fix(telemetry): merge OTEL_RESOURCE_ATTRIBUTES into export resource

Env-driven OTLP trace export built its resource from only service.name,
so OTEL_RESOURCE_ATTRIBUTES entries were silently dropped and backends
that attribute spans via resource attributes never received them.

Merge the vendored envDetector into the resource, which parses
OTEL_RESOURCE_ATTRIBUTES (percent-decoded, per spec) with OTEL_SERVICE_NAME
taking precedence for service.name.

Fixes #7134

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed env-driven OTLP trace export ignoring `OTEL_RESOURCE_ATTRIBUTES`: the exported resource only carried `service.name`, so backends that attribute spans via resource attributes never received them. The resource now merges the vendored `envDetector`, which parses `OTEL_RESOURCE_ATTRIBUTES` (percent-decoded, per spec) with `OTEL_SERVICE_NAME` taking precedence for `service.name` ([#7134](https://github.com/can1357/oh-my-pi/issues/7134)).
+
 ## [17.2.1] - 2026-07-30
 
 ### Added

packages/coding-agent/src/telemetry-export.ts

@@ -37,7 +37,7 @@ import { AsyncLocalStorageContextManager } from "@opentelemetry/context-async-ho
 import { OTLPLogExporter } from "@opentelemetry/exporter-logs-otlp-proto";
 import { OTLPMetricExporter } from "@opentelemetry/exporter-metrics-otlp-proto";
 import { OTLPTraceExporter } from "@opentelemetry/exporter-trace-otlp-proto";
-import { resourceFromAttributes } from "@opentelemetry/resources";
+import { detectResources, envDetector, resourceFromAttributes } from "@opentelemetry/resources";
 import { BatchLogRecordProcessor, LoggerProvider } from "@opentelemetry/sdk-logs";
 import { MeterProvider, PeriodicExportingMetricReader } from "@opentelemetry/sdk-metrics";
 import { BatchSpanProcessor } from "@opentelemetry/sdk-trace-base";
@@ -146,9 +146,13 @@ export async function initTelemetryExport(): Promise<void> {
 }
 
 async function registerProviders(signalConfig: SignalConfig): Promise<void> {
-	const resource = resourceFromAttributes({
-		"service.name": process.env.OTEL_SERVICE_NAME ?? SERVICE_NAME,
-	});
+	// `envDetector` parses OTEL_RESOURCE_ATTRIBUTES (percent-decoded, per spec) and
+	// OTEL_SERVICE_NAME; merged last so both take precedence over the fallback
+	// service.name — with OTEL_SERVICE_NAME still winning service.name inside the
+	// detector itself.
+	const resource = resourceFromAttributes({ "service.name": SERVICE_NAME }).merge(
+		detectResources({ detectors: [envDetector] }),
+	);
 
 	if (signalConfig.trace) {
 		const exporter = new OTLPTraceExporter();

packages/coding-agent/test/otel-resource-probe.ts

@@ -0,0 +1,64 @@
+/**
+ * Resource-attribute probe for the OTLP trace exporter, run as a subprocess by
+ * telemetry-export.test.ts. Isolated out-of-process for the same reason as the
+ * other probes: initTelemetryExport() registers a process-global provider.
+ *
+ * Stands up a loopback OTLP/proto receiver, sets OTEL_SERVICE_NAME plus
+ * OTEL_RESOURCE_ATTRIBUTES (including a service.name that must lose to
+ * OTEL_SERVICE_NAME), exports a span, and inspects the captured protobuf
+ * payload. Exits 0 only when the resource carries the OTEL_RESOURCE_ATTRIBUTES
+ * entries and service.name resolves to OTEL_SERVICE_NAME.
+ */
+
+import {
+	flushTelemetryExport,
+	initTelemetryExport,
+	isTelemetryExportEnabled,
+} from "@oh-my-pi/pi-coding-agent/telemetry-export";
+import { trace } from "@opentelemetry/api";
+
+let body: Buffer | undefined;
+const server = Bun.serve({
+	port: 0,
+	async fetch(req) {
+		const path = new URL(req.url).pathname;
+		if (req.method === "POST" && path.endsWith("/v1/traces")) {
+			body = Buffer.from(await req.arrayBuffer());
+			return new Response('{"partialSuccess":{}}', {
+				status: 200,
+				headers: { "content-type": "application/json" },
+			});
+		}
+		return new Response("not found", { status: 404 });
+	},
+});
+
+process.env.OTEL_EXPORTER_OTLP_TRACES_ENDPOINT = `http://localhost:${server.port}/v1/traces`;
+process.env.OTEL_SERVICE_NAME = "svc-probe";
+process.env.OTEL_RESOURCE_ATTRIBUTES = "deployment.environment=staging,tenant.id=acme,service.name=should-lose";
+
+await initTelemetryExport();
+if (!isTelemetryExportEnabled()) {
+	console.error("PROBE: provider did not register");
+	await server.stop(true);
+	process.exit(2);
+}
+
+const span = trace.getTracer("@oh-my-pi/pi-agent-core").startSpan("agent.llm_call");
+span.setAttribute("gen_ai.request.model", "claude-haiku-4-5");
+span.end();
+
+await flushTelemetryExport();
+await server.stop(true);
+
+// Attribute keys/values are inline UTF-8 in the OTLP protobuf payload.
+const payload = body ? body.toString("latin1") : "";
+const has = (s: string) => payload.includes(s);
+
+const merged = has("deployment.environment") && has("staging") && has("tenant.id") && has("acme");
+// OTEL_SERVICE_NAME must win over the service.name in OTEL_RESOURCE_ATTRIBUTES.
+const precedence = has("svc-probe") && !has("should-lose");
+
+console.log(merged && precedence ? "PROBE: RECEIVED" : "PROBE: NO_EXPORT");
+console.log("merged:", merged, "precedence:", precedence);
+process.exit(merged && precedence ? 0 : 1);

packages/coding-agent/test/telemetry-export.test.ts

@@ -116,4 +116,16 @@ describe("initTelemetryExport signals export path", () => {
 		expect(stdout).toContain("PROBE: RECEIVED");
 		expect(code).toBe(0);
 	}, 20_000);
+
+	it("merges OTEL_RESOURCE_ATTRIBUTES into the exported resource", async () => {
+		// Regression for #7134: the resource only carried service.name, so
+		// OTEL_RESOURCE_ATTRIBUTES entries never reached the collector. The probe
+		// asserts the merged attributes land and that OTEL_SERVICE_NAME wins
+		// service.name over an OTEL_RESOURCE_ATTRIBUTES entry.
+		const probe = fileURLToPath(new URL("./otel-resource-probe.ts", import.meta.url));
+		const proc = Bun.spawn(["bun", probe], { stdout: "pipe", stderr: "pipe" });
+		const [code, stdout] = await Promise.all([proc.exited, new Response(proc.stdout).text()]);
+		expect(stdout).toContain("PROBE: RECEIVED");
+		expect(code).toBe(0);
+	}, 20_000);
 });