Safety & Control
7 min readUpdated: October 2026

How to Prevent Infinite LLM Agent Loops: Runaway Guards & Self-Healing Phases

Infinite loops are the single most expensive and frustrating failure mode in autonomous AI agents. When an agent encounters unexpected tool errors, basic ReAct loops repeatedly call the same faulty tool until token limits or credit cards are exhausted. Smoke Monkey Harness eliminates this with deterministic phase transitions and runaway loop guards.

Technical Review: Smoke Monkey Core Architecture Team
Tested on Node.js 18+ & BunTypeScript 5.x
Quick Answer & Executive Definition

How to Prevent Infinite LLM Agent Loops: Runaway Guards & Self-Healing Phases: Infinite loops are the single most expensive and frustrating failure mode in autonomous AI agents. When an agent encounters unexpected tool errors, basic ReAct loops repeatedly call the same faulty tool until token limits or credit cards are exhausted. Smoke Monkey Harness eliminates this with deterministic phase transitions and runaway loop guards. Designed as a zero-dependency, open-source TypeScript architecture under the MIT License with native Model Context Protocol (MCP) support and deterministic phase state machines.

Key Architectural Takeaways

The Anatomy of an Infinite Agent Loop

In basic prompt-based agent architectures, when a tool execution fails, the error message is appended to the message list. The model sees the failure and frequently attempts the exact same action with minor syntactic variations, creating a circular loop that drains token quotas.

Google Search Questions & Answers

Frequently Asked Questions

Q:What is the default loop limit in Smoke Monkey?

Smoke Monkey defaults to a safe cap of 25 loops per task, which can be configured via the `maxLoops` parameter in `createAgent()`.

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Build with Smoke Monkey Harness

Zero dependencies. 24 built-in tools. Human-in-the-loop safety. 100% open source under the MIT License.

npm install smoke-monkey-harness