diff --git a/schema/google/showcase/v1beta1/echo.proto b/schema/google/showcase/v1beta1/echo.proto
index 101b37c25..3e797adfc 100644
--- a/schema/google/showcase/v1beta1/echo.proto
+++ b/schema/google/showcase/v1beta1/echo.proto
@@ -17,6 +17,7 @@ syntax = "proto3";
 import "google/api/annotations.proto";
 import "google/api/client.proto";
 import "google/api/field_behavior.proto";
+import "google/api/field_info.proto";
 import "google/api/routing.proto";
 import "google/longrunning/operations.proto";
 import "google/protobuf/any.proto";
@@ -209,6 +210,11 @@ message EchoRequest {
 
   // Optional. This field can be set to test the routing annotation on the Echo method.
   string other_header = 5;
+
+  // Based on go/client-populate-request-id-design; subject to change
+  string request_id = 7 [
+    (google.api.field_info).format = UUID4
+  ];
 }
 
 // The response message for the Echo methods.
diff --git a/schema/google/showcase/v1beta1/showcase_v1beta1.yaml b/schema/google/showcase/v1beta1/showcase_v1beta1.yaml
index dc7f0b38a..13235e492 100644
--- a/schema/google/showcase/v1beta1/showcase_v1beta1.yaml
+++ b/schema/google/showcase/v1beta1/showcase_v1beta1.yaml
@@ -83,3 +83,8 @@ http:
     delete: '/v1beta1/{name=operations/**}'
   - selector: google.longrunning.Operations.CancelOperation
     post: '/v1beta1/{name=operations/**}:cancel'
+publishing:
+  method_settings:
+  - selector: google.showcase.v1beta1.Echo.Echo
+    auto_populated_fields:
+    - request_id