refactor(agents): consolidate chat runtime infra under chat/runtime

Move the lower-level runtime/infra modules out of multi_agent_chat/shared/
(they were never used by subagents, so they failed the shared-by-all-siblings
rule) and unify them with the already-relocated checkpointer:

  agents/runtime/                      -> agents/chat/runtime/
  mac/shared/errors.py                 -> chat/runtime/errors.py
  mac/shared/llm_config.py             -> chat/runtime/llm_config.py
  mac/shared/prompt_caching.py         -> chat/runtime/prompt_caching.py
  mac/shared/mention_resolver.py       -> chat/runtime/mention_resolver.py
  mac/shared/path_resolver.py          -> chat/runtime/path_resolver.py

These sit below the agent packages: the boundary + agent factory + shared
middleware depend on them, and they import no agent code (acyclic).

surfsense_backend/app/agents/chat/multi_agent_chat/main_agent/middleware/anonymous_document/middleware.py

@@ -24,13 +24,13 @@ from typing import Any
 from langchain.agents.middleware import AgentMiddleware, AgentState
 from langgraph.runtime import Runtime
 
-from app.agents.chat.multi_agent_chat.shared.path_resolver import (
-    DOCUMENTS_ROOT,
-    safe_filename,
-)
 from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
     SurfSenseFilesystemState,
 )
+from app.agents.chat.runtime.path_resolver import (
+    DOCUMENTS_ROOT,
+    safe_filename,
+)
 
 logger = logging.getLogger(__name__)
 

surfsense_backend/app/agents/chat/multi_agent_chat/main_agent/middleware/knowledge_tree/middleware.py

@@ -34,15 +34,15 @@ from langgraph.runtime import Runtime
 from sqlalchemy import select
 
 from app.agents.chat.multi_agent_chat.shared.filesystem_selection import FilesystemMode
-from app.agents.chat.multi_agent_chat.shared.path_resolver import (
+from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
+from app.agents.chat.runtime.path_resolver import (
     DOCUMENTS_ROOT,
     PathIndex,
     build_path_index,
     doc_to_virtual_path,
 )
-from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
-    SurfSenseFilesystemState,
-)
 from app.db import Document, shielded_async_session
 from app.utils.perf import get_perf_logger
 

surfsense_backend/app/agents/chat/multi_agent_chat/main_agent/runtime/factory.py

@@ -20,13 +20,9 @@ from app.agents.chat.multi_agent_chat.shared.filesystem_selection import (
     FilesystemMode,
     FilesystemSelection,
 )
-from app.agents.chat.multi_agent_chat.shared.llm_config import AgentConfig
 from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.resolver import (
     build_backend_resolver,
 )
-from app.agents.chat.multi_agent_chat.shared.prompt_caching import (
-    apply_litellm_prompt_caching,
-)
 from app.agents.chat.multi_agent_chat.subagents import (
     get_subagents_to_exclude,
     main_prompt_registry_subagent_lines,
@@ -34,6 +30,10 @@ from app.agents.chat.multi_agent_chat.subagents import (
 from app.agents.chat.multi_agent_chat.subagents.mcp_tools.index import (
     load_mcp_tools_by_connector,
 )
+from app.agents.chat.runtime.llm_config import AgentConfig
+from app.agents.chat.runtime.prompt_caching import (
+    apply_litellm_prompt_caching,
+)
 from app.db import ChatVisibility
 from app.services.connector_service import ConnectorService
 from app.services.user_tool_allowlist import (

surfsense_backend/app/agents/chat/multi_agent_chat/shared/middleware/busy_mutex.py

@@ -20,7 +20,7 @@ What this provides:
   tools can poll to abort cooperatively. The event is reset between
   turns. Tools should check ``runtime.context.cancel_event.is_set()``
   in tight inner loops.
-- A typed :class:`~app.agents.chat.multi_agent_chat.shared.errors.BusyError` raised when a
+- A typed :class:`~app.agents.chat.runtime.errors.BusyError` raised when a
   second turn arrives while the lock is held.
 
 Note: SurfSense's ``stream_new_chat`` is the call site that should
@@ -46,7 +46,7 @@ from langchain.agents.middleware.types import (
 from langgraph.config import get_config
 from langgraph.runtime import Runtime
 
-from app.agents.chat.multi_agent_chat.shared.errors import BusyError
+from app.agents.chat.runtime.errors import BusyError
 
 logger = logging.getLogger(__name__)
 

surfsense_backend/app/agents/chat/multi_agent_chat/shared/middleware/filesystem/backends/kb_postgres.py

@@ -45,7 +45,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.document_xml import (
     build_document_xml,
 )
-from app.agents.chat.multi_agent_chat.shared.path_resolver import (
+from app.agents.chat.runtime.path_resolver import (
     DOCUMENTS_ROOT,
     build_path_index,
     doc_to_virtual_path,

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

@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 from app.agents.chat.multi_agent_chat.shared.filesystem_selection import FilesystemMode
-from app.agents.chat.multi_agent_chat.shared.path_resolver import DOCUMENTS_ROOT
+from app.agents.chat.runtime.path_resolver import DOCUMENTS_ROOT
 
 
 def is_cloud(mode: FilesystemMode) -> bool:

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

@@ -11,10 +11,10 @@ from typing import TYPE_CHECKING
 
 from langchain.tools import ToolRuntime
 
-from app.agents.chat.multi_agent_chat.shared.path_resolver import DOCUMENTS_ROOT
 from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
     SurfSenseFilesystemState,
 )
+from app.agents.chat.runtime.path_resolver import DOCUMENTS_ROOT
 
 from ..shared.paths import TEMP_PREFIX, basename
 from .mode import is_cloud

surfsense_backend/app/agents/chat/multi_agent_chat/shared/middleware/filesystem/tools/cd/index.py

@@ -10,10 +10,10 @@ from langchain_core.messages import ToolMessage
 from langchain_core.tools import BaseTool, StructuredTool
 from langgraph.types import Command
 
-from app.agents.chat.multi_agent_chat.shared.path_resolver import DOCUMENTS_ROOT
 from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
     SurfSenseFilesystemState,
 )
+from app.agents.chat.runtime.path_resolver import DOCUMENTS_ROOT
 
 from ...middleware.async_dispatch import run_async_blocking
 from ...middleware.path_resolution import resolve_relative

surfsense_backend/app/agents/chat/multi_agent_chat/shared/middleware/filesystem/tools/mkdir/index.py

@@ -11,10 +11,10 @@ from langchain_core.messages import ToolMessage
 from langchain_core.tools import BaseTool, StructuredTool
 from langgraph.types import Command
 
-from app.agents.chat.multi_agent_chat.shared.path_resolver import DOCUMENTS_ROOT
 from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
     SurfSenseFilesystemState,
 )
+from app.agents.chat.runtime.path_resolver import DOCUMENTS_ROOT
 
 from ...middleware.async_dispatch import run_async_blocking
 from ...middleware.mode import is_cloud

surfsense_backend/app/agents/chat/multi_agent_chat/shared/middleware/filesystem/tools/move_file/helpers.py

@@ -11,11 +11,11 @@ from langgraph.types import Command
 from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.kb_postgres import (
     KBPostgresBackend,
 )
-from app.agents.chat.multi_agent_chat.shared.path_resolver import DOCUMENTS_ROOT
 from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
     SurfSenseFilesystemState,
 )
 from app.agents.chat.multi_agent_chat.shared.state.reducers import _CLEAR
+from app.agents.chat.runtime.path_resolver import DOCUMENTS_ROOT
 
 if TYPE_CHECKING:
     from ...middleware import SurfSenseFilesystemMiddleware

surfsense_backend/app/agents/chat/multi_agent_chat/shared/middleware/filesystem/tools/rm/helpers.py

@@ -15,11 +15,11 @@ from langgraph.types import Command
 from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.kb_postgres import (
     KBPostgresBackend,
 )
-from app.agents.chat.multi_agent_chat.shared.path_resolver import DOCUMENTS_ROOT
 from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
     SurfSenseFilesystemState,
 )
 from app.agents.chat.multi_agent_chat.shared.state.reducers import _CLEAR
+from app.agents.chat.runtime.path_resolver import DOCUMENTS_ROOT
 
 if TYPE_CHECKING:
     from ...middleware import SurfSenseFilesystemMiddleware

surfsense_backend/app/agents/chat/multi_agent_chat/shared/middleware/filesystem/tools/rmdir/helpers.py

