fix(agent): scope subagent reply dedupe to origin message

Made-with: Cursor

nanobot/agent/tools/file_state.py

@@ -4,6 +4,7 @@ from __future__ import annotations
 
 import hashlib
 import os
+from contextvars import ContextVar, Token
 from dataclasses import dataclass
 from pathlib import Path
 
@@ -17,9 +18,6 @@ class ReadState:
     can_dedup: bool
 
 
-_state: dict[str, ReadState] = {}
-
-
 def _hash_file(p: str) -> str | None:
     try:
         return hashlib.sha256(Path(p).read_bytes()).hexdigest()
@@ -27,93 +25,181 @@ def _hash_file(p: str) -> str | None:
         return None
 
 
+class FileStates:
+    """Per-session read/write tracker.
+
+    Owns its own state dict so read-dedup ("File unchanged since last read")
+    and read-before-edit warnings stay scoped to one agent session and do
+    not leak across sessions sharing this process.
+    """
+
+    __slots__ = ("_state",)
+
+    def __init__(self) -> None:
+        self._state: dict[str, ReadState] = {}
+
+    def record_read(self, path: str | Path, offset: int = 1, limit: int | None = None) -> None:
+        """Record that a file was read (called after successful read)."""
+        p = str(Path(path).resolve())
+        try:
+            mtime = os.path.getmtime(p)
+        except OSError:
+            return
+        self._state[p] = ReadState(
+            mtime=mtime,
+            offset=offset,
+            limit=limit,
+            content_hash=_hash_file(p),
+            can_dedup=True,
+        )
+
+    def record_write(self, path: str | Path) -> None:
+        """Record that a file was written (updates mtime in state)."""
+        p = str(Path(path).resolve())
+        try:
+            mtime = os.path.getmtime(p)
+        except OSError:
+            self._state.pop(p, None)
+            return
+        self._state[p] = ReadState(
+            mtime=mtime,
+            offset=1,
+            limit=None,
+            content_hash=_hash_file(p),
+            can_dedup=False,
+        )
+
+    def check_read(self, path: str | Path) -> str | None:
+        """Check if a file has been read and is fresh.
+
+        Returns None if OK, or a warning string.
+        When mtime changed but file content is identical (e.g. touch, editor save),
+        the check passes to avoid false-positive staleness warnings.
+        """
+        p = str(Path(path).resolve())
+        entry = self._state.get(p)
+        if entry is None:
+            return "Warning: file has not been read yet. Read it first to verify content before editing."
+        try:
+            current_mtime = os.path.getmtime(p)
+        except OSError:
+            return None
+        if current_mtime != entry.mtime:
+            if entry.content_hash and _hash_file(p) == entry.content_hash:
+                entry.mtime = current_mtime
+                return None
+            return "Warning: file has been modified since last read. Re-read to verify content before editing."
+        # mtime unchanged - still check content hash to detect quick modifications
+        if entry.content_hash and _hash_file(p) != entry.content_hash:
+            return "Warning: file has been modified since last read. Re-read to verify content before editing."
+        return None
+
+    def is_unchanged(self, path: str | Path, offset: int = 1, limit: int | None = None) -> bool:
+        """Return True if file was previously read with same params and content is unchanged."""
+        p = str(Path(path).resolve())
+        entry = self._state.get(p)
+        if entry is None:
+            return False
+        if not entry.can_dedup:
+            return False
+        if entry.offset != offset or entry.limit != limit:
+            return False
+        try:
+            current_mtime = os.path.getmtime(p)
+        except OSError:
+            return False
+        if current_mtime != entry.mtime:
+            # mtime changed - check if content also changed
+            current_hash = _hash_file(p)
+            if current_hash != entry.content_hash:
+                # Content actually changed - don't dedup
+                entry.can_dedup = False
+                return False
+            # Content identical despite mtime change (e.g. touch) - mark as not dedupable to force full read next time
+            entry.can_dedup = False
+            return True
+        # mtime unchanged - content must be identical
+        return True
+
+    def get(self, path: str | Path) -> ReadState | None:
+        """Return the raw ReadState entry for a path, or None."""
+        return self._state.get(str(Path(path).resolve()))
+
+    def clear(self) -> None:
+        """Clear all tracked state (useful for testing)."""
+        self._state.clear()
+
+
+class FileStateStore:
+    """Lookup table for per-session file read/write state."""
+
+    __slots__ = ("_states_by_key",)
+
+    def __init__(self) -> None:
+        self._states_by_key: dict[str, FileStates] = {}
+
+    def for_session(self, session_key: str | None) -> FileStates:
+        key = session_key or "__default__"
+        states = self._states_by_key.get(key)
+        if states is None:
+            states = FileStates()
+            self._states_by_key[key] = states
+        return states
+
+    def clear(self) -> None:
+        self._states_by_key.clear()
+
+
+_current_file_states: ContextVar[FileStates | None] = ContextVar(
+    "nanobot_file_states",
+    default=None,
+)
+
+
+def current_file_states(default: FileStates) -> FileStates:
+    """Return the FileStates bound to the current agent task, or a fallback."""
+    return _current_file_states.get() or default
+
+
+def bind_file_states(file_states: FileStates) -> Token[FileStates | None]:
+    """Bind file read/write state for the current async task."""
+    return _current_file_states.set(file_states)
+
+
+def reset_file_states(token: Token[FileStates | None]) -> None:
+    _current_file_states.reset(token)
+
+
+# Module-level default instance, retained for backward compatibility with
+# tests and callers that reach in directly. Per-session callers should hold
+# their own FileStates instance instead of touching this one.
+_default = FileStates()
+
+
 def record_read(path: str | Path, offset: int = 1, limit: int | None = None) -> None:
-    """Record that a file was read (called after successful read)."""
-    p = str(Path(path).resolve())
-    try:
-        mtime = os.path.getmtime(p)
-    except OSError:
-        return
-    _state[p] = ReadState(
-        mtime=mtime,
-        offset=offset,
-        limit=limit,
-        content_hash=_hash_file(p),
-        can_dedup=True,
-    )
+    _default.record_read(path, offset=offset, limit=limit)
 
