diff --git a/src/main/protobuf/failure_details.proto b/src/main/protobuf/failure_details.proto
index 8092155..6876240 100644
--- a/src/main/protobuf/failure_details.proto
+++ b/src/main/protobuf/failure_details.proto
@@ -89,6 +89,7 @@
   oneof category {
     Interrupted interrupted = 101;
     ExternalRepository external_repository = 103;
+    BuildProgress build_progress = 104;
   }
 
   reserved 102; // For internal use
@@ -98,6 +99,9 @@
   enum Code {
     // Interrupted at an unspecified time.
     INTERRUPTED_UNSPECIFIED = 0 [(metadata) = { exit_code: 8 }];
+
+    reserved 1; // For internal use
+
     // TODO(mschaller): Add subcategories that specify what was happening at the
     //  time of interruption.
   }
@@ -112,4 +116,14 @@
   }
   Code code = 1;
   // Additional data could include external repository names.
+}
+
+message BuildProgress {
+  enum Code {
+    BUILD_PROGRESS_UNKNOWN = 0 [(metadata) = { exit_code: 37 }];
+
+    reserved 1, 2; // For internal use
+  }
+  Code code = 1;
+  // Additional data could include the build progress upload endpoint.
 }
\ No newline at end of file