refactor(api): drop unused config parameter from build_from_message_file

Both helpers in factories/file_factory/message_files.py are only invoked
from replay paths that intentionally skip re-validation, so the config
argument was always None. Remove it from the signatures and update the
two call sites; module docstring records the design intent.

api/core/agent/base_agent_runner.py

@@ -529,11 +529,9 @@ class BaseAgentRunner(AppRunner):
         image_detail_config = file_extra_config.image_config.detail if file_extra_config.image_config else None
         image_detail_config = image_detail_config or ImagePromptMessageContent.DETAIL.LOW
 
-        # History files were validated on upload; replaying does not re-validate.
         file_objs = file_factory.build_from_message_files(
             message_files=files,
             tenant_id=self.tenant_id,
-            config=None,
             access_controller=_file_access_controller,
         )
         if not file_objs:

api/core/memory/token_buffer_memory.py

@@ -86,13 +86,10 @@ class TokenBufferMemory:
 
         detail = ImagePromptMessageContent.DETAIL.HIGH
         if file_extra_config and app_record:
-            # History files were validated on upload; replaying does not re-validate.
-            # See models/utils/file_input_compat.py for the same pattern.
             file_objs = [
                 file_factory.build_from_message_file(
                     message_file=message_file,
                     tenant_id=app_record.tenant_id,
-                    config=None,
                     access_controller=_file_access_controller,
                 )
                 for message_file in message_files

api/factories/file_factory/message_files.py

@@ -1,11 +1,18 @@
-"""Adapters from persisted message files to graph-layer file values."""
+"""Adapters from persisted message files to graph-layer file values.
+
+Replay paths only: files in conversation history were validated at upload time,
+so these helpers deliberately do not accept (or forward) a ``FileUploadConfig`` —
+re-validation here would break replays whenever workflow ``file_upload`` config
+drifts between rounds. Mirrors ``build_file_from_stored_mapping`` in
+``models/utils/file_input_compat.py``.
+"""
 
 from __future__ import annotations
 
 from collections.abc import Sequence
 
 from core.app.file_access import FileAccessControllerProtocol
-from graphon.file import File, FileBelongsTo, FileTransferMethod, FileUploadConfig
+from graphon.file import File, FileBelongsTo, FileTransferMethod
 from models import MessageFile
 
 from .builders import build_from_mapping
@@ -15,14 +22,12 @@ def build_from_message_files(
     *,
     message_files: Sequence[MessageFile],
     tenant_id: str,
-    config: FileUploadConfig | None = None,
     access_controller: FileAccessControllerProtocol,
 ) -> Sequence[File]:
     return [
         build_from_message_file(
             message_file=message_file,
             tenant_id=tenant_id,
-            config=config,
             access_controller=access_controller,
         )
         for message_file in message_files
@@ -34,7 +39,6 @@ def build_from_message_file(
     *,
     message_file: MessageFile,
     tenant_id: str,
-    config: FileUploadConfig | None,
     access_controller: FileAccessControllerProtocol,
 ) -> File:
     mapping = {
@@ -54,6 +58,5 @@ def build_from_message_file(
     return build_from_mapping(
         mapping=mapping,
         tenant_id=tenant_id,
-        config=config,
         access_controller=access_controller,
     )

api/tests/unit_tests/core/memory/test_token_buffer_memory.py

@@ -198,10 +198,11 @@ class TestBuildPromptMessageWithFiles:
         assert isinstance(result.content[-1], TextPromptMessageContent)
         assert result.content[-1].data == "user text"
 
-    def test_replay_skips_revalidation_by_passing_config_none(self):
+    def test_replay_does_not_pass_config_to_file_factory(self):
         """Replay contract: history files were validated on upload, so this
-        path must call build_from_message_file with config=None. Reverting
-        this would re-trigger ENG-244 whenever workflow config drifts."""
+        path must not forward a FileUploadConfig. The factory's signature
+        no longer accepts ``config``; this test guards against a future
+        regression that re-introduces it."""
         conv = _make_conversation(AppMode.CHAT)
         mem = TokenBufferMemory(conversation=conv, model_instance=_make_model_instance())
 
@@ -237,7 +238,7 @@ class TestBuildPromptMessageWithFiles:
             )
 
         mock_build.assert_called_once()
-        assert mock_build.call_args.kwargs["config"] is None
+        assert "config" not in mock_build.call_args.kwargs
 
     @pytest.mark.parametrize("mode", [AppMode.CHAT, AppMode.AGENT_CHAT, AppMode.COMPLETION])
     def test_chat_mode_with_files_assistant_message(self, mode):