diff --git a/src/main/proto/banyandb/v1/banyandb-measure.proto b/src/main/proto/banyandb/v1/banyandb-measure.proto
index 4160265..973edec 100644
--- a/src/main/proto/banyandb/v1/banyandb-measure.proto
+++ b/src/main/proto/banyandb/v1/banyandb-measure.proto
@@ -156,13 +156,29 @@ message TopNRequest {
   repeated string stages = 9;
 }
 
+// TagFamilySpec defines the specification of a tag family.
+message TagFamilySpec {
+  // name of the tag family
+  string name = 1;
+  // names of tags in the tag family
+  repeated string tag_names = 2;
+}
+
+// DataPointSpec defines the specification of a data point.
+message DataPointSpec {
+  // the tag family specification
+  repeated TagFamilySpec tag_family_spec = 1;
+  // the field names
+  repeated string field_names = 2;
+}
+
 // DataPointValue is the data point for writing. It only contains values.
 message DataPointValue {
   // timestamp is in the timeunit of milliseconds.
   google.protobuf.Timestamp timestamp = 1 [(validate.rules).timestamp.required = true];
-  // the order of tag_families' items match the measure schema
+  // the order of tag_families' items match DataPointSpec
   repeated model.v1.TagFamilyForWrite tag_families = 2 [(validate.rules).repeated.min_items = 1];
-  // the order of fields match the measure schema
+  // the order of fields match DataPointSpec
   repeated model.v1.FieldValue fields = 3;
   // the version of the data point
   int64 version = 4;
@@ -170,12 +186,16 @@ message DataPointValue {
 
 // WriteRequest is the request contract for write
 message WriteRequest {
-  // the metadata is required.
-  common.v1.Metadata metadata = 1 [(validate.rules).message.required = true];
+  // the metadata is required only for the first request of gRPC stream.
+  common.v1.Metadata metadata = 1;
   // the data_point is required.
   DataPointValue data_point = 2 [(validate.rules).message.required = true];
   // the message_id is required.
   uint64 message_id = 3 [(validate.rules).uint64.gt = 0];
+  // the data point specification.
+  // If this is not set with the indicated metadata, use the schema definition.
+  // If this is not set, use the existing spec declaration from previous requests in the current gRPC stream.
+  DataPointSpec data_point_spec = 4;
 }
 
 // WriteResponse is the response contract for write
diff --git a/src/main/proto/banyandb/v1/banyandb-stream.proto b/src/main/proto/banyandb/v1/banyandb-stream.proto
index 5f1f8a6..e3512d5 100644
--- a/src/main/proto/banyandb/v1/banyandb-stream.proto
+++ b/src/main/proto/banyandb/v1/banyandb-stream.proto
@@ -80,6 +80,14 @@ message QueryRequest {
   repeated string stages = 10;
 }
 
+// TagFamilySpec defines the specification of a tag family.
+message TagFamilySpec {
+  // name of the tag family
+  string name = 1;
+  // names of tags in the tag family
+  repeated string tag_names = 2;
+}
+
 message ElementValue {
   // element_id could be span_id of a Span or segment_id of a Segment in the context of stream
   string element_id = 1;
@@ -87,17 +95,21 @@ message ElementValue {
   // 1) either the start time of a Span/Segment,
   // 2) or the timestamp of a log
   google.protobuf.Timestamp timestamp = 2;
-  // the order of tag_families' items match the stream schema
+  // the order of tag_families' items match TagFamilySpec
   repeated model.v1.TagFamilyForWrite tag_families = 3;
 }
 
 message WriteRequest {
-  // the metadata is required.
-  common.v1.Metadata metadata = 1 [(validate.rules).message.required = true];
+  // the metadata is required only for the first request of gRPC stream.
+  common.v1.Metadata metadata = 1;
   // the element is required.
   ElementValue element = 2 [(validate.rules).message.required = true];
   // the message_id is required.
   uint64 message_id = 3 [(validate.rules).uint64.gt = 0];
+  // the tag family specification.
+  // If this is not set with the indicated metadata, use the schema definition.
+  // If this is not set, use the existing spec declaration from previous requests in the current gRPC stream.
+  repeated TagFamilySpec tag_family_spec = 4;
 }
 
 message WriteResponse {
diff --git a/src/main/proto/banyandb/v1/banyandb-trace.proto b/src/main/proto/banyandb/v1/banyandb-trace.proto
index d58c969..1549435 100644
--- a/src/main/proto/banyandb/v1/banyandb-trace.proto
+++ b/src/main/proto/banyandb/v1/banyandb-trace.proto
@@ -21,16 +21,21 @@ package banyandb.trace.v1;
 
 import "banyandb/v1/banyandb-common.proto";
 import "banyandb/v1/banyandb-model.proto";
+import "validate/validate.proto";
 
 option go_package = "github.com/apache/skywalking-banyandb/api/proto/banyandb/trace/v1";
 option java_package = "org.apache.skywalking.banyandb.trace.v1";
 
-// Write messages
+message TagSpec {
+  repeated string tag_names = 1;
+}
+
 message WriteRequest {
   common.v1.Metadata metadata = 1;
-  repeated model.v1.TagValue tags = 2;
+  repeated model.v1.TagValue tags = 2 [(validate.rules).repeated.min_items = 1];
   bytes span = 3;
-  uint64 version = 4;
+  uint64 version = 4 [(validate.rules).uint64.gt = 0];
+  TagSpec tag_spec = 5;
 }
 
 message WriteResponse {