summarization.py — langchain Source File

Source Code

"""Summarization middleware."""

import uuid
import warnings
from collections.abc import Callable, Iterable, Mapping
from functools import partial
from typing import Any, Literal, cast

from langchain_core.messages import (
    AIMessage,
    AnyMessage,
    MessageLikeRepresentation,
    RemoveMessage,
    ToolMessage,
)
from langchain_core.messages.human import HumanMessage
from langchain_core.messages.utils import (
    count_tokens_approximately,
    get_buffer_string,
    trim_messages,
)
from langgraph.graph.message import (
    REMOVE_ALL_MESSAGES,
)
from langgraph.runtime import Runtime
from typing_extensions import override

from langchain.agents.middleware.types import AgentMiddleware, AgentState, ContextT, ResponseT
from langchain.chat_models import BaseChatModel, init_chat_model

TokenCounter = Callable[[Iterable[MessageLikeRepresentation]], int]

DEFAULT_SUMMARY_PROMPT = """<role>
Context Extraction Assistant
</role>

<primary_objective>
Your sole objective in this task is to extract the highest quality/most relevant context from the conversation history below.
</primary_objective>

<objective_information>
You're nearing the total number of input tokens you can accept, so you must extract the highest quality/most relevant pieces of information from your conversation history.
This context will then overwrite the conversation history presented below. Because of this, ensure the context you extract is only the most important information to continue working toward your overall goal.
</objective_information>

<instructions>
The conversation history below will be replaced with the context you extract in this step.
You want to ensure that you don't repeat any actions you've already completed, so the context you extract from the conversation history should be focused on the most important information to your overall goal.

You should structure your summary using the following sections. Each section acts as a checklist - you must populate it with relevant information or explicitly state "None" if there is nothing to report for that section:

## SESSION INTENT
What is the user's primary goal or request? What overall task are you trying to accomplish? This should be concise but complete enough to understand the purpose of the entire session.

## SUMMARY
Extract and record all of the most important context from the conversation history. Include important choices, conclusions, or strategies determined during this conversation. Include the reasoning behind key decisions. Document any rejected options and why they were not pursued.

## ARTIFACTS
What artifacts, files, or resources were created, modified, or accessed during this conversation? For file modifications, list specific file paths and briefly describe the changes made to each. This section prevents silent loss of artifact information.

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