diff --git a/src/promptflow/promptflow/_core/_errors.py b/src/promptflow/promptflow/_core/_errors.py
index 2fe691b94e0..a7d9c1e1291 100644
--- a/src/promptflow/promptflow/_core/_errors.py
+++ b/src/promptflow/promptflow/_core/_errors.py
@@ -43,6 +43,10 @@ class ToolCanceledError(UserErrorException):
     pass
 
 
+class InvalidSource(ValidationException):
+    pass
+
+
 class ToolLoadError(UserErrorException):
     """Exception raised when tool load failed."""
 
diff --git a/src/promptflow/promptflow/_core/tool_meta_generator.py b/src/promptflow/promptflow/_core/tool_meta_generator.py
index 189caec1f1e..e5f34c837d6 100644
--- a/src/promptflow/promptflow/_core/tool_meta_generator.py
+++ b/src/promptflow/promptflow/_core/tool_meta_generator.py
@@ -256,6 +256,7 @@ def generate_python_meta_dict(name, content, source=None):
     return asdict_without_none(generate_python_tool(name, content, source))
 
 
+# Only used in non-code first experience.
 def generate_python_meta(name, content, source=None):
     return json.dumps(generate_python_meta_dict(name, content, source), indent=2)
 
@@ -269,12 +270,12 @@ def generate_tool_meta_dict_by_file(path: str, tool_type: ToolType):
     note that if a python file is passed, correct working directory must be set and should be added to sys.path.
     """
     tool_type = ToolType(tool_type)
-    file = Path(path).resolve()
+    file = Path(path)
     if not file.is_file():
         raise MetaFileNotFound(
             message_format="Generate tool meta failed for {tool_type} tool. Meta file '{file_path}' can not be found.",
             tool_type=tool_type.value,
-            file_path=str(file),
+            file_path=path,  # Use a relative path here to make the error message more readable.
         )
     try:
         content = file.read_text(encoding="utf-8")
@@ -286,7 +287,7 @@ def generate_tool_meta_dict_by_file(path: str, tool_type: ToolType):
                 "Read meta file '{file_path}' failed: {error_type_and_message}"
             ),
             tool_type=tool_type.value,
-            file_path=str(file),
+            file_path=path,
             error_type_and_message=error_type_and_message,
         ) from e
 
diff --git a/src/promptflow/promptflow/_core/tools_manager.py b/src/promptflow/promptflow/_core/tools_manager.py
index f8231d82af7..503a5faceb6 100644
--- a/src/promptflow/promptflow/_core/tools_manager.py
+++ b/src/promptflow/promptflow/_core/tools_manager.py
@@ -12,7 +12,13 @@
 from pathlib import Path
 from typing import Callable, Dict, List, Mapping, Optional, Tuple, Union
 
-from promptflow._core._errors import InputTypeMismatch, MissingRequiredInputs, PackageToolNotFoundError, ToolLoadError
+from promptflow._core._errors import (
+    InputTypeMismatch,
+    InvalidSource,
+    MissingRequiredInputs,
+    PackageToolNotFoundError,
+    ToolLoadError,
+)
 from promptflow._core.tool_meta_generator import (
     _parse_tool_from_function,
     collect_tool_function_in_module,
@@ -416,8 +422,19 @@ def load_tool_for_package_node(self, node: Node) -> Tool:
 
     def load_tool_for_script_node(self, node: Node) -> Tuple[types.ModuleType, Tool]:
         if node.source.path is None:
-            raise UserErrorException(f"Node {node.name} does not have source path defined.")
+            raise InvalidSource(
+                target=ErrorTarget.EXECUTOR,
+                message_format="Load tool failed for node '{node_name}'. The source path is 'None'.",
+                node_name=node.name,
+            )
         path = node.source.path
+        if not (self._working_dir / path).is_file():
+            raise InvalidSource(
+                target=ErrorTarget.EXECUTOR,
+                message_format="Load tool failed for node '{node_name}'. Tool file '{source_path}' can not be found.",
+                source_path=path,
+                node_name=node.name,
+            )
         m = load_python_module_from_file(self._working_dir / path)
         if m is None:
             raise CustomToolSourceLoadError(f"Cannot load module from {path}.")
diff --git a/src/promptflow/promptflow/executor/_errors.py b/src/promptflow/promptflow/executor/_errors.py
index ce2afcd8bc8..e77a0920747 100644
--- a/src/promptflow/promptflow/executor/_errors.py
+++ b/src/promptflow/promptflow/executor/_errors.py
@@ -76,10 +76,6 @@ def __init__(
         )
 
