Building an AI agent on your laptop is magic. You give it tools, it browses the web, it writes code. But when you try to run that same agent for 100 concurrent users, the magic turns into a nightmare of memory leaks, zombie processes, and potential security breaches.

The "Happy Path" Trap

Most developer demos look like this:

agent = Agent(tools=[Browser(), FileSystem()])
agent.run("Research competitors")

This works perfectly for one user. But what happens when User A’s agent decides to fs.read_file('../.env')? Or when User B’s browser tool hits a page with infinite scroll and eats 8GB of RAM?

The Three Horsemen of Agent Infrastructure

1. Isolation Leaks

Shared runtimes mean shared secrets. Without strict kernel-level isolation, agents can snoop on each other. If Agent A sets an environment variable OPENAI_API_KEY, Agent B running in the same process might be able to read it.

2. Resource Exhaustion

LLMs love loops. One "thought loop" can spawn 1,000 requests or burn 100% CPU, killing the server for everyone else. Traditional web servers have timeouts for requests (e.g., 30s), but agentic tasks often need to run for 5-10 minutes.

3. Zombie Processes

If an agent crashes midway through a Selenium browser session, who cleans up the Chrome process? Over time, these "zombie" processes accumulate until your server falls over.

The Solution: Kubernetes-Style Orchestration

We realized that agents are just containers that talk back. To run them safely, you need the same primitives that cloud providers use:

• Ephemeral Sandboxes: Every agent run spins up a fresh, isolated Firecracker microVM or container. No state leaks.
• Hard Limits: Cap CPU, RAM, and—critically—Time. If an agent loops for 5 minutes, kill it.
• Egress Filtering: Don’t let agents scan your internal network (192.168.x.x). Block it at the network level.

Conclusion

The transition from "demo" to "production" is all about handling the failure modes. At Runctl, we believe developers should focus on the agent’s logic, while the infrastructure handles the isolation, scheduling, and cleanup.

This article was originally published on the Runctl Engineering Blog. We are building the K8s-style runtime for autonomous agents—give it a try if you are scaling past localhost.