Capstone: Designing a Production LangGraph System

Congratulations on making it to the end. Now it is time to put it all together.

The Challenge

Design a "Personal Medical Researcher" agent.

• Input: User symptoms and age.
• Goal: Provide a list of potential conditions and recommended lifestyle changes.
• Constraint 1: Must use reliable medical sources (no hallucinations).
• Constraint 2: Must have a disclaimer that this is not medical advice.
• Constraint 3: Must escalate to a recommendation to "See a Doctor" if specific keywords (chest pain, etc.) appear.

The Architecture

Your task is to draw the graph for this system.

Suggested Nodes

1. SafetyGuard: Scans input for emergencies.
2. Planner: Breaks down the research questions.
3. PubMedSearch: Tool to search medical journals.
4. Synthesizer: Combines research into a draft.
5. ComplianceCheck: Ensures disclaimers are present.

Reference Solution

graph TD
    UserInput --> Safety{Emergency?}
    
    Safety -- "Yes" --> Alert[Critical Alert]
    Safety -- "No" --> Plan[Research Planner]
    
    Plan --> Search1[Search Symptoms]
    Plan --> Search2[Search Treatments]
    
    Search1 --> Synth[Synthesize Report]
    Search2 --> Synth
    
    Synth --> Compliance{Compliance Check}
    
    Compliance -- "Fail" --> Synth
    Compliance -- "Pass" --> Final[Final Response]
    
    style Safety fill:#ffcdd2,stroke:#d32f2f
    style Compliance fill:#fff9c4,stroke:#fbc02d
    style Final fill:#c8e6c9,stroke:#2e7d32

Final Takeaways

• LangGraph brings structure to the unstructured world of LLMs.
• State replaces Prompt Engineering: Instead of a 10-page prompt, build a 10-step state machine.
• Visual Thinking: If you can draw it, you can build it.

Good luck building your own graphs!