fix(exec): isolate exec session managers

nanobot/agent/loop.py

@@ -28,6 +28,7 @@ from nanobot.agent.model_runtime import ModelRuntimeResolver
 from nanobot.agent.runner import _MAX_INJECTIONS_PER_TURN, AgentRunner, AgentRunSpec
 from nanobot.agent.subagent import SubagentManager
 from nanobot.agent.tools.context import RequestContext, bind_request_context, reset_request_context
+from nanobot.agent.tools.exec_session import ExecSessionManager
 from nanobot.agent.tools.file_state import FileStateStore, bind_file_states, reset_file_states
 from nanobot.agent.tools.message import MessageTool
 from nanobot.agent.tools.registry import ToolRegistry
@@ -355,6 +356,7 @@ class AgentLoop:
         # One file-read/write tracker per logical session. The tool registry is
         # shared by this loop, so tools resolve the active state via contextvars.
         self._file_state_store = FileStateStore()
+        self._exec_session_manager = ExecSessionManager()
         self.runner = AgentRunner()
         self.subagents = SubagentManager(
             workspace=workspace,
@@ -540,6 +542,7 @@ class AgentLoop:
             bus=self.bus,
             subagent_manager=self.subagents,
             cron_service=self.cron_service,
+            exec_session_manager=self._exec_session_manager,
             sessions=self.sessions,
             provider_snapshot_loader=provider_snapshot_loader,
             image_generation_provider_configs=self._image_generation_provider_configs,

nanobot/agent/subagent.py

@@ -19,6 +19,7 @@ from nanobot.agent.tools.context import (
     bind_request_context,
     reset_request_context,
 )
+from nanobot.agent.tools.exec_session import ExecSessionManager
 from nanobot.agent.tools.file_state import FileStates
 from nanobot.agent.tools.loader import ToolLoader
 from nanobot.agent.tools.registry import ToolRegistry
@@ -143,6 +144,7 @@ class SubagentManager:
             else defaults.fail_on_tool_error
         )
         self.runner = AgentRunner()
+        self._exec_session_manager = ExecSessionManager()
         self._llm_wall_timeout_for_session = llm_wall_timeout_for_session
         self._running_tasks: dict[str, asyncio.Task[None]] = {}
         self._task_statuses: dict[str, SubagentStatus] = {}
@@ -204,6 +206,7 @@ class SubagentManager:
         ctx = ToolContext(
             config=cfg,
             workspace=str(root.resolve()),
+            exec_session_manager=self._exec_session_manager,
             file_state_store=FileStates(),
             workspace_sandbox=workspace_sandbox_status(
                 restrict_to_workspace=cfg.restrict_to_workspace,

nanobot/agent/tools/context.py

@@ -71,6 +71,7 @@ class ToolContext:
     bus: Any | None = None
     subagent_manager: Any | None = None
     cron_service: Any | None = None
+    exec_session_manager: Any | None = None
     sessions: Any | None = None
     file_state_store: Any = field(default=None)
     provider_snapshot_loader: Callable[[], Any] | None = None

nanobot/agent/tools/exec_session.py

@@ -250,11 +250,7 @@ class ExecSessionManager:
             session = self._sessions.get(session_id)
         if session is None:
             raise KeyError(session_id)
-        if (
-            owner_session_key
-            and session.owner_session_key
-            and session.owner_session_key != owner_session_key
-        ):
+        if session.owner_session_key and session.owner_session_key != owner_session_key:
             raise KeyError(session_id)
 
         if chars:
@@ -296,9 +292,7 @@ class ExecSessionManager:
                     owner_session_key=session.owner_session_key,
                 )
                 for session_id, session in sorted(self._sessions.items())
-                if not owner_session_key
-                or not session.owner_session_key
-                or session.owner_session_key == owner_session_key
+                if session.owner_session_key == owner_session_key
             ]
 
     async def _cleanup_locked(self) -> None:
@@ -442,7 +436,7 @@ class WriteStdinTool(Tool):
 
     @classmethod
     def create(cls, ctx: Any) -> Tool:
-        return cls()
+        return cls(manager=getattr(ctx, "exec_session_manager", None))
 
     @property
     def exclusive(self) -> bool:
@@ -586,7 +580,7 @@ class ListExecSessionsTool(Tool):
 
     @classmethod
     def create(cls, ctx: Any) -> Tool:
-        return cls()
+        return cls(manager=getattr(ctx, "exec_session_manager", None))
 
     @property
     def name(self) -> str:

nanobot/agent/tools/shell.py

@@ -188,6 +188,7 @@ class ExecTool(Tool):
             allowed_env_keys=cfg.allowed_env_keys,
             allow_patterns=cfg.allow_patterns,
             deny_patterns=cfg.deny_patterns,
+            session_manager=getattr(ctx, "exec_session_manager", None),
         )
 
     def __init__(