fix: emit workbench sse accepted span (#1816)

internal/cloud/server-workbench-http.ts

@@ -15,6 +15,7 @@ import {
 } from "./server-http-utils.ts";
 import { createWorkbenchReadModel } from "./workbench-read-model.ts";
 import { createWorkbenchTurnProjection, createWorkbenchTurnTimingProjection, durableTraceStatus, RUNNING_STATUSES, TERMINAL_STATUSES } from "./workbench-turn-projection.ts";
+import { emitHttpServerRequestSpan } from "./otel-trace.ts";
 
 const DEFAULT_PAGE_LIMIT = 50;
 const DEFAULT_SESSION_LIST_LIMIT = 20;
@@ -131,6 +132,7 @@ export async function handleWorkbenchRealtimeHttp(request, response, url, option
     heartbeatMs,
     outboxMode: typeof (options.runtimeStore ?? null)?.readWorkbenchProjectionOutbox === "function"
   });
+  emitWorkbenchRealtimeAcceptedOtelSpan(request, options.env);
   if (activeTraceId) {
     await (perf ? perf.measure("workbench_initial_trace", () => writeTraceRealtimeSnapshot({ writeEvent, options, actor: auth.actor, traceId: activeTraceId, reason: "initial" })) : writeTraceRealtimeSnapshot({ writeEvent, options, actor: auth.actor, traceId: activeTraceId, reason: "initial" }));
     const runtimeStore = options.runtimeStore ?? null;
@@ -245,6 +247,25 @@ function attachWorkbenchRealtimeOtelContext(request, fields = {}) {
   };
 }
 
+function emitWorkbenchRealtimeAcceptedOtelSpan(request, env = process.env) {
+  const context = request?.hwlabHttpRequestContext;
+  if (!context?.traceId) return;
+  const endedAtMs = Date.now();
+  void emitHttpServerRequestSpan(context, env, {
+    startTimeMs: context.startedAtMs,
+    endTimeMs: endedAtMs,
+    statusCode: 200,
+    method: "GET",
+    route: "/v1/workbench/events",
+    attributes: {
+      ...(context.otelAttributes ?? {}),
+      "http.closed_by": "sse-accepted",
+      "workbench.sse.lifecycle": "accepted",
+      "workbench.sse.accept_latency_ms": Math.max(0, endedAtMs - Number(context.startedAtMs ?? endedAtMs))
+    }
+  }).catch(() => undefined);
+}
+
 function realtimeEventCreatedAt(payload) {
   const candidates = [payload?.event?.createdAt, payload?.snapshot?.lastEvent?.createdAt, payload?.turn?.updatedAt];
   for (const value of candidates) {