feat: enhance performance logging and caching in various components

- Introduced slow callback logging in FastAPI to identify blocking calls.
- Added performance logging for agent creation and tool loading processes.
- Implemented caching for MCP tools to reduce redundant server calls.
- Enhanced sandbox management with in-process caching for improved efficiency.
- Refactored several functions for better readability and performance tracking.
- Updated tests to ensure proper functionality of new features and optimizations.

surfsense_backend/app/routes/new_chat_routes.py

@@ -10,6 +10,8 @@ These endpoints support the ThreadHistoryAdapter pattern from assistant-ui:
 - POST /threads/{thread_id}/messages - Append message
 """
 
+import asyncio
+import logging
 from datetime import UTC, datetime
 
 from fastapi import APIRouter, Depends, HTTPException, Request
@@ -52,10 +54,8 @@ from app.tasks.chat.stream_new_chat import stream_new_chat, stream_resume_chat
 from app.users import current_active_user
 from app.utils.rbac import check_permission
 
-import asyncio
-import logging
-
 _logger = logging.getLogger(__name__)
+_background_tasks: set[asyncio.Task] = set()
 
 router = APIRouter()
 
@@ -75,15 +75,25 @@ def _try_delete_sandbox(thread_id: int) -> None:
         try:
             await delete_sandbox(thread_id)
         except Exception:
-            _logger.warning("Background sandbox delete failed for thread %s", thread_id, exc_info=True)
+            _logger.warning(
+                "Background sandbox delete failed for thread %s",
+                thread_id,
+                exc_info=True,
+            )
         try:
             delete_local_sandbox_files(thread_id)
         except Exception:
-            _logger.warning("Local sandbox file cleanup failed for thread %s", thread_id, exc_info=True)
+            _logger.warning(
+                "Local sandbox file cleanup failed for thread %s",
+                thread_id,
+                exc_info=True,
+            )
 
     try:
         loop = asyncio.get_running_loop()
-        loop.create_task(_bg())
+        task = loop.create_task(_bg())
+        _background_tasks.add(task)
+        task.add_done_callback(_background_tasks.discard)
     except RuntimeError:
         pass
 

surfsense_backend/app/routes/sandbox_routes.py

@@ -87,7 +87,7 @@ async def download_sandbox_file(
     # Fall back to live sandbox download
     try:
         sandbox = await get_or_create_sandbox(thread_id)
-        raw_sandbox = sandbox._sandbox  # noqa: SLF001
+        raw_sandbox = sandbox._sandbox
         content: bytes = await asyncio.to_thread(raw_sandbox.fs.download_file, path)
     except Exception as exc:
         logger.warning("Sandbox file download failed for %s: %s", path, exc)

surfsense_backend/app/routes/search_source_connectors_routes.py

@@ -2735,7 +2735,10 @@ async def create_mcp_connector(
             f"for user {user.id} in search space {search_space_id}"
         )
 
-        # Convert to read schema
+        from app.agents.new_chat.tools.mcp_tool import invalidate_mcp_tools_cache
+
+        invalidate_mcp_tools_cache(search_space_id)
+
         connector_read = SearchSourceConnectorRead.model_validate(db_connector)
         return MCPConnectorRead.from_connector(connector_read)
 
@@ -2910,6 +2913,10 @@ async def update_mcp_connector(
 
         logger.info(f"Updated MCP connector {connector_id}")
 
+        from app.agents.new_chat.tools.mcp_tool import invalidate_mcp_tools_cache
+
+        invalidate_mcp_tools_cache(connector.search_space_id)
+
         connector_read = SearchSourceConnectorRead.model_validate(connector)
         return MCPConnectorRead.from_connector(connector_read)
 
@@ -2960,9 +2967,14 @@ async def delete_mcp_connector(
             "You don't have permission to delete this connector",
         )
 
+        search_space_id = connector.search_space_id
         await session.delete(connector)
         await session.commit()
 
+        from app.agents.new_chat.tools.mcp_tool import invalidate_mcp_tools_cache
+
+        invalidate_mcp_tools_cache(search_space_id)
+
         logger.info(f"Deleted MCP connector {connector_id}")
 
     except HTTPException: