langfuse-observability

# Langfuse Observability ## Overview Set up monitoring for your Langfuse integration: Prometheus metrics for trace/generation throughput, Grafana dashboards, alert rules, and integration with Langfuse's built-in analytics dashboards and Metrics API. ## Prerequisites - Langfuse SDK integrated and producing traces - For custom metrics: Prometheus + Grafana (or compatible stack) - For Langfuse analytics: access to the Langfuse UI dashboard ## Instructions ### Step 1: Langfuse Built-In Dashboards Langfuse provides pre-built dashboards in the UI at `https://cloud.langfuse.com` (or your self-hosted URL): - **Overview**: Total traces, generations, scores, and errors - **Cost Dashboard**: Token usage and costs over time, broken down by model, user, session - **Latency Dashboard**: Response times across models and user segments - **Custom Dashboards**: Build your own with the query engine (multi-level aggregations, filters by user/model/tag) **Accessing via Metrics API:** ```typescript import { LangfuseClient } from "@langfuse/client"; const langfuse = new LangfuseClient(); // Fetch aggregated metrics programmatically const traces = await langfuse.api.traces.list({ fromTimestamp: new Date(Date.now() - 3600000).toISOString(), // Last hour limit: 100, }); console.log(`Traces in last hour: ${traces.data.length}`); // Get observations with cost data const observations = await langfuse.api.observations.list({ type: "GENERATION", fromTimestamp: new Date(Date.now() - 86400...