About otel-expo-style
An Expo-focused skill for adding OpenTelemetry observability to mobile apps while preserving runtime guards. It covers SDK setup, instrumentation, and business-operation spans.
Key features
- 01Runtime-aware initialization
- 02OpenTelemetry tracer and meter setup
- 03Automatic fetch/XHR instrumentation
- 04Business-operation spans and metrics
- 05Superlog endpoint and token configuration
Use cases
- 01Initializing telemetry only in supported Expo builds
- 02Tracing API calls without wrapping app code
- 03Recording spans and counters for business operations
Install
Copy the command and run it in a terminal.
npx skills add https:/ / github.com/ superloglabs/ skills --skill otel-expo-styleAfter installing, type/otel-expo-stylein Claude Code to confirm it loaded.
Details
From the project READMEOTel Expo Style
Preserve existing runtime guards. If the app avoids native SDKs in Expo Go or an unsupported runtime branch, initialize OTel only inside the supported branch.
const isExpoGo = process.env.EXPO_PUBLIC_RUNTIME === "expo-go";
if (!isExpoGo) {
initObservability();
Sentry.init({ dsn: process.env.EXPO_PUBLIC_SENTRY_DSN });
}
registerRootComponent(App);
In supported builds, call initObservability() before Sentry and before app
registration/user code.
SDK Shape
Use native OTel JS APIs and browser/mobile-compatible providers/exporters. Do
not create recordCounter, sendSuperlogSpan, or tracking-specific helper
files.
export const tracer = trace.getTracer("mugline.mobile");
export const meter = metrics.getMeter("mugline.mobile");
export const ordersSubmitted = meter.createCounter("mug.orders.submitted");
Add automatic fetch/XHR instrumentation when compatible so API calls get spans without wrapping application code.
Product Actions
Wrap low-risk business operations with native active spans.
await tracer.startActiveSpan("mug.order.submit", async (span) => {
try {
span.setAttribute("tenant.id", tenantId);
ordersSubmitted.add(1, { "tenant.id": tenantId, outcome: "success" });
} catch (error) {
span.recordException(error as Error);
span.setStatus({ code: SpanStatusCode.ERROR });
throw error;
} finally {
span.end();
}
});
Configuration
Inline the endpoint and sl_public_ token directly in the observability module.
The token is project-scoped, write-only, and intended to be safe in client
bundles. Avoid EXPO_PUBLIC_* env vars for Superlog so the mobile build does
not depend on deploy-time configuration.
const SUPERLOG_ENDPOINT = "https://intake.superlog.sh";
const SUPERLOG_PUBLIC_TOKEN = "sl_public_...";
const SERVICE_NAME = "mugline-mobile";
// The token MUST be sent as the `x-api-key` header. Ingest only reads
// `x-api-key` or `Authorization: Bearer <token>`; any other header name 401s.
function superlogHeaders(token: string): Record<string, string> {
return { "x-api-key": token };
}
const exporter = new OTLPTraceExporter({
url: `${SUPERLOG_ENDPOINT}/v1/traces`,
headers: superlogHeaders(SUPERLOG_PUBLIC_TOKEN),
});