langchain-notepad-middleware 0.1.0

A LangChain agent middleware that provides a plain-text scratchpad/notepad.

LangChain Notepad Middleware

A production-grade LangChain middleware that provides a plain-text persistent "scratchpad" (notepad) for agents to store intermediate state across multi-hop tasks.

Installation

pip install langchain-notepad-middleware

Usage

from langchain.agents import create_agent
from langchain_middleware_notepad import NotePadMiddleware

# Create an agent with the middleware
agent = create_agent(
    model="openai:gpt-4o",
    tools=[...],  # Your other tools
    middleware=[NotePadMiddleware()],
)

How it Works

The middleware injects a system prompt instructing the model to use the notepad for scratchpad memory. It also registers 5 tools for manipulating the notepad state:

1. notepad_append(text): Append text to the note.
2. notepad_replace(text): Overwrite the entire note.
3. notepad_read(): Read the current note content.
4. notepad_is_exist(): Check if a non-empty note exists.
5. notepad_clear(): Clear the note.

The state is stored in a simple string field notepad within the agent state.

Best Practices

• Use append for logging cumulative steps.
• Use replace when summarizing or changing topics.
• The middleware automatically injects prompt guidance, so you don't typically need to manually prompt the agent to use it, although specific task instructions help.