I got hit with a $400 AI agent bill overnight. Here's the 5-line fix.

My LangChain agent entered a loop at 2am. By morning: $400 gone.

The problem isn't the loop. The problem is nothing stopped it.
Logging doesn't stop it. Alerts don't stop it. They tell you after.

What you need is a gate that fires before the LLM call — not after.

I built Valta for exactly this. Here's how it works in 5 lines:

python
from langchain_valta import ValtaBudgetTool
from langchain.agents import initialize_agent

guard = ValtaBudgetTool(api_key="vk_live_...", agent_id="my-agent")
agent = initialize_agent(tools=[guard, ...your_tools], llm=llm)