@@ -16,11 +16,11 @@ from langgraph.types import Command
 from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.kb_postgres import (
     KBPostgresBackend,
 )
-from app.agents.chat.multi_agent_chat.shared.path_resolver import DOCUMENTS_ROOT
 from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
     SurfSenseFilesystemState,
 )
 from app.agents.chat.multi_agent_chat.shared.state.reducers import _CLEAR
+from app.agents.chat.runtime.path_resolver import DOCUMENTS_ROOT
 
 from ...middleware.path_resolution import current_cwd
 from ...shared.paths import is_ancestor_of

surfsense_backend/app/agents/chat/multi_agent_chat/shared/middleware/kb_persistence.py

@@ -47,12 +47,6 @@ from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.agents.chat.multi_agent_chat.shared.feature_flags import get_flags
 from app.agents.chat.multi_agent_chat.shared.filesystem_selection import FilesystemMode
-from app.agents.chat.multi_agent_chat.shared.path_resolver import (
-    DOCUMENTS_ROOT,
-    parse_documents_path,
-    safe_folder_segment,
-    virtual_path_to_doc,
-)
 from app.agents.chat.multi_agent_chat.shared.receipts.receipt import (
     Receipt,
     make_receipt,
@@ -61,6 +55,12 @@ from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
     SurfSenseFilesystemState,
 )
 from app.agents.chat.multi_agent_chat.shared.state.reducers import _CLEAR
+from app.agents.chat.runtime.path_resolver import (
+    DOCUMENTS_ROOT,
+    parse_documents_path,
+    safe_folder_segment,
+    virtual_path_to_doc,
+)
 from app.db import (
     AgentActionLog,
     Chunk,

surfsense_backend/app/agents/chat/multi_agent_chat/shared/middleware/knowledge_search.py

@@ -47,14 +47,14 @@ from app.agents.chat.multi_agent_chat.shared.date_filters import (
 )
 from app.agents.chat.multi_agent_chat.shared.feature_flags import get_flags
 from app.agents.chat.multi_agent_chat.shared.filesystem_selection import FilesystemMode
-from app.agents.chat.multi_agent_chat.shared.path_resolver import (
+from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
+from app.agents.chat.runtime.path_resolver import (
     PathIndex,
     build_path_index,
     doc_to_virtual_path,
 )
-from app.agents.chat.multi_agent_chat.shared.state.filesystem_state import (
-    SurfSenseFilesystemState,
-)
 from app.db import (
     NATIVE_TO_LEGACY_DOCTYPE,
     Chunk,

surfsense_backend/app/agents/chat/multi_agent_chat/shared/middleware/permissions/deny.py

@@ -11,8 +11,8 @@ from typing import Any
 
 from langchain_core.messages import ToolMessage
 
-from app.agents.chat.multi_agent_chat.shared.errors import StreamingError
 from app.agents.chat.multi_agent_chat.shared.permissions import Rule
+from app.agents.chat.runtime.errors import StreamingError
 
 
 def build_deny_message(tool_call: dict[str, Any], rule: Rule) -> ToolMessage:

surfsense_backend/app/agents/chat/multi_agent_chat/shared/middleware/permissions/middleware/core.py

@@ -26,8 +26,8 @@ from langchain_core.messages import AIMessage, ToolMessage
 from langchain_core.tools import BaseTool
 from langgraph.runtime import Runtime
 
