Fix tool name collisions across namespaces

lib/mcp/string_utils.rb

@@ -4,16 +4,16 @@ module MCP
   module StringUtils
     extend self
 
+    NAMESPACE_SEPARATOR = "/"
+
     def handle_from_class_name(class_name)
-      underscore(demodulize(class_name))
+      class_name.to_s.split("::").map do |name|
+        underscore(name)
+      end.join(NAMESPACE_SEPARATOR)
     end
 
     private
 
-    def demodulize(path)
-      path.to_s.split("::").last || path.to_s
-    end
-
     def underscore(camel_cased_word)
       camel_cased_word.dup
         .gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2')

test/mcp/prompt_test.rb

@@ -102,7 +102,7 @@ def template(args, server_context:)
 
       prompt = DefaultNamePrompt
 
-      assert_equal "default_name_prompt", prompt.name_value
+      assert_equal "mcp/prompt_test/default_name_prompt", prompt.name_value
       assert_equal "a mock prompt for testing", prompt.description
       assert_equal "test_argument", prompt.arguments.first.name
     end
@@ -184,7 +184,7 @@ class NoArgumentsPrompt < Prompt
       prompt = NoArgumentsPrompt
 
       expected = {
-        name: "no_arguments_prompt",
+        name: "mcp/prompt_test/no_arguments_prompt",
         description: "No arguments prompt",
       }
 

test/mcp/server_test.rb

@@ -372,6 +372,22 @@ def call(message:, server_context: nil)
       assert_instrumentation_data({ method: "tools/call", tool_name: "tool_that_raises" })
     end
 
+    test "registers tools with the same class name in different namespaces" do
+      module Foo
+        class Example < Tool
+        end
+      end
+
+      class Bar
+        class Example < Tool
+        end
+      end
+
+      server = Server.new(tools: [Foo::Example, Bar::Example])
+
+      assert_equal(2, server.tools.count)
+    end
+
     test "#handle_json returns error response with isError true if the tool raises an error" do
       request = JSON.generate({
         jsonrpc: "2.0",

test/mcp/string_utils_test.rb

@@ -10,13 +10,13 @@ def test_handle_from_class_name_returns_the_class_name_without_the_module_for_a_
     end
 
     def test_handle_from_class_name_returns_the_class_name_without_the_module_for_a_class_with_a_single_parent_module
-      assert_equal("test", StringUtils.handle_from_class_name("Module::Test"))
-      assert_equal("test_class", StringUtils.handle_from_class_name("Module::TestClass"))
+      assert_equal("module/test", StringUtils.handle_from_class_name("Module::Test"))
+      assert_equal("module/test_class", StringUtils.handle_from_class_name("Module::TestClass"))
     end
 
     def test_handle_from_class_name_returns_the_class_name_without_the_module_for_a_class_with_multiple_parent_modules
-      assert_equal("test", StringUtils.handle_from_class_name("Module::Submodule::Test"))
-      assert_equal("test_class", StringUtils.handle_from_class_name("Module::Submodule::TestClass"))
+      assert_equal("module/submodule/test", StringUtils.handle_from_class_name("Module::Submodule::Test"))
+      assert_equal("module/submodule/test_class", StringUtils.handle_from_class_name("Module::Submodule::TestClass"))
     end
   end
 end

test/mcp/tool_test.rb

@@ -89,7 +89,7 @@ class DefaultNameTool < Tool
 
       tool = DefaultNameTool
 
-      assert_equal "default_name_tool", tool.tool_name
+      assert_equal "mcp/tool_test/default_name_tool", tool.tool_name
     end
 
     test "input schema defaults to an empty hash" do