diff --git a/google/rpc/context/BUILD.bazel b/google/rpc/context/BUILD.bazel
index bc584e86..e6aeb265 100644
--- a/google/rpc/context/BUILD.bazel
+++ b/google/rpc/context/BUILD.bazel
@@ -14,6 +14,7 @@ proto_library(
         "attribute_context.proto",
     ],
     deps = [
+        "@com_google_protobuf//:any_proto",
         "@com_google_protobuf//:struct_proto",
         "@com_google_protobuf//:timestamp_proto",
     ],
@@ -63,6 +64,7 @@ moved_proto_library(
     name = "attribute_context_moved_proto",
     srcs = [":attribute_context_proto"],
     deps = [
+        "@com_google_protobuf//:any_proto",
         "@com_google_protobuf//:struct_proto",
         "@com_google_protobuf//:timestamp_proto",
     ],
diff --git a/google/rpc/context/attribute_context.proto b/google/rpc/context/attribute_context.proto
index e60a5ae9..b0f262ac 100644
--- a/google/rpc/context/attribute_context.proto
+++ b/google/rpc/context/attribute_context.proto
@@ -16,6 +16,7 @@ syntax = "proto3";
 
 package google.rpc.context;
 
+import "google/protobuf/any.proto";
 import "google/protobuf/struct.proto";
 import "google/protobuf/timestamp.proto";
 
@@ -107,10 +108,10 @@ message AttributeContext {
     // value(s) depends on the `issuer`, but typically include one or more of
     // the following pieces of information:
     //
-    // *  The services intended to receive the credential such as
-    //    ["pubsub.googleapis.com", "storage.googleapis.com"]
+    // *  The services intended to receive the credential. For example,
+    //    ["https://pubsub.googleapis.com/", "https://storage.googleapis.com/"].
     // *  A set of service-based scopes. For example,
-    //    ["https://www.googleapis.com/auth/cloud-platform"]
+    //    ["https://www.googleapis.com/auth/cloud-platform"].
     // *  The client id of an app, such as the Firebase project id for JWTs
     //    from Firebase Auth.
     //
@@ -284,4 +285,7 @@ message AttributeContext {
 
   // Represents an API operation that is involved to a network activity.
   Api api = 6;
+
+  // Supports extensions for advanced use cases, such as logs and metrics.
+  repeated google.protobuf.Any extensions = 8;
 }
diff --git a/google/rpc/error_details.proto b/google/rpc/error_details.proto
index fd9361a0..c4d6c4b7 100644
--- a/google/rpc/error_details.proto
+++ b/google/rpc/error_details.proto
@@ -89,6 +89,7 @@ message QuotaFailure {
 //
 // Example of an error when contacting the "pubsub.googleapis.com" API when it
 // is not enabled:
+//
 //     { "reason": "API_DISABLED"
 //       "domain": "googleapis.com"
 //       "metadata": {
@@ -96,17 +97,18 @@ message QuotaFailure {
 //         "service": "pubsub.googleapis.com"
 //       }
 //     }
+//
 // This response indicates that the pubsub.googleapis.com API is not enabled.
 //
 // Example of an error that is returned when attempting to create a Spanner
 // instance in a region that is out of stock:
+//
 //     { "reason": "STOCKOUT"
 //       "domain": "spanner.googleapis.com",
 //       "metadata": {
 //         "availableRegions": "us-central1,us-east2"
 //       }
 //     }
-//
 message ErrorInfo {
   // The reason of the error. This is a constant value that identifies the
   // proximate cause of the error. Error reasons are unique within a particular
@@ -114,11 +116,12 @@ message ErrorInfo {
   // /[A-Z0-9_]+/.
   string reason = 1;
 
-  // The logical grouping to which the "reason" belongs.  Often "domain" will
-  // contain the registered service name of the tool or product that is the
-  // source of the error. Example: "pubsub.googleapis.com". If the error is
-  // common across many APIs, the first segment of the example above will be
-  // omitted.  The value will be, "googleapis.com".
+  // The logical grouping to which the "reason" belongs. The error domain
+  // is typically the registered service name of the tool or product that
+  // generates the error. Example: "pubsub.googleapis.com". If the error is
+  // generated by some common infrastructure, the error domain must be a
+  // globally unique value that identifies the infrastructure. For Google API
+  // infrastructure, the error domain is "googleapis.com".
   string domain = 2;
 
   // Additional structured details about this error.