dynamite: Output tag descriptions

packages/dynamite/lib/src/models/tag.dart

@@ -6,10 +6,13 @@ part 'tag.g.dart';
 class Tag {
   Tag({
     required this.name,
+    this.description,
   });
 
   factory Tag.fromJson(final Map<String, dynamic> json) => _$TagFromJson(json);
   Map<String, dynamic> toJson() => _$TagToJson(this);
 
   final String name;
+
+  final String? description;
 }

packages/dynamite/lib/src/models/tag.g.dart

@@ -9,13 +9,25 @@ part of 'tag.dart';
 Tag _$TagFromJson(Map<String, dynamic> json) {
   $checkKeys(
     json,
-    allowedKeys: const ['name'],
+    allowedKeys: const ['name', 'description'],
   );
   return Tag(
     name: json['name'] as String,
+    description: json['description'] as String?,
   );
 }
 
-Map<String, dynamic> _$TagToJson(Tag instance) => <String, dynamic>{
-      'name': instance.name,
-    };
+Map<String, dynamic> _$TagToJson(Tag instance) {
+  final val = <String, dynamic>{
+    'name': instance.name,
+  };
+
+  void writeNotNull(String key, dynamic value) {
+    if (value != null) {
+      val[key] = value;
+    }
+  }
+
+  writeNotNull('description', instance.description);
+  return val;
+}

packages/dynamite/lib/src/openapi_builder.dart

@@ -536,8 +536,14 @@ class OpenAPIBuilder implements Builder {
                     ),
                   );
               }
+              final matchedTags = spec.tags?.where((final t) => t.name == tag).toList();
               b
                 ..name = '$prefix${isRootClient ? 'Client' : _clientName(tag)}'
+                ..docs.addAll(
+                  _descriptionToDocs(
+                    matchedTags != null && matchedTags.isNotEmpty ? matchedTags.single.description : null,
+                  ),
+                )
                 ..methods.addAll(
                   [
                     for (final path in paths.keys) ...[