diff --git a/processor/messages/src/lib.rs b/processor/messages/src/lib.rs
index b07f79a0..73b187c1 100644
--- a/processor/messages/src/lib.rs
+++ b/processor/messages/src/lib.rs
@@ -134,6 +134,7 @@ pub mod coordinator {
 
   #[derive(Clone, PartialEq, Eq, Debug, Zeroize, Serialize, Deserialize)]
   pub enum ProcessorMessage {
+    SubstrateBlockAck { block: u64, plans: Vec<[u8; 32]> },
     BatchPreprocess { id: SignId, preprocess: Vec<u8> },
     BatchShare { id: SignId, share: [u8; 32] },
   }
@@ -151,6 +152,7 @@ pub mod substrate {
     },
     SubstrateBlock {
       context: SubstrateContext,
+      block: u64,
       key: Vec<u8>,
       burns: Vec<OutInstructionWithBalance>,
     },
diff --git a/processor/src/main.rs b/processor/src/main.rs
index 79362116..d39ea9cb 100644
--- a/processor/src/main.rs
+++ b/processor/src/main.rs
@@ -383,6 +383,7 @@ async fn handle_coordinator_msg<D: Db, C: Coin, Co: Coordinator>(
 
         messages::substrate::CoordinatorMessage::SubstrateBlock {
           context,
+          block,
           key: key_vec,
           burns,
         } => {
@@ -422,6 +423,15 @@ async fn handle_coordinator_msg<D: Db, C: Coin, Co: Coordinator>(
             .expect("key we don't have a scheduler for acknowledged a block")
             .schedule(outputs, payments);
 
+          coordinator
+            .send(ProcessorMessage::Coordinator(
+              messages::coordinator::ProcessorMessage::SubstrateBlockAck {
+                block,
+                plans: plans.iter().map(|plan| plan.id()).collect(),
+              },
+            ))
+            .await;
+
           sign_plans(
             txn,
             coin,