Cline rules

1# Metrics
2 
3## Brief overview
4 
5The proxy collects per-request metrics using Cloudflare Analytics Engine. Metrics collection is gated by the `LOG_METRICS` environment variable.
6 
7## Enabling metrics
8 
9Set `LOG_METRICS = "true"` in `wrangler.toml` or via environment variable. When disabled (default), no metrics are collected or written.
10 
11```toml
12[vars]
13LOG_METRICS = "true"
14```
15 
16## Collected metrics
17 
18| Metric | Type | Description |
19|--------|------|-------------|
20| `requestId` | string | Unique request identifier |
21| `model` | string | Resolved model ID |
22| `provider` | string | Provider name (nvidia, openrouter, etc.) |
23| `isStream` | boolean | Whether the request was streaming |
24| `upstreamLatencyMs` | number | Time to first byte from upstream |
25| `totalProxyMs` | number | Total time spent in the proxy |
26| `ttftMs` | number | Time to first token (streaming only) |
27| `generationTimeMs` | number | Generation time in ms (streaming only) |
28| `tokensPerSecond` | number | Estimated tokens per second |
29| `promptTokens` | number | Prompt tokens (non-streaming only) |
30| `completionTokens` | number | Completion tokens (non-streaming only) |
31| `totalTokens` | number | Total tokens (non-streaming only) |
32| `finishReason` | string | Finish reason from upstream |
33| `upstreamStatus` | number | HTTP status from upstream |
34| `errorType` | string | Error type if the request failed |
35| `errorMessage` | string | Error message if the request failed |
36 
37## Implementation
38 
39Metrics are collected via the `MetricsCollector` class in `metrics/metrics-collector.ts`. The `writeMetrics()` method checks `LOG_METRICS === 'true'` before writing to Analytics Engine.
40 
41```typescript
42// metrics/metrics-collector.ts
43private writeMetrics(metrics: RequestMetrics): void {
44  if (this.env.LOG_METRICS !== 'true') {
45    return
46  }
47 
48  logger.info('[METRICS]', JSON.stringify(metrics))
49 
50  this.env.ANALYTICS.writeDataPoint({
51    // ... Analytics Engine data point
52  })
53}
54```
55