "either";
           description =
@@ -1520,6 +1523,32 @@ let
               t2
             ];
           };
+          # We have to be really careful of recursively-defined types here. either is the type used
+          # to allow finitely-sized values for recursively-defined types, so we have to put limits
+          # on how we recurse when looking for submodules. To that end, we'll look for submodule
+          # children, and only recurse into either itself. This means `either str submodule` will
+          # work, and `either str (attrsOf submodule)` won't, but that's better than nothing.
+          getSubOptions =
+            prefix:
+            lib.recursiveUpdateUntil
+              (
+                _: a: b:
+                lib.isOption a || lib.isOption b
+              )
+              (optionalAttrs (isEitherOrSubmodule t2) (t2.getSubOptions prefix))
+              (optionalAttrs (isEitherOrSubmodule t1) (t1.getSubOptions prefix));
+          getSubModules =
+            let
+              t1sm = if isEitherOrSubmodule t1 then t1.getSubModules else null;
+              t2sm = if isEitherOrSubmodule t2 then t2.getSubModules else null;
+            in
+            if t1sm == null then t2sm else t1sm;
+          substSubModules =
+            m:
+            let
+              t1sm = if isEitherOrSubmodule t1 then t1.getSubModules else null;
+            in
+            if t1sm == null then either t1 (t2.substSubModules m) else either (t1.substSubModules m) t2;
           nestedTypes.left = t1;
           nestedTypes.right = t2;
         };
diff --git a/nixos/modules/programs/dconf.nix b/nixos/modules/programs/dconf.nix
index 767a0bf9632f2..c8bd55a4ecb43 100644
--- a/nixos/modules/programs/dconf.nix
+++ b/nixos/modules/programs/dconf.nix
@@ -122,7 +122,7 @@ let
           type = attrs;
           default = { };
           description = "An attrset used to generate dconf keyfile.";
-          example = literalExpression ''
+          example = lib.literalExpression ''
             with lib.gvariant;
             {
               "com/raggesilver/BlackBox" = {
@@ -139,7 +139,7 @@ let
             A list of dconf keys to be lockdown. This doesn't take effect if `lockAll`
             is set.
           '';
-          example = literalExpression ''
+          example = lib.literalExpression ''
             [ "/org/gnome/desktop/background/picture-uri" ]
           '';
         };
diff --git a/nixos/modules/programs/pay-respects.nix b/nixos/modules/programs/pay-respects.nix
index b8fc8e3749367..42ae360bdb41a 100644
--- a/nixos/modules/programs/pay-respects.nix
+++ b/nixos/modules/programs/pay-respects.nix
@@ -143,6 +143,7 @@ in
             };
             locale = mkOption {
               default = toLower (replaceStrings [ "_" ] [ "-" ] (substring 0 5 config.i18n.defaultLocale));
+              defaultText = literalExpression ''toLower (replaceStrings [ "_" ] [ "-" ] (substring 0 5 config.i18n.defaultLocale))'';
               example = "nl-be";
               type = str;
               description = ''
diff --git a/nixos/modules/services/backup/libvirtd-autosnapshot.nix b/nixos/modules/services/backup/libvirtd-autosnapshot.nix
index 51412aa4f810b..d2b0a7e87c236 100644
--- a/nixos/modules/services/backup/libvirtd-autosnapshot.nix
+++ b/nixos/modules/services/backup/libvirtd-autosnapshot.nix
@@ -185,7 +185,7 @@ in
                     default = null;
                     description = ''
                       Type of snapshot to create (internal or external).
-                      If not specified, uses global snapshotType (${toString cfg.snapshotType}).
+                      If not specified, uses global snapshotType.
                     '';
                   };
                   keep = lib.mkOption {
@@ -193,7 +193,7 @@ in
                     default = null;
                     description = ''
                       Number of snapshots to keep for this VM.
-                      If not specified, uses global keep (${toString cfg.keep}).
+                      If not specified, uses global keep.
