diff --git a/crates/pool/proto/op_pool/op_pool.proto b/crates/pool/proto/op_pool/op_pool.proto
index d5cd68805..0b1e6ab65 100644
--- a/crates/pool/proto/op_pool/op_pool.proto
+++ b/crates/pool/proto/op_pool/op_pool.proto
@@ -511,7 +511,7 @@ message PaymasterBalanceTooLow {
 
 message MaxOperationsReachedError {
   uint64 num_ops = 1;
-  bytes entity_address = 2;
+  Entity entity = 2;
 }
 
 message EntityThrottledError {
diff --git a/crates/pool/src/mempool/uo_pool.rs b/crates/pool/src/mempool/uo_pool.rs
index 925de0bef..2805def3a 100644
--- a/crates/pool/src/mempool/uo_pool.rs
+++ b/crates/pool/src/mempool/uo_pool.rs
@@ -477,7 +477,7 @@ where
             {
                 return Err(MempoolError::MaxOperationsReached(
                     self.config.same_sender_mempool_count,
-                    pool_op.uo.sender(),
+                    Entity::account(pool_op.uo.sender()),
                 ));
             }
 
@@ -490,7 +490,7 @@ where
                 if state.pool.address_count(&entity.address) >= ops_allowed as usize {
                     return Err(MempoolError::MaxOperationsReached(
                         ops_allowed as usize,
-                        entity.address,
+                        entity,
                     ));
                 }
             }
diff --git a/crates/pool/src/server/remote/error.rs b/crates/pool/src/server/remote/error.rs
index 99a2286ec..33ae98209 100644
--- a/crates/pool/src/server/remote/error.rs
+++ b/crates/pool/src/server/remote/error.rs
@@ -83,7 +83,7 @@ impl TryFrom<ProtoMempoolError> for MempoolError {
             Some(mempool_error::Error::MaxOperationsReached(e)) => {
                 MempoolError::MaxOperationsReached(
                     e.num_ops as usize,
-                    from_bytes(&e.entity_address)?,
+                    (&e.entity.context("should have entity in error")?).try_into()?,
                 )
             }
             Some(mempool_error::Error::EntityThrottled(e)) => MempoolError::EntityThrottled(
@@ -168,11 +168,11 @@ impl From<MempoolError> for ProtoMempoolError {
                     },
                 )),
             },
-            MempoolError::MaxOperationsReached(ops, addr) => ProtoMempoolError {
+            MempoolError::MaxOperationsReached(ops, entity) => ProtoMempoolError {
                 error: Some(mempool_error::Error::MaxOperationsReached(
                     MaxOperationsReachedError {
                         num_ops: ops as u64,
-                        entity_address: addr.to_proto_bytes(),
+                        entity: Some((&entity).into()),
                     },
                 )),
             },
diff --git a/crates/rpc/src/eth/error.rs b/crates/rpc/src/eth/error.rs
index 0c58697a7..b180ea3f5 100644
--- a/crates/rpc/src/eth/error.rs
+++ b/crates/rpc/src/eth/error.rs
@@ -93,8 +93,8 @@ pub enum EthRpcError {
     #[error("operation is out of time range")]
     OutOfTimeRange(OutOfTimeRangeData),
     /// Max operations reached for this sender
-    #[error("Max operations ({0}) reached for sender {1:#032x} due to being unstaked")]
-    MaxOperationsReached(usize, Address),
+    #[error("Max operations ({0}) reached for {1} due to being unstaked")]
+    MaxOperationsReached(usize, Entity),
     /// Entity throttled or banned
     #[error("{} {:#032x} throttled or banned", .0.kind, .0.address)]
     ThrottledOrBanned(Entity),
diff --git a/crates/types/src/pool/error.rs b/crates/types/src/pool/error.rs
index 752030d98..e81603251 100644
--- a/crates/types/src/pool/error.rs
+++ b/crates/types/src/pool/error.rs
@@ -56,7 +56,7 @@ pub enum MempoolError {
     ReplacementUnderpriced(U256, U256),
     /// Max operations reached for unstaked sender [UREP-010] or unstaked non-sender entity [UREP-020]
     #[error("Max operations ({0}) reached for entity {1}")]
-    MaxOperationsReached(usize, Address),
+    MaxOperationsReached(usize, Entity),
     /// Multiple roles violation
     /// Spec rule: STO-040
     #[error("A {} at {} in this UserOperation is used as a sender entity in another UserOperation currently in mempool.", .0.kind, .0.address)]