diff --git a/aip/general/0157.md b/aip/general/0157.md
index fb9066a0bc..94df946890 100644
--- a/aip/general/0157.md
+++ b/aip/general/0157.md
@@ -19,16 +19,15 @@ APIs **may** support partial responses in one of two ways:
 ### Field masks parameter
 
 Field masks (`google.protobuf.FieldMask`) can be used for granting the user
-fine-grained control over what fields are returned. An API **should** support the mask in a side channel.
-For example, the parameter can be specified either using an HTTP query
+fine-grained control over what fields are returned. An API **should** support the mask being specified
+in a side channel. For example, the parameter can be specified either using an HTTP query
 parameter, an HTTP header, or a [gRPC metadata entry][1]. Google Cloud APIs specify field masks as a [system parameter][0].
 
-Field masks **should not** be specified in the [request](./0157.md#read-masks-as-a-request-field).
+Field masks **should not** be specified as a field on the [request message](./0157.md#read-masks-as-a-request-field).
 
-- The value of the field mask parameter **must** be a `google.protobuf.FieldMask`.
+- The value of the field mask parameter **must** be interpreted as a repeated `google.protobuf.FieldMask`.
 - The field mask parameter **must** be optional:
-  - An explicit value of `"*"` **should** be supported, and **must** return all
-    fields.
+  - An explicit value of `"*"` **should** be supported, and **must** return all fields.
   - If the field mask parameter is omitted, it **must** default to `"*"`, unless otherwise documented.
 - An API **may** allow read masks with non-terminal repeated fields (unlike
   update masks), but is not obligated to do so.
@@ -89,4 +88,4 @@ enum BookView {
 
 [0]: https://cloud.google.com/apis/docs/system-parameters
 [1]: https://grpc.io/docs/what-is-grpc/core-concepts/#metadata
-[AIP-126]: ./0126.md
\ No newline at end of file
+[AIP-126]: ./0126.md