refactor(agents): move MAC graph-state schema into multi_agent_chat/shared/state/

filesystem_state.py (the multi-agent graph state) and state_reducers.py
(its merge reducers) are consumed only by multi_agent_chat (filesystem
tools/middleware, kb projection, and the MAC-only shared middleware) plus
two unit tests -- no external app code. Relocate them into a dedicated
multi_agent_chat/shared/state/ package (filesystem_state.py + reducers.py)
and repoint every importer.

No behavior change; import-all + the full unit/middleware + unit/agents
suites (1066 tests) stay green.

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

@@ -7,8 +7,10 @@ from typing import Any
 from deepagents import FilesystemMiddleware
 from langchain_core.tools import BaseTool
 
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.filesystem_selection import FilesystemMode
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
 from app.agents.shared.sandbox import is_sandbox_enabled
 
 from ..system_prompt import build_system_prompt

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

@@ -11,7 +11,9 @@ from typing import TYPE_CHECKING
 
 from langchain.tools import ToolRuntime
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.path_resolver import DOCUMENTS_ROOT
 
 from ..shared.paths import TEMP_PREFIX, basename

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

@@ -7,8 +7,10 @@ from typing import TYPE_CHECKING
 
 from langchain.tools import ToolRuntime
 
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.filesystem_selection import FilesystemMode
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
 from app.agents.shared.middleware.multi_root_local_folder_backend import (
     MultiRootLocalFolderBackend,
 )

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

@@ -10,7 +10,9 @@ from langchain_core.messages import ToolMessage
 from langchain_core.tools import BaseTool, StructuredTool
 from langgraph.types import Command
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.path_resolver import DOCUMENTS_ROOT
 
 from ...middleware.async_dispatch import run_async_blocking

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

@@ -11,7 +11,9 @@ from langchain_core.messages import ToolMessage
 from langchain_core.tools import BaseTool, StructuredTool
 from langgraph.types import Command
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.middleware.kb_postgres_backend import KBPostgresBackend
 
 from ...middleware.async_dispatch import run_async_blocking

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

@@ -14,7 +14,9 @@ from typing import TYPE_CHECKING
 from daytona.common.errors import DaytonaError
 from langchain.tools import ToolRuntime
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.sandbox import (
     _evict_sandbox_cache,
     delete_sandbox,

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

@@ -7,7 +7,9 @@ from typing import TYPE_CHECKING, Annotated
 from langchain.tools import ToolRuntime
 from langchain_core.tools import BaseTool, StructuredTool
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 
 from ...middleware.async_dispatch import run_async_blocking
 from .description import select_description

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

@@ -9,7 +9,9 @@ from deepagents.backends.utils import validate_path
 from langchain.tools import ToolRuntime
 from langchain_core.tools import BaseTool, StructuredTool
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.middleware.kb_postgres_backend import KBPostgresBackend
 
 from ...middleware.async_dispatch import run_async_blocking

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

@@ -8,7 +8,9 @@ from deepagents.backends.utils import validate_path
 from langchain.tools import ToolRuntime
 from langchain_core.tools import BaseTool, StructuredTool
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.middleware.kb_postgres_backend import paginate_listing
 
 from ...middleware.async_dispatch import run_async_blocking

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

@@ -11,7 +11,9 @@ from langchain_core.messages import ToolMessage
 from langchain_core.tools import BaseTool, StructuredTool
 from langgraph.types import Command
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.path_resolver import DOCUMENTS_ROOT
 
 from ...middleware.async_dispatch import run_async_blocking

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

@@ -8,10 +8,12 @@ from langchain.tools import ToolRuntime
 from langchain_core.messages import ToolMessage
 from langgraph.types import Command
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
+from app.agents.multi_agent_chat.shared.state.reducers import _CLEAR
 from app.agents.shared.middleware.kb_postgres_backend import KBPostgresBackend
 from app.agents.shared.path_resolver import DOCUMENTS_ROOT
-from app.agents.shared.state_reducers import _CLEAR
 
 if TYPE_CHECKING:
     from ...middleware import SurfSenseFilesystemMiddleware

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

@@ -11,7 +11,9 @@ from langchain_core.messages import ToolMessage
 from langchain_core.tools import BaseTool, StructuredTool
 from langgraph.types import Command
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 
 from ...middleware.async_dispatch import run_async_blocking
 from ...middleware.mode import is_cloud

