diff --git a/coordinator/src/substrate/mod.rs b/coordinator/src/substrate/mod.rs
index fa699305..19d76ff9 100644
--- a/coordinator/src/substrate/mod.rs
+++ b/coordinator/src/substrate/mod.rs
@@ -23,7 +23,11 @@ use processor_messages::{SubstrateContext, key_gen::KeyGenId, CoordinatorMessage
 
 use tokio::time::sleep;
 
-use crate::{Db, processors::Processors, tributary::TributarySpec};
+use crate::{
+  Db,
+  processors::Processors,
+  tributary::{TributarySpec, TributaryDb},
+};
 
 mod db;
 pub use db::*;
@@ -298,6 +302,12 @@ async fn handle_block<
     if !SubstrateDb::<D>::handled_event(&db.0, hash, event_id) {
       log::info!("found fresh key gen event {:?}", key_gen);
       if let ValidatorSetsEvent::KeyGen { set, key_pair } = key_gen {
+        // Immediately ensure this key pair is accessible to the tributary, before we fire any
+        // events off of it
+        let mut txn = db.0.txn();
+        TributaryDb::<D>::set_key_pair(&mut txn, set, &key_pair);
+        txn.commit();
+
         handle_key_gen(key, processors, serai, &block, set, key_pair).await?;
       } else {
         panic!("KeyGen event wasn't KeyGen: {key_gen:?}");
diff --git a/coordinator/src/tributary/db.rs b/coordinator/src/tributary/db.rs
index 04c42748..6b423b03 100644
--- a/coordinator/src/tributary/db.rs
+++ b/coordinator/src/tributary/db.rs
@@ -4,7 +4,7 @@ use scale::{Encode, Decode};
 
 use ciphersuite::{group::GroupEncoding, Ciphersuite, Ristretto};
 
-use serai_client::validator_sets::primitives::KeyPair;
+use serai_client::validator_sets::primitives::{ValidatorSet, KeyPair};
 
 pub use serai_db::*;
 
@@ -87,6 +87,16 @@ impl<D: Db> TributaryDb<D> {
       .map(|bytes| KeyPair::decode(&mut bytes.as_slice()).unwrap())
   }
 
+  pub fn key_pair_key(set: ValidatorSet) -> Vec<u8> {
+    Self::tributary_key(b"key_pair", set.encode())
+  }
+  pub fn set_key_pair(txn: &mut D::Transaction<'_>, set: ValidatorSet, key_pair: &KeyPair) {
+    txn.put(Self::key_pair_key(set), key_pair.encode());
+  }
+  pub fn key_pair<G: Get>(getter: &G, set: ValidatorSet) -> Option<KeyPair> {
+    Some(KeyPair::decode(&mut getter.get(Self::key_pair_key(set))?.as_slice()).unwrap())
+  }
+
   fn recognized_id_key(label: &'static str, genesis: [u8; 32], id: [u8; 32]) -> Vec<u8> {
     Self::tributary_key(b"recognized", [label.as_bytes(), genesis.as_ref(), id.as_ref()].concat())
   }
diff --git a/coordinator/src/tributary/handle.rs b/coordinator/src/tributary/handle.rs
index 657a0b50..37fd4108 100644
--- a/coordinator/src/tributary/handle.rs
+++ b/coordinator/src/tributary/handle.rs
@@ -522,6 +522,7 @@ pub async fn handle_application_tx<
     }
 
     Transaction::SignPreprocess(data) => {
+      let key_pair = TributaryDb::<D>::key_pair(txn, spec.set());
       match handle(
         txn,
         Zone::Sign,
@@ -537,7 +538,14 @@ pub async fn handle_application_tx<
             .send(
               spec.set().network,
               CoordinatorMessage::Sign(sign::CoordinatorMessage::Preprocesses {
-                id: SignId { key: todo!(), id: data.plan, attempt: data.attempt },
+                id: SignId {
+                  key: key_pair
+                    .expect("completed SignPreprocess despite not setting the key pair")
+                    .1
+                    .into(),
+                  id: data.plan,
+                  attempt: data.attempt,
+                },
                 preprocesses,
               }),
             )
@@ -548,6 +556,7 @@ pub async fn handle_application_tx<
       }
     }
     Transaction::SignShare(data) => {
+      let key_pair = TributaryDb::<D>::key_pair(txn, spec.set());
       match handle(
         txn,
         Zone::Sign,
@@ -563,7 +572,14 @@ pub async fn handle_application_tx<
             .send(
               spec.set().network,
               CoordinatorMessage::Sign(sign::CoordinatorMessage::Shares {
-                id: SignId { key: todo!(), id: data.plan, attempt: data.attempt },
+                id: SignId {
+                  key: key_pair
+                    .expect("completed SignShares despite not setting the key pair")
+                    .1
+                    .into(),
+                  id: data.plan,
+                  attempt: data.attempt,
+                },
                 shares,
               }),
             )
@@ -573,6 +589,8 @@ pub async fn handle_application_tx<
         None => {}
       }
     }
-    Transaction::SignCompleted(_, _, _) => todo!(),
+    Transaction::SignCompleted(_, _, _) => {
+      // TODO
+    }
   }
 }