refactor(multi-agent): add shared middleware factory per concept

surfsense_backend/app/agents/multi_agent_chat/middleware/shared/anthropic_cache.py

@@ -0,0 +1,9 @@
+"""Anthropic prompt caching annotations on system/tool/message blocks."""
+
+from __future__ import annotations
+
+from langchain_anthropic.middleware import AnthropicPromptCachingMiddleware
+
+
+def build_anthropic_cache_mw() -> AnthropicPromptCachingMiddleware:
+    return AnthropicPromptCachingMiddleware(unsupported_model_behavior="ignore")

surfsense_backend/app/agents/multi_agent_chat/middleware/shared/compaction.py

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+"""Context-window summarization with SurfSense protected sections."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from deepagents.backends import StateBackend
+from langchain_core.language_models import BaseChatModel
+
+from app.agents.new_chat.middleware import create_surfsense_compaction_middleware
+
+
+def build_compaction_mw(llm: BaseChatModel) -> Any:
+    return create_surfsense_compaction_middleware(llm, StateBackend)

surfsense_backend/app/agents/multi_agent_chat/middleware/shared/file_intent.py

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+"""File-intent classifier that gates strict write contracts."""
+
+from __future__ import annotations
+
+from langchain_core.language_models import BaseChatModel
+
+from app.agents.new_chat.middleware import FileIntentMiddleware
+
+
+def build_file_intent_mw(llm: BaseChatModel) -> FileIntentMiddleware:
+    return FileIntentMiddleware(llm=llm)

surfsense_backend/app/agents/multi_agent_chat/middleware/shared/filesystem.py

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+"""SurfSense filesystem tools/middleware."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from app.agents.new_chat.filesystem_selection import FilesystemMode
+from app.agents.new_chat.middleware import SurfSenseFilesystemMiddleware
+
+
+def build_filesystem_mw(
+    *,
+    backend_resolver: Any,
+    filesystem_mode: FilesystemMode,
+    search_space_id: int,
+    user_id: str | None,
+    thread_id: int | None,
+) -> SurfSenseFilesystemMiddleware:
+    return SurfSenseFilesystemMiddleware(
+        backend=backend_resolver,
+        filesystem_mode=filesystem_mode,
+        search_space_id=search_space_id,
+        created_by_id=user_id,
+        thread_id=thread_id,
+    )

surfsense_backend/app/agents/multi_agent_chat/middleware/shared/memory.py

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+"""User/team memory injection prepended to the conversation."""
+
+from __future__ import annotations
+
+from app.agents.new_chat.middleware import MemoryInjectionMiddleware
+from app.db import ChatVisibility
+
+
+def build_memory_mw(
+    *,
+    user_id: str | None,
+    search_space_id: int,
+    visibility: ChatVisibility,
+) -> MemoryInjectionMiddleware:
+    return MemoryInjectionMiddleware(
+        user_id=user_id,
+        search_space_id=search_space_id,
+        thread_visibility=visibility,
+    )

surfsense_backend/app/agents/multi_agent_chat/middleware/shared/patch_tool_calls.py

@@ -0,0 +1,9 @@
+"""Repair dangling tool-call sequences before each agent turn."""
+
+from __future__ import annotations
+
+from deepagents.middleware.patch_tool_calls import PatchToolCallsMiddleware
+
+
+def build_patch_tool_calls_mw() -> PatchToolCallsMiddleware:
+    return PatchToolCallsMiddleware()

surfsense_backend/app/agents/multi_agent_chat/middleware/shared/todos.py

@@ -0,0 +1,9 @@
+"""Todo-list middleware (each consumer needs its own instance)."""
+
+from __future__ import annotations
+
+from langchain.agents.middleware import TodoListMiddleware
+
+
+def build_todos_mw() -> TodoListMiddleware:
+    return TodoListMiddleware()