diff --git a/examples/google_tracer.rb b/examples/google_tracer.rb
index 0f378eb..3c6ac3d 100755
--- a/examples/google_tracer.rb
+++ b/examples/google_tracer.rb
@@ -7,6 +7,7 @@
 # Add lib directory to load path
 $LOAD_PATH.unshift(File.expand_path("../lib", __dir__))
 
+require "securerandom"
 require "openlayer"
 require "openlayer/integrations/google_conversational_search_tracer"
 require "google/cloud/discovery_engine/v1"
@@ -19,19 +20,25 @@
   api_key: ENV["OPENLAYER_API_KEY"]
 )
 
-# Enable tracing - this patches the client to send all queries to Openlayer
+# Enable tracing - this patches the client to send all queries to Openlayer.
+# additional_columns here is a static default applied to every trace sent
+# through this client.
 Openlayer::Integrations::GoogleConversationalSearchTracer.trace_client(
   google_client,
   openlayer_client: openlayer,
-  inference_pipeline_id: ENV["OPENLAYER_INFERENCE_PIPELINE_ID"]
+  inference_pipeline_id: ENV["OPENLAYER_INFERENCE_PIPELINE_ID"],
+  additional_columns: {environment: "production"}
 )
 
 # Use the client normally - all answer_query calls are now automatically traced!
+# additional_columns here is per-call; it takes precedence over the static
+# default above on a key conflict.
 response = google_client.answer_query(
   serving_config: ENV["GOOGLE_SERVING_CONFIG"],
   query: Google::Cloud::DiscoveryEngine::V1::Query.new(
     text: "What is the meaning of life?"
-  )
+  ),
+  additional_columns: {trace_id: SecureRandom.uuid}
 )
 
 puts "Answer: #{response.answer.answer_text}"
diff --git a/lib/openlayer/integrations/google_conversational_search_tracer.rb b/lib/openlayer/integrations/google_conversational_search_tracer.rb
index aef47a6..23ed398 100644
--- a/lib/openlayer/integrations/google_conversational_search_tracer.rb
+++ b/lib/openlayer/integrations/google_conversational_search_tracer.rb
@@ -21,15 +21,25 @@ module Integrations
     #   Openlayer::Integrations::GoogleConversationalSearchTracer.trace_client(
     #     google_client,
     #     openlayer_client: openlayer,
-    #     inference_pipeline_id: 'your-pipeline-id'
+    #     inference_pipeline_id: 'your-pipeline-id',
+    #     additional_columns: { environment: 'production' }
     #   )
     #
-    #   # Now all answer_query calls are automatically traced
+    #   # Now all answer_query calls are automatically traced! Pass
+    #   # additional_columns on an individual call to attach data (like your
+    #   # own trace ID) to just that row; it takes precedence over the
+    #   # static defaults above on a key conflict.
     #   response = google_client.answer_query(
     #     serving_config: "projects/.../servingConfigs/default",
-    #     query: { text: "What is the meaning of life?" }
+    #     query: { text: "What is the meaning of life?" },
+    #     additional_columns: { trace_id: "abc-123" }
     #   )
     class GoogleConversationalSearchTracer
+      # Row keys computed by this tracer. Any key in a caller-supplied
+      # additional_columns hash matching one of these is dropped, so custom
+      # data can never overwrite core trace fields.
+      RESERVED_ROW_KEYS = [:query, :answer, :latency_ms, :timestamp, :metadata, :steps, :context, :session_id, :user_id].freeze
+
       # Enable tracing on a Google ConversationalSearchService client
       #
       # @param client [Google::Cloud::DiscoveryEngine::V1::ConversationalSearchService::Client]
@@ -42,8 +52,12 @@ class GoogleConversationalSearchTracer
       #   Optional session ID to use for all traces. Takes precedence over auto-extracted sessions.
       # @param user_id [String, nil]
       #   Optional user ID to use for all traces.
+      # @param additional_columns [Hash, nil]
+      #   Optional static column values merged into every trace sent through this client (e.g. `{ environment: 'production' }`).
+      #   A value passed to an individual answer_query call takes precedence over these on a key conflict. Keys colliding
+      #   with a reserved row column (query, answer, latency_ms, timestamp, metadata, steps, context, session_id, user_id) are dropped.
       # @return [void]
-      def self.trace_client(client, openlayer_client:, inference_pipeline_id:, session_id: nil, user_id: nil)
+      def self.trace_client(client, openlayer_client:, inference_pipeline_id:, session_id: nil, user_id: nil, additional_columns: {})
         # Store original method reference
         original_answer_query = client.method(:answer_query)
 
@@ -52,6 +66,10 @@ def self.trace_client(client, openlayer_client:, inference_pipeline_id:, session
           # Capture start time
           start_time = Time.now
 