-from app.agents.chat.multi_agent_chat.shared.errors import CorrectedError, RejectedError
 from app.agents.chat.multi_agent_chat.shared.permissions import Ruleset
+from app.agents.chat.runtime.errors import CorrectedError, RejectedError
 from app.services.user_tool_allowlist import TrustedToolSaver
 
 from ..ask.edit import merge_edited_args

surfsense_backend/app/agents/chat/runtime/__init__.py

@@ -0,0 +1,16 @@
+"""Lower-level runtime infrastructure for the chat agents.
+
+Modules here are the foundation layer used to *run* chat agents: wired by the
+boundary (routes/tasks) and/or imported by the agent factory + shared
+middleware, but never part of any single agent's domain logic. Because they sit
+below the agent packages, both the boundary and the agents may depend on them
+(forward dependency), while they never import agent code.
+
+Contents:
+- ``checkpointer``      LangGraph Postgres checkpoint saver (boundary lifespan)
+- ``llm_config``        LLM provider/model configuration resolution
+- ``prompt_caching``    LiteLLM prompt-caching configuration
+- ``errors``            agent-runtime error contracts (raised by MW, caught at boundary)
+- ``path_resolver``     filesystem path resolution helpers
+- ``mention_resolver``  @-mention resolution helpers
+"""

surfsense_backend/app/agents/chat/runtime/llm_config.py

@@ -27,7 +27,7 @@ from litellm import get_model_info
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.agents.chat.multi_agent_chat.shared.prompt_caching import (
+from app.agents.chat.runtime.prompt_caching import (
     apply_litellm_prompt_caching,
 )
 from app.services.llm_router_service import (

surfsense_backend/app/agents/chat/runtime/mention_resolver.py

@@ -36,7 +36,7 @@ from dataclasses import dataclass, field
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.agents.chat.multi_agent_chat.shared.path_resolver import (
+from app.agents.chat.runtime.path_resolver import (
     DOCUMENTS_ROOT,
     build_path_index,
     doc_to_virtual_path,

surfsense_backend/app/agents/chat/runtime/prompt_caching.py

@@ -68,7 +68,7 @@ from typing import TYPE_CHECKING, Any
 from langchain_core.language_models import BaseChatModel
 
 if TYPE_CHECKING:
-    from app.agents.chat.multi_agent_chat.shared.llm_config import AgentConfig
+    from app.agents.chat.runtime.llm_config import AgentConfig
 
 logger = logging.getLogger(__name__)
 

surfsense_backend/app/agents/runtime/__init__.py

@@ -1,6 +0,0 @@
-"""Agent runtime infrastructure wired by the boundary (not agent code).
-
-Modules here are cross-agent infra used to *run* agents (e.g. the LangGraph
-Postgres checkpointer), as opposed to ``app/agents/shared/`` which holds code
-imported by 2+ sibling agent packages.
-"""

surfsense_backend/app/app.py

@@ -23,7 +23,7 @@ from starlette.requests import Request as StarletteRequest
 from starlette.responses import Response as StarletteResponse
 from uvicorn.middleware.proxy_headers import ProxyHeadersMiddleware
 
-from app.agents.runtime.checkpointer import (
+from app.agents.chat.runtime.checkpointer import (
     close_checkpointer,
     setup_checkpointer_tables,
 )

surfsense_backend/app/automations/actions/builtin/agent_task/invoke.py

@@ -11,7 +11,7 @@ from langgraph.types import Command
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.agents.chat.multi_agent_chat import create_multi_agent_chat_deep_agent
-from app.agents.chat.multi_agent_chat.shared.mention_resolver import (
+from app.agents.chat.runtime.mention_resolver import (
     resolve_mentions,
     substitute_in_text,
 )

surfsense_backend/app/automations/services/model_policy.py

@@ -39,7 +39,7 @@ def _is_premium_global(kind: ModelKind, config_id: int) -> bool:
 
     cfg: dict | None = None
     if kind == "llm":
-        from app.agents.chat.multi_agent_chat.shared.llm_config import (
+        from app.agents.chat.runtime.llm_config import (
             load_global_llm_config_by_id,
         )
 

surfsense_backend/app/routes/anonymous_chat_routes.py

@@ -236,7 +236,7 @@ async def stream_anonymous_chat(
             detail="No-login mode is not enabled.",
         )
 
