From 881ff712523ca9148ec0917e84ec8c436a90b12e Mon Sep 17 00:00:00 2001 From: DanielWalnut <45447813+hetaoBackend@users.noreply.github.com> Date: Sat, 9 May 2026 19:39:36 +0800 Subject: [PATCH] fix(harness): preserve dynamic context across summarization (#2823) --- .../middlewares/dynamic_context_middleware.py | 15 ++++++- .../middlewares/summarization_middleware.py | 21 ++++++++++ .../tests/test_dynamic_context_middleware.py | 24 +++++++++++ .../tests/test_summarization_middleware.py | 42 +++++++++++++++++++ 4 files changed, 100 insertions(+), 2 deletions(-) diff --git a/backend/packages/harness/deerflow/agents/middlewares/dynamic_context_middleware.py b/backend/packages/harness/deerflow/agents/middlewares/dynamic_context_middleware.py index b7b0950e6..714cabaf2 100644 --- a/backend/packages/harness/deerflow/agents/middlewares/dynamic_context_middleware.py +++ b/backend/packages/harness/deerflow/agents/middlewares/dynamic_context_middleware.py @@ -45,6 +45,7 @@ logger = logging.getLogger(__name__) _DATE_RE = re.compile(r"([^<]+)") _DYNAMIC_CONTEXT_REMINDER_KEY = "dynamic_context_reminder" +_SUMMARY_MESSAGE_NAME = "summary" def _extract_date(content: str) -> str | None: @@ -72,6 +73,16 @@ def _last_injected_date(messages: list) -> str | None: return None +def is_dynamic_context_reminder(message: object) -> bool: + """Return whether *message* is a hidden dynamic-context reminder.""" + return isinstance(message, HumanMessage) and bool(message.additional_kwargs.get(_DYNAMIC_CONTEXT_REMINDER_KEY)) + + +def _is_user_injection_target(message: object) -> bool: + """Return whether *message* can receive a dynamic-context reminder.""" + return isinstance(message, HumanMessage) and not is_dynamic_context_reminder(message) and message.name != _SUMMARY_MESSAGE_NAME + + class DynamicContextMiddleware(AgentMiddleware): """Inject memory and current date into HumanMessages as a . @@ -163,7 +174,7 @@ class DynamicContextMiddleware(AgentMiddleware): if last_date is None: # ── First turn: inject full reminder as a separate HumanMessage ───── - first_idx = next((i for i, m in enumerate(messages) if isinstance(m, HumanMessage)), None) + first_idx = next((i for i, m in enumerate(messages) if _is_user_injection_target(m)), None) if first_idx is None: return None full_reminder = self._build_full_reminder() @@ -181,7 +192,7 @@ class DynamicContextMiddleware(AgentMiddleware): return None # ── Midnight crossed: inject date-update reminder as a separate HumanMessage ── - last_human_idx = next((i for i in reversed(range(len(messages))) if isinstance(messages[i], HumanMessage)), None) + last_human_idx = next((i for i in reversed(range(len(messages))) if _is_user_injection_target(messages[i])), None) if last_human_idx is None: return None diff --git a/backend/packages/harness/deerflow/agents/middlewares/summarization_middleware.py b/backend/packages/harness/deerflow/agents/middlewares/summarization_middleware.py index 65b98f9f5..af0881e88 100644 --- a/backend/packages/harness/deerflow/agents/middlewares/summarization_middleware.py +++ b/backend/packages/harness/deerflow/agents/middlewares/summarization_middleware.py @@ -14,6 +14,7 @@ from langgraph.config import get_config from langgraph.graph.message import REMOVE_ALL_MESSAGES from langgraph.runtime import Runtime +from deerflow.agents.middlewares.dynamic_context_middleware import is_dynamic_context_reminder from deerflow.agents.middlewares.tool_call_metadata import clone_ai_message_with_tool_calls logger = logging.getLogger(__name__) @@ -135,6 +136,7 @@ class DeerFlowSummarizationMiddleware(SummarizationMiddleware): return None messages_to_summarize, preserved_messages = self._partition_with_skill_rescue(messages, cutoff_index) + messages_to_summarize, preserved_messages = self._preserve_dynamic_context_reminders(messages_to_summarize, preserved_messages) self._fire_hooks(messages_to_summarize, preserved_messages, runtime) summary = self._create_summary(messages_to_summarize) new_messages = self._build_new_messages(summary) @@ -160,6 +162,7 @@ class DeerFlowSummarizationMiddleware(SummarizationMiddleware): return None messages_to_summarize, preserved_messages = self._partition_with_skill_rescue(messages, cutoff_index) + messages_to_summarize, preserved_messages = self._preserve_dynamic_context_reminders(messages_to_summarize, preserved_messages) self._fire_hooks(messages_to_summarize, preserved_messages, runtime) summary = await self._acreate_summary(messages_to_summarize) new_messages = self._build_new_messages(summary) @@ -179,6 +182,24 @@ class DeerFlowSummarizationMiddleware(SummarizationMiddleware): """ return [HumanMessage(content=f"Here is a summary of the conversation to date:\n\n{summary}", name="summary")] + def _preserve_dynamic_context_reminders( + self, + messages_to_summarize: list[AnyMessage], + preserved_messages: list[AnyMessage], + ) -> tuple[list[AnyMessage], list[AnyMessage]]: + """Keep hidden dynamic-context reminders out of