Cost and Reliability

Every loop costs money.

The Token Explosion

If an agent gets stuck in a loop for 20 steps, and each step uses 4k context: 20 steps * 4,000 tokens * $0.03/1k = $2.40 One bad user request can cost you $2.40. Ten thousand users = Bankruptcy.

graph TD
    User --> Agent
    Agent --> Loop{Stuck?}
    Loop -- Yes --> Retry[Retry Step]
    Retry --> Cost[$$$ Usage Spikes]
    Cost --> Retry
    Loop -- No --> Success
    
    style Cost fill:#ffcdd2,stroke:#d32f2f

Reliability

A single monolithic prompt is a "Single Point of Failure".

• If the prompt is too long, the LLM "forgets" instructions in the middle.
• If one part of the logic fails (e.g., JSON formatting), the whole chain fails.

LangGraph breaks this monolith into small, reliable nodes. If one node fails, you only retry that node, not the whole 10,000 token chain.