diff --git a/main.go b/main.go
index c7f61eb..5d39be2 100644
--- a/main.go
+++ b/main.go
@@ -115,6 +115,9 @@ func main() {
 	if resp.Status.Class() != gemini.StatusSuccess {
 		log.Fatalf("%d %s", resp.Status, resp.Meta)
 	}
+	if resp.Meta != "text/gemini" && !strings.HasPrefix(resp.Meta, "text/gemini;") {
+		log.Fatal("mime type is not text/gemini")
+	}
 	aw := AtomWriter{
 		Title: "",
 		Items: nil,