summary compression. + + These reminders carry the current date and optional memory. If summarization + removes them, DynamicContextMiddleware can mistake the summary HumanMessage + for the first user message and inject the reminder in the wrong place. + """ + reminders = [msg for msg in messages_to_summarize if is_dynamic_context_reminder(msg)] + if not reminders: + return messages_to_summarize, preserved_messages + + remaining = [msg for msg in messages_to_summarize if not is_dynamic_context_reminder(msg)] + return remaining, reminders + preserved_messages + def _partition_with_skill_rescue( self, messages: list[AnyMessage], diff --git a/backend/tests/test_dynamic_context_middleware.py b/backend/tests/test_dynamic_context_middleware.py index 267460fd7..a82f0891a 100644 --- a/backend/tests/test_dynamic_context_middleware.py +++ b/backend/tests/test_dynamic_context_middleware.py @@ -139,6 +139,30 @@ def test_injects_only_into_first_human_message_not_later_ones(): assert all(m.id != "msg-2" for m in msgs) +def test_summary_human_message_is_not_used_as_injection_target(): + """After summarization, the synthetic summary HumanMessage is not a user turn.""" + mw = _make_middleware() + state = { + "messages": [ + HumanMessage(content="Here is a summary of the conversation to date:\n\n...", id="summary-1", name="summary"), + AIMessage(content="Earlier reply"), + HumanMessage(content="Follow-up", id="msg-2"), + ] + } + + with mock.patch("deerflow.agents.lead_agent.prompt._get_memory_context", return_value=""), mock.patch("deerflow.agents.middlewares.dynamic_context_middleware.datetime") as mock_dt: + mock_dt.now.return_value.strftime.return_value = "2026-05-08, Friday" + result = mw.before_agent(state, _fake_runtime()) + + assert result is not None + msgs = result["messages"] + assert len(msgs) == 2 + assert msgs[0].id == "msg-2" + assert msgs[0].additional_kwargs.get(_DYNAMIC_CONTEXT_REMINDER_KEY) is True + assert msgs[1].id == "msg-2__user" + assert msgs[1].content == "Follow-up" + + # --------------------------------------------------------------------------- # Edge cases # --------------------------------------------------------------------------- diff --git a/backend/tests/test_summarization_middleware.py b/backend/tests/test_summarization_middleware.py index abed0105a..cbd94e434 100644 --- a/backend/tests/test_summarization_middleware.py +++ b/backend/tests/test_summarization_middleware.py @@ -1,12 +1,14 @@ from __future__ import annotations from types import SimpleNamespace +from unittest import mock from unittest.mock import MagicMock import pytest from langchain_core.messages import AIMessage, HumanMessage, RemoveMessage, ToolMessage from deerflow.agents.memory.summarization_hook import memory_flush_hook +from deerflow.agents.middlewares.dynamic_context_middleware import _DYNAMIC_CONTEXT_REMINDER_KEY, DynamicContextMiddleware from deerflow.agents.middlewares.summarization_middleware import DeerFlowSummarizationMiddleware, SummarizationEvent from deerflow.config.memory_config import MemoryConfig @@ -20,6 +22,14 @@ def _messages() -> list: ] +def _dynamic_context_reminder(msg_id: str = "reminder-1") -> HumanMessage: + return HumanMessage( + content="\n2026-05-08, Friday\n", + id=msg_id, + additional_kwargs={"hide_from_ui": True, _DYNAMIC_CONTEXT_REMINDER_KEY: True}, + ) + + def _runtime(thread_id: str | None = "thread-1", agent_name: str | None = None) -> SimpleNamespace: context = {} if thread_id is not None: @@ -98,6 +108,38 @@ def test_before_summarization_hook_receives_messages_before_compression() -> Non assert result["messages"][1].content.startswith("Here is a summary") +def test_dynamic_context_reminder_is_preserved_across_summarization() -> None: + captured: list[SummarizationEvent] = [] + middleware = _middleware(before_summarization=[captured.append]) + reminder = _dynamic_context_reminder() + + result = middleware.before_model( + { + "messages": [ + reminder, + HumanMessage(content="user-1"), + AIMessage(content="assistant-1"), + HumanMessage(content="user-2"), + ] + }, + _runtime(), + ) + + assert len(captured) == 1 + assert [message.content for message in captured[0].messages_to_summarize] == ["user-1"] + assert captured[0].preserved_messages[0] is reminder + + emitted = result["messages"] + assert isinstance(emitted[0], RemoveMessage) + assert emitted[1].name == "summary" + assert emitted[2] is reminder + + followup_state = {"messages": [*emitted[1:], HumanMessage(content="Follow-up", id="msg-2")]} + with mock.patch("deerflow.agents.middlewares.dynamic_context_middleware.datetime") as mock_dt: + mock_dt.now.return_value.strftime.return_value = "2026-05-08, Friday" + assert DynamicContextMiddleware().before_agent(followup_state, _runtime()) is None + + def test_before_summarization_hook_not_called_when_threshold_not_met() -> None: captured: list[SummarizationEvent] = [] middleware = _middleware(before_summarization=[captured.append], trigger=("messages", 10))