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f093702e4e
Resolves https://github.com/langchain-ai/langchain/issues/35585 This would previously raise KeyError: ```python from typing import Annotated from langchain_core.tools import tool from langchain.agents import create_agent from typing_extensions import NotRequired from langgraph.prebuilt import InjectedState from langchain.agents import AgentState class CustomAgentState(AgentState): city: NotRequired[str] @tool def get_weather(city: Annotated[str | None, InjectedState("city")] = None) -> str: """Get weather for a given city.""" if city is None: city = "Boston" return f"It's always sunny in {city}!" agent = create_agent( model="claude-sonnet-4-6", tools=[get_weather], system_prompt="You are a helpful assistant", state_schema=CustomAgentState, ) input_message = { "role": "user", "content": "What's the weather?", } result = agent.invoke({"messages": [input_message]}) for m in result["messages"]: m.pretty_print() ``` --------- Co-authored-by: Sydney Runkle <sydneymarierunkle@gmail.com>