From 3c74a098cf475be5951e506e74e9ce612643b337 Mon Sep 17 00:00:00 2001
From: Chris <chris@ardenholt.com>
Date: Wed, 12 Aug 2026 00:42:56 -0700
Subject: [PATCH] feat: add metrics collection and export

- New MetricsCollector class for tracking cache performance
- JSON export support for analytics
- Hit rate averaging over time
---
 src/metrics.ts | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 src/metrics.ts

diff --git a/src/metrics.ts b/src/metrics.ts
new file mode 100644
index 0000000..a74523c
--- /dev/null
+++ b/src/metrics.ts
@@ -0,0 +1,31 @@
+import { CachedPromptStats } from './index';
+
+export interface MetricsSnapshot {
+  timestamp: number;
+  hitRate: number;
+  tokensSaved: number;
+  stats: CachedPromptStats;
+}
+
+export class MetricsCollector {
+  private snapshots: MetricsSnapshot[] = [];
+
+  recordSnapshot(hitRate: number, tokensSaved: number, stats: CachedPromptStats): void {
+    this.snapshots.push({
+      timestamp: Date.now(),
+      hitRate,
+      tokensSaved,
+      stats,
+    });
+  }
+
+  exportJSON(): string {
+    return JSON.stringify(this.snapshots, null, 2);
+  }
+
+  averageHitRate(): number {
+    if (this.snapshots.length === 0) return 0;
+    const sum = this.snapshots.reduce((acc, s) => acc + s.hitRate, 0);
+    return sum / this.snapshots.length;
+  }
+}