 
-class InvalidSource(ValidationException):
-    pass
-
-
 class NodeInputValidationError(InvalidFlowRequest):
     pass
 
diff --git a/src/promptflow/promptflow/executor/_tool_resolver.py b/src/promptflow/promptflow/executor/_tool_resolver.py
index 437d311f81f..b700aca6c3c 100644
--- a/src/promptflow/promptflow/executor/_tool_resolver.py
+++ b/src/promptflow/promptflow/executor/_tool_resolver.py
@@ -10,6 +10,7 @@
 from pathlib import Path
 from typing import Callable, List, Optional
 
+from promptflow._core._errors import InvalidSource
 from promptflow._core.connection_manager import ConnectionManager
 from promptflow._core.tool import STREAMING_OPTION_PARAMETER_ATTR
 from promptflow._core.tools_manager import BuiltinsManager, ToolLoader, connection_type_to_api_mapping
@@ -25,7 +26,6 @@
     EmptyLLMApiMapping,
     InvalidConnectionType,
     InvalidCustomLLMTool,
-    InvalidSource,
     NodeInputValidationError,
     ResolveToolError,
     ValueTypeUnresolved,
diff --git a/src/promptflow/tests/executor/e2etests/test_executor_validation.py b/src/promptflow/tests/executor/e2etests/test_executor_validation.py
index f09997fa41a..b9edd260018 100644
--- a/src/promptflow/tests/executor/e2etests/test_executor_validation.py
+++ b/src/promptflow/tests/executor/e2etests/test_executor_validation.py
@@ -4,8 +4,7 @@
 
 import pytest
 
-from promptflow._core._errors import FlowOutputUnserializable
-from promptflow._core.tool_meta_generator import PythonParsingError
+from promptflow._core._errors import FlowOutputUnserializable, InvalidSource
 from promptflow._core.tools_manager import APINotFound
 from promptflow._sdk._constants import DAG_FILE_NAME
 from promptflow._utils.utils import dump_list_to_jsonl
@@ -20,7 +19,6 @@
     InputReferenceNotFound,
     InputTypeError,
     InvalidConnectionType,
-    InvalidSource,
     NodeCircularDependency,
     NodeInputValidationError,
     NodeReferenceNotFound,
@@ -46,7 +44,7 @@ class TestValidation:
                 (
                     "Tool load failed in 'wrong_llm': "
                     "(InvalidConnectionType) Connection type CustomConnection is not supported for LLM."
-                )
+                ),
             ),
             (
                 "nodes_names_duplicated",
@@ -154,7 +152,7 @@ def test_executor_create_failure_type_and_message(
     @pytest.mark.parametrize(
         "flow_folder, yml_file, error_class, inner_class",
         [
-            ("source_file_missing", "flow.dag.python.yaml", ResolveToolError, PythonParsingError),
+            ("source_file_missing", "flow.dag.python.yaml", ResolveToolError, InvalidSource),
         ],
     )
     def test_executor_create_failure_type(self, flow_folder, yml_file, error_class, inner_class, dev_connections):
diff --git a/src/promptflow/tests/executor/unittests/_core/test_tools_manager.py b/src/promptflow/tests/executor/unittests/_core/test_tools_manager.py
index aa7098507bc..2d0f38c2928 100644
--- a/src/promptflow/tests/executor/unittests/_core/test_tools_manager.py
+++ b/src/promptflow/tests/executor/unittests/_core/test_tools_manager.py
@@ -6,7 +6,7 @@
 from mock import MagicMock
 
 from promptflow import tool
-from promptflow._core._errors import InputTypeMismatch, PackageToolNotFoundError
+from promptflow._core._errors import InputTypeMismatch, InvalidSource, PackageToolNotFoundError
 from promptflow._core.tools_manager import (
     BuiltinsManager,
     ToolLoader,
@@ -124,6 +124,27 @@ def test_load_tool_for_script_node(self):
         tool = tool_loader.load_tool_for_node(node)
         assert tool.name == "sample_tool"
 
