diff --git a/src/bridge/Inbox.sol b/src/bridge/Inbox.sol
index 8559bf21..079a9f8a 100644
--- a/src/bridge/Inbox.sol
+++ b/src/bridge/Inbox.sol
@@ -109,6 +109,7 @@ contract Inbox is AbsInbox, IInbox {
         if (!_chainIdChanged()) revert NotForked();
         // solhint-disable-next-line avoid-tx-origin
         if (msg.sender != tx.origin) revert NotOrigin();
+        // no code size check required because we only want to know if msg.sender is an EOA to undo alias
         // arbos will discard unsigned tx with gas limit too large
         if (gasLimit > type(uint64).max) {
             revert GasLimitTooLarge();
@@ -142,6 +143,7 @@ contract Inbox is AbsInbox, IInbox {
         if (!_chainIdChanged()) revert NotForked();
         // solhint-disable-next-line avoid-tx-origin
         if (msg.sender != tx.origin) revert NotOrigin();
+        // no code size check required because we only want to know if msg.sender is an EOA to undo alias
         // arbos will discard unsigned tx with gas limit too large
         if (gasLimit > type(uint64).max) {
             revert GasLimitTooLarge();
@@ -174,6 +176,7 @@ contract Inbox is AbsInbox, IInbox {
         if (!_chainIdChanged()) revert NotForked();
         // solhint-disable-next-line avoid-tx-origin
         if (msg.sender != tx.origin) revert NotOrigin();
+        // no code size check required because we only want to know if msg.sender is an EOA to undo alias
         // arbos will discard unsigned tx with gas limit too large
         if (gasLimit > type(uint64).max) {
             revert GasLimitTooLarge();