-    from app.agents.chat.multi_agent_chat.shared.llm_config import (
+    from app.agents.chat.runtime.llm_config import (
         AgentConfig,
         create_chat_litellm_from_agent_config,
     )
@@ -352,7 +352,7 @@ async def stream_anonymous_chat(
         from langchain_core.messages import AIMessage, HumanMessage
 
         from app.agents.chat.anonymous_chat import create_anonymous_chat_agent
-        from app.agents.runtime.checkpointer import get_checkpointer
+        from app.agents.chat.runtime.checkpointer import get_checkpointer
         from app.db import shielded_async_session
         from app.services.new_streaming_service import VercelStreamingService
         from app.services.token_tracking_service import start_turn

surfsense_backend/app/routes/documents_routes.py

@@ -7,7 +7,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.future import select
 from sqlalchemy.orm import selectinload
 
-from app.agents.chat.multi_agent_chat.shared.path_resolver import virtual_path_to_doc
+from app.agents.chat.runtime.path_resolver import virtual_path_to_doc
 from app.db import (
     Chunk,
     Document,

surfsense_backend/app/routes/new_chat_routes.py

@@ -1934,7 +1934,7 @@ async def regenerate_response(
     """
     from langchain_core.messages import HumanMessage
 
-    from app.agents.runtime.checkpointer import get_checkpointer
+    from app.agents.chat.runtime.checkpointer import get_checkpointer
 
     try:
         # Verify thread exists and user has permission

surfsense_backend/app/services/llm_service.py

@@ -204,7 +204,7 @@ async def validate_llm_config(
         if litellm_params:
             litellm_kwargs.update(litellm_params)
 
-        from app.agents.chat.multi_agent_chat.shared.llm_config import (
+        from app.agents.chat.runtime.llm_config import (
             SanitizedChatLiteLLM,
         )
 
@@ -381,7 +381,7 @@ async def get_search_space_llm_instance(
             if disable_streaming:
                 litellm_kwargs["disable_streaming"] = True
 
-            from app.agents.chat.multi_agent_chat.shared.llm_config import (
+            from app.agents.chat.runtime.llm_config import (
                 SanitizedChatLiteLLM,
             )
 
@@ -462,7 +462,7 @@ async def get_search_space_llm_instance(
         if disable_streaming:
             litellm_kwargs["disable_streaming"] = True
 
-        from app.agents.chat.multi_agent_chat.shared.llm_config import (
+        from app.agents.chat.runtime.llm_config import (
             SanitizedChatLiteLLM,
         )
 
@@ -586,7 +586,7 @@ async def get_vision_llm(
             if global_cfg.get("litellm_params"):
                 litellm_kwargs.update(global_cfg["litellm_params"])
 
-            from app.agents.chat.multi_agent_chat.shared.llm_config import (
+            from app.agents.chat.runtime.llm_config import (
                 SanitizedChatLiteLLM,
             )
 
@@ -642,7 +642,7 @@ async def get_vision_llm(
         if vision_cfg.litellm_params:
             litellm_kwargs.update(vision_cfg.litellm_params)
 
-        from app.agents.chat.multi_agent_chat.shared.llm_config import (
+        from app.agents.chat.runtime.llm_config import (
             SanitizedChatLiteLLM,
         )
 
@@ -689,7 +689,7 @@ def get_planner_llm() -> ChatLiteLLM | None:
     Callers MUST fall back to their chat LLM when this returns ``None`` so
     deployments without a planner config keep working unchanged.
     """
-    from app.agents.chat.multi_agent_chat.shared.llm_config import (
+    from app.agents.chat.runtime.llm_config import (
         create_chat_litellm_from_config,
     )
 

surfsense_backend/app/services/provider_capabilities.py

@@ -53,7 +53,7 @@ logger = logging.getLogger(__name__)
 #
 # Owned here because ``app.services.provider_capabilities`` is the
 # only edge that's safe to call from ``app.config``'s YAML loader at
-# class-body init time. ``app.agents.chat.multi_agent_chat.shared.llm_config`` re-exports
+# class-body init time. ``app.agents.chat.runtime.llm_config`` re-exports
 # this constant under the historical ``PROVIDER_MAP`` name; placing the
 # map there directly would re-introduce the
 # ``app.config -> ... -> deliverables/tools/generate_image ->

surfsense_backend/app/services/revert_service.py

@@ -38,7 +38,7 @@ from typing import Any, Literal
 from sqlalchemy import delete, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.agents.chat.multi_agent_chat.shared.path_resolver import (
+from app.agents.chat.runtime.path_resolver import (
     DOCUMENTS_ROOT,
     safe_filename,
     safe_folder_segment,