                     '';
                   };
                 };
diff --git a/nixos/modules/services/mail/rspamd.nix b/nixos/modules/services/mail/rspamd.nix
index 715376e24f883..fb750507d902f 100644
--- a/nixos/modules/services/mail/rspamd.nix
+++ b/nixos/modules/services/mail/rspamd.nix
@@ -33,11 +33,13 @@ let
         owner = mkOption {
           type = types.str;
           default = "${cfg.user}";
+          defaultText = literalExpression "config.services.rspamd.user";
           description = "Owner to set on unix socket";
         };
         group = mkOption {
           type = types.str;
           default = "${cfg.group}";
+          defaultText = literalExpression "config.services.rspamd.group";
           description = "Group to set on unix socket";
         };
         rawEntry = mkOption {
diff --git a/nixos/modules/services/security/tor.nix b/nixos/modules/services/security/tor.nix
index 1c2cc65862e6b..b8652f67b0f2c 100644
--- a/nixos/modules/services/security/tor.nix
+++ b/nixos/modules/services/security/tor.nix
@@ -91,6 +91,9 @@ let
         (enum [ "auto" ])
       ]);
     default = null;
+    description = ''
+      Port number or "auto".
+    '';
   };
   optionPorts =
     optionName:
@@ -114,6 +117,7 @@ let
             SessionGroup = lib.mkOption {
               type = nullOr int;
               default = null;
+              description = descriptionGeneric "SocksPort";
             };
           }
           // lib.genAttrs isolateFlags (
@@ -121,6 +125,7 @@ let
             lib.mkOption {
               type = types.bool;
               default = false;
+              description = descriptionGeneric "SocksPort";
             }
           );
           config = {
@@ -183,6 +188,7 @@ let
             SessionGroup = lib.mkOption {
               type = nullOr int;
               default = null;
+              description = descriptionGeneric "SocksPort";
             };
           }
           // lib.genAttrs flags (
@@ -190,6 +196,7 @@ let
             lib.mkOption {
               type = types.bool;
               default = false;
+              description = descriptionGeneric "SocksPort";
             }
           );
           config = lib.mkIf doConfig {
@@ -204,6 +211,7 @@ let
   optionFlags = lib.mkOption {
     type = with lib.types; listOf str;
     default = [ ];
+    internal = true;
   };
   optionORPort =
     optionName:
@@ -239,6 +247,7 @@ let
                   lib.mkOption {
                     type = types.bool;
                     default = false;
+                    description = descriptionGeneric "ORPort";
                   }
                 );
                 config = {
@@ -727,7 +736,9 @@ in
                         { ... }:
                         {
                           options = {
-                            port = optionPort;
+                            port = optionPort // {
+                              description = "Virtual port number.";
+                            };
                             target = lib.mkOption {
                               default = null;
                               type = nullOr (
@@ -737,11 +748,14 @@ in
                                     options = {
                                       unix = optionUnix;
                                       addr = optionAddress;
-                                      port = optionPort;
+                                      port = optionPort // {
+                                        description = "Port number."; # we shouldn't accept auto here
+                                      };
                                     };
                                   }
                                 )
                               );
+                              description = descriptionGeneric "HiddenServicePort";
                             };
                           };
                         }
@@ -924,6 +938,7 @@ in
                         lib.mkOption {
                           type = types.bool;
                           default = false;
+                          description = descriptionGeneric "ControlPort";
                         }
                       );
                       config = {
diff --git a/nixos/modules/services/web-apps/movim.nix b/nixos/modules/services/web-apps/movim.nix
index 766798dd06022..e1d3367276a96 100644
--- a/nixos/modules/services/web-apps/movim.nix
+++ b/nixos/modules/services/web-apps/movim.nix
@@ -295,11 +295,12 @@ in
                     };
                   };
                 };
+                description = "Script minification options";
               };
               style = mkOption {
                 type = types.submodule {
                   options = {
-                    enable = mkEnableOption "Script minification via Lightning CSS";
+                    enable = mkEnableOption "Style minification via Lightning CSS";
                     target = mkOption {
                       type = types.nullOr types.nonEmptyStr;
                       default = null;
@@ -311,6 +312,7 @@ in
                     };
                   };
                 };
+                description = "Style minification options";
               };
               svg = mkOption {
                 type = types.submodule {
@@ -318,6 +320,7 @@ in
                     enable = mkEnableOption "SVG minification via Scour";
                   };
                 };
+                description = "SVG minification options";
               };
             };
           }