 
 def record_write(path: str | Path) -> None:
-    """Record that a file was written (updates mtime in state)."""
-    p = str(Path(path).resolve())
-    try:
-        mtime = os.path.getmtime(p)
-    except OSError:
-        _state.pop(p, None)
-        return
-    _state[p] = ReadState(
-        mtime=mtime,
-        offset=1,
-        limit=None,
-        content_hash=_hash_file(p),
-        can_dedup=False,
-    )
+    _default.record_write(path)
 
 
 def check_read(path: str | Path) -> str | None:
-    """Check if a file has been read and is fresh.
-
-    Returns None if OK, or a warning string.
-    When mtime changed but file content is identical (e.g. touch, editor save),
-    the check passes to avoid false-positive staleness warnings.
-    """
-    p = str(Path(path).resolve())
-    entry = _state.get(p)
-    if entry is None:
-        return "Warning: file has not been read yet. Read it first to verify content before editing."
-    try:
-        current_mtime = os.path.getmtime(p)
-    except OSError:
-        return None
-    if current_mtime != entry.mtime:
-        if entry.content_hash and _hash_file(p) == entry.content_hash:
-            entry.mtime = current_mtime
-            return None
-        return "Warning: file has been modified since last read. Re-read to verify content before editing."
-    # mtime unchanged - still check content hash to detect quick modifications
-    if entry.content_hash and _hash_file(p) != entry.content_hash:
-        return "Warning: file has been modified since last read. Re-read to verify content before editing."
-    return None
+    return _default.check_read(path)
 
 
 def is_unchanged(path: str | Path, offset: int = 1, limit: int | None = None) -> bool:
-    """Return True if file was previously read with same params and content is unchanged."""
-    p = str(Path(path).resolve())
-    entry = _state.get(p)
-    if entry is None:
-        return False
-    if not entry.can_dedup:
-        return False
-    if entry.offset != offset or entry.limit != limit:
-        return False
-    try:
-        current_mtime = os.path.getmtime(p)
-    except OSError:
-        return False
-    if current_mtime != entry.mtime:
-        # mtime changed - check if content also changed
-        current_hash = _hash_file(p)
-        if current_hash != entry.content_hash:
-            # Content actually changed - don't dedup
-            entry.can_dedup = False
-            return False
-        # Content identical despite mtime change (e.g. touch) - mark as not dedupable to force full read next time
-        entry.can_dedup = False
-        return True
-    # mtime unchanged - content must be identical
-    return True
+    return _default.is_unchanged(path, offset=offset, limit=limit)
 
 
 def clear() -> None:
-    """Clear all tracked state (useful for testing)."""
-    _state.clear()
+    _default.clear()
+
+
+# Legacy attribute for callers that reached into the module-level dict
+# directly (filesystem.py used to do this). Kept as a property-like accessor
+# so existing imports keep working.
+def __getattr__(name: str):
+    if name == "_state":
+        return _default._state
+    raise AttributeError(name)

nanobot/agent/tools/filesystem.py

@@ -9,7 +9,7 @@ from typing import Any
 
 from nanobot.agent.tools.base import Tool, tool_parameters
 from nanobot.agent.tools.schema import BooleanSchema, IntegerSchema, StringSchema, tool_parameters_schema
-from nanobot.agent.tools import file_state
+from nanobot.agent.tools.file_state import FileStates, _hash_file, current_file_states
 from nanobot.utils.helpers import build_image_content_blocks, detect_image_mime
 from nanobot.config.paths import get_media_dir
 
@@ -49,10 +49,22 @@ class _FsTool(Tool):
         workspace: Path | None = None,
         allowed_dir: Path | None = None,
         extra_allowed_dirs: list[Path] | None = None,
+        file_states: FileStates | None = None,
     ):
         self._workspace = workspace
         self._allowed_dir = allowed_dir
         self._extra_allowed_dirs = extra_allowed_dirs
+        # Explicit state is used by isolated runners like Dream/subagents.
+        # Main AgentLoop tools leave this unset and resolve state from the
+        # current async task, which keeps shared tool instances session-safe.
+        self._explicit_file_states = file_states
+        self._fallback_file_states = FileStates()
+
+    @property
+    def _file_states(self) -> FileStates:
+        if self._explicit_file_states is not None:
+            return self._explicit_file_states
+        return current_file_states(self._fallback_file_states)
 
     def _resolve(self, path: str) -> Path:
         return _resolve_path(path, self._workspace, self._allowed_dir, self._extra_allowed_dirs)
@@ -184,7 +196,7 @@ class ReadFileTool(_FsTool):
 
             # Read dedup: same path + offset + limit + unchanged mtime → stub
             # Always check for external modifications before dedup
-            entry = file_state._state.get(str(fp.resolve()))
+            entry = self._file_states.get(fp)
             try:
                 current_mtime = os.path.getmtime(fp)
             except OSError:
@@ -193,21 +205,21 @@ class ReadFileTool(_FsTool):
                 if current_mtime != entry.mtime:
                     # File was modified externally - force full read and mark as not dedupable
                     entry.can_dedup = False
-                    file_state.record_read(fp, offset=offset, limit=limit)  # Update state with new mtime
+                    self._file_states.record_read(fp, offset=offset, limit=limit)  # Update state with new mtime
                     # Continue to read full content (don't return dedup message)
                 else:
                     # File unchanged - return dedup message
                     # But only if content is actually unchanged (not just mtime)
-                    current_hash = file_state._hash_file(str(fp))
+                    current_hash = _hash_file(str(fp))
                     if current_hash == entry.content_hash:
                         return f"[File unchanged since last read: {path}]"
                     else:
                         # Content changed despite same mtime - force full read
                         entry.can_dedup = False
-                        file_state.record_read(fp, offset=offset, limit=limit)
+                        self._file_states.record_read(fp, offset=offset, limit=limit)
             else:
                 # No previous state or marked as not dedupable - read full content
-                file_state.record_read(fp, offset=offset, limit=limit)
+                self._file_states.record_read(fp, offset=offset, limit=limit)
                 # Force full read by setting can_dedup to False for this read
                 if entry:
                     entry.can_dedup = False
@@ -256,7 +268,7 @@ class ReadFileTool(_FsTool):
                 result += f"\n\n(Showing lines {offset}-{end} of {total}. Use offset={end + 1} to continue.)"
             else:
                 result += f"\n\n(End of file — {total} lines total)"
-            file_state.record_read(fp, offset=offset, limit=limit)
+            self._file_states.record_read(fp, offset=offset, limit=limit)
             return result
         except PermissionError as e:
             return f"Error: {e}"
@@ -365,7 +377,7 @@ class WriteFileTool(_FsTool):
             fp = self._resolve(path)
             fp.parent.mkdir(parents=True, exist_ok=True)
             fp.write_text(content, encoding="utf-8")
-            file_state.record_write(fp)
+            self._file_states.record_write(fp)
             return f"Successfully wrote {len(content)} characters to {fp}"
         except PermissionError as e:
             return f"Error: {e}"
@@ -699,7 +711,7 @@ class EditFileTool(_FsTool):
                 if old_text == "":
                     fp.parent.mkdir(parents=True, exist_ok=True)
                     fp.write_text(new_text, encoding="utf-8")
-                    file_state.record_write(fp)
+                    self._file_states.record_write(fp)
                     return f"Successfully created {fp}"
                 return self._file_not_found_msg(path, fp)
 
