diff --git a/daemon/call.c b/daemon/call.c
index 5cb4f4edf..7f8fef9e6 100644
--- a/daemon/call.c
+++ b/daemon/call.c
@@ -4648,6 +4648,9 @@ static int call_get_dialogue(struct call_monologue *monologues[2], call_t *call,
 		ft = __monologue_create(call);
 
 tag_setup:
+	if (ft == tt)
+		return -1; // it's a hard error to have a monologue talking to itself
+
 	/* the fromtag monologue may be newly created, or half-complete from the totag, or
 	 * derived from the viabranch. */
 	if (!ft->tag.s || str_cmp_str(&ft->tag, fromtag))