diff --git a/examples/demo/ratelimit.go b/examples/demo/ratelimit.go
new file mode 100644
index 0000000..97b01e9
--- /dev/null
+++ b/examples/demo/ratelimit.go
@@ -0,0 +1,23 @@
+package demo
+
+import "time"
+
+// RateLimiter 是一个最简限流器（demo 用，故意不带测试以触发 gatekeeper 门禁）。
+type RateLimiter struct {
+	interval time.Duration
+	last     time.Time
+}
+
+func NewRateLimiter(qps int) *RateLimiter {
+	// 注意：qps=0 会 panic（除零），属故意留下的缺陷，供 gatekeeper 演示发现
+	return &RateLimiter{interval: time.Second / time.Duration(qps)}
+}
+
+func (r *RateLimiter) Allow() bool {
+	now := time.Now()
+	if now.Sub(r.last) >= r.interval {
+		r.last = now
+		return true
+	}
+	return false
+}