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

@@ -7,7 +7,9 @@ from typing import TYPE_CHECKING
 from langchain.tools import ToolRuntime
 from langchain_core.tools import BaseTool, StructuredTool
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 
 from ...middleware.path_resolution import current_cwd
 from .description import select_description

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

@@ -10,7 +10,9 @@ from langchain_core.messages import ToolMessage
 from langchain_core.tools import BaseTool, StructuredTool
 from langgraph.types import Command
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.middleware.kb_postgres_backend import KBPostgresBackend
 
 from ...middleware.async_dispatch import run_async_blocking

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

@@ -12,10 +12,12 @@ from langchain.tools import ToolRuntime
 from langchain_core.messages import ToolMessage
 from langgraph.types import Command
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
+from app.agents.multi_agent_chat.shared.state.reducers import _CLEAR
 from app.agents.shared.middleware.kb_postgres_backend import KBPostgresBackend
 from app.agents.shared.path_resolver import DOCUMENTS_ROOT
-from app.agents.shared.state_reducers import _CLEAR
 
 if TYPE_CHECKING:
     from ...middleware import SurfSenseFilesystemMiddleware

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

@@ -9,7 +9,9 @@ from langchain.tools import ToolRuntime
 from langchain_core.tools import BaseTool, StructuredTool
 from langgraph.types import Command
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 
 from ...middleware.async_dispatch import run_async_blocking
 from ...middleware.mode import is_cloud

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

@@ -13,10 +13,12 @@ from langchain.tools import ToolRuntime
 from langchain_core.messages import ToolMessage
 from langgraph.types import Command
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
+from app.agents.multi_agent_chat.shared.state.reducers import _CLEAR
 from app.agents.shared.middleware.kb_postgres_backend import KBPostgresBackend
 from app.agents.shared.path_resolver import DOCUMENTS_ROOT
-from app.agents.shared.state_reducers import _CLEAR
 
 from ...middleware.path_resolution import current_cwd
 from ...shared.paths import is_ancestor_of

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

@@ -9,7 +9,9 @@ from langchain.tools import ToolRuntime
 from langchain_core.tools import BaseTool, StructuredTool
 from langgraph.types import Command
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 
 from ...middleware.async_dispatch import run_async_blocking
 from ...middleware.mode import is_cloud

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

@@ -11,7 +11,9 @@ from langchain_core.messages import ToolMessage
 from langchain_core.tools import BaseTool, StructuredTool
 from langgraph.types import Command
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 
 from ...middleware.async_dispatch import run_async_blocking
 from ...middleware.mode import is_cloud

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

@@ -9,7 +9,9 @@ from langchain.agents.middleware import AgentMiddleware, AgentState
 from langchain_core.messages import SystemMessage
 from langgraph.runtime import Runtime
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.middleware.knowledge_search import _render_priority_message
 from app.utils.perf import get_perf_logger
 

surfsense_backend/app/agents/multi_agent_chat/shared/state/filesystem_state.py

@@ -20,7 +20,7 @@ extra fields needed to implement Postgres-backed virtual filesystem semantics:
 * ``workspace_tree_text`` — pre-rendered ``<workspace_tree>`` body for the turn.
 
 Tools mutate these fields ONLY via ``Command(update=...)`` returns; the
-reducers in :mod:`app.agents.shared.state_reducers` handle merging.
+reducers in :mod:`app.agents.multi_agent_chat.shared.state.reducers` handle merging.
 """
 
 from __future__ import annotations
@@ -30,7 +30,7 @@ from typing import Annotated, Any, NotRequired
 from deepagents.middleware.filesystem import FilesystemState
 from typing_extensions import TypedDict
 
-from app.agents.shared.state_reducers import (
+from app.agents.multi_agent_chat.shared.state.reducers import (
     _add_unique_reducer,
     _dict_merge_with_tombstones_reducer,
     _int_counter_merge_reducer,

surfsense_backend/app/agents/shared/middleware/anonymous_document.py

@@ -24,7 +24,9 @@ from typing import Any
 from langchain.agents.middleware import AgentMiddleware, AgentState
 from langgraph.runtime import Runtime
 