+          # Extract per-call additional columns before forwarding to the
+          # real client; Google's client never sees this key
+          call_additional_columns = kwargs.delete(:additional_columns)
+
           # Execute the original method
           response = original_answer_query.call(*args, **kwargs, &block)
 
@@ -69,7 +87,9 @@ def self.trace_client(client, openlayer_client:, inference_pipeline_id:, session
               openlayer_client: openlayer_client,
               inference_pipeline_id: inference_pipeline_id,
               session_id: session_id,
-              user_id: user_id
+              user_id: user_id,
+              additional_columns: additional_columns,
+              call_additional_columns: call_additional_columns
             )
           rescue StandardError => e
             # Never break the user's application due to tracing errors
@@ -95,8 +115,10 @@ def self.trace_client(client, openlayer_client:, inference_pipeline_id:, session
       # @param inference_pipeline_id [String] Pipeline ID
       # @param session_id [String, nil] Optional session ID (takes precedence over auto-extracted)
       # @param user_id [String, nil] Optional user ID
+      # @param additional_columns [Hash, nil] Optional static column values (see {.trace_client})
+      # @param call_additional_columns [Hash, nil] Optional per-call column values; takes precedence over additional_columns
       # @return [void]
-      def self.send_trace(args:, kwargs:, response:, start_time:, end_time:, openlayer_client:, inference_pipeline_id:, session_id: nil, user_id: nil)
+      def self.send_trace(args:, kwargs:, response:, start_time:, end_time:, openlayer_client:, inference_pipeline_id:, session_id: nil, user_id: nil, additional_columns: {}, call_additional_columns: {})
         # Calculate latency
         latency_ms = ((end_time - start_time) * 1000).round(2)
 
@@ -199,6 +221,12 @@ def self.send_trace(args:, kwargs:, response:, start_time:, end_time:, openlayer
           trace_data[:config][:userIdColumnName] = "user_id"
         end
 
+        # Merge additional columns (per-call values take precedence over
+        # static defaults; keys colliding with reserved row columns are
+        # dropped so custom data can never corrupt core trace fields)
+        extra_columns = resolve_additional_columns(additional_columns, call_additional_columns)
+        trace_data[:rows][0].merge!(extra_columns) unless extra_columns.empty?
+
         # Send to Openlayer
         openlayer_client
           .inference_pipelines
@@ -594,6 +622,45 @@ def self.extract_query_understanding_info(answer)
         nil
       end
 