surfsense_backend/app/tasks/chat/streaming/agent/builder.py

@@ -12,7 +12,7 @@ from typing import Any
 from app.agents.chat.multi_agent_chat.shared.filesystem_selection import (
     FilesystemSelection,
 )
-from app.agents.chat.multi_agent_chat.shared.llm_config import AgentConfig
+from app.agents.chat.runtime.llm_config import AgentConfig
 from app.db import ChatVisibility
 from app.services.connector_service import ConnectorService
 

surfsense_backend/app/tasks/chat/streaming/errors/classifier.py

@@ -7,11 +7,11 @@ import logging
 import time
 from typing import Any, Literal
 
-from app.agents.chat.multi_agent_chat.shared.errors import BusyError
 from app.agents.chat.multi_agent_chat.shared.middleware.busy_mutex import (
     get_cancel_state,
     is_cancel_requested,
 )
+from app.agents.chat.runtime.errors import BusyError
 
 TURN_CANCELLING_INITIAL_DELAY_MS = 200
 TURN_CANCELLING_BACKOFF_FACTOR = 2

surfsense_backend/app/tasks/chat/streaming/flows/new_chat/input_state.py

@@ -29,7 +29,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.future import select
 
 from app.agents.chat.multi_agent_chat.shared.filesystem_selection import FilesystemMode
-from app.agents.chat.multi_agent_chat.shared.mention_resolver import (
+from app.agents.chat.runtime.mention_resolver import (
     resolve_mentions,
     substitute_in_text,
 )

surfsense_backend/app/tasks/chat/streaming/flows/new_chat/llm_capability.py

@@ -15,7 +15,7 @@ tells the user what to change.
 
 from __future__ import annotations
 
-from app.agents.chat.multi_agent_chat.shared.llm_config import AgentConfig
+from app.agents.chat.runtime.llm_config import AgentConfig
 from app.observability import otel as ot
 
 

surfsense_backend/app/tasks/chat/streaming/flows/new_chat/title_gen.py

@@ -30,7 +30,7 @@ from app.prompts import TITLE_GENERATION_PROMPT
 from app.services.new_streaming_service import VercelStreamingService
 
 if TYPE_CHECKING:
-    from app.agents.chat.multi_agent_chat.shared.llm_config import AgentConfig
+    from app.agents.chat.runtime.llm_config import AgentConfig
     from app.services.token_tracking_service import TokenAccumulator
 
 

surfsense_backend/app/tasks/chat/streaming/flows/shared/llm_bundle.py

@@ -14,7 +14,7 @@ from typing import Any
 
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.agents.chat.multi_agent_chat.shared.llm_config import (
+from app.agents.chat.runtime.llm_config import (
     AgentConfig,
     create_chat_litellm_from_agent_config,
     create_chat_litellm_from_config,

surfsense_backend/app/tasks/chat/streaming/flows/shared/pre_stream_setup.py

@@ -4,7 +4,7 @@ from __future__ import annotations
 
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.agents.runtime.checkpointer import get_checkpointer
+from app.agents.chat.runtime.checkpointer import get_checkpointer
 from app.db import SearchSourceConnectorType
 from app.services.connector_service import ConnectorService
 
@@ -33,7 +33,7 @@ async def setup_connector_and_firecrawl(
 async def get_chat_checkpointer():
     """Resolve the PostgreSQL checkpointer for persistent conversation memory.
 
-    Thin wrapper around ``app.agents.runtime.checkpointer.get_checkpointer`` so
+    Thin wrapper around ``app.agents.chat.runtime.checkpointer.get_checkpointer`` so
     flow orchestrators can rely on a streaming-local symbol and we have a hook
     point if the checkpointer source ever needs to vary per flow.
     """

surfsense_backend/app/tasks/chat/streaming/flows/shared/premium_quota.py

@@ -19,7 +19,7 @@ from dataclasses import dataclass
 from typing import TYPE_CHECKING
 from uuid import UUID
 
