diff --git a/main.go b/main.go
index cfffede..dd836d7 100644
--- a/main.go
+++ b/main.go
@@ -383,11 +383,45 @@ func distributeSQS(app *appctx, runID string, tagFilters []string, metadata map[
 	return true
 }
 
+type cancelledEntry struct {
+	expiresAt time.Time
+}
+
 type appctx struct {
-	pub      *lspubsub.PubsubPublisher // starter publisher topic
-	rpub     *lspubsub.PubsubPublisher // topic to publish reports
-	mtx      *sync.Mutex
-	topicArn *string
+	pub           *lspubsub.PubsubPublisher // starter publisher topic
+	rpub          *lspubsub.PubsubPublisher // topic to publish reports
+	mtx           *sync.Mutex
+	topicArn      *string
+	cancelledMtx  sync.RWMutex
+	cancelledRuns map[string]cancelledEntry // run_ids that have been cancelled, with expiry
+}
+
+const cancelledRunTTL = 10 * time.Minute
+
+func (a *appctx) cancelRun(runID string) {
+	a.cancelledMtx.Lock()
+	defer a.cancelledMtx.Unlock()
+	a.cancelledRuns[runID] = cancelledEntry{expiresAt: time.Now().Add(cancelledRunTTL)}
+	log.Printf("cancelRun: run_id=%s will expire at %s", runID, a.cancelledRuns[runID].expiresAt.Format(time.RFC3339))
+}
+
+func (a *appctx) isRunCancelled(runID string) bool {
+	if runID == "" {
+		return false
+	}
+	a.cancelledMtx.RLock()
+	entry, ok := a.cancelledRuns[runID]
+	a.cancelledMtx.RUnlock()
+	if !ok {
+		return false
+	}
+	if time.Now().After(entry.expiresAt) {
+		a.cancelledMtx.Lock()
+		delete(a.cancelledRuns, runID)
+		a.cancelledMtx.Unlock()
+		return false
+	}
+	return true
 }
 
 // Our message processing callback.
@@ -484,6 +518,10 @@ func process(ctx any, data []byte) error {
 		}
 	case "process":
 		log.Printf("process: %+v", c)
+		if app.isRunCancelled(c.ID) {
+			log.Printf("process: run_id=%s is cancelled, skipping scenario %s", c.ID, c.Scenario)
+			return nil
+		}
 		doScenario(&doScenarioInput{
 			app:           app,
 			ScenarioFiles: []string{c.Scenario},
@@ -558,7 +596,50 @@ func handleScenarioCompletion(ctx any, data []byte) error {
         }
     }
 
-	case "completed":
+    case "cancelled":
+    log.Printf("run cancelled: run_id=%s repo=%s sha=%s pr=%s",
+        msg.RunID, msg.Repository, msg.CommitSHA, msg.PRNumber)
+    if app, ok := ctx.(*appctx); ok && app != nil && msg.RunID != "" {
+        app.cancelRun(msg.RunID)
+        log.Printf("cancelled: run_id=%s marked as cancelled in-process, pending scenarios will be skipped", msg.RunID)
+    }
+
+    if msg.CommitSHA == "" || msg.Repository == "" {
+        log.Printf("cancelled: missing commit_sha or repository, skipping github status update")
+        return nil
+    }
+
+    if err := postCommitStatus(
+        githubtoken,
+        msg.CommitSHA,
+        msg.Repository,
+        msg.RunURL,
+        "failure",
+        fmt.Sprintf("Test run cancelled — PR #%s was closed", msg.PRNumber),
+    ); err != nil {
+        log.Printf("postCommitStatus (cancelled) failed: %v", err)
+    }
+    if repslack != "" {
+        payload := SlackMessage{
+            Attachments: []SlackAttachment{
+                {
+                    Color: "warning",
+                    Title: "Test Run Cancelled",
+                    Text: fmt.Sprintf("*PR #%s* in `%s` was closed.\nIn-progress test run `%s` has been cancelled.\n<%s|View workflow>",
+                        msg.PRNumber, msg.Repository, msg.RunID, msg.RunURL),
+                    Footer:    fmt.Sprintf("oops • pr: %s • sha: %.7s", msg.PRNumber, msg.CommitSHA),
+                    Timestamp: time.Now().Unix(),
+                    MrkdwnIn:  []string{"text"},
+                },
+            },
+        }
+
+        if err := payload.Notify(repslack); err != nil {
+            log.Printf("Notify (slack) cancelled failed: %v", err)
+        }
+    }
+
+    case "completed":
 		log.Printf("run completed: run_id=%s overall_status=%s failed=%d repo=%s sha=%s",
 			msg.RunID, msg.OverallStatus, msg.FailedCount, msg.Repository, msg.CommitSHA)
 
@@ -657,7 +738,8 @@ func run(ctx context.Context, done chan error) {
 	}
 
 	app := &appctx{
-		mtx: &sync.Mutex{},
+		mtx:           &sync.Mutex{},
+		cancelledRuns: make(map[string]cancelledEntry),
 	}
 	ctx0, cancelCtx0 := context.WithCancel(ctx)
 	defer cancelCtx0()
@@ -754,7 +836,7 @@ func run(ctx context.Context, done chan error) {
 
 		done1 := make(chan error, 1)
 		go func() {
-			ls := lspubsub.NewLengthySubscriber(nil, project, scenariopubsub, handleScenarioCompletion)
+			ls := lspubsub.NewLengthySubscriber(app, project, scenariopubsub, handleScenarioCompletion)
 			err := ls.Start(ctx0, done1)
 			if err != nil {
 				log.Fatalf("listener for scenario progress failed: %v", err)