diff --git a/lib/tests/misc.nix b/lib/tests/misc.nix
index cf7fa9f2e284..3059878ba069 100644
--- a/lib/tests/misc.nix
+++ b/lib/tests/misc.nix
@@ -1959,6 +1959,18 @@ runTests {
     expr = (with types; int).description;
     expected = "signed integer";
   };
+  testTypeDescriptionIntsPositive = {
+    expr = (with types; ints.positive).description;
+    expected = "positive integer, meaning >0";
+  };
+  testTypeDescriptionIntsPositiveOrEnumAuto = {
+    expr = (with types; either ints.positive (enum ["auto"])).description;
+    expected = ''positive integer, meaning >0, or value "auto" (singular enum)'';
+  };
+  testTypeDescriptionListOfPositive = {
+    expr = (with types; listOf ints.positive).description;
+    expected = "list of (positive integer, meaning >0)";
+  };
   testTypeDescriptionListOfInt = {
     expr = (with types; listOf int).description;
     expected = "list of signed integer";
diff --git a/lib/types.nix b/lib/types.nix
index 4378568c141f..cea63c598321 100644
--- a/lib/types.nix
+++ b/lib/types.nix
@@ -113,9 +113,14 @@ rec {
     , # Description of the type, defined recursively by embedding the wrapped type if any.
       description ? null
       # A hint for whether or not this description needs parentheses. Possible values:
-      #  - "noun": a simple noun phrase such as "positive integer"
-      #  - "conjunction": a phrase with a potentially ambiguous "or" connective.
+      #  - "noun": a noun phrase
+      #    Example description: "positive integer",
+      #  - "conjunction": a phrase with a potentially ambiguous "or" connective
+      #    Example description: "int or string"
       #  - "composite": a phrase with an "of" connective
+      #    Example description: "list of string"
+      #  - "nonRestrictiveClause": a noun followed by a comma and a clause
+      #    Example description: "positive integer, meaning >0"
       # See the `optionDescriptionPhrase` function.
     , descriptionClass ? null
     , # DO NOT USE WITHOUT KNOWING WHAT YOU ARE DOING!
@@ -338,10 +343,12 @@ rec {
         unsigned = addCheck types.int (x: x >= 0) // {
           name = "unsignedInt";
           description = "unsigned integer, meaning >=0";
+          descriptionClass = "nonRestrictiveClause";
         };
         positive = addCheck types.int (x: x > 0) // {
           name = "positiveInt";
           description = "positive integer, meaning >0";
+          descriptionClass = "nonRestrictiveClause";
         };
         u8 = unsign 8 256;
         u16 = unsign 16 65536;
@@ -383,10 +390,12 @@ rec {
       nonnegative = addCheck number (x: x >= 0) // {
         name = "numberNonnegative";
         description = "nonnegative integer or floating point number, meaning >=0";
+        descriptionClass = "nonRestrictiveClause";
       };
       positive = addCheck number (x: x > 0) // {
         name = "numberPositive";
         description = "positive integer or floating point number, meaning >0";
+        descriptionClass = "nonRestrictiveClause";
       };
     };
 
@@ -463,6 +472,7 @@ rec {
     passwdEntry = entryType: addCheck entryType (str: !(hasInfix ":" str || hasInfix "\n" str)) // {
       name = "passwdEntry ${entryType.name}";
       description = "${optionDescriptionPhrase (class: class == "noun") entryType}, not containing newlines or colons";
+      descriptionClass = "nonRestrictiveClause";
     };
 
     attrs = mkOptionType {
@@ -870,7 +880,13 @@ rec {
     # Either value of type `t1` or `t2`.
     either = t1: t2: mkOptionType rec {
       name = "either";
-      description = "${optionDescriptionPhrase (class: class == "noun" || class == "conjunction") t1} or ${optionDescriptionPhrase (class: class == "noun" || class == "conjunction" || class == "composite") t2}";
+      description =
+        if t1.descriptionClass or null == "nonRestrictiveClause"
+        then
+          # Plain, but add comma
+          "${t1.description}, or ${optionDescriptionPhrase (class: class == "noun" || class == "conjunction") t2}"
+        else
+          "${optionDescriptionPhrase (class: class == "noun" || class == "conjunction") t1} or ${optionDescriptionPhrase (class: class == "noun" || class == "conjunction" || class == "composite") t2}";
       descriptionClass = "conjunction";
       check = x: t1.check x || t2.check x;
       merge = loc: defs: