diff --git a/src/formats/json/JsonFormatError.ts b/src/formats/json/JsonFormatError.ts
new file mode 100644
index 0000000000..aa6842d68a
--- /dev/null
+++ b/src/formats/json/JsonFormatError.ts
@@ -0,0 +1,14 @@
+import { AbstractFormatError } from "../../errors/AbstractFormatError";
+
+/**
+ * This error indicates problem with parsing of CSV
+ *
+ * @public exported from `@promptbook/core`
+ */
+export class CsvFormatError extends AbstractFormatError {
+    public readonly name = 'CsvFormatError';
+    public constructor(message: string) {
+        super(message);
+        Object.setPrototypeOf(this, CsvFormatError.prototype);
+    }
+}
diff --git a/src/formats/xml/XmlFormatError.ts b/src/formats/xml/XmlFormatError.ts
new file mode 100644
index 0000000000..a8098bd4c0
--- /dev/null
+++ b/src/formats/xml/XmlFormatError.ts
@@ -0,0 +1,14 @@
+import { AbstractFormatError } from '../../errors/AbstractFormatError';
+
+/**
+ * This error indicates problem with parsing of XML
+ *
+ * @public exported from `@promptbook/core`
+ */
+export class XmlFormatError extends AbstractFormatError {
+    public readonly name = 'XmlFormatError';
+    public constructor(message: string) {
+        super(message);
+        Object.setPrototypeOf(this, CsvFormatError.prototype);
+    }
+}
diff --git a/src/formats/xml/XmlFormatParser.ts b/src/formats/xml/XmlFormatParser.ts
index ec1863ef8f..e1d262f609 100644
--- a/src/formats/xml/XmlFormatParser.ts
+++ b/src/formats/xml/XmlFormatParser.ts
@@ -3,13 +3,20 @@ import { TODO_USE } from '../../utils/organization/TODO_USE';
 import type { FormatParser } from '../_common/FormatParser';
 import { isValidXmlString } from './utils/isValidXmlString';
 
+/**
+ * Semantic helper
+ *
+ * For example `"<foo>bar</foo>"`
+ */
+export type string_xml = string;
+
 /**
  * Definition for XML format
  *
  * @private still in development [🏢]
  */
 export const XmlFormatParser: FormatParser<
-    string /* <- [0] */,
+    string_xml /* <- [0] */,
     string /* <- [👨‍⚖️] */,
     TODO_any /* <- [1] */,
     TODO_any /* <- [1] */
@@ -18,7 +25,7 @@ export const XmlFormatParser: FormatParser<
 
     mimeType: 'application/xml',
 
-    isValid(value, settings, schema): value is string /* <- [0] */ {
+    isValid(value, settings, schema): value is string_xml /* <- [0] */ {
         TODO_USE(value /* <- TODO: Use value here */);
         TODO_USE(settings /* <- TODO: Use settings here */);
         TODO_USE(schema /* <- TODO: Use schema here */);
diff --git a/src/formats/xml/utils/isValidXmlString.test.ts b/src/formats/xml/utils/isValidXmlString.test.ts
index 35898f09c5..82c8530f95 100644
--- a/src/formats/xml/utils/isValidXmlString.test.ts
+++ b/src/formats/xml/utils/isValidXmlString.test.ts
@@ -27,4 +27,9 @@ describe('isValidXmlString', () => {
         expect(isValidXmlString(null as unknown as string)).toBe(false);
         expect(isValidXmlString(undefined as unknown as string)).toBe(false);
     });
+
+    it('should return false for strings with only whitespace', () => {
+        const whitespaceString = '   ';
+        expect(isValidXmlString(whitespaceString)).toBe(false);
+    });
 });
diff --git a/src/formats/xml/utils/isValidXmlString.ts b/src/formats/xml/utils/isValidXmlString.ts
index df628acf4b..3238fbce9f 100644
--- a/src/formats/xml/utils/isValidXmlString.ts
+++ b/src/formats/xml/utils/isValidXmlString.ts
@@ -1,25 +1,19 @@
-import { assertsError } from '../../../errors/assertsError';
+import { string_xml } from '../XmlFormatDefinition';
+import { validateXmlString } from './validateXmlString';
 
 /**
- * Function to check if a string is valid XML
+ * Function to check if a string is valid XML.
  *
- * @param value
- * @returns True if the string is a valid XML string, false otherwise
+ * @param value - The string to check.
+ * @returns True if the string is a valid XML string, false otherwise.
  *
  * @public exported from `@promptbook/utils`
  */
-export function isValidXmlString(value: string): boolean {
+export function isValidXmlString(value: unknown): value is string_xml {
     try {
-        const parser = new DOMParser();
-        const parsedDocument = parser.parseFromString(value, 'application/xml');
-        const parserError = parsedDocument.getElementsByTagName('parsererror');
-
-        if (parserError.length > 0) {
-            return false;
-        }
+        validateXmlString(value);
         return true;
-    } catch (error) {
-        assertsError(error);
+    } catch {
         return false;
     }
 }
diff --git a/src/formats/xml/utils/validateXmlString.ts b/src/formats/xml/utils/validateXmlString.ts
new file mode 100644
index 0000000000..a3c776175d
--- /dev/null
+++ b/src/formats/xml/utils/validateXmlString.ts
@@ -0,0 +1,31 @@
+import { assertsError } from '../../../errors/assertsError';
+import { CsvFormatError } from '../../csv/CsvFormatError';
+import { string_xml } from '../XmlFormatDefinition';
+
+/**
+ * Function to validate if a string is a valid XML string.
+ * Throws an error if the string is not valid XML.
+ *
+ * @param value - The string to validate.
+ * @throws Error if the string is not valid XML.
+ *
+ * @public exported from `@promptbook/utils`
+ */
+
+export function validateXmlString(value: unknown): string_xml {
+    if (typeof value !== 'string' || value.trim() === '') {
+        throw new Error('Invalid XML: Input is not a valid string.');
+    }
+    try {
+        const parser = new DOMParser();
+        const parsedDocument = parser.parseFromString(value, 'application/xml');
+        const parserError = parsedDocument.getElementsByTagName('parsererror');
+
+        if (parserError.length > 0) {
+            throw new CsvFormatError('Invalid XML: Parsing error detected.');
+        }
+    } catch (error) {
+        assertsError(error);
+        throw error;
+    }
+}
diff --git a/src/types/typeAliases.ts b/src/types/typeAliases.ts
index 44f33f9bfe..0fb919d36f 100644
--- a/src/types/typeAliases.ts
+++ b/src/types/typeAliases.ts
@@ -223,15 +223,7 @@ export type string_knowledge_source_link = string_url | string_filename;
  */
 export type string_html = string;
 
-/**
- * Semantic helper
- *
- * For example `"<foo>bar</foo>"`
- *
- *
- * TODO: [🎞️] Probbably use some object-based method for working with XMLs
- */
-export type string_xml = string;
+
 
 /**
  * Semantic helper