diff --git a/mark.go b/mark.go
index 91359c8..927994f 100644
--- a/mark.go
+++ b/mark.go
@@ -102,6 +102,7 @@ func Run(config Config) error {
 		}
 	}
 
+	var hasErrors bool
 	for _, file := range files {
 		log.Infof(nil, "processing %s", file)
 
@@ -109,6 +110,7 @@ func Run(config Config) error {
 		if err != nil {
 			if config.ContinueOnError {
 				log.Errorf(err, "processing %s", file)
+				hasErrors = true
 				continue
 			}
 			return err
@@ -122,6 +124,10 @@ func Run(config Config) error {
 		}
 	}
 
+	if hasErrors {
+		return fmt.Errorf("one or more files failed to process")
+	}
+
 	return nil
 }
 
@@ -300,6 +306,9 @@ func ProcessFile(file string, api *confluence.API, config Config) (*confluence.P
 		if err != nil {
 			return nil, fmt.Errorf("unable to retrieve page by id: %w", err)
 		}
+		if pg == nil {
+			return nil, fmt.Errorf("page with id %q not found", config.PageID)
+		}
 		target = pg
 	}
 
diff --git a/markdown/markdown_test.go b/markdown/markdown_test.go
index eb0313e..3f21b7b 100644
--- a/markdown/markdown_test.go
+++ b/markdown/markdown_test.go
@@ -181,5 +181,8 @@ func TestContinueOnError(t *testing.T) {
 	}
 
 	err := cmd.Run(context.TODO(), argList)
-	assert.NoError(t, err, "App should run without errors when continue-on-error is enabled")
+	// --continue-on-error processes all files even when some fail, but still
+	// returns an error to allow callers/CI to detect partial failures.
+	assert.Error(t, err, "App should report partial failure when continue-on-error is enabled and some files fail")
+	assert.ErrorContains(t, err, "one or more files failed to process")
 }