diff --git a/src/bridge/AbsInbox.sol b/src/bridge/AbsInbox.sol
index e612b9b2b..3f69643c6 100644
--- a/src/bridge/AbsInbox.sol
+++ b/src/bridge/AbsInbox.sol
@@ -5,13 +5,13 @@
 pragma solidity ^0.8.4;
 
 import {
+    CalldataNotSameAsTx,
     DataTooLarge,
     GasLimitTooLarge,
     InsufficientValue,
     InsufficientSubmissionCost,
     L1Forked,
     NotAllowedOrigin,
-    NotTopLevel,
     NotRollupOrOwner,
     RetryableData
 } from "../libraries/Error.sol";
@@ -140,7 +140,7 @@ abstract contract AbsInbox is DelegateCallAware, PausableUpgradeable, IInboxBase
         bytes calldata messageData
     ) external whenNotPaused onlyAllowed returns (uint256) {
         if (_chainIdChanged()) revert L1Forked();
-        if (!CallerChecker.isCallerTopLevel()) revert NotTopLevel();
+        if (!CallerChecker.isCalldataSameAsTx()) revert CalldataNotSameAsTx();
         if (messageData.length > maxDataSize) revert DataTooLarge(messageData.length, maxDataSize);
         uint256 msgNum = _deliverToBridge(L2_MSG, msg.sender, keccak256(messageData), 0);
         emit InboxMessageDeliveredFromOrigin(msgNum);
diff --git a/src/bridge/SequencerInbox.sol b/src/bridge/SequencerInbox.sol
index d02929e7d..d2445cd61 100644
--- a/src/bridge/SequencerInbox.sol
+++ b/src/bridge/SequencerInbox.sol
@@ -19,7 +19,7 @@ import {
     NoSuchKeyset,
     NotForked,
     NotBatchPosterManager,
-    NotTopLevel,
+    CalldataNotSameAsTx,
     RollupNotChanged,
     DataBlobsNotSupported,
     InitParamZero,
@@ -335,7 +335,7 @@ contract SequencerInbox is DelegateCallAware, GasRefundEnabled, ISequencerInbox
         uint256 prevMessageCount,
         uint256 newMessageCount
     ) external refundsGas(gasRefunder, IReader4844(address(0))) {
-        if (!CallerChecker.isCallerTopLevel()) revert NotTopLevel();
+        if (!CallerChecker.isCalldataSameAsTx()) revert CalldataNotSameAsTx();
         if (!isBatchPoster[msg.sender]) revert NotBatchPoster();
         if (isDelayProofRequired(afterDelayedMessagesRead)) revert DelayProofRequired();
 
@@ -388,7 +388,7 @@ contract SequencerInbox is DelegateCallAware, GasRefundEnabled, ISequencerInbox
         uint256 newMessageCount,
         DelayProof calldata delayProof
     ) external refundsGas(gasRefunder, IReader4844(address(0))) {
-        if (!CallerChecker.isCallerTopLevel()) revert NotTopLevel();
+        if (!CallerChecker.isCalldataSameAsTx()) revert CalldataNotSameAsTx();
         if (!isBatchPoster[msg.sender]) revert NotBatchPoster();
         if (!isDelayBufferable) revert NotDelayBufferable();
 
@@ -438,7 +438,7 @@ contract SequencerInbox is DelegateCallAware, GasRefundEnabled, ISequencerInbox
         // submit a batch spending report to refund the entity that produced the blob batch data
         // same as using calldata, we only submit spending report if the caller is the origin of the tx
         // such that one cannot "double-claim" batch posting refund in the same tx
-        if (CallerChecker.isCallerTopLevel() && !isUsingFeeToken) {
+        if (CallerChecker.isCalldataSameAsTx() && !isUsingFeeToken) {
             submitBatchSpendingReport(dataHash, seqMessageIndex, block.basefee, blobGas);
         }
     }
diff --git a/src/libraries/CallerChecker.sol b/src/libraries/CallerChecker.sol
index f4ef6efed..3965fbaea 100644
--- a/src/libraries/CallerChecker.sol
+++ b/src/libraries/CallerChecker.sol
@@ -4,12 +4,12 @@
 
 pragma solidity ^0.8.0;
 
-library CallerChecker {
+library CalldataChecker {
     /**
-     * @notice A EIP-7702 safe check for top level caller, used to ensure the calldata is available in the tx
-     * @return bool true if the caller is a top level caller, false otherwise
+     * @notice A EIP-7702 safe check to ensure the calldata is available in the top level tx
+     * @return bool true if calldata is guaranteed to be available in the top level tx
      */
-    function isCallerTopLevel() internal view returns (bool) {
+    function isCalldataSameAsTx() internal view returns (bool) {
         // solhint-disable-next-line avoid-tx-origin
         return msg.sender == tx.origin && msg.sender.code.length == 0;
     }
diff --git a/src/libraries/Error.sol b/src/libraries/Error.sol
index c600ff3a8..8bb190da8 100644
--- a/src/libraries/Error.sol
+++ b/src/libraries/Error.sol
@@ -13,8 +13,8 @@ error HadZeroInit();
 /// @dev Thrown when post upgrade init validation fails
 error BadPostUpgradeInit();
 
-/// @dev Thrown when the caller is not a top level caller
-error NotTopLevel();
+/// @dev Thrown when the calldata is not same as the top level tx
+error CalldataNotSameAsTx();
 
 /// @dev Thrown when non owner tries to access an only-owner function
 /// @param sender The msg.sender who is not the owner
diff --git a/src/libraries/GasRefundEnabled.sol b/src/libraries/GasRefundEnabled.sol
index f96574aac..c75879b12 100644
--- a/src/libraries/GasRefundEnabled.sol
+++ b/src/libraries/GasRefundEnabled.sol
@@ -25,7 +25,7 @@ abstract contract GasRefundEnabled {
             startGasLeft += calldataWords * 6 + (calldataWords ** 2) / 512;
             // if triggered in a contract call, the spender may be overrefunded by appending dummy data to the call
             // so we check if it is a top level call, which would mean the sender paid calldata as part of tx.input
-            if (!CallerChecker.isCallerTopLevel()) {
+            if (!CallerChecker.isCalldataSameAsTx()) {
                 // We can't be sure if this calldata came from the top level tx,
                 // so to be safe we tell the gas refunder there was no calldata.
                 calldataSize = 0;