diff --git a/modules/services/logging/logstash.nix b/modules/services/logging/logstash.nix
index 32e2f17d189..bb3b83dd230 100644
--- a/modules/services/logging/logstash.nix
+++ b/modules/services/logging/logstash.nix
@@ -86,12 +86,13 @@ in
       inputConfig = mkOption {
         default = {};
         description = ''
-          A nixexpr representing a logstash configuration's input section.
-          logstash configs are name-value pairs, where values can be bools,
+          An attribute set (or an expression generated by mkNameValuePairs)
+          representing a logstash configuration's input section.
+          Logstash configs are name-value pairs, where values can be bools,
           strings, numbers, arrays, hashes, or other name-value pairs,
-          and names are strings that can be repeated. name-value pairs with no
-          repeats are represented by attr sets. bools, strings, ints, and
-          arrays are mapped directly. name-value pairs with repeats can be
+          and names are strings that can be repeated. Name-value pairs with no
+          repeats are represented by attr sets. Bools, strings, ints, and
+          arrays are mapped directly. Name-value pairs with repeats can be
           generated by the config.lib.logstash.mkNameValuePairs function, which
           takes a list of attrsets and combines them while preserving attribute
           name duplicates if they occur. Similarly, there are the mkFloat and
@@ -104,7 +105,8 @@ in
       filterConfig = mkOption {
         default = {};
         description = ''
-          An attr set representing a logstash configuration's filter section.
+          An attribute set (or an expression generated by mkNameValuePairs)
+          representing a logstash configuration's filter section.
           See inputConfig description for details.
         '';
         merge = mergeConfigs;
@@ -113,7 +115,8 @@ in
       outputConfig = mkOption {
         default = {};
         description = ''
-          An attr set representing a logstash configuration's output section.
+          An attribute set (or an expression generated by mkNameValuePairs)
+          representing a logstash configuration's output section.
           See inputConfig description for details.
         '';
         merge = mergeConfigs;