diff --git a/data/api/client-server/account-data.yaml b/data/api/client-server/account-data.yaml
index 3ebc0464..98bda9ee 100644
--- a/data/api/client-server/account-data.yaml
+++ b/data/api/client-server/account-data.yaml
@@ -73,7 +73,8 @@ paths:
             type: object
         400:
           description: |-
-            The request body is not a JSON object. Errcode: `M_NOT_JSON`.
+            The request body is not a JSON object. Errcode: `M_BAD_JSON`
+            or `M_NOT_JSON`.
           examples:
             application/json: {
               "errcode": "M_NOT_JSON",
@@ -215,8 +216,9 @@ paths:
             type: object
         400:
           description: |-
-            The request body is not a JSON object (errcode `M_NOT_JSON`), or the
-            given `roomID` is not a valid room ID (errcode `M_INVALID_PARAM`).
+            The request body is not a JSON object (errcode `M_BAD_JSON` or
+            `M_NOT_JSON`), or the given `roomID` is not a valid room ID
+            (errcode `M_INVALID_PARAM`).
           examples:
             application/json: {
               "errcode": "M_NOT_JSON",