Merge branch 'main' into fix-2804

This commit is contained in:
Willem Jiang
2026-05-16 09:27:40 +08:00
committed by GitHub
101 changed files with 6081 additions and 707 deletions
@@ -104,45 +104,46 @@ class DanglingToolCallMiddleware(AgentMiddleware[AgentState]):
return "[Tool call was interrupted and did not return a result.]"
def _build_patched_messages(self, messages: list) -> list | None:
"""Return a new message list with patches inserted at the correct positions.
"""Return messages with tool results grouped after their tool-call AIMessage.
For each AIMessage with dangling tool_calls (no corresponding ToolMessage),
a synthetic ToolMessage is inserted immediately after that AIMessage.
Returns None if no patches are needed.
This normalizes model-bound causal order before provider serialization while
preserving already-valid transcripts unchanged.
"""
# Collect IDs of all existing ToolMessages
existing_tool_msg_ids: set[str] = set()
tool_messages_by_id: dict[str, ToolMessage] = {}
for msg in messages:
if isinstance(msg, ToolMessage):
existing_tool_msg_ids.add(msg.tool_call_id)
tool_messages_by_id.setdefault(msg.tool_call_id, msg)
# Check if any patching is needed
needs_patch = False
tool_call_ids: set[str] = set()
for msg in messages:
if getattr(msg, "type", None) != "ai":
continue
for tc in self._message_tool_calls(msg):
tc_id = tc.get("id")
if tc_id and tc_id not in existing_tool_msg_ids:
needs_patch = True
break
if needs_patch:
break
if tc_id:
tool_call_ids.add(tc_id)
if not needs_patch:
return None
# Build new list with patches inserted right after each dangling AIMessage
patched: list = []
patched_ids: set[str] = set()
consumed_tool_msg_ids: set[str] = set()
patch_count = 0
for msg in messages:
if isinstance(msg, ToolMessage) and msg.tool_call_id in tool_call_ids:
continue
patched.append(msg)
if getattr(msg, "type", None) != "ai":
continue
for tc in self._message_tool_calls(msg):
tc_id = tc.get("id")
if tc_id and tc_id not in existing_tool_msg_ids and tc_id not in patched_ids:
if not tc_id or tc_id in consumed_tool_msg_ids:
continue
existing_tool_msg = tool_messages_by_id.get(tc_id)
if existing_tool_msg is not None:
patched.append(existing_tool_msg)
consumed_tool_msg_ids.add(tc_id)
else:
patched.append(
ToolMessage(
content=self._synthetic_tool_message_content(tc),
@@ -151,10 +152,14 @@ class DanglingToolCallMiddleware(AgentMiddleware[AgentState]):
status="error",
)
)
patched_ids.add(tc_id)
consumed_tool_msg_ids.add(tc_id)
patch_count += 1
logger.warning(f"Injecting {patch_count} placeholder ToolMessage(s) for dangling tool calls")
if patched == messages:
return None
if patch_count:
logger.warning(f"Injecting {patch_count} placeholder ToolMessage(s) for dangling tool calls")
return patched
@override
@@ -7,17 +7,21 @@ reminder message so the model still knows about the outstanding todo list.
Additionally, this middleware prevents the agent from exiting the loop while
there are still incomplete todo items. When the model produces a final response
(no tool calls) but todos are not yet complete, the middleware injects a reminder
and jumps back to the model node to force continued engagement.
(no tool calls) but todos are not yet complete, the middleware queues a reminder
for the next model request and jumps back to the model node to force continued
engagement. The completion reminder is injected via ``wrap_model_call`` instead
of being persisted into graph state as a normal user-visible message.
"""
from __future__ import annotations
import threading
from collections.abc import Awaitable, Callable
from typing import Any, override
from langchain.agents.middleware import TodoListMiddleware
from langchain.agents.middleware.todo import PlanningState, Todo
from langchain.agents.middleware.types import hook_config
from langchain.agents.middleware.types import ModelCallResult, ModelRequest, ModelResponse, hook_config
from langchain_core.messages import AIMessage, HumanMessage
from langgraph.runtime import Runtime
@@ -55,6 +59,51 @@ def _format_todos(todos: list[Todo]) -> str:
return "\n".join(lines)
def _format_completion_reminder(todos: list[Todo]) -> str:
"""Format a completion reminder for incomplete todo items."""
incomplete = [t for t in todos if t.get("status") != "completed"]
incomplete_text = "\n".join(f"- [{t.get('status', 'pending')}] {t.get('content', '')}" for t in incomplete)
return (
"<system_reminder>\n"
"You have incomplete todo items that must be finished before giving your final response:\n\n"
f"{incomplete_text}\n\n"
"Please continue working on these tasks. Call `write_todos` to mark items as completed "
"as you finish them, and only respond when all items are done.\n"
"</system_reminder>"
)
_TOOL_CALL_FINISH_REASONS = {"tool_calls", "function_call"}
def _has_tool_call_intent_or_error(message: AIMessage) -> bool:
"""Return True when an AIMessage is not a clean final answer.
Todo completion reminders should only fire when the model has produced a
plain final response. Provider/tool parsing details have moved across
LangChain versions and integrations, so keep all tool-intent/error signals
behind this helper instead of checking one concrete field at the call site.
"""
if message.tool_calls:
return True
if getattr(message, "invalid_tool_calls", None):
return True
# Backward/provider compatibility: some integrations preserve raw or legacy
# tool-call intent in additional_kwargs even when structured tool_calls is
# empty. If this helper changes, update the matching sentinel test
# `TestToolCallIntentOrError.test_langchain_ai_message_tool_fields_are_explicitly_handled`;
# if that test fails after a LangChain upgrade, review this helper so new
# tool-call/error fields are not silently treated as clean final answers.
additional_kwargs = getattr(message, "additional_kwargs", {}) or {}
if additional_kwargs.get("tool_calls") or additional_kwargs.get("function_call"):
return True
response_metadata = getattr(message, "response_metadata", {}) or {}
return response_metadata.get("finish_reason") in _TOOL_CALL_FINISH_REASONS
class TodoMiddleware(TodoListMiddleware):
"""Extends TodoListMiddleware with `write_todos` context-loss detection.
@@ -89,6 +138,7 @@ class TodoMiddleware(TodoListMiddleware):
formatted = _format_todos(todos)
reminder = HumanMessage(
name="todo_reminder",
additional_kwargs={"hide_from_ui": True},
content=(
"<system_reminder>\n"
"Your todo list from earlier is no longer visible in the current context window, "
@@ -113,6 +163,100 @@ class TodoMiddleware(TodoListMiddleware):
# Maximum number of completion reminders before allowing the agent to exit.
# This prevents infinite loops when the agent cannot make further progress.
_MAX_COMPLETION_REMINDERS = 2
# Hard cap for per-run reminder bookkeeping in long-lived middleware instances.
_MAX_COMPLETION_REMINDER_KEYS = 4096
def __init__(self, *args: Any, **kwargs: Any) -> None:
super().__init__(*args, **kwargs)
self._lock = threading.Lock()
self._pending_completion_reminders: dict[tuple[str, str], list[str]] = {}
self._completion_reminder_counts: dict[tuple[str, str], int] = {}
self._completion_reminder_touch_order: dict[tuple[str, str], int] = {}
self._completion_reminder_next_order = 0
@staticmethod
def _get_thread_id(runtime: Runtime) -> str:
context = getattr(runtime, "context", None)
thread_id = context.get("thread_id") if context else None
return str(thread_id) if thread_id else "default"
@staticmethod
def _get_run_id(runtime: Runtime) -> str:
context = getattr(runtime, "context", None)
run_id = context.get("run_id") if context else None
return str(run_id) if run_id else "default"
def _pending_key(self, runtime: Runtime) -> tuple[str, str]:
return self._get_thread_id(runtime), self._get_run_id(runtime)
def _touch_completion_reminder_key_locked(self, key: tuple[str, str]) -> None:
self._completion_reminder_next_order += 1
self._completion_reminder_touch_order[key] = self._completion_reminder_next_order
def _completion_reminder_keys_locked(self) -> set[tuple[str, str]]:
keys = set(self._pending_completion_reminders)
keys.update(self._completion_reminder_counts)
keys.update(self._completion_reminder_touch_order)
return keys
def _drop_completion_reminder_key_locked(self, key: tuple[str, str]) -> None:
self._pending_completion_reminders.pop(key, None)
self._completion_reminder_counts.pop(key, None)
self._completion_reminder_touch_order.pop(key, None)
def _prune_completion_reminder_state_locked(self, protected_key: tuple[str, str]) -> None:
keys = self._completion_reminder_keys_locked()
overflow = len(keys) - self._MAX_COMPLETION_REMINDER_KEYS
if overflow <= 0:
return
candidates = [key for key in keys if key != protected_key]
candidates.sort(key=lambda key: self._completion_reminder_touch_order.get(key, 0))
for key in candidates[:overflow]:
