diff --git a/lib/roast/cogs/agent/providers/claude/message.rb b/lib/roast/cogs/agent/providers/claude/message.rb
index e51b084f..739f372c 100644
--- a/lib/roast/cogs/agent/providers/claude/message.rb
+++ b/lib/roast/cogs/agent/providers/claude/message.rb
@@ -22,26 +22,24 @@ def from_json(json, raw_dump_file: nil)
               #: (Hash[Symbol, untyped]) -> Message
               def from_hash(hash)
                 type = hash.delete(:type)&.to_sym
-                case type
-                when :assistant
-                  Messages::AssistantMessage.new(type:, hash:)
-                when :result
-                  Messages::ResultMessage.new(type:, hash:)
-                when :system
-                  Messages::SystemMessage.new(type:, hash:)
-                when :text
-                  Messages::TextMessage.new(type:, hash:)
-                when :thinking
-                  Messages::ThinkingMessage.new(type:, hash:)
-                when :tool_result
-                  Messages::ToolResultMessage.new(type:, hash:)
-                when :tool_use
-                  Messages::ToolUseMessage.new(type:, hash:)
-                when :user
-                  Messages::UserMessage.new(type:, hash:)
+                message_class = resolve_message_class(type)
+                message_class.new(type:, hash:)
+              end
+
+              private
+
+              #: (Symbol?) -> singleton(Message)
+              def resolve_message_class(type)
+                return Messages::UnknownMessage if type.nil?
+
+                class_name = "#{type}_message".camelize
+                if Messages.const_defined?(class_name, false)
+                  Messages.const_get(class_name, false) # rubocop:disable Sorbet/ConstantsFromStrings
                 else
-                  Messages::UnknownMessage.new(type:, hash:)
+                  Messages::UnknownMessage
                 end
+              rescue NameError
+                Messages::UnknownMessage
               end
             end
 
diff --git a/test/roast/cogs/agent/providers/claude/message_test.rb b/test/roast/cogs/agent/providers/claude/message_test.rb
index 3e2abdd5..070141ba 100644
--- a/test/roast/cogs/agent/providers/claude/message_test.rb
+++ b/test/roast/cogs/agent/providers/claude/message_test.rb
@@ -149,6 +149,13 @@ class MessageTest < ActiveSupport::TestCase
               assert_kind_of Messages::UnknownMessage, message
             end
 
+            test "from_hash with invalid constant name type creates UnknownMessage" do
+              hash = { type: :"some-hyphenated-type", foo: "bar" }
+              message = Message.from_hash(hash)
+
+              assert_kind_of Messages::UnknownMessage, message
+            end
+
             test "from_hash removes type from hash" do
               hash = { type: :text, text: "Hello" }
               Message.from_hash(hash)