diff --git a/envoy/extensions/filters/http/ext_proc/v3alpha/ext_proc.proto b/envoy/extensions/filters/http/ext_proc/v3alpha/ext_proc.proto
index c072b100..c4175d5d 100644
--- a/envoy/extensions/filters/http/ext_proc/v3alpha/ext_proc.proto
+++ b/envoy/extensions/filters/http/ext_proc/v3alpha/ext_proc.proto
@@ -118,13 +118,13 @@ message ExternalProcessor {
   // for the list of supported attributes and their types.
   repeated string response_attributes = 6;
 
-  // [#not-implemented-hide:]
   // Specifies the timeout for each individual message sent on the stream and
   // when the filter is running in synchronous mode. Whenever
   // the proxy sends a message on the stream that requires a response, it will
   // reset this timer, and will stop processing and return an error (subject
-  // to the processing mode) if the timer expires. There is no timeout when
-  // the filter is running in asynchronous mode. Default is 200 ms.
+  // to the processing mode) if the timer expires before a matching response.
+  // is received. There is no timeout when the filter is running in asynchronous
+  // mode. Default is 200 milliseconds.
   google.protobuf.Duration message_timeout = 7;
 
   // [#not-implemented-hide:]