@@ -22,6 +22,7 @@
 
 ### Changes
 
+- [BREAKING] Refactored `NoteSyncRecord` to returned a fixed-size `NoteMetadataHeader` ([#1720](https://github.com/0xMiden/node/issues/1720)).
 - [BREAKING] Removed obsolete `SyncState` RPC endpoint; clients should use `SyncNotes`, `SyncNullifiers`, `SyncAccountVault`, `SyncAccountStorageMaps`, `SyncTransactions`, or `SyncChainMmr` instead ([#1636](https://github.com/0xMiden/node/pull/1636)).
 - Added account ID limits for `SyncTransactions`, `SyncAccountVault`, and `SyncAccountStorageMaps` to `GetLimits` responses ([#1636](https://github.com/0xMiden/node/pull/1636)).
 - [BREAKING] Added typed `GetAccountError` for `GetAccount` endpoint, splitting `BlockNotAvailable` into `UnknownBlock` and `BlockPruned`. `AccountNotFound` and `AccountNotPublic` now return `InvalidArgument` gRPC status instead of `NotFound`; clients should parse the error details discriminant rather than branching on status codes ([#1646](https://github.com/0xMiden/node/pull/1646)).
 
@@ -149,7 +149,7 @@ pub async fn bench_sync_nullifiers(
         let note_ids = response
             .notes
             .iter()
-            .map(|n| n.note_id.unwrap())
+            .map(|n| n.inclusion_proof.as_ref().unwrap().note_id.unwrap())
             .collect::<Vec<proto::note::NoteId>>();
 
         // Get the notes nullifiers, limiting to 20 notes maximum
 
@@ -4,11 +4,13 @@ use miden_protocol::crypto::merkle::SparseMerklePath;
 use miden_protocol::note::{
     Note,
     NoteAttachment,
+    NoteAttachmentKind,
     NoteDetails,
     NoteHeader,
     NoteId,
     NoteInclusionProof,
     NoteMetadata,
+    NoteMetadataHeader,
     NoteScript,
     NoteTag,
     NoteType,
@@ -44,6 +46,49 @@ impl TryFrom<proto::note::NoteType> for NoteType {
     }
 }
 
+// NOTE ATTACHMENT KIND
+// ================================================================================================
+
+impl From<NoteAttachmentKind> for proto::note::NoteAttachmentKind {
+    fn from(kind: NoteAttachmentKind) -> Self {
+        match kind {
+            NoteAttachmentKind::None => proto::note::NoteAttachmentKind::None,
+            NoteAttachmentKind::Word => proto::note::NoteAttachmentKind::Word,
+            NoteAttachmentKind::Array => proto::note::NoteAttachmentKind::Array,
+        }
+    }
+}
+
+impl TryFrom<proto::note::NoteAttachmentKind> for NoteAttachmentKind {
+    type Error = ConversionError;
+
+    fn try_from(kind: proto::note::NoteAttachmentKind) -> Result<Self, Self::Error> {
+        match kind {
+            proto::note::NoteAttachmentKind::None => Ok(NoteAttachmentKind::None),
+            proto::note::NoteAttachmentKind::Word => Ok(NoteAttachmentKind::Word),
+            proto::note::NoteAttachmentKind::Array => Ok(NoteAttachmentKind::Array),
+            proto::note::NoteAttachmentKind::Unspecified => {
+                Err(ConversionError::EnumDiscriminantOutOfRange)
+            },
+        }
+    }
+}
+
+// NOTE METADATA HEADER
+// ================================================================================================
+
+impl From<NoteMetadataHeader> for proto::note::NoteMetadataHeader {
+    fn from(header: NoteMetadataHeader) -> Self {
+        Self {
+            sender: Some(header.sender().into()),
+            note_type: proto::note::NoteType::from(header.note_type()) as i32,
+            tag: header.tag().as_u32(),
+            attachment_kind: proto::note::NoteAttachmentKind::from(header.attachment_kind()) as i32,
+            attachment_scheme: header.attachment_scheme().as_u32(),
+        }
+    }
+}
+
 // NOTE METADATA
 // ================================================================================================
 