+      # Merge static and per-call additional columns into a single Hash of
+      # extra row columns. Call-level values take precedence over static
+      # ones on key conflict, and any key colliding with a reserved row
+      # column is dropped.
+      #
+      # @param static_columns [Object] Value passed to trace_client (expected Hash)
+      # @param call_columns [Object] Value passed to an individual answer_query call (expected Hash)
+      # @return [Hash] Extra columns safe to merge onto a trace row
+      def self.resolve_additional_columns(static_columns, call_columns)
+        merged = normalize_additional_columns(static_columns).merge(normalize_additional_columns(call_columns))
+
+        merged.each_with_object({}) do |(key, value), result|
+          if RESERVED_ROW_KEYS.include?(key)
+            warn_if_debug("[Openlayer] additional_columns key :#{key} collides with a reserved column and was ignored")
+          else
+            result[key] = value
+          end
+        end
+      end
+
+      # Normalize an additional_columns value into a Hash with Symbol keys.
+      # Non-Hash input (or a key that can't be a Symbol) is dropped rather
+      # than raising, so a caller mistake can never break tracing.
+      #
+      # @param columns [Object] Expected to be a Hash of column name => value
+      # @return [Hash]
+      def self.normalize_additional_columns(columns)
+        return {} unless columns.is_a?(Hash)
+
+        columns.each_with_object({}) do |(key, value), result|
+          next unless key.respond_to?(:to_sym)
+
+          result[key.to_sym] = value
+        end
+      rescue StandardError => e
+        warn_if_debug("[Openlayer] Failed to normalize additional columns: #{e.message}")
+        {}
+      end
+
       # Safely extract a field from an object
       #
       # @param obj [Object] Object to extract from
@@ -659,6 +726,8 @@ def self.warn_if_debug(message)
                            :extract_session,
                            :extract_user_pseudo_id,
                            :extract_query_understanding_info,
+                           :resolve_additional_columns,
+                           :normalize_additional_columns,
                            :safe_extract,
                            :safe_count,
                            :extract_timestamp
diff --git a/rbi/openlayer/integrations.rbi b/rbi/openlayer/integrations.rbi
index 421bce5..2cf90e8 100644
--- a/rbi/openlayer/integrations.rbi
+++ b/rbi/openlayer/integrations.rbi
@@ -10,7 +10,8 @@ module Openlayer
           openlayer_client: Openlayer::Client,
           inference_pipeline_id: String,
           session_id: T.nilable(String),
-          user_id: T.nilable(String)
+          user_id: T.nilable(String),
+          additional_columns: T::Hash[Symbol, T.untyped]
         ).void
       end
       def self.trace_client(
@@ -18,7 +19,8 @@ module Openlayer
         openlayer_client:,
         inference_pipeline_id:,
         session_id: nil,
-        user_id: nil
+        user_id: nil,
+        additional_columns: {}
       )
       end
     end
diff --git a/test/openlayer/integrations/google_conversational_search_tracer_test.rb b/test/openlayer/integrations/google_conversational_search_tracer_test.rb
new file mode 100644
index 0000000..05620c0
--- /dev/null
+++ b/test/openlayer/integrations/google_conversational_search_tracer_test.rb
@@ -0,0 +1,144 @@
+# frozen_string_literal: true
+
+require_relative "../test_helper"
+require_relative "../../../lib/openlayer/integrations/google_conversational_search_tracer"
+
+module Openlayer
+  module Test
+    module Integrations
+    end
+  end
+end
+
+class Openlayer::Test::Integrations::GoogleConversationalSearchTracerTest < Minitest::Test
+  Tracer = Openlayer::Integrations::GoogleConversationalSearchTracer
+
+  class FakeAnswer
+    attr_reader :answer_text
+
+    def initialize(answer_text)
+      @answer_text = answer_text
+    end
+  end
+
+  class FakeResponse
+    attr_reader :answer
+
+    def initialize(answer_text)
+      @answer = FakeAnswer.new(answer_text)
+    end
+  end
+
+  class FakeGoogleClient
+    def answer_query(serving_config:, query:) # rubocop:disable Lint/UnusedMethodArgument
+      FakeResponse.new("hi")
+    end
+  end
+
+  class FakeDataResource
+    attr_reader :calls
+
+    def initialize
+      @calls = []
+    end
+
+    def stream(inference_pipeline_id, **trace_data)
+      @calls << {inference_pipeline_id: inference_pipeline_id}.merge(trace_data)
+    end
+  end
+
+  class FakeInferencePipelines
+    attr_reader :data
+
+    def initialize(data)
+      @data = data
+    end
+  end
+
+  class FakeOpenlayerClient
+    attr_reader :inference_pipelines
+
+    def initialize
+      @data = FakeDataResource.new
+      @inference_pipelines = FakeInferencePipelines.new(@data)
+    end
+
+    def last_row
+      @data.calls.last[:rows][0]
+    end
+  end
+
+  def setup
+    @openlayer_client = FakeOpenlayerClient.new
+    @start_time = Time.now
+    @end_time = @start_time + 1
+  end
+
+  def trace_row(**overrides)
+    defaults = {
+      args: [],
+      kwargs: {query: "hello"},
+      response: FakeResponse.new("hi"),
+      start_time: @start_time,
+      end_time: @end_time,
+      openlayer_client: @openlayer_client,
+      inference_pipeline_id: "pipeline-id"
+    }
+
+    Tracer.send_trace(**defaults, **overrides)
+    @openlayer_client.last_row
+  end
+
+  def test_static_additional_columns_appear_on_the_row
+    row = trace_row(additional_columns: {environment: "production"})
+
+    assert_equal("production", row[:environment])
+  end
+
+  def test_per_call_additional_columns_appear_on_the_row
+    row = trace_row(call_additional_columns: {trace_id: "abc-123"})
+
+    assert_equal("abc-123", row[:trace_id])
+  end
+
+  def test_per_call_additional_columns_override_static_on_conflict
+    row = trace_row(
+      additional_columns: {trace_id: "static-value"},
+      call_additional_columns: {trace_id: "call-value"}
+    )
+
+    assert_equal("call-value", row[:trace_id])
+  end
+
+  def test_reserved_keys_are_dropped_even_as_string_keys
+    row = trace_row(additional_columns: {"answer" => "hijacked", trace_id: "abc-123"})
+
+    assert_equal("hi", row[:answer])
+    assert_equal("abc-123", row[:trace_id])
+  end
+
+  def test_non_hash_additional_columns_does_not_raise
+    row = trace_row(additional_columns: "not-a-hash", call_additional_columns: nil)
+
+    assert_equal("hi", row[:answer])
+  end
+
+  def test_trace_client_strips_additional_columns_before_forwarding_to_google_client
+    google_client = FakeGoogleClient.new
+
+    Tracer.trace_client(
+      google_client,
+      openlayer_client: @openlayer_client,
+      inference_pipeline_id: "pipeline-id"
+    )
+
+    response = google_client.answer_query(
+      serving_config: "config",
+      query: "hello",
+      additional_columns: {trace_id: "abc-123"}
+    )
+
+    assert_equal("hi", response.answer.answer_text)
+    assert_equal("abc-123", @openlayer_client.last_row[:trace_id])
+  end
+end