diff --git a/stovepipe/controller/build/build.go b/stovepipe/controller/build/build.go
index 8891f23d..3f6c9e0c 100644
--- a/stovepipe/controller/build/build.go
+++ b/stovepipe/controller/build/build.go
@@ -137,7 +137,9 @@ func (c *Controller) Process(ctx context.Context, delivery consumer.Delivery) er
 		baseURI = request.BaseURI
 	}
 
-	buildID, err := buildRunner.Trigger(ctx, baseURI, request.URI, nil)
+	buildID, err := buildRunner.Trigger(ctx, baseURI, request.URI, entity.BuildMetadata{
+		entity.BuildMetadataKeyRequestID: request.ID,
+	})
 	if err != nil {
 		return fmt.Errorf("failed to trigger build for request %s: %w", request.ID, err)
 	}
diff --git a/stovepipe/controller/build/build_test.go b/stovepipe/controller/build/build_test.go
index 905f41dd..b7e6657f 100644
--- a/stovepipe/controller/build/build_test.go
+++ b/stovepipe/controller/build/build_test.go
@@ -199,6 +199,10 @@ func processingRequest(strategy entity.BuildStrategy, baseURI string) entity.Req
 	}
 }
 
+func requestBuildMetadata() entity.BuildMetadata {
+	return entity.BuildMetadata{entity.BuildMetadataKeyRequestID: testID}
+}
+
 func TestProcess(t *testing.T) {
 	tests := []struct {
 		name      string
@@ -213,7 +217,7 @@ func TestProcess(t *testing.T) {
 				req := processingRequest(entity.BuildStrategyIncrementalSinceGreen, testBaseURI)
 				m.reqStore.EXPECT().Get(gomock.Any(), testID).Return(req, nil)
 				m.runnerFactory.EXPECT().For(buildrunner.Config{QueueName: testQueue}).Return(m.runner, nil)
-				m.runner.EXPECT().Trigger(gomock.Any(), testBaseURI, testHeadURI, entity.BuildMetadata(nil)).Return(entity.BuildID{ID: testBuildID}, nil)
+				m.runner.EXPECT().Trigger(gomock.Any(), testBaseURI, testHeadURI, requestBuildMetadata()).Return(entity.BuildID{ID: testBuildID}, nil)
 				build := entity.Build{
 					ID:        testBuildID,
 					RequestID: testID,
@@ -231,7 +235,7 @@ func TestProcess(t *testing.T) {
 				req := processingRequest(entity.BuildStrategyFull, testBaseURI)
 				m.reqStore.EXPECT().Get(gomock.Any(), testID).Return(req, nil)
 				m.runnerFactory.EXPECT().For(buildrunner.Config{QueueName: testQueue}).Return(m.runner, nil)
-				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, entity.BuildMetadata(nil)).Return(entity.BuildID{ID: testBuildID}, nil)
+				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, requestBuildMetadata()).Return(entity.BuildID{ID: testBuildID}, nil)
 				build := entity.Build{
 					ID:        testBuildID,
 					RequestID: testID,
@@ -319,7 +323,7 @@ func TestProcess(t *testing.T) {
 				req := processingRequest(entity.BuildStrategyFull, "")
 				m.reqStore.EXPECT().Get(gomock.Any(), testID).Return(req, nil)
 				m.runnerFactory.EXPECT().For(buildrunner.Config{QueueName: testQueue}).Return(m.runner, nil)
-				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, entity.BuildMetadata(nil)).Return(entity.BuildID{}, errors.New("runner down"))
+				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, requestBuildMetadata()).Return(entity.BuildID{}, errors.New("runner down"))
 			},
 		},
 		{
@@ -329,7 +333,7 @@ func TestProcess(t *testing.T) {
 				req := processingRequest(entity.BuildStrategyFull, "")
 				m.reqStore.EXPECT().Get(gomock.Any(), testID).Return(req, nil)
 				m.runnerFactory.EXPECT().For(buildrunner.Config{QueueName: testQueue}).Return(m.runner, nil)
-				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, entity.BuildMetadata(nil)).Return(entity.BuildID{ID: testBuildID}, nil)
+				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, requestBuildMetadata()).Return(entity.BuildID{ID: testBuildID}, nil)
 				m.buildStore.EXPECT().Create(gomock.Any(), gomock.Any()).Return(storage.ErrAlreadyExists)
 			},
 		},
@@ -341,7 +345,7 @@ func TestProcess(t *testing.T) {
 				req := processingRequest(entity.BuildStrategyFull, "")
 				m.reqStore.EXPECT().Get(gomock.Any(), testID).Return(req, nil)
 				m.runnerFactory.EXPECT().For(buildrunner.Config{QueueName: testQueue}).Return(m.runner, nil)
-				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, entity.BuildMetadata(nil)).Return(entity.BuildID{ID: testBuildID}, nil)
+				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, requestBuildMetadata()).Return(entity.BuildID{ID: testBuildID}, nil)
 				m.buildStore.EXPECT().Create(gomock.Any(), gomock.Any()).Return(errors.New("db down"))
 			},
 		},
@@ -352,7 +356,7 @@ func TestProcess(t *testing.T) {
 				req := processingRequest(entity.BuildStrategyFull, "")
 				m.reqStore.EXPECT().Get(gomock.Any(), testID).Return(req, nil)
 				m.runnerFactory.EXPECT().For(buildrunner.Config{QueueName: testQueue}).Return(m.runner, nil)
-				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, entity.BuildMetadata(nil)).Return(entity.BuildID{ID: testBuildID}, nil)
+				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, requestBuildMetadata()).Return(entity.BuildID{ID: testBuildID}, nil)
 				createCall := m.buildStore.EXPECT().Create(gomock.Any(), gomock.Any()).Return(nil)
 				request := entity.Request{ID: testID, Queue: testQueue}
 				m.materializer.EXPECT().PersistLog(
@@ -375,7 +379,7 @@ func TestProcess(t *testing.T) {
 				req := processingRequest(entity.BuildStrategyFull, "")
 				m.reqStore.EXPECT().Get(gomock.Any(), testID).Return(req, nil)
 				m.runnerFactory.EXPECT().For(buildrunner.Config{QueueName: testQueue}).Return(m.runner, nil)
-				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, entity.BuildMetadata(nil)).Return(entity.BuildID{ID: testBuildID}, nil)
+				m.runner.EXPECT().Trigger(gomock.Any(), "", testHeadURI, requestBuildMetadata()).Return(entity.BuildID{ID: testBuildID}, nil)
 				createCall := m.buildStore.EXPECT().Create(gomock.Any(), gomock.Any()).Return(nil)
 				logCall := expectBuildTriggered(m).After(createCall)
 				m.publisher.EXPECT().Publish(gomock.Any(), "buildsignal", gomock.Any()).Return(errors.New("queue down")).After(logCall)
diff --git a/stovepipe/entity/build.go b/stovepipe/entity/build.go
index e278bf90..43f0aefc 100644
--- a/stovepipe/entity/build.go
+++ b/stovepipe/entity/build.go
@@ -14,6 +14,11 @@
 
 package entity
 
+const (
+	// BuildMetadataKeyRequestID identifies the Stovepipe request associated with a build.
+	BuildMetadataKeyRequestID = "request_id"
+)
+
 // BuildStatus defines the possible states of a build. Shaped the same as
 // SubmitQueue's own BuildStatus (submitqueue/entity/build.go), but defined
 // locally rather than shared — see build.md's "Alternatives considered for
@@ -80,8 +85,5 @@ type BuildID struct {
 }
 
 // BuildMetadata carries caller-supplied, provider-echoed free-form metadata
-// about a build. The runner must not depend on its contents. Empty today;
-// expected to carry real data eventually (e.g. conflict-graph info, or other
-// upstream decisions relevant to the build) once a concrete need lands in
-// either domain — the shape is deferred until then, not decided here.
+// about a build. The runner must not require any key to trigger a build.
 type BuildMetadata map[string]string