From 15e96303ef20d5886afa150566434fc1ea02efc8 Mon Sep 17 00:00:00 2001
From: Jiayi Zheng <thebluber@gmail.com>
Date: Tue, 8 Jul 2025 19:56:53 +0200
Subject: [PATCH 1/2] Add method in langfuce tracer for updating a trace with
 output

---
 lib/llm_eval_ruby/api_clients/langfuse.rb    | 9 +++++++++
 lib/llm_eval_ruby/trace_adapters/langfuse.rb | 9 +++++++++
 lib/llm_eval_ruby/tracer.rb                  | 8 ++++++++
 3 files changed, 26 insertions(+)

diff --git a/lib/llm_eval_ruby/api_clients/langfuse.rb b/lib/llm_eval_ruby/api_clients/langfuse.rb
index d0a2b8a..0316aa4 100644
--- a/lib/llm_eval_ruby/api_clients/langfuse.rb
+++ b/lib/llm_eval_ruby/api_clients/langfuse.rb
@@ -35,6 +35,15 @@ def create_trace(params = {})
         create_event(type: "trace-create", body:)
       end
 
+      def update_trace(params = {})
+        body = {
+          id: params[:id],
+          output: params[:output]
+        }
+        # WARNING! trace-create is used for update as well they do upsert if id is provided
+        create_event(type: "trace-create", body:)
+      end
+
       def create_span(params = {})
         body = {
           id: params[:id],
diff --git a/lib/llm_eval_ruby/trace_adapters/langfuse.rb b/lib/llm_eval_ruby/trace_adapters/langfuse.rb
index ec45070..e7b93d6 100644
--- a/lib/llm_eval_ruby/trace_adapters/langfuse.rb
+++ b/lib/llm_eval_ruby/trace_adapters/langfuse.rb
@@ -17,6 +17,15 @@ def trace(**kwargs)
           trace
         end
 
+        def update_trace(**kwargs)
+          trace = TraceTypes::Trace.new(**kwargs)
+          response = client.update_trace(trace.to_h)
+
+          logger.warn "Failed to update trace" if response["successes"].blank?
+
+          trace
+        end
+
         def span(**kwargs)
           span = TraceTypes::Span.new(id: SecureRandom.uuid, **kwargs)
           response = client.create_span(span.to_h)
diff --git a/lib/llm_eval_ruby/tracer.rb b/lib/llm_eval_ruby/tracer.rb
index 18b2d1d..06c97f2 100644
--- a/lib/llm_eval_ruby/tracer.rb
+++ b/lib/llm_eval_ruby/tracer.rb
@@ -11,6 +11,10 @@ def self.trace(...)
       new(adapter: LlmEvalRuby.config.adapter).trace(...)
     end
 
+    def self.update_trace(...)
+      new(adapter: LlmEvalRuby.config.adapter).update_trace(...)
+    end
+
     def self.span(...)
       new(adapter: LlmEvalRuby.config.adapter).span(...)
     end
@@ -38,6 +42,10 @@ def trace(...)
       adapter.trace(...)
     end
 
+    def update_trace(...)
+      adapter.update_trace(...)
+    end
+
     def span(...)
       adapter.span(...)
     end

From 844016c00922a404160660c7baa25a7e30c8a1e5 Mon Sep 17 00:00:00 2001
From: Jiayi Zheng <thebluber@gmail.com>
Date: Tue, 8 Jul 2025 20:02:54 +0200
Subject: [PATCH 2/2] Add update_trace to local adapter to not break it

---
 lib/llm_eval_ruby/trace_adapters/local.rb | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/llm_eval_ruby/trace_adapters/local.rb b/lib/llm_eval_ruby/trace_adapters/local.rb
index 567f68a..db84e5e 100644
--- a/lib/llm_eval_ruby/trace_adapters/local.rb
+++ b/lib/llm_eval_ruby/trace_adapters/local.rb
@@ -14,6 +14,14 @@ def trace(**kwargs)
           trace
         end
 
+        def update_trace(**kwargs)
+          trace = TraceTypes::Trace.new(id: SecureRandom.uuid, **kwargs)
+
+          logger.info("Trace updated: #{JSON.pretty_generate(trace.to_h)}")
+
+          trace
+        end
+
         def span(**kwargs)
           span = TraceTypes::Span.new(id: SecureRandom.uuid, **kwargs)