+    @pytest.mark.parametrize(
+        "source_path, error_message",
+        [
+            (None, "Load tool failed for node 'test'. The source path is 'None'."),
+            ("invalid_file.py", "Load tool failed for node 'test'. Tool file 'invalid_file.py' can not be found."),
+        ],
+    )
+    def test_load_tool_for_script_node_exception(self, source_path, error_message):
+        working_dir = Path(__file__).parent
+        tool_loader = ToolLoader(working_dir=working_dir)
+        node: Node = Node(
+            name="test",
+            tool="sample_tool",
+            inputs={},
+            type=ToolType.PYTHON,
+            source=ToolSource(type=ToolSourceType.Code, path=source_path),
+        )
+        with pytest.raises(InvalidSource) as ex:
+            tool_loader.load_tool_for_script_node(node)
+        assert str(ex.value) == error_message
+
 
 # This tool is for testing tools_manager.ToolLoader.load_tool_for_script_node
 @tool
diff --git a/src/promptflow/tests/executor/unittests/_utils/test_generate_tool_meta_utils.py b/src/promptflow/tests/executor/unittests/_utils/test_generate_tool_meta_utils.py
index f4980108f32..5d02df31b73 100644
--- a/src/promptflow/tests/executor/unittests/_utils/test_generate_tool_meta_utils.py
+++ b/src/promptflow/tests/executor/unittests/_utils/test_generate_tool_meta_utils.py
@@ -123,7 +123,7 @@ def test_generate_tool_meta_dict_by_file(self, flow_dir, tool_path, tool_type):
                 "python",
                 cd_and_run,
                 r"\(MetaFileNotFound\) Generate tool meta failed for python tool. "
-                r"Meta file '.*aaa.py' can not be found.",
+                r"Meta file 'aaa.py' can not be found.",
                 id="MetaFileNotFound",
             ),
             pytest.param(
@@ -132,7 +132,7 @@ def test_generate_tool_meta_dict_by_file(self, flow_dir, tool_path, tool_type):
                 "python",
                 cd_and_run_with_read_text_error,
                 r"\(MetaFileReadError\) Generate tool meta failed for python tool. "
-                r"Read meta file '.*divide_num.py' failed: \(Exception\) Mock read text error.",
+                r"Read meta file 'divide_num.py' failed: \(Exception\) Mock read text error.",
                 id="MetaFileReadError",
             ),
             pytest.param(
diff --git a/src/promptflow/tests/executor/unittests/executor/test_tool_resolver.py b/src/promptflow/tests/executor/unittests/executor/test_tool_resolver.py
index 46d21a57f65..0a8ba5a4fc8 100644
--- a/src/promptflow/tests/executor/unittests/executor/test_tool_resolver.py
+++ b/src/promptflow/tests/executor/unittests/executor/test_tool_resolver.py
@@ -7,6 +7,7 @@
 import pytest
 from jinja2 import TemplateSyntaxError
 
+from promptflow._core._errors import InvalidSource
 from promptflow._core.tools_manager import ToolLoader
 from promptflow._internal import tool
 from promptflow._sdk.entities import CustomConnection, CustomStrongTypeConnection
@@ -18,7 +19,6 @@
 from promptflow.executor._errors import (
     ConnectionNotFound,
     InvalidConnectionType,
-    InvalidSource,
     NodeInputValidationError,
     ResolveToolError,
     ValueTypeUnresolved,