@@ -718,11 +730,11 @@ class EditFileTool(_FsTool):
                 if content.strip():
                     return f"Error: Cannot create file — {path} already exists and is not empty."
                 fp.write_text(new_text, encoding="utf-8")
-                file_state.record_write(fp)
+                self._file_states.record_write(fp)
                 return f"Successfully edited {fp}"
 
             # Read-before-edit check
-            warning = file_state.check_read(fp)
+            warning = self._file_states.check_read(fp)
 
             raw = fp.read_bytes()
             uses_crlf = b"\r\n" in raw
@@ -767,7 +779,7 @@ class EditFileTool(_FsTool):
                 new_content = new_content.replace("\n", "\r\n")
 
             fp.write_bytes(new_content.encode("utf-8"))
-            file_state.record_write(fp)
+            self._file_states.record_write(fp)
             msg = f"Successfully edited {fp}"
             if warning:
                 msg = f"{warning}\n{msg}"

nanobot/agent/tools/mcp.py

@@ -4,7 +4,7 @@ import asyncio
 import os
 import re
 import shutil
-from contextlib import AsyncExitStack
+from contextlib import AsyncExitStack, suppress
 from typing import Any
 
 import httpx
@@ -609,10 +609,8 @@ async def connect_mcp_servers(
                     "only JSON-RPC to stdout and sends logs/debug output to stderr instead."
                 )
             logger.error("MCP server '{}': failed to connect: {}{}", name, e, hint)
-            try:
+            with suppress(Exception):
                 await server_stack.aclose()
-            except Exception:
-                pass
             return name, None
 
     server_stacks: dict[str, AsyncExitStack] = {}

nanobot/agent/tools/search.py

@@ -5,6 +5,7 @@ from __future__ import annotations
 import fnmatch
 import os
 import re
+from contextlib import suppress
 from pathlib import Path, PurePosixPath
 from typing import Any, Iterable, TypeVar
 
@@ -92,10 +93,8 @@ class _SearchTool(_FsTool):
 
     def _display_path(self, target: Path, root: Path) -> str:
         if self._workspace:
-            try:
+            with suppress(ValueError):
                 return target.relative_to(self._workspace).as_posix()
-            except ValueError:
-                pass
         return target.relative_to(root).as_posix()
 
     def _iter_files(self, root: Path) -> Iterable[Path]:

nanobot/agent/tools/shell.py

@@ -5,6 +5,7 @@ import os
 import re
 import shutil
 import sys
+from contextlib import suppress
 from pathlib import Path
 from typing import Any
 
@@ -212,9 +213,8 @@ class ExecTool(Tool):
         """Kill a subprocess and reap it to prevent zombies."""
         process.kill()
         try:
-            await asyncio.wait_for(process.wait(), timeout=5.0)
-        except asyncio.TimeoutError:
-            pass
+            with suppress(asyncio.TimeoutError):
+                await asyncio.wait_for(process.wait(), timeout=5.0)
         finally:
             if not _IS_WINDOWS:
                 try:

nanobot/agent/tools/spawn.py

@@ -25,7 +25,10 @@ class SpawnTool(Tool):
         self._origin_channel: ContextVar[str] = ContextVar("spawn_origin_channel", default="cli")
         self._origin_chat_id: ContextVar[str] = ContextVar("spawn_origin_chat_id", default="direct")
         self._session_key: ContextVar[str] = ContextVar("spawn_session_key", default="cli:direct")
-        self._origin_message_id: str | None = None
+        self._origin_message_id: ContextVar[str | None] = ContextVar(
+            "spawn_origin_message_id",
+            default=None,
+        )
 
     def set_context(self, channel: str, chat_id: str, effective_key: str | None = None) -> None:
         """Set the origin context for subagent announcements."""
@@ -35,7 +38,7 @@ class SpawnTool(Tool):
 
     def set_origin_message_id(self, message_id: str | None) -> None:
         """Set the source message id for downstream deduplication."""
-        self._origin_message_id = message_id
+        self._origin_message_id.set(message_id)
 
     @property
     def name(self) -> str:
@@ -59,5 +62,5 @@ class SpawnTool(Tool):
             origin_channel=self._origin_channel.get(),
             origin_chat_id=self._origin_chat_id.get(),
             session_key=self._session_key.get(),
-            origin_message_id=self._origin_message_id,
+            origin_message_id=self._origin_message_id.get(),
         )