diff --git a/generated/descriptors.json b/generated/descriptors.json
index bd6044e..43880fb 100644
--- a/generated/descriptors.json
+++ b/generated/descriptors.json
@@ -27753,6 +27753,14 @@
               "number": 5,
               "type": "TYPE_MESSAGE",
               "typeName": ".chromiumos.test.api.metadata.PublishRdbMetadata.Sources"
+            },
+            {
+              "jsonName": "baseVariant",
+              "label": "LABEL_REPEATED",
+              "name": "base_variant",
+              "number": 6,
+              "type": "TYPE_MESSAGE",
+              "typeName": ".chromiumos.test.api.metadata.PublishRdbMetadata.BaseVariantEntry"
             }
           ],
           "name": "PublishRdbMetadata",
@@ -27775,6 +27783,28 @@
                 }
               ],
               "name": "Sources"
+            },
+            {
+              "field": [
+                {
+                  "jsonName": "key",
+                  "label": "LABEL_OPTIONAL",
+                  "name": "key",
+                  "number": 1,
+                  "type": "TYPE_STRING"
+                },
+                {
+                  "jsonName": "value",
+                  "label": "LABEL_OPTIONAL",
+                  "name": "value",
+                  "number": 2,
+                  "type": "TYPE_STRING"
+                }
+              ],
+              "name": "BaseVariantEntry",
+              "options": {
+                "mapEntry": true
+              }
             }
           ]
         }
diff --git a/go/test/api/metadata/publish_rdb_metadata.pb.go b/go/test/api/metadata/publish_rdb_metadata.pb.go
index 9a1a8d8..db2d562 100644
--- a/go/test/api/metadata/publish_rdb_metadata.pb.go
+++ b/go/test/api/metadata/publish_rdb_metadata.pb.go
@@ -25,6 +25,7 @@
 	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
 )
 
+// NEXT TAG: 7
 type PublishRdbMetadata struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
@@ -42,6 +43,10 @@
 	TesthausUrl string `protobuf:"bytes,4,opt,name=testhaus_url,json=testhausUrl,proto3" json:"testhaus_url,omitempty"`
 	// The code sources tested.
 	Sources *PublishRdbMetadata_Sources `protobuf:"bytes,5,opt,name=sources,proto3" json:"sources,omitempty"`
+	// BaseVariant will be added to the variant of each test result within an
+	// invocation. If there are duplicate keys, the variant value given by the
+	// test command always wins.
+	BaseVariant map[string]string `protobuf:"bytes,6,rep,name=base_variant,json=baseVariant,proto3" json:"base_variant,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
 }
 
