diff --git a/api/core/file/helpers.py b/api/core/file/helpers.py
index 6d553d7dc6..2ac483673a 100644
--- a/api/core/file/helpers.py
+++ b/api/core/file/helpers.py
@@ -8,8 +8,9 @@ import urllib.parse
 from configs import dify_config
 
 
-def get_signed_file_url(upload_file_id: str, as_attachment=False) -> str:
-    url = f"{dify_config.FILES_URL}/files/{upload_file_id}/file-preview"
+def get_signed_file_url(upload_file_id: str, as_attachment=False, for_external: bool = True) -> str:
+    base_url = dify_config.FILES_URL if for_external else (dify_config.INTERNAL_FILES_URL or dify_config.FILES_URL)
+    url = f"{base_url}/files/{upload_file_id}/file-preview"
 
     timestamp = str(int(time.time()))
     nonce = os.urandom(16).hex()
diff --git a/api/core/file/models.py b/api/core/file/models.py
index d149205d77..6324523b22 100644
--- a/api/core/file/models.py
+++ b/api/core/file/models.py
@@ -112,17 +112,17 @@ class File(BaseModel):
 
         return text
 
-    def generate_url(self) -> str | None:
+    def generate_url(self, for_external: bool = True) -> str | None:
         if self.transfer_method == FileTransferMethod.REMOTE_URL:
             return self.remote_url
         elif self.transfer_method == FileTransferMethod.LOCAL_FILE:
             if self.related_id is None:
                 raise ValueError("Missing file related_id")
-            return helpers.get_signed_file_url(upload_file_id=self.related_id)
+            return helpers.get_signed_file_url(upload_file_id=self.related_id, for_external=for_external)
         elif self.transfer_method in [FileTransferMethod.TOOL_FILE, FileTransferMethod.DATASOURCE_FILE]:
             assert self.related_id is not None
             assert self.extension is not None
-            return sign_tool_file(tool_file_id=self.related_id, extension=self.extension)
+            return sign_tool_file(tool_file_id=self.related_id, extension=self.extension, for_external=for_external)
         return None
 
     def to_plugin_parameter(self) -> dict[str, Any]:
@@ -133,7 +133,7 @@ class File(BaseModel):
             "extension": self.extension,
             "size": self.size,
             "type": self.type,
-            "url": self.generate_url(),
+            "url": self.generate_url(for_external=False),
         }
 
     @model_validator(mode="after")
diff --git a/api/core/tools/signature.py b/api/core/tools/signature.py
index fef3157f27..22e099deba 100644
--- a/api/core/tools/signature.py
+++ b/api/core/tools/signature.py
@@ -7,12 +7,12 @@ import time
 from configs import dify_config
 
 
-def sign_tool_file(tool_file_id: str, extension: str) -> str:
+def sign_tool_file(tool_file_id: str, extension: str, for_external: bool = True) -> str:
     """
     sign file to get a temporary url for plugin access
     """
-    # Use internal URL for plugin/tool file access in Docker environments
-    base_url = dify_config.INTERNAL_FILES_URL or dify_config.FILES_URL
+    # Use internal URL for plugin/tool file access in Docker environments, unless for_external is True
+    base_url = dify_config.FILES_URL if for_external else (dify_config.INTERNAL_FILES_URL or dify_config.FILES_URL)
     file_preview_url = f"{base_url}/files/tools/{tool_file_id}{extension}"
 
     timestamp = str(int(time.time()))
diff --git a/api/tests/unit_tests/core/workflow/nodes/llm/test_file_saver.py b/api/tests/unit_tests/core/workflow/nodes/llm/test_file_saver.py
index e8f257bf2f..1e224d56a5 100644
--- a/api/tests/unit_tests/core/workflow/nodes/llm/test_file_saver.py
+++ b/api/tests/unit_tests/core/workflow/nodes/llm/test_file_saver.py
@@ -78,7 +78,7 @@ class TestFileSaverImpl:
             file_binary=_PNG_DATA,
             mimetype=mime_type,
         )
-        mocked_sign_file.assert_called_once_with(mock_tool_file.id, ".png")
+        mocked_sign_file.assert_called_once_with(tool_file_id=mock_tool_file.id, extension=".png", for_external=True)
 
     def test_save_remote_url_request_failed(self, monkeypatch: pytest.MonkeyPatch):
         _TEST_URL = "https://example.com/image.png"