diff --git a/packages/better-auth/src/adapters/mongodb-adapter/mongodb-adapter.ts b/packages/better-auth/src/adapters/mongodb-adapter/mongodb-adapter.ts
index af5b05f541..f3f2053c18 100644
--- a/packages/better-auth/src/adapters/mongodb-adapter/mongodb-adapter.ts
+++ b/packages/better-auth/src/adapters/mongodb-adapter/mongodb-adapter.ts
@@ -604,7 +604,7 @@ export const mongodbAdapter = (
 					if (customIdGen) {
 						return data;
 					}
-					if (action === "update") {
+					if (action !== "create") {
 						return data;
 					}
 					if (Array.isArray(data)) {
diff --git a/packages/core/src/db/adapter/factory.ts b/packages/core/src/db/adapter/factory.ts
index ac7da3628d..cdd52e4535 100644
--- a/packages/core/src/db/adapter/factory.ts
+++ b/packages/core/src/db/adapter/factory.ts
@@ -474,9 +474,19 @@ export const createAdapterFactory =
 		const transformWhereClause = <W extends Where[] | undefined>({
 			model,
 			where,
+			action,
 		}: {
 			where: W;
 			model: string;
+			action:
+				| "create"
+				| "update"
+				| "findOne"
+				| "findMany"
+				| "updateMany"
+				| "delete"
+				| "deleteMany"
+				| "count";
 		}): W extends undefined ? undefined : CleanedWhere[] => {
 			if (!where) return undefined as any;
 			const newMappedKeys = config.mapKeysTransformInput ?? {};
@@ -562,6 +572,18 @@ export const createAdapterFactory =
 					}
 				}
 
+				if (config.customTransformInput) {
+					newValue = config.customTransformInput({
+						data: newValue,
+						fieldAttributes: fieldAttr,
+						field: fieldName,
+						model: getModelName(model),
+						schema,
+						options,
+						action,
+					});
+				}
+
 				return {
 					operator,
 					connector,
@@ -727,6 +749,7 @@ export const createAdapterFactory =
 						connector: "AND",
 					},
 				],
+				action: "findOne",
 			});
 			try {
 				if (joinConfig.relation === "one-to-one") {
@@ -886,6 +909,7 @@ export const createAdapterFactory =
 				const where = transformWhereClause({
 					model: unsafeModel,
 					where: unsafeWhere,
+					action: "update",
 				});
 				debugLog(
 					{ method: "update" },
@@ -946,6 +970,7 @@ export const createAdapterFactory =
 				const where = transformWhereClause({
 					model: unsafeModel,
 					where: unsafeWhere,
+					action: "updateMany",
 				});
 				unsafeModel = getDefaultModelName(unsafeModel);
 				debugLog(
@@ -1001,6 +1026,7 @@ export const createAdapterFactory =
 				const where = transformWhereClause({
 					model: unsafeModel,
 					where: unsafeWhere,
+					action: "findOne",
 				});
 				unsafeModel = getDefaultModelName(unsafeModel);
 				let join: JoinConfig | undefined;
@@ -1078,6 +1104,7 @@ export const createAdapterFactory =
 				const where = transformWhereClause({
 					model: unsafeModel,
 					where: unsafeWhere,
+					action: "findMany",
 				});
 				unsafeModel = getDefaultModelName(unsafeModel);
 				let join: JoinConfig | undefined;
@@ -1151,6 +1178,7 @@ export const createAdapterFactory =
 				const where = transformWhereClause({
 					model: unsafeModel,
 					where: unsafeWhere,
+					action: "delete",
 				});
 				unsafeModel = getDefaultModelName(unsafeModel);
 				debugLog(
@@ -1183,6 +1211,7 @@ export const createAdapterFactory =
 				const where = transformWhereClause({
 					model: unsafeModel,
 					where: unsafeWhere,
+					action: "deleteMany",
 				});
 				unsafeModel = getDefaultModelName(unsafeModel);
 				debugLog(
@@ -1216,6 +1245,7 @@ export const createAdapterFactory =
 				const where = transformWhereClause({
 					model: unsafeModel,
 					where: unsafeWhere,
+					action: "count",
 				});
 				unsafeModel = getDefaultModelName(unsafeModel);
 				debugLog(
diff --git a/packages/core/src/db/adapter/index.ts b/packages/core/src/db/adapter/index.ts
index 531211a26e..d11761734a 100644
--- a/packages/core/src/db/adapter/index.ts
+++ b/packages/core/src/db/adapter/index.ts
@@ -203,7 +203,15 @@ export interface DBAdapterFactoryConfig<
 				/**
 				 * The action which was called from the adapter.
 				 */
-				action: "create" | "update" | "findOne" | "findMany";
+				action:
+					| "create"
+					| "update"
+					| "findOne"
+					| "findMany"
+					| "updateMany"
+					| "delete"
+					| "deleteMany"
+					| "count";
 				/**
 				 * The model name.
 				 */
diff --git a/packages/core/src/db/adapter/types.ts b/packages/core/src/db/adapter/types.ts
index 083a4c7234..a52fb64fda 100644
--- a/packages/core/src/db/adapter/types.ts
+++ b/packages/core/src/db/adapter/types.ts
@@ -111,9 +111,19 @@ export type AdapterFactoryCustomizeAdapterCreator = (config: {
 	transformWhereClause: <W extends Where[] | undefined>({
 		model,
 		where,
+		action,
 	}: {
 		where: W;
 		model: string;
+		action:
+			| "create"
+			| "update"
+			| "findOne"
+			| "findMany"
+			| "updateMany"
+			| "delete"
+			| "deleteMany"
+			| "count";
 	}) => W extends undefined ? undefined : CleanedWhere[];
 }) => CustomAdapter;