 func (x *PublishRdbMetadata) Reset() {
@@ -112,6 +117,13 @@
 	return nil
 }
 
+func (x *PublishRdbMetadata) GetBaseVariant() map[string]string {
+	if x != nil {
+		return x.BaseVariant
+	}
+	return nil
+}
+
 // Sources captures information about the code sources tested by
 // the invocation.
 type PublishRdbMetadata_Sources struct {
@@ -194,7 +206,7 @@
 	0x65, 0x74, 0x61, 0x64, 0x61, 0x74, 0x61, 0x1a, 0x2a, 0x63, 0x68, 0x72, 0x6f, 0x6d, 0x69, 0x75,
 	0x6d, 0x6f, 0x73, 0x2f, 0x74, 0x65, 0x73, 0x74, 0x2f, 0x61, 0x72, 0x74, 0x69, 0x66, 0x61, 0x63,
 	0x74, 0x2f, 0x74, 0x65, 0x73, 0x74, 0x5f, 0x72, 0x65, 0x73, 0x75, 0x6c, 0x74, 0x2e, 0x70, 0x72,
-	0x6f, 0x74, 0x6f, 0x22, 0x83, 0x03, 0x0a, 0x12, 0x50, 0x75, 0x62, 0x6c, 0x69, 0x73, 0x68, 0x52,
+	0x6f, 0x74, 0x6f, 0x22, 0xa9, 0x04, 0x0a, 0x12, 0x50, 0x75, 0x62, 0x6c, 0x69, 0x73, 0x68, 0x52,
 	0x64, 0x62, 0x4d, 0x65, 0x74, 0x61, 0x64, 0x61, 0x74, 0x61, 0x12, 0x32, 0x0a, 0x15, 0x63, 0x75,
 	0x72, 0x72, 0x65, 0x6e, 0x74, 0x5f, 0x69, 0x6e, 0x76, 0x6f, 0x63, 0x61, 0x74, 0x69, 0x6f, 0x6e,
 	0x5f, 0x69, 0x64, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x13, 0x63, 0x75, 0x72, 0x72, 0x65,
@@ -213,16 +225,27 @@
 	0x74, 0x65, 0x73, 0x74, 0x2e, 0x61, 0x70, 0x69, 0x2e, 0x6d, 0x65, 0x74, 0x61, 0x64, 0x61, 0x74,
 	0x61, 0x2e, 0x50, 0x75, 0x62, 0x6c, 0x69, 0x73, 0x68, 0x52, 0x64, 0x62, 0x4d, 0x65, 0x74, 0x61,
 	0x64, 0x61, 0x74, 0x61, 0x2e, 0x53, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x73, 0x52, 0x07, 0x73, 0x6f,
-	0x75, 0x72, 0x63, 0x65, 0x73, 0x1a, 0x52, 0x0a, 0x07, 0x53, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x73,
-	0x12, 0x17, 0x0a, 0x07, 0x67, 0x73, 0x5f, 0x70, 0x61, 0x74, 0x68, 0x18, 0x01, 0x20, 0x01, 0x28,
-	0x09, 0x52, 0x06, 0x67, 0x73, 0x50, 0x61, 0x74, 0x68, 0x12, 0x2e, 0x0a, 0x13, 0x69, 0x73, 0x5f,
-	0x64, 0x65, 0x70, 0x6c, 0x6f, 0x79, 0x6d, 0x65, 0x6e, 0x74, 0x5f, 0x64, 0x69, 0x72, 0x74, 0x79,
-	0x18, 0x02, 0x20, 0x01, 0x28, 0x08, 0x52, 0x11, 0x69, 0x73, 0x44, 0x65, 0x70, 0x6c, 0x6f, 0x79,
-	0x6d, 0x65, 0x6e, 0x74, 0x44, 0x69, 0x72, 0x74, 0x79, 0x42, 0x38, 0x5a, 0x36, 0x67, 0x6f, 0x2e,
-	0x63, 0x68, 0x72, 0x6f, 0x6d, 0x69, 0x75, 0x6d, 0x2e, 0x6f, 0x72, 0x67, 0x2f, 0x63, 0x68, 0x72,
-	0x6f, 0x6d, 0x69, 0x75, 0x6d, 0x6f, 0x73, 0x2f, 0x63, 0x6f, 0x6e, 0x66, 0x69, 0x67, 0x2f, 0x67,
-	0x6f, 0x2f, 0x74, 0x65, 0x73, 0x74, 0x2f, 0x61, 0x70, 0x69, 0x2f, 0x6d, 0x65, 0x74, 0x61, 0x64,
-	0x61, 0x74, 0x61, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
+	0x75, 0x72, 0x63, 0x65, 0x73, 0x12, 0x64, 0x0a, 0x0c, 0x62, 0x61, 0x73, 0x65, 0x5f, 0x76, 0x61,
+	0x72, 0x69, 0x61, 0x6e, 0x74, 0x18, 0x06, 0x20, 0x03, 0x28, 0x0b, 0x32, 0x41, 0x2e, 0x63, 0x68,
+	0x72, 0x6f, 0x6d, 0x69, 0x75, 0x6d, 0x6f, 0x73, 0x2e, 0x74, 0x65, 0x73, 0x74, 0x2e, 0x61, 0x70,
+	0x69, 0x2e, 0x6d, 0x65, 0x74, 0x61, 0x64, 0x61, 0x74, 0x61, 0x2e, 0x50, 0x75, 0x62, 0x6c, 0x69,
+	0x73, 0x68, 0x52, 0x64, 0x62, 0x4d, 0x65, 0x74, 0x61, 0x64, 0x61, 0x74, 0x61, 0x2e, 0x42, 0x61,
+	0x73, 0x65, 0x56, 0x61, 0x72, 0x69, 0x61, 0x6e, 0x74, 0x45, 0x6e, 0x74, 0x72, 0x79, 0x52, 0x0b,
+	0x62, 0x61, 0x73, 0x65, 0x56, 0x61, 0x72, 0x69, 0x61, 0x6e, 0x74, 0x1a, 0x52, 0x0a, 0x07, 0x53,
+	0x6f, 0x75, 0x72, 0x63, 0x65, 0x73, 0x12, 0x17, 0x0a, 0x07, 0x67, 0x73, 0x5f, 0x70, 0x61, 0x74,
+	0x68, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x06, 0x67, 0x73, 0x50, 0x61, 0x74, 0x68, 0x12,
+	0x2e, 0x0a, 0x13, 0x69, 0x73, 0x5f, 0x64, 0x65, 0x70, 0x6c, 0x6f, 0x79, 0x6d, 0x65, 0x6e, 0x74,
+	0x5f, 0x64, 0x69, 0x72, 0x74, 0x79, 0x18, 0x02, 0x20, 0x01, 0x28, 0x08, 0x52, 0x11, 0x69, 0x73,
+	0x44, 0x65, 0x70, 0x6c, 0x6f, 0x79, 0x6d, 0x65, 0x6e, 0x74, 0x44, 0x69, 0x72, 0x74, 0x79, 0x1a,
+	0x3e, 0x0a, 0x10, 0x42, 0x61, 0x73, 0x65, 0x56, 0x61, 0x72, 0x69, 0x61, 0x6e, 0x74, 0x45, 0x6e,
+	0x74, 0x72, 0x79, 0x12, 0x10, 0x0a, 0x03, 0x6b, 0x65, 0x79, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09,
+	0x52, 0x03, 0x6b, 0x65, 0x79, 0x12, 0x14, 0x0a, 0x05, 0x76, 0x61, 0x6c, 0x75, 0x65, 0x18, 0x02,
+	0x20, 0x01, 0x28, 0x09, 0x52, 0x05, 0x76, 0x61, 0x6c, 0x75, 0x65, 0x3a, 0x02, 0x38, 0x01, 0x42,
+	0x38, 0x5a, 0x36, 0x67, 0x6f, 0x2e, 0x63, 0x68, 0x72, 0x6f, 0x6d, 0x69, 0x75, 0x6d, 0x2e, 0x6f,
+	0x72, 0x67, 0x2f, 0x63, 0x68, 0x72, 0x6f, 0x6d, 0x69, 0x75, 0x6d, 0x6f, 0x73, 0x2f, 0x63, 0x6f,
+	0x6e, 0x66, 0x69, 0x67, 0x2f, 0x67, 0x6f, 0x2f, 0x74, 0x65, 0x73, 0x74, 0x2f, 0x61, 0x70, 0x69,
+	0x2f, 0x6d, 0x65, 0x74, 0x61, 0x64, 0x61, 0x74, 0x61, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f,
+	0x33,
 }
 
 var (
@@ -237,20 +260,22 @@
 	return file_chromiumos_test_api_metadata_publish_rdb_metadata_proto_rawDescData
 }
 
-var file_chromiumos_test_api_metadata_publish_rdb_metadata_proto_msgTypes = make([]protoimpl.MessageInfo, 2)
+var file_chromiumos_test_api_metadata_publish_rdb_metadata_proto_msgTypes = make([]protoimpl.MessageInfo, 3)
 var file_chromiumos_test_api_metadata_publish_rdb_metadata_proto_goTypes = []interface{}{
 	(*PublishRdbMetadata)(nil),         // 0: chromiumos.test.api.metadata.PublishRdbMetadata
 	(*PublishRdbMetadata_Sources)(nil), // 1: chromiumos.test.api.metadata.PublishRdbMetadata.Sources
-	(*artifact.TestResult)(nil),        // 2: chromiumos.test.artifact.TestResult
+	nil,                                // 2: chromiumos.test.api.metadata.PublishRdbMetadata.BaseVariantEntry
+	(*artifact.TestResult)(nil),        // 3: chromiumos.test.artifact.TestResult
 }
 var file_chromiumos_test_api_metadata_publish_rdb_metadata_proto_depIdxs = []int32{
-	2, // 0: chromiumos.test.api.metadata.PublishRdbMetadata.test_result:type_name -> chromiumos.test.artifact.TestResult
+	3, // 0: chromiumos.test.api.metadata.PublishRdbMetadata.test_result:type_name -> chromiumos.test.artifact.TestResult
 	1, // 1: chromiumos.test.api.metadata.PublishRdbMetadata.sources:type_name -> chromiumos.test.api.metadata.PublishRdbMetadata.Sources
-	2, // [2:2] is the sub-list for method output_type
-	2, // [2:2] is the sub-list for method input_type
-	2, // [2:2] is the sub-list for extension type_name
-	2, // [2:2] is the sub-list for extension extendee
-	0, // [0:2] is the sub-list for field type_name
+	2, // 2: chromiumos.test.api.metadata.PublishRdbMetadata.base_variant:type_name -> chromiumos.test.api.metadata.PublishRdbMetadata.BaseVariantEntry
+	3, // [3:3] is the sub-list for method output_type
+	3, // [3:3] is the sub-list for method input_type
+	3, // [3:3] is the sub-list for extension type_name
+	3, // [3:3] is the sub-list for extension extendee
+	0, // [0:3] is the sub-list for field type_name
 }
 
