diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index 5eebf0b10b..e95d29fdad 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -524,7 +524,7 @@ inform_testing_reachability(void)
 
 /** Return true iff we should send a create_fast cell to build a circuit
  * starting at <b>router</b>.  (If <b>router</b> is NULL, we don't have
- * information on the router. */
+ * information on the router, so return false.) */
 static INLINE int
 should_use_create_fast_for_router(routerinfo_t *router)
 {