self._drop_completion_reminder_key_locked(key)
def _queue_completion_reminder(self, runtime: Runtime, reminder: str) -> None:
key = self._pending_key(runtime)
with self._lock:
self._pending_completion_reminders.setdefault(key, []).append(reminder)
self._completion_reminder_counts[key] = self._completion_reminder_counts.get(key, 0) + 1
self._touch_completion_reminder_key_locked(key)
self._prune_completion_reminder_state_locked(protected_key=key)
def _completion_reminder_count_for_runtime(self, runtime: Runtime) -> int:
key = self._pending_key(runtime)
with self._lock:
return self._completion_reminder_counts.get(key, 0)
def _drain_completion_reminders(self, runtime: Runtime) -> list[str]:
key = self._pending_key(runtime)
with self._lock:
reminders = self._pending_completion_reminders.pop(key, [])
if reminders or key in self._completion_reminder_counts:
self._touch_completion_reminder_key_locked(key)
return reminders
def _clear_other_run_completion_reminders(self, runtime: Runtime) -> None:
thread_id, current_run_id = self._pending_key(runtime)
with self._lock:
for key in self._completion_reminder_keys_locked():
if key[0] == thread_id and key[1] != current_run_id:
self._drop_completion_reminder_key_locked(key)
def _clear_current_run_completion_reminders(self, runtime: Runtime) -> None:
key = self._pending_key(runtime)
with self._lock:
self._drop_completion_reminder_key_locked(key)
@override
def before_agent(self, state: PlanningState, runtime: Runtime) -> dict[str, Any] | None:
self._clear_other_run_completion_reminders(runtime)
return None
@override
async def abefore_agent(self, state: PlanningState, runtime: Runtime) -> dict[str, Any] | None:
self._clear_other_run_completion_reminders(runtime)
return None
@hook_config(can_jump_to=["model"])
@override
@@ -137,10 +281,12 @@ class TodoMiddleware(TodoListMiddleware):
if base_result is not None:
return base_result
# 2. Only intervene when the agent wants to exit (no tool calls).
# 2. Only intervene when the agent wants to exit cleanly. Tool-call
# intent or tool-call parse errors should be handled by the tool path
# instead of being masked by todo reminders.
messages = state.get("messages") or []
last_ai = next((m for m in reversed(messages) if isinstance(m, AIMessage)), None)
if not last_ai or last_ai.tool_calls:
if not last_ai or _has_tool_call_intent_or_error(last_ai):
return None
# 3. Allow exit when all todos are completed or there are no todos.
@@ -149,24 +295,14 @@ class TodoMiddleware(TodoListMiddleware):
return None
# 4. Enforce a reminder cap to prevent infinite re-engagement loops.
if _completion_reminder_count(messages) >= self._MAX_COMPLETION_REMINDERS:
if self._completion_reminder_count_for_runtime(runtime) >= self._MAX_COMPLETION_REMINDERS:
return None
# 5. Inject a reminder and force the agent back to the model.
incomplete = [t for t in todos if t.get("status") != "completed"]
incomplete_text = "\n".join(f"- [{t.get('status', 'pending')}] {t.get('content', '')}" for t in incomplete)
reminder = HumanMessage(
name="todo_completion_reminder",
content=(
"<system_reminder>\n"
"You have incomplete todo items that must be finished before giving your final response:\n\n"
f"{incomplete_text}\n\n"
"Please continue working on these tasks. Call `write_todos` to mark items as completed "
"as you finish them, and only respond when all items are done.\n"
"</system_reminder>"
),
)
return {"jump_to": "model", "messages": [reminder]}
# 5. Queue a reminder for the next model request and jump back. We must
# not persist this control prompt as a normal HumanMessage, otherwise it
# can leak into user-visible message streams and saved transcripts.
self._queue_completion_reminder(runtime, _format_completion_reminder(todos))
return {"jump_to": "model"}
@override
@hook_config(can_jump_to=["model"])
@@ -177,3 +313,47 @@ class TodoMiddleware(TodoListMiddleware):
) -> dict[str, Any] | None:
"""Async version of after_model."""
