diff --git a/lib/httpx/plugins/cookies/cookie.rb b/lib/httpx/plugins/cookies/cookie.rb
index 2b8db659..9289a1c7 100644
--- a/lib/httpx/plugins/cookies/cookie.rb
+++ b/lib/httpx/plugins/cookies/cookie.rb
@@ -107,6 +107,8 @@ module HTTPX
 
         @path ||= "/"
         raise ArgumentError, "name must be specified" if @name.nil?
+
+        @name = @name.to_s
       end
 
       def expires
@@ -122,7 +124,7 @@ module HTTPX
       # Returns a string for use in the Cookie header, i.e. `name=value`
       # or `name="value"`.
       def cookie_value
-        "#{@name}=#{Scanner.quote(@value)}"
+        "#{@name}=#{Scanner.quote(@value.to_s)}"
       end
       alias_method :to_s, :cookie_value
 
diff --git a/sig/plugins/cookies/cookie.rbs b/sig/plugins/cookies/cookie.rbs
index 7568d8d3..03670504 100644
--- a/sig/plugins/cookies/cookie.rbs
+++ b/sig/plugins/cookies/cookie.rbs
@@ -31,19 +31,17 @@ module HTTPX
 
       def valid_for_uri?: (uri) -> bool
 
-      def self.new: (Cookie) -> untyped
-                    | (cookie_attributes) -> untyped
-                    | (String, String) -> untyped
-                    | (String, String, cookie_attributes) -> untyped
+      def self.new: (Cookie) -> instance
+                    | (cookie_attributes) -> instance
+                    | (_ToS, _ToS, ?cookie_attributes) -> instance
 
       def self.path_match?: (String, String) -> bool
 
       private
 
       def initialize: (cookie_attributes) -> untyped
-                    | (String, String) -> untyped
-                    | (String, String, cookie_attributes?) -> untyped
-      
+                    | (_ToS, _ToS, ?cookie_attributes) -> untyped
+
       def acceptable_from_uri?: (uri) -> bool
     end
   end