-from app.agents.chat.multi_agent_chat.shared.llm_config import AgentConfig
+from app.agents.chat.runtime.llm_config import AgentConfig
 from app.db import shielded_async_session
 
 if TYPE_CHECKING:

surfsense_backend/app/tasks/chat/streaming/flows/shared/terminal_error.py

@@ -14,7 +14,7 @@ import traceback
 from collections.abc import Iterator
 from typing import Any, Literal
 
-from app.agents.chat.multi_agent_chat.shared.errors import BusyError
+from app.agents.chat.runtime.errors import BusyError
 from app.observability import metrics as ot_metrics, otel as ot
 from app.services.new_streaming_service import VercelStreamingService
 from app.tasks.chat.streaming.errors.classifier import classify_stream_exception

surfsense_backend/tests/e2e/run_backend.py

@@ -239,11 +239,11 @@ def _patch_llm_bindings() -> None:
 
     chat_targets = [
         (
-            "app.agents.chat.multi_agent_chat.shared.llm_config.create_chat_litellm_from_agent_config",
+            "app.agents.chat.runtime.llm_config.create_chat_litellm_from_agent_config",
             fake_create_chat_litellm_from_agent_config,
         ),
         (
-            "app.agents.chat.multi_agent_chat.shared.llm_config.create_chat_litellm_from_config",
+            "app.agents.chat.runtime.llm_config.create_chat_litellm_from_config",
             fake_create_chat_litellm_from_config,
         ),
         (

surfsense_backend/tests/e2e/run_celery.py

@@ -212,11 +212,11 @@ def _patch_llm_bindings() -> None:
 
     chat_targets = [
         (
-            "app.agents.chat.multi_agent_chat.shared.llm_config.create_chat_litellm_from_agent_config",
+            "app.agents.chat.runtime.llm_config.create_chat_litellm_from_agent_config",
             fake_create_chat_litellm_from_agent_config,
         ),
         (
-            "app.agents.chat.multi_agent_chat.shared.llm_config.create_chat_litellm_from_config",
+            "app.agents.chat.runtime.llm_config.create_chat_litellm_from_config",
             fake_create_chat_litellm_from_config,
         ),
         (

surfsense_backend/tests/unit/agents/new_chat/test_busy_mutex.py

@@ -4,7 +4,6 @@ from __future__ import annotations
 
 import pytest
 
-from app.agents.chat.multi_agent_chat.shared.errors import BusyError
 from app.agents.chat.multi_agent_chat.shared.middleware.busy_mutex import (
     BusyMutexMiddleware,
     end_turn,
@@ -14,6 +13,7 @@ from app.agents.chat.multi_agent_chat.shared.middleware.busy_mutex import (
     request_cancel,
     reset_cancel,
 )
+from app.agents.chat.runtime.errors import BusyError
 
 pytestmark = pytest.mark.unit
 

surfsense_backend/tests/unit/agents/new_chat/test_mention_resolver.py

@@ -15,14 +15,14 @@ from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 
-from app.agents.chat.multi_agent_chat.shared import mention_resolver
+from app.agents.chat.runtime import mention_resolver
-from app.agents.chat.multi_agent_chat.shared.mention_resolver import (
+from app.agents.chat.runtime.mention_resolver import (
     ResolvedMention,
     ResolvedMentionSet,
     resolve_mentions,
     substitute_in_text,
 )
-from app.agents.chat.multi_agent_chat.shared.path_resolver import (
+from app.agents.chat.runtime.path_resolver import (
     DOCUMENTS_ROOT,
     PathIndex,
 )

surfsense_backend/tests/unit/agents/new_chat/test_path_resolver.py

@@ -7,7 +7,7 @@ from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 
-from app.agents.chat.multi_agent_chat.shared.path_resolver import (
+from app.agents.chat.runtime.path_resolver import (
     DOCUMENTS_ROOT,
     PathIndex,
     doc_to_virtual_path,

surfsense_backend/tests/unit/agents/new_chat/test_prompt_caching.py

@@ -1,5 +1,5 @@
 r"""Tests for ``apply_litellm_prompt_caching`` in
-:mod:`app.agents.chat.multi_agent_chat.shared.prompt_caching`.
+:mod:`app.agents.chat.runtime.prompt_caching`.
 
