diff --git a/proto/mf.proto b/proto/mf.proto
index 3a849fa..12ca402 100644
--- a/proto/mf.proto
+++ b/proto/mf.proto
@@ -2,43 +2,54 @@ syntax = "proto3";
 
 option go_package = "mfer";
 
+import "google/protobuf/timestamp.proto";
+
 message MFFile {
     enum Version {
         NONE = 0;
         ONE = 1; // only one for now
     }
-    Version version = 1;
-    bytes innerMessage = 2;
 
+    // required mffile root attributes 1xx
+    Version version = 101;
+    bytes innerMessage = 102;
     // these are used solely to detect corruption/truncation
     // and not for cryptographic integrity.
-    uint64 size = 3;
-    bytes sha256 = 4;
+    uint64 size = 103;
+    bytes sha256 = 104;
 
+    // 2xx for optional manifest root attributes
     // think we might use gosignify instead of gpg:
     // github.com/frankbraun/gosignify
 
     //detached signature, ascii or binary
-    optional bytes signature = 5;
+    optional bytes signature = 201;
     //full GPG key id
-    optional bytes signer = 6;
+    optional bytes signer = 202;
     //full GPG signing public key, ascii or binary
-    optional bytes signingPubKey = 7;
+    optional bytes signingPubKey = 203;
 }
 
 message MFFilePath {
-    string path = 1;
-    uint64 size = 2;
-    // when verifying, count(hashes) must be > 0.
-    optional repeated MFFileChecksum hashes = 201;
-    optional string mimeType = 101;
-    optional string mtime = 102;
-    optional string ctime = 103;
-    optional string atime = 104;
+
+    // required attributes:
+    string path = 101;
+    uint64 size = 102;
+
+    // gotta have at least one:
+    repeated MFFileChecksum hashes = 201;
+
+    // optional per-file metadata
+    optional string mimeType = 301;
+    optional string mtime = 302;
+    optional string ctime = 303;
+    optional string atime = 304;
 
 }
 
 message MFFileChecksum {
+    // 1.0 golang implementation must write a multihash here
+    // it's ok to only ever use/verify sha256 multihash
     bytes multiHash = 1;
 }
 
@@ -47,7 +58,13 @@ message MFFileInner {
         NONE = 0;
         ONE = 1; // only one for now
     }
-    Version version = 1;
-    uint64 count = 2;
-    repeated MFFilePath files = 3;
+    Version version = 101;
+
+    // required manifest attributes:
+    uint64 fileCount = 102;
+    repeated MFFilePath files = 103;
+
+    // optional manifest attributes 2xx:
+    optional google.protobuf.Timestamp createdAt = 201;
 }
+