return self.after_model(state, runtime)
@staticmethod
def _format_pending_completion_reminders(reminders: list[str]) -> str:
return "\n\n".join(dict.fromkeys(reminders))
def _augment_request(self, request: ModelRequest) -> ModelRequest:
reminders = self._drain_completion_reminders(request.runtime)
if not reminders:
return request
new_messages = [
*request.messages,
HumanMessage(
content=self._format_pending_completion_reminders(reminders),
name="todo_completion_reminder",
additional_kwargs={"hide_from_ui": True},
),
]
return request.override(messages=new_messages)
@override
def wrap_model_call(
self,
request: ModelRequest,
handler: Callable[[ModelRequest], ModelResponse],
) -> ModelCallResult:
return handler(self._augment_request(request))
@override
async def awrap_model_call(
self,
request: ModelRequest,
handler: Callable[[ModelRequest], Awaitable[ModelResponse]],
) -> ModelCallResult:
return await handler(self._augment_request(request))
@override
def after_agent(self, state: PlanningState, runtime: Runtime) -> dict[str, Any] | None:
self._clear_current_run_completion_reminders(runtime)
return None
@override
async def aafter_agent(self, state: PlanningState, runtime: Runtime) -> dict[str, Any] | None:
self._clear_current_run_completion_reminders(runtime)
return None
@@ -9,7 +9,7 @@ from typing import Any, override
from langchain.agents import AgentState
from langchain.agents.middleware import AgentMiddleware
from langchain.agents.middleware.todo import Todo
from langchain_core.messages import AIMessage
from langchain_core.messages import AIMessage, ToolMessage
from langgraph.runtime import Runtime
logger = logging.getLogger(__name__)
@@ -217,6 +217,17 @@ def _infer_step_kind(message: AIMessage, actions: list[dict[str, Any]]) -> str:
return "thinking"
def _has_tool_call(message: AIMessage, tool_call_id: str) -> bool:
"""Return True if the AIMessage contains a tool_call with the given id."""
for tc in message.tool_calls or []:
if isinstance(tc, dict):
if tc.get("id") == tool_call_id:
return True
elif hasattr(tc, "id") and tc.id == tool_call_id:
return True
return False
def _build_attribution(message: AIMessage, todos: list[Todo]) -> dict[str, Any]:
tool_calls = getattr(message, "tool_calls", None) or []
actions: list[dict[str, Any]] = []
@@ -261,8 +272,51 @@ class TokenUsageMiddleware(AgentMiddleware):
if not messages:
return None
# Annotate subagent token usage onto the AIMessage that dispatched it.
# When a task tool completes, its usage is cached by tool_call_id. Detect
# the ToolMessage → search backward for the corresponding AIMessage → merge.
# Walk backward through consecutive ToolMessages before the new AIMessage
# so that multiple concurrent task tool calls all get their subagent tokens
# written back to the same dispatch message (merging into one update).
state_updates: dict[int, AIMessage] = {}
if len(messages) >= 2:
from deerflow.tools.builtins.task_tool import pop_cached_subagent_usage
idx = len(messages) - 2
while idx >= 0:
tool_msg = messages[idx]
if not isinstance(tool_msg, ToolMessage) or not tool_msg.tool_call_id:
break
subagent_usage = pop_cached_subagent_usage(tool_msg.tool_call_id)
if subagent_usage:
# Search backward from the ToolMessage to find the AIMessage
# that dispatched it. A single model response can dispatch
# multiple task tool calls, so we can't assume a fixed offset.
dispatch_idx = idx - 1
while dispatch_idx >= 0:
candidate = messages[dispatch_idx]
if isinstance(candidate, AIMessage) and _has_tool_call(candidate, tool_msg.tool_call_id):
# Accumulate into an existing update for the same
# AIMessage (multiple task calls in one response),
# or merge fresh from the original message.
existing_update = state_updates.get(dispatch_idx)
prev = existing_update.usage_metadata if existing_update else (getattr(candidate, "usage_metadata", None) or {})
merged = {
**prev,
"input_tokens": prev.get("input_tokens", 0) + subagent_usage["input_tokens"],
"output_tokens": prev.get("output_tokens", 0) + subagent_usage["output_tokens"],
"total_tokens": prev.get("total_tokens", 0) + subagent_usage["total_tokens"],
}
state_updates[dispatch_idx] = candidate.model_copy(update={"usage_metadata": merged})
break
dispatch_idx -= 1
idx -= 1
last = messages[-1]
if not isinstance(last, AIMessage):
if state_updates:
return {"messages": [state_updates[idx] for idx in sorted(state_updates)]}
return None
usage = getattr(last, "usage_metadata", None)
@@ -288,11 +342,12 @@ class TokenUsageMiddleware(AgentMiddleware):
additional_kwargs = dict(getattr(last, "additional_kwargs", {}) or {})
if additional_kwargs.get(TOKEN_USAGE_ATTRIBUTION_KEY) == attribution:
return None
return {"messages": [state_updates[idx] for idx in sorted(state_updates)]} if state_updates else None
additional_kwargs[TOKEN_USAGE_ATTRIBUTION_KEY] = attribution
updated_msg = last.model_copy(update={"additional_kwargs": additional_kwargs})
return {"messages": [updated_msg]}
state_updates[len(messages) - 1] = updated_msg
return {"messages": [state_updates[idx] for idx in sorted(state_updates)]}
@override
def after_model(self, state: AgentState, runtime: Runtime) -> dict | None: