Fix tool name collisions across namespaces

This fixes an issue where only one tool could be registered when tools shared the same name,
even if they were in different namespaces. With this change, tools in different namespaces
can be registered as separate tools, so multiple tools with the same name can be registered.

Fixes #197

Author: koic

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