How to Build a Guardrail Metrics Monitor in Python

import random
import time
from collections import defaultdict


class GuardrailMetricsMonitor:
    def __init__(self):
        self.metrics = defaultdict(list)
        self.thresholds = {
            "prompt_toxicity": 0.8,
            "response_length": 500,
            "latency_ms": 1000,
        }

    def record(self, metric_name, value):
        self.metrics[metric_name].append(value)

    def check(self, metric_name, value):
        threshold = self.thresholds[metric_name]
        status = "PASS" if value <= threshold else "ALERT"
        if status == "ALERT":
            self.record(f"{metric_name}_alerts", time.time())
        return status

    def summary(self):
        result = {}
        for name, values in self.metrics.items():
            if values:
                result[name] = {
                    "count": len(values),
                    "avg": round(sum(values) / len(values), 2),
                    "max": max(values),
                }
        return result


if __name__ == "__main__":
    monitor = GuardrailMetricsMonitor()
    names = ["prompt_toxicity", "response_length", "latency_ms"]

    for _ in range(10):
        metric = random.choice(names)
        value = random.uniform(0, 1.2) * (500 if metric == "response_length" else 1)
        status = monitor.check(metric, value)
        monitor.record(metric, value)
        print(f"{metric}: {value:.2f} -> {status}")

    print("\nSummary:")
    for name, stats in monitor.summary().items():
        print(f"  {name}: {stats}")