diff --git a/api/core/file/file_manager.py b/api/core/file/file_manager.py
index ada19ef8c..f8c050c2a 100644
--- a/api/core/file/file_manager.py
+++ b/api/core/file/file_manager.py
@@ -7,6 +7,7 @@ from core.model_runtime.entities import (
     AudioPromptMessageContent,
     DocumentPromptMessageContent,
     ImagePromptMessageContent,
+    TextPromptMessageContent,
     VideoPromptMessageContent,
 )
 from core.model_runtime.entities.message_entities import PromptMessageContentUnionTypes
@@ -44,11 +45,44 @@ def to_prompt_message_content(
     *,
     image_detail_config: ImagePromptMessageContent.DETAIL | None = None,
 ) -> PromptMessageContentUnionTypes:
+    """
+    Convert a file to prompt message content.
+
+    This function converts files to their appropriate prompt message content types.
+    For supported file types (IMAGE, AUDIO, VIDEO, DOCUMENT), it creates the
+    corresponding message content with proper encoding/URL.
+
+    For unsupported file types, instead of raising an error, it returns a
+    TextPromptMessageContent with a descriptive message about the file.
+
+    Args:
+        f: The file to convert
+        image_detail_config: Optional detail configuration for image files
+
+    Returns:
+        PromptMessageContentUnionTypes: The appropriate message content type
+
+    Raises:
+        ValueError: If file extension or mime_type is missing
+    """
     if f.extension is None:
         raise ValueError("Missing file extension")
     if f.mime_type is None:
         raise ValueError("Missing file mime_type")
 
+    prompt_class_map: Mapping[FileType, type[PromptMessageContentUnionTypes]] = {
+        FileType.IMAGE: ImagePromptMessageContent,
+        FileType.AUDIO: AudioPromptMessageContent,
+        FileType.VIDEO: VideoPromptMessageContent,
+        FileType.DOCUMENT: DocumentPromptMessageContent,
+    }
+
+    # Check if file type is supported
+    if f.type not in prompt_class_map:
+        # For unsupported file types, return a text description
+        return TextPromptMessageContent(data=f"[Unsupported file type: {f.filename} ({f.type.value})]")
+
+    # Process supported file types
     params = {
         "base64_data": _get_encoded_string(f) if dify_config.MULTIMODAL_SEND_FORMAT == "base64" else "",
         "url": _to_url(f) if dify_config.MULTIMODAL_SEND_FORMAT == "url" else "",
@@ -58,17 +92,7 @@ def to_prompt_message_content(
     if f.type == FileType.IMAGE:
         params["detail"] = image_detail_config or ImagePromptMessageContent.DETAIL.LOW
 
-    prompt_class_map: Mapping[FileType, type[PromptMessageContentUnionTypes]] = {
-        FileType.IMAGE: ImagePromptMessageContent,
-        FileType.AUDIO: AudioPromptMessageContent,
-        FileType.VIDEO: VideoPromptMessageContent,
-        FileType.DOCUMENT: DocumentPromptMessageContent,
-    }
-
-    try:
-        return prompt_class_map[f.type].model_validate(params)
-    except KeyError:
-        raise ValueError(f"file type {f.type} is not supported")
+    return prompt_class_map[f.type].model_validate(params)
 
 
 def download(f: File, /):
diff --git a/api/factories/file_factory.py b/api/factories/file_factory.py
index 25d139049..c974dbb70 100644
--- a/api/factories/file_factory.py
+++ b/api/factories/file_factory.py
@@ -148,9 +148,7 @@ def _build_from_local_file(
     if strict_type_validation and detected_file_type.value != specified_type:
         raise ValueError("Detected file type does not match the specified type. Please verify the file.")
 
-    file_type = (
-        FileType(specified_type) if specified_type and specified_type != FileType.CUSTOM.value else detected_file_type
-    )
+    file_type = FileType(specified_type) if specified_type and specified_type != FileType.CUSTOM else detected_file_type
 
     return File(
         id=mapping.get("id"),
@@ -199,9 +197,7 @@ def _build_from_remote_url(
             raise ValueError("Detected file type does not match the specified type. Please verify the file.")
 
         file_type = (
-            FileType(specified_type)
-            if specified_type and specified_type != FileType.CUSTOM.value
-            else detected_file_type
+            FileType(specified_type) if specified_type and specified_type != FileType.CUSTOM else detected_file_type
         )
 
         return File(
@@ -286,9 +282,7 @@ def _build_from_tool_file(
     if strict_type_validation and specified_type and detected_file_type.value != specified_type:
         raise ValueError("Detected file type does not match the specified type. Please verify the file.")
 
-    file_type = (
-        FileType(specified_type) if specified_type and specified_type != FileType.CUSTOM.value else detected_file_type
-    )
+    file_type = FileType(specified_type) if specified_type and specified_type != FileType.CUSTOM else detected_file_type
 
     return File(
         id=mapping.get("id"),