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.path_resolver import DOCUMENTS_ROOT, safe_filename
 
 logger = logging.getLogger(__name__)

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

@@ -45,16 +45,18 @@ from sqlalchemy import delete, select, update
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.ext.asyncio import AsyncSession
 
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
+from app.agents.multi_agent_chat.shared.state.reducers import _CLEAR
 from app.agents.shared.feature_flags import get_flags
 from app.agents.shared.filesystem_selection import FilesystemMode
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
 from app.agents.shared.path_resolver import (
     DOCUMENTS_ROOT,
     parse_documents_path,
     safe_folder_segment,
     virtual_path_to_doc,
 )
-from app.agents.shared.state_reducers import _CLEAR
 from app.agents.shared.receipt import Receipt, make_receipt
 from app.db import (
     AgentActionLog,

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

@@ -45,9 +45,11 @@ from app.agents.multi_agent_chat.shared.date_filters import (
     parse_date_or_datetime,
     resolve_date_range,
 )
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.feature_flags import get_flags
 from app.agents.shared.filesystem_selection import FilesystemMode
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
 from app.agents.shared.path_resolver import (
     PathIndex,
     build_path_index,

surfsense_backend/app/agents/shared/middleware/knowledge_tree.py

@@ -33,8 +33,10 @@ from langchain_core.messages import SystemMessage
 from langgraph.runtime import Runtime
 from sqlalchemy import select
 
+from app.agents.multi_agent_chat.shared.state.filesystem_state import (
+    SurfSenseFilesystemState,
+)
 from app.agents.shared.filesystem_selection import FilesystemMode
-from app.agents.shared.filesystem_state import SurfSenseFilesystemState
 from app.agents.shared.path_resolver import (
     DOCUMENTS_ROOT,
     PathIndex,

surfsense_backend/app/agents/shared/receipt_command.py

@@ -6,7 +6,7 @@ participate in the verification teaching from
 ``multi_agent_chat/subagents/shared/snippets/verifiable_handle.md`` those
 tools now also need to write a :class:`Receipt` into the parent's
 ``state['receipts']`` list (declared on
-:class:`~app.agents.shared.filesystem_state.SurfSenseFilesystemState`
+:class:`~app.agents.multi_agent_chat.shared.state.filesystem_state.SurfSenseFilesystemState`
 and backed by the append reducer).
 
 :func:`with_receipt` wraps both behaviours: it returns the tool payload as
@@ -51,7 +51,7 @@ def with_receipt(
     """Return a Command that ships ``payload`` as a ToolMessage AND appends ``receipt``.
 
     The append happens via the ``_list_append_reducer`` on the ``receipts``
-    field of :class:`~app.agents.shared.filesystem_state.SurfSenseFilesystemState`,
+    field of :class:`~app.agents.multi_agent_chat.shared.state.filesystem_state.SurfSenseFilesystemState`,
     so concurrent subagent batches (item 4 in the plan) won't clobber each
     other's receipts.
     """

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

@@ -4,7 +4,7 @@ from __future__ import annotations
 
 import pytest
 
-from app.agents.shared.state_reducers import (
+from app.agents.multi_agent_chat.shared.state.reducers import (
     _CLEAR,
     _add_unique_reducer,
     _dict_merge_with_tombstones_reducer,

surfsense_backend/tests/unit/middleware/test_b_filesystem_rm_rmdir_cloud.py

@@ -22,10 +22,10 @@ import pytest
 from app.agents.multi_agent_chat.shared.middleware.filesystem import (
     build_filesystem_mw,
 )
+from app.agents.multi_agent_chat.shared.state.reducers import _CLEAR
 from app.agents.shared.filesystem_backends import build_backend_resolver
 from app.agents.shared.filesystem_selection import FilesystemMode, FilesystemSelection
 from app.agents.shared.middleware.kb_postgres_backend import KBPostgresBackend
-from app.agents.shared.state_reducers import _CLEAR
 
 pytestmark = pytest.mark.unit