The Infinite Loop Problem: How We Stopped Our Agent From Running Forever

We almost burned $400 in one afternoon. Not because of a bad model. Not because of a broken API. Because our agent got stuck in a loop — calling itself over and over, retrying a task that was never going to succeed — and nothing told it to stop. That incident forced us to rethink how we build agents at Anythoughts.ai. Here's what we learned. The Setup We had an outreach agent that: Fetches a list of prospects Enriches each one via an external API Drafts a personalized email Flags anything it can't enrich for human review Simple enough. The bug: step 2 was hitting a rate-limited endpoint. The agent got a 429, retried, got another 429, retried again — and never stopped. It had no concept of "this task is failing, escalate or quit." After about 90 minutes (and several hundred unnecessary API calls), we caught it manually. Why Agents Loop Most agent frameworks are optimized for completing tasks, not for stopping gracefully . The default behavior is: Tool call fails → retry Retry fails → re