diff --git a/crates/invoker-impl/src/invocation_task.rs b/crates/invoker-impl/src/invocation_task.rs
index bed21d83d..87b51cb71 100644
--- a/crates/invoker-impl/src/invocation_task.rs
+++ b/crates/invoker-impl/src/invocation_task.rs
@@ -599,8 +599,10 @@ where
             ProtocolMessage::new_start_message(
                 Bytes::copy_from_slice(&self.full_invocation_id.to_invocation_id_bytes()),
                 self.full_invocation_id.to_string(),
+                Some(self.full_invocation_id.service_id.key.clone()),
                 journal_size,
                 is_partial,
+                iter::empty(),
                 state_entries,
             ),
         )
diff --git a/crates/service-protocol/src/message/encoding.rs b/crates/service-protocol/src/message/encoding.rs
index 3a2050110..25f0f80e2 100644
--- a/crates/service-protocol/src/message/encoding.rs
+++ b/crates/service-protocol/src/message/encoding.rs
@@ -352,8 +352,15 @@ mod tests {
         let encoder = Encoder::new(protocol_version);
         let mut decoder = Decoder::default();
 
-        let expected_msg_0 =
-            ProtocolMessage::new_start_message("key".into(), "key".into(), 1, true, vec![]);
+        let expected_msg_0 = ProtocolMessage::new_start_message(
+            "key".into(),
+            "key".into(),
+            Some("key".into()),
+            1,
+            true,
+            vec![],
+            vec![],
+        );
 
         let expected_msg_1: ProtocolMessage =
             ProtobufRawEntryCodec::serialize_as_unary_input_entry(Bytes::from_static(
diff --git a/crates/service-protocol/src/message/mod.rs b/crates/service-protocol/src/message/mod.rs
index 01145bdce..fc0e9661c 100644
--- a/crates/service-protocol/src/message/mod.rs
+++ b/crates/service-protocol/src/message/mod.rs
@@ -44,8 +44,10 @@ impl ProtocolMessage {
     pub fn new_start_message(
         id: Bytes,
         debug_id: String,
+        key: Option<Bytes>,
         known_entries: u32,
         partial_state: bool,
+        headers: impl IntoIterator<Item = (String, String)>,
         state_map_entries: impl IntoIterator<Item = (Bytes, Bytes)>,
     ) -> Self {
         Self::Start(pb::protocol::StartMessage {
@@ -57,7 +59,13 @@ impl ProtocolMessage {
                 .into_iter()
                 .map(|(key, value)| pb::protocol::start_message::StateEntry { key, value })
                 .collect(),
-            ..pb::protocol::StartMessage::default()
+            key: key
+                .and_then(|b| String::from_utf8(b.to_vec()).ok())
+                .unwrap_or_default(),
+            headers: headers
+                .into_iter()
+                .map(|(key, value)| pb::protocol::Header { key, value })
+                .collect(),
         })
     }
 
diff --git a/crates/worker/src/partition/services/non_deterministic/remote_context.rs b/crates/worker/src/partition/services/non_deterministic/remote_context.rs
index 55eb300e2..66ef41d37 100644
--- a/crates/worker/src/partition/services/non_deterministic/remote_context.rs
+++ b/crates/worker/src/partition/services/non_deterministic/remote_context.rs
@@ -788,9 +788,11 @@ impl<'a, State: StateReader + Send + Sync> RemoteContextBuiltInService
                 ProtocolMessage::new_start_message(
                     Bytes::copy_from_slice(&virtual_invocation_id.to_bytes()),
                     virtual_invocation_id.to_string(),
+                    None,
                     length,
                     true, // TODO add eager state
                     iter::empty(),
+                    iter::empty(),
                 ),
             )
             .expect("Encoding messages to a BytesMut should be infallible, unless OOM is reached.");