Expose RubyLLM tool classes via MetaToolService (#12)

* Expose RubyLLM tool classes via MetaToolService

* Fix hook preservation in ruby_llm_tools

Author: sh1nj1

README.md

@@ -99,6 +99,23 @@ Tools::MetaToolService.new.register_tool(
 
 These hooks are executed around the tool's entrypoint method for both RubyLLM and FastMCP wrappers.
 
+## Using Tools in Host Application
+
+You can easily fetch the generated RubyLLM tool classes for use in your host application (e.g., when calling an LLM API):
+
+```ruby
+# Fetch specific tool classes by name
+tool_classes = Tools::MetaToolService.ruby_llm_tools(['book_meeting', 'calculator'])
+
+# Use them with RubyLLM
+response = RubyLLM.chat(
+  messages: messages,
+  tools: tool_classes,
+  model: 'gpt-4o'
+)
+```
+
+
 ## Development
 
 After checking out the repo, run `bundle install` to install dependencies. Then, run `bundle exec rails test` to run the tests.

app/services/tools/meta_tool_service.rb

@@ -65,6 +65,17 @@ def register_tool(class_name, before_call: nil, after_call: nil)
       { error: "Could not find #{class_name}: #{e.message}" }
     end
 
+    sig { params(tool_names: T::Array[String]).returns(T::Array[T.class_of(Object)]) }
+    def self.ruby_llm_tools(tool_names)
+      ToolMeta.registry.filter_map do |service_class|
+        schema = ToolSchema::Builder.build(service_class)
+        next unless tool_names.include?(schema[:name])
+
+        tool_class_name = ToolSchema::RubyLlmFactory.tool_class_name(service_class)
+        Tools.const_get(tool_class_name) if Tools.const_defined?(tool_class_name)
+      end
+    end
+
     private
 
     sig { params(query: T.nilable(String)).returns(T::Hash[Symbol, T.untyped]) }

test/meta_tool_service_test.rb

@@ -102,6 +102,39 @@ def test_register_tool_with_hooks_ruby_llm
     assert after_called, 'After hook should be called for RubyLLM tool'
   end
 
+  def test_ruby_llm_tools_returns_correct_tool_classes
+    # Register a tool first
+    meta_service.register_tool('Tools::SampleService')
+
+    tools = Tools::MetaToolService.ruby_llm_tools(['sample'])
+    assert_equal 1, tools.size
+    assert_equal Tools::Sample, tools.first
+    assert_includes tools.first.ancestors, RubyLLM::Tool
+
+    # Test with non-existent tool
+    tools = Tools::MetaToolService.ruby_llm_tools(['non_existent'])
+    assert_empty tools
+  end
+
+  def test_ruby_llm_tools_preserves_hooks
+    ToolMeta.clear_registry
+    before_called = false
+
+    meta_service.register_tool(
+      'Tools::SampleService',
+      before_call: ->(_args) { before_called = true }
+    )
+
+    # Fetch tool using the public API
+    tools = Tools::MetaToolService.ruby_llm_tools(['sample'])
+    assert_equal 1, tools.size
+
+    # Execute to check if hook persists
+    tools.first.new.execute(name: 'Hook Check')
+
+    assert before_called, 'Before hook should be preserved when fetching via ruby_llm_tools'
+  end
+
   private
 
   def meta_service