 func init() { file_chromiumos_test_api_metadata_publish_rdb_metadata_proto_init() }
@@ -290,7 +315,7 @@
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: file_chromiumos_test_api_metadata_publish_rdb_metadata_proto_rawDesc,
 			NumEnums:      0,
-			NumMessages:   2,
+			NumMessages:   3,
 			NumExtensions: 0,
 			NumServices:   0,
 		},
diff --git a/proto/chromiumos/test/api/metadata/publish_rdb_metadata.proto b/proto/chromiumos/test/api/metadata/publish_rdb_metadata.proto
index b6df947..002a18b 100644
--- a/proto/chromiumos/test/api/metadata/publish_rdb_metadata.proto
+++ b/proto/chromiumos/test/api/metadata/publish_rdb_metadata.proto
@@ -10,6 +10,7 @@
 
 import "chromiumos/test/artifact/test_result.proto";
 
+// NEXT TAG: 7
 message PublishRdbMetadata {
   // Current invocation id
   string current_invocation_id = 1;
@@ -47,4 +48,9 @@
 
   // The code sources tested.
   Sources sources = 5;
+
+  // BaseVariant will be added to the variant of each test result within an
+  // invocation. If there are duplicate keys, the variant value given by the
+  // test command always wins.
+  map<string, string> base_variant = 6;
 }
diff --git a/python/chromiumos/test/api/metadata/publish_rdb_metadata_pb2.py b/python/chromiumos/test/api/metadata/publish_rdb_metadata_pb2.py
index ca7a637..654491b 100644
--- a/python/chromiumos/test/api/metadata/publish_rdb_metadata_pb2.py
+++ b/python/chromiumos/test/api/metadata/publish_rdb_metadata_pb2.py
@@ -20,7 +20,7 @@
   syntax='proto3',
   serialized_options=b'Z6go.chromium.org/chromiumos/config/go/test/api/metadata',
   create_key=_descriptor._internal_create_key,
-  serialized_pb=b'\n7chromiumos/test/api/metadata/publish_rdb_metadata.proto\x12\x1c\x63hromiumos.test.api.metadata\x1a*chromiumos/test/artifact/test_result.proto\"\xa3\x02\n\x12PublishRdbMetadata\x12\x1d\n\x15\x63urrent_invocation_id\x18\x01 \x01(\t\x12\x39\n\x0btest_result\x18\x02 \x01(\x0b\x32$.chromiumos.test.artifact.TestResult\x12\x19\n\rstainless_url\x18\x03 \x01(\tB\x02\x18\x01\x12\x14\n\x0ctesthaus_url\x18\x04 \x01(\t\x12I\n\x07sources\x18\x05 \x01(\x0b\x32\x38.chromiumos.test.api.metadata.PublishRdbMetadata.Sources\x1a\x37\n\x07Sources\x12\x0f\n\x07gs_path\x18\x01 \x01(\t\x12\x1b\n\x13is_deployment_dirty\x18\x02 \x01(\x08\x42\x38Z6go.chromium.org/chromiumos/config/go/test/api/metadatab\x06proto3'
+  serialized_pb=b'\n7chromiumos/test/api/metadata/publish_rdb_metadata.proto\x12\x1c\x63hromiumos.test.api.metadata\x1a*chromiumos/test/artifact/test_result.proto\"\xb0\x03\n\x12PublishRdbMetadata\x12\x1d\n\x15\x63urrent_invocation_id\x18\x01 \x01(\t\x12\x39\n\x0btest_result\x18\x02 \x01(\x0b\x32$.chromiumos.test.artifact.TestResult\x12\x19\n\rstainless_url\x18\x03 \x01(\tB\x02\x18\x01\x12\x14\n\x0ctesthaus_url\x18\x04 \x01(\t\x12I\n\x07sources\x18\x05 \x01(\x0b\x32\x38.chromiumos.test.api.metadata.PublishRdbMetadata.Sources\x12W\n\x0c\x62\x61se_variant\x18\x06 \x03(\x0b\x32\x41.chromiumos.test.api.metadata.PublishRdbMetadata.BaseVariantEntry\x1a\x37\n\x07Sources\x12\x0f\n\x07gs_path\x18\x01 \x01(\t\x12\x1b\n\x13is_deployment_dirty\x18\x02 \x01(\x08\x1a\x32\n\x10\x42\x61seVariantEntry\x12\x0b\n\x03key\x18\x01 \x01(\t\x12\r\n\x05value\x18\x02 \x01(\t:\x02\x38\x01\x42\x38Z6go.chromium.org/chromiumos/config/go/test/api/metadatab\x06proto3'
   ,
   dependencies=[chromiumos_dot_test_dot_artifact_dot_test__result__pb2.DESCRIPTOR,])
 
@@ -61,8 +61,46 @@
   extension_ranges=[],
   oneofs=[
   ],
-  serialized_start=370,
-  serialized_end=425,
+  serialized_start=459,
+  serialized_end=514,
+)
+
+_PUBLISHRDBMETADATA_BASEVARIANTENTRY = _descriptor.Descriptor(
+  name='BaseVariantEntry',
+  full_name='chromiumos.test.api.metadata.PublishRdbMetadata.BaseVariantEntry',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  create_key=_descriptor._internal_create_key,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='key', full_name='chromiumos.test.api.metadata.PublishRdbMetadata.BaseVariantEntry.key', index=0,
+      number=1, type=9, cpp_type=9, label=1,
+      has_default_value=False, default_value=b"".decode('utf-8'),
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+    _descriptor.FieldDescriptor(
+      name='value', full_name='chromiumos.test.api.metadata.PublishRdbMetadata.BaseVariantEntry.value', index=1,
+      number=2, type=9, cpp_type=9, label=1,
+      has_default_value=False, default_value=b"".decode('utf-8'),
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  serialized_options=b'8\001',
+  is_extendable=False,
+  syntax='proto3',
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=516,
+  serialized_end=566,
 )
 
 _PUBLISHRDBMETADATA = _descriptor.Descriptor(
@@ -108,10 +146,17 @@
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
       serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+    _descriptor.FieldDescriptor(
+      name='base_variant', full_name='chromiumos.test.api.metadata.PublishRdbMetadata.base_variant', index=5,
+      number=6, type=11, cpp_type=10, label=3,
+      has_default_value=False, default_value=[],
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
   ],
   extensions=[
   ],
-  nested_types=[_PUBLISHRDBMETADATA_SOURCES, ],
+  nested_types=[_PUBLISHRDBMETADATA_SOURCES, _PUBLISHRDBMETADATA_BASEVARIANTENTRY, ],
   enum_types=[
   ],
   serialized_options=None,
@@ -121,12 +166,14 @@
   oneofs=[
   ],
   serialized_start=134,
-  serialized_end=425,
+  serialized_end=566,
 )
 
 _PUBLISHRDBMETADATA_SOURCES.containing_type = _PUBLISHRDBMETADATA
+_PUBLISHRDBMETADATA_BASEVARIANTENTRY.containing_type = _PUBLISHRDBMETADATA
 _PUBLISHRDBMETADATA.fields_by_name['test_result'].message_type = chromiumos_dot_test_dot_artifact_dot_test__result__pb2._TESTRESULT
 _PUBLISHRDBMETADATA.fields_by_name['sources'].message_type = _PUBLISHRDBMETADATA_SOURCES
+_PUBLISHRDBMETADATA.fields_by_name['base_variant'].message_type = _PUBLISHRDBMETADATA_BASEVARIANTENTRY
 DESCRIPTOR.message_types_by_name['PublishRdbMetadata'] = _PUBLISHRDBMETADATA
 _sym_db.RegisterFileDescriptor(DESCRIPTOR)
 
@@ -138,14 +185,23 @@
     # @@protoc_insertion_point(class_scope:chromiumos.test.api.metadata.PublishRdbMetadata.Sources)
     })
   ,
+
+  'BaseVariantEntry' : _reflection.GeneratedProtocolMessageType('BaseVariantEntry', (_message.Message,), {
+    'DESCRIPTOR' : _PUBLISHRDBMETADATA_BASEVARIANTENTRY,
+    '__module__' : 'chromiumos.test.api.metadata.publish_rdb_metadata_pb2'
+    # @@protoc_insertion_point(class_scope:chromiumos.test.api.metadata.PublishRdbMetadata.BaseVariantEntry)
+    })
+  ,
   'DESCRIPTOR' : _PUBLISHRDBMETADATA,
   '__module__' : 'chromiumos.test.api.metadata.publish_rdb_metadata_pb2'
   # @@protoc_insertion_point(class_scope:chromiumos.test.api.metadata.PublishRdbMetadata)
   })
 _sym_db.RegisterMessage(PublishRdbMetadata)
 _sym_db.RegisterMessage(PublishRdbMetadata.Sources)
+_sym_db.RegisterMessage(PublishRdbMetadata.BaseVariantEntry)
 
 
 DESCRIPTOR._options = None
+_PUBLISHRDBMETADATA_BASEVARIANTENTRY._options = None
 _PUBLISHRDBMETADATA.fields_by_name['stainless_url']._options = None
 # @@protoc_insertion_point(module_scope)