 The helper replaces the legacy ``AnthropicPromptCachingMiddleware`` (which
 never activated for our LiteLLM stack) with LiteLLM-native multi-provider
@@ -34,8 +34,8 @@ from typing import Any
 
 import pytest
 
-from app.agents.chat.multi_agent_chat.shared.llm_config import AgentConfig
+from app.agents.chat.runtime.llm_config import AgentConfig
-from app.agents.chat.multi_agent_chat.shared.prompt_caching import (
+from app.agents.chat.runtime.prompt_caching import (
     apply_litellm_prompt_caching,
 )
 

surfsense_backend/tests/unit/automations/services/test_model_policy.py

@@ -44,7 +44,7 @@ def patched_globals(monkeypatch: pytest.MonkeyPatch):
         -2: {"id": -2, "billing_tier": "free"},
     }
     monkeypatch.setattr(
-        "app.agents.chat.multi_agent_chat.shared.llm_config.load_global_llm_config_by_id",
+        "app.agents.chat.runtime.llm_config.load_global_llm_config_by_id",
         lambda cid: llm_configs.get(cid),
     )
 

surfsense_backend/tests/unit/middleware/test_knowledge_tree.py

@@ -12,7 +12,7 @@ from __future__ import annotations
 from app.agents.chat.multi_agent_chat.main_agent.middleware.knowledge_tree.middleware import (
     KnowledgeTreeMiddleware,
 )
-from app.agents.chat.multi_agent_chat.shared.path_resolver import DOCUMENTS_ROOT
+from app.agents.chat.runtime.path_resolver import DOCUMENTS_ROOT
 
 
 def _compute(folder_paths: list[str], doc_paths: list[str]) -> set[str]:
@@ -88,7 +88,7 @@ class TestFormatTreeRendering:
         folder_paths: list[str],
         doc_specs: list[dict],
     ) -> str:
-        from app.agents.chat.multi_agent_chat.shared.path_resolver import PathIndex
+        from app.agents.chat.runtime.path_resolver import PathIndex
 
         index = PathIndex(
             folder_paths={i + 1: p for i, p in enumerate(folder_paths)},

surfsense_backend/tests/unit/services/test_supports_image_input.py

@@ -227,7 +227,7 @@ global_llm_configs:
 
 
 def test_agent_config_from_yaml_explicit_overrides_resolver():
-    from app.agents.chat.multi_agent_chat.shared.llm_config import AgentConfig
+    from app.agents.chat.runtime.llm_config import AgentConfig
 
     cfg_text_only = AgentConfig.from_yaml_config(
         {
@@ -256,7 +256,7 @@ def test_agent_config_from_yaml_explicit_overrides_resolver():
 def test_agent_config_from_yaml_unannotated_uses_resolver():
     """Without an explicit YAML key, AgentConfig defers to the catalog
     resolver — for ``gpt-4o`` LiteLLM's map says supports_vision=True."""
-    from app.agents.chat.multi_agent_chat.shared.llm_config import AgentConfig
+    from app.agents.chat.runtime.llm_config import AgentConfig
 
     cfg = AgentConfig.from_yaml_config(
         {
@@ -275,7 +275,7 @@ def test_agent_config_auto_mode_supports_image_input():
     so users can keep their selection on Auto with a vision-capable
     deployment somewhere in the pool. The router's own `allowed_fails`
     handles non-vision deployments via fallback."""
-    from app.agents.chat.multi_agent_chat.shared.llm_config import AgentConfig
+    from app.agents.chat.runtime.llm_config import AgentConfig
 
     auto = AgentConfig.from_auto_mode()
     assert auto.supports_image_input is True

surfsense_backend/tests/unit/services/test_vision_llm_api_base_defense.py

@@ -61,7 +61,7 @@ async def test_get_vision_llm_global_openrouter_sets_api_base():
             return_value=cfg,
         ),
         patch(
-            "app.agents.chat.multi_agent_chat.shared.llm_config.SanitizedChatLiteLLM",
+            "app.agents.chat.runtime.llm_config.SanitizedChatLiteLLM",
             new=FakeSanitized,
         ),
     ):