diff --git a/Changelog.md b/Changelog.md
index a168e7a906..3c94d82dc0 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -8,6 +8,7 @@
 
 ### ✨ New features and improvements
 - Added a confirm dialog to the Upload Scans form that appears when no template divisions are assigned to the selected exam template (#7993)
+- Forward the test batch id to the autotester so AI grading telemetry can attribute mass-grading runs (#7991)
 - Migrated `MarkingSchemesTable` component to React Table V8 (#7985)
 - Removed Graders Subcomponent and added a Graders column in the Assignment Grades tab (#7967)
 - Added GET and PATCH /overall_comment API routes (#7963)
diff --git a/app/helpers/automated_tests_helper.rb b/app/helpers/automated_tests_helper.rb
index 9666027a84..365ee9ecaf 100644
--- a/app/helpers/automated_tests_helper.rb
+++ b/app/helpers/automated_tests_helper.rb
@@ -111,10 +111,11 @@ def test_data(test_run_ids)
   end
 
   def get_markus_address(host_with_port)
+    base = ENV.fetch('MARKUS_URL', host_with_port)
     if Rails.application.config.relative_url_root.nil?
-      host_with_port
+      base
     else
-      host_with_port + Rails.application.config.relative_url_root
+      base + Rails.application.config.relative_url_root
     end
   end
 
@@ -209,6 +210,8 @@ def run_tests(assignment, host_with_port, group_ids, role, collected: true, batc
       req.body = {
         test_data: test_data,
         categories: role.student? ? ['student'] : ['instructor'],
+        # Maps to TestBatch.id for telemetry attribution; null for solo runs.
+        batch_id: batch&.id,
         request_high_priority: batch.nil? && role.student?
       }.to_json
       res = send_request!(req, uri)
@@ -307,10 +310,11 @@ def set_headers(req, api_key)
 
     # Get the current URL for this MarkUs instance (adds the relative url root to +host_with_port+) if it exists.
     def get_markus_address(host_with_port)
+      base = ENV.fetch('MARKUS_URL', host_with_port)
       if Rails.application.config.relative_url_root.nil?
-        host_with_port
+        base
       else
-        host_with_port + Rails.application.config.relative_url_root
+        base + Rails.application.config.relative_url_root
       end
     end
 
diff --git a/spec/jobs/autotest_run_job_spec.rb b/spec/jobs/autotest_run_job_spec.rb
index 00512018c7..72a447beae 100644
--- a/spec/jobs/autotest_run_job_spec.rb
+++ b/spec/jobs/autotest_run_job_spec.rb
@@ -287,6 +287,28 @@
           end
         end
       end
+
+      context 'batch_id attribution' do
+        it 'forwards the batch id for a multi-group run' do
+          expect_any_instance_of(AutotestRunJob).to receive(:send_request!) do |_j, net_obj|
+            expect(JSON.parse(net_obj.body)['batch_id']).to eq TestBatch.first.id
+            dummy_return
+          end
+          subject
+        end
+
+        context 'when there is a single group' do
+          let(:n_groups) { 1 }
+
+          it 'forwards a null batch id for a solo run' do
+            expect_any_instance_of(AutotestRunJob).to receive(:send_request!) do |_j, net_obj|
+              expect(JSON.parse(net_obj.body)).to include('batch_id' => nil)
+              dummy_return
+            end
+            subject
+          end
+        end
+      end
     end
 
     context 'tests are not set up' do