Fix instrumentation: style, empty metadata check, streaming tool spans

- Add blank line after SpanKind module for consistent style
- Use metadata&.any? to avoid iterating empty hash
- Skip tool span creation during streaming to prevent orphan spans

Author: pcomans

lib/ruby_llm/chat.rb

@@ -19,6 +19,7 @@ def initialize(model: nil, provider: nil, assume_model_exists: false, context: n
       @session_id = session_id || SecureRandom.uuid
       @metadata = {}
       @temperature = nil
+      @streaming_active = false
       @messages = []
       @tools = {}
       @params = {}
@@ -140,6 +141,8 @@ def complete(&)
     private
 
     def complete_without_instrumentation(&)
+      @streaming_active = block_given?
+
       response = @provider.complete(
         messages,
         tools: @tools,
@@ -152,6 +155,8 @@ def complete_without_instrumentation(&)
       )
 
       finalize_response(response, &)
+    ensure
+      @streaming_active = false
     end
 
     def complete_with_span(span, &)
@@ -292,11 +297,19 @@ def handle_tool_calls(response, &) # rubocop:disable Metrics/PerceivedComplexity
     end
 
     def execute_tool(tool_call)
+      # Skip instrumentation for streaming (tool spans would be orphaned without parent chat span)
+      return execute_tool_without_instrumentation(tool_call) if @streaming_active
+
       Instrumentation.tracer.in_span('ruby_llm.tool', kind: Instrumentation::SpanKind::INTERNAL) do |span|
         execute_tool_with_span(tool_call, span)
       end
     end
 
+    def execute_tool_without_instrumentation(tool_call)
+      tool = tools[tool_call.name.to_sym]
+      tool.call(tool_call.arguments)
+    end
+
     def execute_tool_with_span(tool_call, span)
       tool = tools[tool_call.name.to_sym]
       args = tool_call.arguments

lib/ruby_llm/instrumentation.rb

@@ -11,6 +11,7 @@ module SpanKind
       CLIENT = :client
       INTERNAL = :internal
     end
+
     class << self
       def enabled?
         return false unless RubyLLM.config.tracing_enabled
@@ -157,7 +158,7 @@ def build_request_attributes(model:, provider:, session_id:, temperature: nil, m
             'gen_ai.conversation.id' => session_id
           }
           attrs['gen_ai.request.temperature'] = temperature if temperature
-          build_metadata_attributes(attrs, metadata) if metadata
+          build_metadata_attributes(attrs, metadata) if metadata&.any?
           attrs
         end