mirror of
https://github.com/langchain-ai/langgraph.git
synced 2026-09-01 04:39:01 +02:00
docs: cross link working w/ memory in tools (#4464)
This commit is contained in:
@@ -112,7 +112,7 @@ from langgraph.prebuilt import create_react_agent
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# highlight-next-line
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def prompt(state: AgentState, config: RunnableConfig) -> list[AnyMessage]: # (1)!
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user_name = config.get("configurable", {}).get("user_name")
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user_name = config["configurable"].get("user_name")
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system_msg = f"You are a helpful assistant. Address the user as {user_name}."
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return [{"role": "system", "content": system_msg}] + state["messages"]
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@@ -107,7 +107,7 @@ Common use cases:
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config: RunnableConfig,
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) -> list[AnyMessage]:
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# highlight-next-line
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user_name = config.get("configurable", {}).get("user_name")
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user_name = config["configurable"].get("user_name")
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system_msg = f"You are a helpful assistant. User's name is {user_name}"
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return [{"role": "system", "content": system_msg}] + state["messages"]
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@@ -162,7 +162,7 @@ Common use cases:
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})
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```
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## Tools
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## Accessing Context in Tools
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Tools can access context through special parameter **annotations**.
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@@ -183,7 +183,7 @@ Tools can access context through special parameter **annotations**.
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) -> str:
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"""Look up user info."""
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# highlight-next-line
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user_id = config.get("configurable", {}).get("user_id")
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user_id = config["configurable"].get("user_id")
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return "User is John Smith" if user_id == "user_123" else "Unknown user"
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agent = create_react_agent(
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@@ -231,66 +231,6 @@ Tools can access context through special parameter **annotations**.
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})
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```
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### Update Context from Tools
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## Update context from tools
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Tools can modify the agent's state during execution. This is useful for persisting intermediate results or making information accessible to subsequent tools or prompts.
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```python
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from typing import Annotated
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from langchain_core.tools import InjectedToolCallId
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from langchain_core.messages import ToolMessage
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from langgraph.prebuilt import InjectedState
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from langgraph.types import Command
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class CustomState(AgentState):
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# highlight-next-line
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user_name: str
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def get_user_info(
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# highlight-next-line
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tool_call_id: Annotated[str, InjectedToolCallId],
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# highlight-next-line
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config: RunnableConfig
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) -> Command:
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"""Look up user info."""
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# highlight-next-line
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user_id = config.get("configurable", {}).get("user_id")
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name = "John Smith" if user_id == "user_123" else "Unknown user"
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return Command(update={
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# highlight-next-line
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"user_name": name,
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# update the message history
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# highlight-next-line
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"messages": [
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ToolMessage(
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"Successfully looked up user information",
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# highlight-next-line
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tool_call_id=tool_call_id
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)
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]
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})
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def greet(
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# highlight-next-line
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state: Annotated[CustomState, InjectedState]
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) -> str:
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"""Use this to greet the user once you found their info."""
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user_name = state["user_name"]
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return f"Hello {user_name}!"
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agent = create_react_agent(
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model="anthropic:claude-3-7-sonnet-latest",
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tools=[get_user_info, greet],
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# highlight-next-line
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state_schema=CustomState
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)
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agent.invoke(
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{"messages": [{"role": "user", "content": "greet the user"}]},
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# highlight-next-line
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config={"configurable": {"user_id": "user_123"}}
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)
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```
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For more details, see [how to update state from tools](../how-tos/update-state-from-tools.ipynb).
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Tools can update agent's context (state and long-term memory) during execution. This is useful for persisting intermediate results or making information accessible to subsequent tools or prompts. See [Memory](./memory.md#read-short-term) guide for more information.
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+103
-4
@@ -149,6 +149,104 @@ agent = create_react_agent(
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To learn more about using `pre_model_hook` for managing message history, see this [how-to guide](../how-tos/create-react-agent-manage-message-history.ipynb)
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### Read in tools { #read-short-term }
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LangGraph allows agent to access its short-term memory (state) inside the tools.
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```python
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from typing import Annotated
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from langgraph.prebuilt import InjectedState, create_react_agent
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class CustomState(AgentState):
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# highlight-next-line
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user_id: str
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def get_user_info(
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# highlight-next-line
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state: Annotated[CustomState, InjectedState]
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) -> str:
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"""Look up user info."""
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# highlight-next-line
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user_id = state["user_id"]
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return "User is John Smith" if user_id == "user_123" else "Unknown user"
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agent = create_react_agent(
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model="anthropic:claude-3-7-sonnet-latest",
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tools=[get_user_info],
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# highlight-next-line
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state_schema=CustomState,
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)
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agent.invoke({
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"messages": "look up user information",
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# highlight-next-line
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"user_id": "user_123"
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})
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```
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See the [Context](./context.md#__tabbed_2_2) guide for more information.
