Update unit2/langgraph/agent.ipynb
fix typo
The LangGraph notebook update looks solid — the state machine approach in unit2/langgraph/agent.ipynb is a good way to teach conditional edges and tool-calling loops without burying learners in framework boilerplate.
One thing worth flagging for the curriculum: as students move from toy agents to multi-agent graphs (which LangGraph supports natively via StateGraph with subgraph nodes), they'll hit a real design question that the notebook doesn't address — how does one agent verify the identity or claimed capabilities of another agent it's invoking? Right now most course material treats agent-to-agent calls as trusted by default, which works fine in a notebook but creates bad habits for production. The HN thread on human review in production agents keeps circling back to this: people add human-in-the-loop checkpoints partly because they can't trust intermediate agents in the graph. This is exactly the problem we work on at AgentGraph — giving each agent node a verifiable identity so trust decisions can be made at the edge rather than by pausing the whole graph for a human.
A small addition to the notebook — even just a comment block explaining that in production you'd want to verify the tool-calling agent's identity before accepting its output — would make agents-course/notebooks meaningfully more useful than most LangGraph tutorials out there. The gap between "it works in a notebook" and "it works in a system with multiple agents and real stakes" is mostly about trust architecture, and the course is in a good position to introduce that concept early.