diff --git a/src/account/SemiModularAccount.sol b/src/account/SemiModularAccount.sol
index 8fe637a4..f16d2363 100644
--- a/src/account/SemiModularAccount.sol
+++ b/src/account/SemiModularAccount.sol
@@ -7,7 +7,7 @@ import {PackedUserOperation} from "@eth-infinitism/account-abstraction/interface
 
 import {ModuleEntityLib} from "../helpers/ModuleEntityLib.sol";
 
-import {ModuleEntity, ValidationConfig} from "../interfaces/IModularAccount.sol";
+import {IModularAccount, ModuleEntity, ValidationConfig} from "../interfaces/IModularAccount.sol";
 
 import {MessageHashUtils} from "@openzeppelin/contracts/utils/cryptography/MessageHashUtils.sol";
 import {SignatureChecker} from "@openzeppelin/contracts/utils/cryptography/SignatureChecker.sol";
@@ -83,6 +83,11 @@ contract SemiModularAccount is UpgradeableModularAccount {
         revert InitializerDisabled();
     }
 
+    /// @inheritdoc IModularAccount
+    function accountId() external pure override returns (string memory) {
+        return "erc6900/reference-semi-modular-account/0.8.0";
+    }
+
     function _execUserOpValidation(
         ModuleEntity userOpValidationFunction,
         PackedUserOperation memory userOp,
diff --git a/src/account/UpgradeableModularAccount.sol b/src/account/UpgradeableModularAccount.sol
index 2a58f4b9..12ab1da8 100644
--- a/src/account/UpgradeableModularAccount.sol
+++ b/src/account/UpgradeableModularAccount.sol
@@ -276,6 +276,11 @@ contract UpgradeableModularAccount is
         return getAccountStorage().supportedIfaces[interfaceId] > 0;
     }
 
+    /// @inheritdoc IModularAccount
+    function accountId() external pure virtual returns (string memory) {
+        return "erc6900/reference-modular-account/0.8.0";
+    }
+
     /// @inheritdoc UUPSUpgradeable
     /// @notice May be validated by a global validation.
     function upgradeToAndCall(address newImplementation, bytes memory data)
diff --git a/src/helpers/KnownSelectors.sol b/src/helpers/KnownSelectors.sol
index 84c400cf..ba772d66 100644
--- a/src/helpers/KnownSelectors.sol
+++ b/src/helpers/KnownSelectors.sol
@@ -22,18 +22,20 @@ library KnownSelectors {
         return
         // check against IAccount methods
         selector == IAccount.validateUserOp.selector
-        // check against module manager methods
+        // check against IModularAccount methods
         || selector == IModularAccount.installExecution.selector
             || selector == IModularAccount.uninstallExecution.selector
+            || selector == IModularAccount.installValidation.selector
+            || selector == IModularAccount.uninstallValidation.selector || selector == IModularAccount.execute.selector
+            || selector == IModularAccount.executeBatch.selector
+            || selector == IModularAccount.executeWithAuthorization.selector
+            || selector == IModularAccount.accountId.selector
         // check against IERC165 methods
         || selector == IERC165.supportsInterface.selector
         // check against UUPSUpgradeable methods
         || selector == UUPSUpgradeable.proxiableUUID.selector
             || selector == UUPSUpgradeable.upgradeToAndCall.selector
-        // check against IModularAccount methods
-        || selector == IModularAccount.execute.selector || selector == IModularAccount.executeBatch.selector
-            || selector == IModularAccount.executeWithAuthorization.selector
-        // check against account loupe methods
+        // check against IAccountLoupe methods
         || selector == IAccountLoupe.getExecutionData.selector
             || selector == IAccountLoupe.getValidationData.selector;
     }
diff --git a/src/interfaces/IModularAccount.sol b/src/interfaces/IModularAccount.sol
index f6212b54..dcad3ee8 100644
--- a/src/interfaces/IModularAccount.sol
+++ b/src/interfaces/IModularAccount.sol
@@ -97,4 +97,9 @@ interface IModularAccount {
         ExecutionManifest calldata manifest,
         bytes calldata moduleUninstallData
     ) external;
+
+    /// @notice Return a unique identifier for the account implementation.
+    /// @dev This function MUST return a string in the format "vendor/account/semver".
+    /// @return The account ID.
+    function accountId() external view returns (string memory);
 }
diff --git a/test/account/UpgradeableModularAccount.t.sol b/test/account/UpgradeableModularAccount.t.sol
index cfc99497..a2ac85b0 100644
--- a/test/account/UpgradeableModularAccount.t.sol
+++ b/test/account/UpgradeableModularAccount.t.sol
@@ -184,6 +184,16 @@ contract UpgradeableModularAccountTest is AccountTestBase {
         _printStorageReadsAndWrites(address(account2));
     }
 
+    function test_accountId() public {
+        string memory accountId = account1.accountId();
+        assertEq(
+            accountId,
+            vm.envOr("SMA_TEST", false)
+                ? "erc6900/reference-semi-modular-account/0.8.0"
+                : "erc6900/reference-modular-account/0.8.0"
+        );
+    }
+
     function test_contractInteraction() public {
         PackedUserOperation memory userOp = PackedUserOperation({
             sender: address(account1),