diff --git a/libs/partners/ollama/tests/unit_tests/test_chat_models_v1.py b/libs/partners/ollama/tests/unit_tests/test_chat_models_v1.py
index e039bfbd62e..e0350d0211b 100644
--- a/libs/partners/ollama/tests/unit_tests/test_chat_models_v1.py
+++ b/libs/partners/ollama/tests/unit_tests/test_chat_models_v1.py
@@ -1,5 +1,6 @@
 """Unit tests for ChatOllamaV1."""
 
+import json
 import logging
 from typing import Any
 from unittest.mock import MagicMock, patch
@@ -23,6 +24,7 @@ from langchain_ollama._compat import (
 )
 from langchain_ollama.chat_models_v1 import (
     ChatOllamaV1,
+    _parse_arguments_from_tool_call,
     _parse_json_string,
 )
 
@@ -280,6 +282,24 @@ def test_parse_json_string_skip_returns_input_on_failure() -> None:
     assert result == malformed_string
 
 
+def test__parse_arguments_from_tool_call() -> None:
+    """Test that string arguments are preserved as strings in tool call parsing.
+
+    This test verifies the fix for PR #30154 which addressed an issue where
+    string-typed tool arguments (like IDs or long strings) were being incorrectly
+    processed. The parser should preserve string values as strings rather than
+    attempting to parse them as JSON when they're already valid string arguments.
+
+    The test uses a long string ID to ensure string arguments maintain their
+    original type after parsing, which is critical for tools expecting string inputs.
+    """
+    raw_response = '{"model":"sample-model","message":{"role":"assistant","content":"","tool_calls":[{"function":{"name":"get_profile_details","arguments":{"arg_1":"12345678901234567890123456"}}}]},"done":false}'  # noqa: E501
+    raw_tool_calls = json.loads(raw_response)["message"]["tool_calls"]
+    response = _parse_arguments_from_tool_call(raw_tool_calls[0])
+    assert response is not None
+    assert isinstance(response["arg_1"], str)
+
+
 def test_load_response_with_empty_content_is_skipped(
     caplog: pytest.LogCaptureFixture,
 ) -> None: