diff --git a/api/doc/thor.yaml b/api/doc/thor.yaml
index a5b614425..334e89517 100644
--- a/api/doc/thor.yaml
+++ b/api/doc/thor.yaml
@@ -1557,7 +1557,7 @@ components:
           pattern: '^0x[0-9a-f]{40}$'
         topics:
           type: array
-          minItems: 1
+          minItems: 0
           nullable: false
           required: true
           description: |