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### Write from tools { #write-short-term }
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To modify the agent's short-term memory (state) during execution, you can return state updates directly from the tools. This is useful for persisting intermediate results or making information accessible to subsequent tools or prompts.
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```python
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from typing import Annotated
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from langchain_core.tools import InjectedToolCallId
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from langchain_core.runnables import RunnableConfig
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from langchain_core.messages import ToolMessage
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from langgraph.prebuilt import InjectedState, create_react_agent
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from langgraph.prebuilt.chat_agent_executor import AgentState
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from langgraph.types import Command
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class CustomState(AgentState):
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# highlight-next-line
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user_name: str
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def update_user_info(
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tool_call_id: Annotated[str, InjectedToolCallId],
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config: RunnableConfig
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) -> Command:
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"""Look up and update user info."""
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user_id = config["configurable"].get("user_id")
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name = "John Smith" if user_id == "user_123" else "Unknown user"
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# highlight-next-line
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return Command(update={
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# highlight-next-line
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"user_name": name,
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# update the message history
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"messages": [
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ToolMessage(
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"Successfully looked up user information",
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tool_call_id=tool_call_id
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)
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]
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})
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def greet(
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# highlight-next-line
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state: Annotated[CustomState, InjectedState]
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) -> str:
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"""Use this to greet the user once you found their info."""
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user_name = state["user_name"]
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return f"Hello {user_name}!"
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agent = create_react_agent(
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model="anthropic:claude-3-7-sonnet-latest",
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tools=[get_user_info, greet],
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# highlight-next-line
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state_schema=CustomState
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)
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agent.invoke(
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{"messages": [{"role": "user", "content": "greet the user"}]},
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# highlight-next-line
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config={"configurable": {"user_id": "user_123"}}
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)
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```
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For more details, see [how to update state from tools](../how-tos/update-state-from-tools.ipynb).
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## Long-term memory
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Use long-term memory to store user-specific or application-specific data across conversations. This is useful for applications like chatbots, where you want to remember user preferences or other information.
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@@ -158,9 +256,10 @@ To use long-term memory, you need to:
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1. [Configure a store](../how-tos/cross-thread-persistence.ipynb) to persist data across invocations.
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2. Use the [`get_store`][langgraph.config.get_store] function to access the store from within tools or prompts.
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### Reading
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### Read { #read-long-term }
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```python title="A tool the agent can use to look up user information"
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from langchain_core.runnables import RunnableConfig
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from langgraph.config import get_store
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from langgraph.prebuilt import create_react_agent
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from langgraph.store.memory import InMemoryStore
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@@ -183,7 +282,7 @@ def get_user_info(config: RunnableConfig) -> str:
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# Same as that provided to `create_react_agent`
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# highlight-next-line
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store = get_store() # (6)!
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user_id = config.get("configurable", {}).get("user_id")
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user_id = config["configurable"].get("user_id")
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# highlight-next-line
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user_info = store.get(("users",), user_id) # (7)!
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return str(user_info.value) if user_info else "Unknown user"
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@@ -212,7 +311,7 @@ agent.invoke(
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7. The `get` method is used to retrieve data from the store. The first argument is the namespace, and the second argument is the key. This will return a `StoreValue` object, which contains the value and metadata about the value.
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8. The `store` is passed to the agent. This enables the agent to access the store when running tools. You can also use the `get_store` function to access the store from anywhere in your code.
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### Writing
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### Write { #write-long-term }
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```python title="Example of a tool that updates user information"
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from typing_extensions import TypedDict
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@@ -231,7 +330,7 @@ def save_user_info(user_info: UserInfo, config: RunnableConfig) -> str: # (3)!
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# Same as that provided to `create_react_agent`
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# highlight-next-line
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store = get_store() # (4)!
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user_id = config.get("configurable", {}).get("user_id")
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user_id = config["configurable"].get("user_id")
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# highlight-next-line
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store.put(("users",), user_id, user_info) # (5)!
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return "Successfully saved user info."
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@@ -271,6 +271,13 @@ By default, the agent will catch all exceptions raised during tool calls and wil
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See [API reference][langgraph.prebuilt.tool_node.ToolNode] for more information on different tool error handling options.
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## Working with memory
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LangGraph allows access to short-term and long-term memory from tools. See [Memory](./memory.md) guide for more information on:
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* how to [read](./memory.md#read-short-term) from and [write](./memory.md#write-short-term) to **short-term** memory
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* how to [read](./memory.md#read-long-term) from and [write](./memory.md#write-long-term) to **long-term** memory
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## Prebuilt tools
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LangChain supports a wide range of prebuilt tool integrations for interacting with APIs, databases, file systems, web data, and more. These tools extend the functionality of agents and enable rapid development.
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