 
@@ -197,17 +197,14 @@ impl From<NoteRecord> for proto::note::CommittedNote {
 
 impl From<NoteRecord> for proto::note::NoteSyncRecord {
     fn from(value: NoteRecord) -> Self {
-        let note_id = value.note_id.into();
-        let note_index_in_block = value.note_index.leaf_index_value().into();
-        let metadata = value.metadata.into();
-        let inclusion_path = value.inclusion_path.into();
-
-        proto::note::NoteSyncRecord {
-            note_id: Some(note_id),
-            note_index_in_block,
-            metadata: Some(metadata),
-            inclusion_path: Some(inclusion_path),
-        }
+        let metadata_header = Some(value.metadata.to_header().into());
+        let inclusion_proof = Some(proto::note::NoteInclusionInBlockProof {
+            note_id: Some(value.note_id.into()),
+            block_num: value.block_num.as_u32(),
+            note_index_in_block: value.note_index.leaf_index_value().into(),
+            inclusion_path: Some(value.inclusion_path.into()),
+        });
+        Self { metadata_header, inclusion_proof }
     }
 }
 
@@ -228,12 +225,14 @@ pub struct NoteSyncRecord {
 
 impl From<NoteSyncRecord> for proto::note::NoteSyncRecord {
     fn from(note: NoteSyncRecord) -> Self {
-        Self {
-            note_index_in_block: note.note_index.leaf_index_value().into(),
+        let metadata_header = Some(note.metadata.to_header().into());
+        let inclusion_proof = Some(proto::note::NoteInclusionInBlockProof {
             note_id: Some(note.note_id.into()),
-            metadata: Some(note.metadata.into()),
-            inclusion_path: Some(Into::into(note.inclusion_path)),
-        }
+            block_num: note.block_num.as_u32(),
+            note_index_in_block: note.note_index.leaf_index_value().into(),
+            inclusion_path: Some(note.inclusion_path.into()),
+        });
+        Self { metadata_header, inclusion_proof }
     }
 }
 
 
@@ -17,6 +17,18 @@ enum NoteType {
     NOTE_TYPE_PRIVATE = 2;
 }
 
+// The kind of a note attachment.
+enum NoteAttachmentKind {
+    // Unspecified attachment kind (default value, should not be used).
+    NOTE_ATTACHMENT_KIND_UNSPECIFIED = 0;
+    // No attachment.
+    NOTE_ATTACHMENT_KIND_NONE = 1;
+    // A single word attachment.
+    NOTE_ATTACHMENT_KIND_WORD = 2;
+    // An array attachment.
+    NOTE_ATTACHMENT_KIND_ARRAY = 3;
+}
+
 // Represents a note's ID.
 message NoteId {
     // A unique identifier of the note which is a 32-byte commitment to the underlying note data.
@@ -29,6 +41,29 @@ message NoteIdList {
     repeated NoteId ids = 1;
 }
 
+// Represents the header of a note's metadata.
+//
+// Contains the sender, note type, tag and attachment type information, but not the full
+// attachment data. See `miden_protocol::note::NoteMetadataHeader` for more info.
+message NoteMetadataHeader {
+    // The account which sent the note.
+    account.AccountId sender = 1;
+
+    // The type of the note.
+    NoteType note_type = 2;
+
+    // A value which can be used by the recipient to identify notes intended for them.
+    //
+    // See `miden_protocol::note::note_tag` for more info.
+    fixed32 tag = 3;
+
+    // The kind of the note attachment.
+    NoteAttachmentKind attachment_kind = 4;
+
+    // The scheme identifier of the note attachment.
+    fixed32 attachment_scheme = 5;
+}
+
 // Represents a note's metadata.
 message NoteMetadata {
     // The account which sent the note.
@@ -105,19 +140,16 @@ message NoteInclusionInBlockProof {
     primitives.SparseMerklePath inclusion_path = 4;
 }
 
-// Represents proof of a note inclusion in the block.
+// Represents a note's metadata header together with proof of inclusion in a block.
+//
+// To get the full `NoteMetadata` (including
+// attachment), use `GetNotesById`.
 message NoteSyncRecord {
-    // A unique identifier of the note which is a 32-byte commitment to the underlying note data.
-    NoteId note_id = 1;
+    // The fixed-size metadata header of the note.
+    NoteMetadataHeader metadata_header = 1;
 
-    // The index of the note in the block.
-    uint32 note_index_in_block = 2;
-
-    // The note's metadata.
-    NoteMetadata metadata = 3;
-
-    // The note's inclusion proof in the block.
-    primitives.SparseMerklePath inclusion_path = 4;
+    // Proof of the note's inclusion in a block.
+    NoteInclusionInBlockProof inclusion_proof = 2;
 }
 
 // Represents a note header.