Infinite Agent Loops

# Comprehensive loop detection for agent execution
class LoopDetector:
    def __init__(self, max_steps: int = 15, max_repeated_action: int = 3):
        self.max_steps = max_steps
        self.max_repeated = max_repeated_action
        self.history = []

    def check(self, action: str, args: dict) -> dict:
        """
        Check for loop conditions before executing a step.
        Returns a result indicating if the agent should continue or stop.
        """
        self.history.append({"action": action, "args": str(args)})
        step = len(self.history)

        # Check 1: Absolute step limit
        if step > self.max_steps:
            return {
                "should_stop": True,
                "reason": f"Step limit exceeded: {step}/{self.max_steps}"
            }

        # Check 2: Repeated identical action + args (exact loop)
        current = f"{action}:{args}"
        recent = [f"{h['action']}:{h['args']}" for h in self.history[-5:]]
        if recent.count(current) >= self.max_repeated:
            return {
                "should_stop": True,
                "reason": f"Exact loop detected: '{action}' with same args repeated {self.max_repeated}x"
            }

        # Check 3: Same action type repeated too many times (even with different args)
        recent_actions = [h["action"] for h in self.history[-6:]]
        if recent_actions.count(action) >= self.max_repeated + 1:
            return {
                "should_stop": True,
                "reason": f"Action '{action}' repeated {self.max_repeated+1}x in last 6 steps — possible loop"
            }

        # Check 4: No progress — state data hasn't grown in last 5 steps
        return {"should_stop": False, "step": step}

detector = LoopDetector(max_steps=10, max_repeated_action=3)

# Simulate a loop
actions = ["web_search", "web_search", "web_search", "web_search"]
for a in actions:
    result = detector.check(a, {"query": "same query"})
    print(f"  Step {result.get('step','?')}: {a} → {'STOP: ' + result['reason'] if result['should_stop'] else 'continue'}")
    if result["should_stop"]:
        break