Setup Sentry Tracing Skill

Setup Sentry Tracing

Configure Sentry's performance monitoring to track transactions and spans.

Invoke This Skill When

User asks to "enable tracing" or "add performance monitoring"
User wants to track API response times, page loads, or latency
User asks about tracesSampleRate or custom spans

Quick Reference

| Platform | Enable | Custom Span | |----------|--------|-------------| | JS/Browser | tracesSampleRate + browserTracingIntegration() | Sentry.startSpan() | | Next.js | tracesSampleRate (auto-integrated) | Sentry.startSpan() | | Node.js | tracesSampleRate | Sentry.startSpan() | | Python | traces_sample_rate | @sentry_sdk.trace or start_span() | | Ruby | traces_sample_rate | start_span() |

JavaScript Setup

Enable tracing

Sentry.init({
  dsn: "YOUR_DSN",
  tracesSampleRate: 1.0,  // 1.0 = 100%, lower for production
  integrations: [Sentry.browserTracingIntegration()],  // Browser/React only
  tracePropagationTargets: ["localhost", /^https:\/\/api\./],
});

Custom spans

// Async operation
const result = await Sentry.startSpan(
  { name: "fetch-user", op: "http.client" },
  async () => {
    return await fetch("/api/user").then(r => r.json());
  }
);

// Nested spans
await Sentry.startSpan({ name: "checkout", op: "transaction" }, async () => {
  await Sentry.startSpan({ name: "validate", op: "validation" }, validateCart);
  await Sentry.startSpan({ name: "payment", op: "payment" }, processPayment);
});

Dynamic sampling

tracesSampler: ({ name, parentSampled }) => {
  if (name.includes("healthcheck")) return 0;
  if (name.includes("checkout")) return 1.0;
  if (parentSampled !== undefined) return parentSampled;
  return 0.1;
},

Python Setup

Enable tracing

sentry_sdk.init(
    dsn="YOUR_DSN",
    traces_sample_rate=1.0,
)

Custom spans

# Decorator
@sentry_sdk.trace
def expensive_function():
    return do_work()

# Context manager
with sentry_sdk.start_span(name="process-order", op="task") as span:
    span.set_data("order.id", order_id)
    process(order_id)

Dynamic sampling

def traces_sampler(ctx):
    name = ctx.get("transaction_context", {}).get("name", "")
    if "healthcheck" in name: return 0
    if "checkout" in name: return 1.0
    return 0.1

sentry_sdk.init(dsn="YOUR_DSN", traces_sampler=traces_sampler)

Ruby Setup

Sentry.init do |config|
  config.dsn = "YOUR_DSN"
  config.traces_sample_rate = 1.0
end

Common Operation Types

| op Value | Use Case | |------------|----------| | http.client | Outgoing HTTP | | http.server | Incoming HTTP | | db / db.query | Database | | cache | Cache operations | | task | Background jobs | | function | Function calls |

Sampling Recommendations

| Traffic | Rate | |---------|------| | Development | 1.0 | | Low (<1K req/min) | 0.5 - 1.0 | | Medium (1K-10K) | 0.1 - 0.5 | | High (>10K) | 0.01 - 0.1 |

Distributed Tracing

Configure tracePropagationTargets to send trace headers to your APIs:

tracePropagationTargets: ["localhost", "https://api.yourapp.com"],

For Next.js 14+ App Router, add to root layout:

export async function generateMetadata() {
  return { other: { ...Sentry.getTraceData() } };
}

Troubleshooting

| Issue | Solution | |-------|----------| | Transactions not appearing | Check tracesSampleRate > 0, verify DSN | | Browser traces missing | Add browserTracingIntegration() | | Distributed traces disconnected | Check tracePropagationTargets, CORS headers | | Too many transactions | Lower sample rate, use tracesSampler to filter |

Agent Skills: Setup Sentry Tracing

Skill Files