diff --git a/cmd/web/openapi.yml b/cmd/web/openapi.yml
index c3b2c8f..b8b888a 100644
--- a/cmd/web/openapi.yml
+++ b/cmd/web/openapi.yml
@@ -79,6 +79,12 @@ paths:
       responses:
         200:
           description: Votes cast
+        400:
+          description: Request malformed
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ErrorResponse"
         404:
           description: Election not found
           content: