diff --git a/internal/cloud/server-workbench-http.ts b/internal/cloud/server-workbench-http.ts
index d1b1c4f6..7379ed97 100644
--- a/internal/cloud/server-workbench-http.ts
+++ b/internal/cloud/server-workbench-http.ts
@@ -74,23 +74,30 @@ export async function handleWorkbenchReadModelHttp(request, response, url, optio
 }
 
 export async function handleWorkbenchRealtimeHttp(request, response, url, options = {}) {
-  if (request.method !== "GET") return methodNotAllowed(response, "GET");
-  const perf = options.backendPerformance;
-  const auth = perf ? await perf.measure("workbench_auth", () => authenticateWorkbenchRead(request, response, options)) : await authenticateWorkbenchRead(request, response, options);
-  if (!auth) return;
+  try {
+    if (request.method !== "GET") return methodNotAllowed(response, "GET");
+    const requestedSessionId = safeSessionId(url.searchParams.get("sessionId") ?? url.searchParams.get("includeSessionId"));
+    const requestedTraceId = safeTraceId(url.searchParams.get("traceId"));
+    const heartbeatMs = parsePositiveInteger(options.env?.HWLAB_WORKBENCH_SSE_HEARTBEAT_MS, DEFAULT_WORKBENCH_SSE_HEARTBEAT_MS);
+    attachWorkbenchRealtimeOtelContext(request, {
+      sessionId: requestedSessionId,
+      traceId: requestedTraceId,
+      heartbeatMs,
+      outboxMode: typeof (options.runtimeStore ?? null)?.readWorkbenchProjectionOutbox === "function"
+    });
+    const perf = options.backendPerformance;
+    const auth = perf ? await perf.measure("workbench_auth", () => authenticateWorkbenchRead(request, response, options)) : await authenticateWorkbenchRead(request, response, options);
+    if (!auth) return;
 
-  if (url.searchParams.has("projectId") || url.searchParams.has("workspaceId")) {
-    sendJson(response, 400, workbenchError("workbench_authority_removed", "Workbench read model is keyed by sessionId/threadId/traceId only."));
-    return;
-  }
+    if (url.searchParams.has("projectId") || url.searchParams.has("workspaceId")) {
+      sendJson(response, 400, workbenchError("workbench_authority_removed", "Workbench read model is keyed by sessionId/threadId/traceId only."));
+      return;
+    }
 
-  const requestedSessionId = safeSessionId(url.searchParams.get("sessionId") ?? url.searchParams.get("includeSessionId"));
-  const requestedTraceId = safeTraceId(url.searchParams.get("traceId"));
-  const heartbeatMs = parsePositiveInteger(options.env?.HWLAB_WORKBENCH_SSE_HEARTBEAT_MS, DEFAULT_WORKBENCH_SSE_HEARTBEAT_MS);
-  const traceStore = options.traceStore ?? defaultCodeAgentTraceStore;
-  const readModel = createWorkbenchReadModel(options, auth.actor);
-  let closed = false;
-  const cleanup = [];
+    const traceStore = options.traceStore ?? defaultCodeAgentTraceStore;
+    const readModel = createWorkbenchReadModel(options, auth.actor);
+    let closed = false;
+    const cleanup = [];
 
   response.writeHead(200, {
     "content-type": "text/event-stream; charset=utf-8",
@@ -231,6 +238,9 @@ export async function handleWorkbenchRealtimeHttp(request, response, url, option
     closed = true;
     for (const item of cleanup.splice(0)) item();
   });
+  } catch (error) {
+    handleWorkbenchRealtimeFailure(request, response, url, options, error);
+  }
 }
 
 function attachWorkbenchRealtimeOtelContext(request, fields = {}) {
@@ -268,6 +278,42 @@ function emitWorkbenchRealtimeAcceptedOtelSpan(request, env = process.env) {
   }).catch(() => undefined);
 }
 
+function handleWorkbenchRealtimeFailure(request, response, url, options = {}, error) {
+  const classified = classifyWorkbenchReadModelFailure(error);
+  const context = request?.hwlabHttpRequestContext;
+  if (context) {
+    context.route = "/v1/workbench/events";
+    context.otelAttributes = {
+      ...(context.otelAttributes ?? {}),
+      "workbench.route": "events",
+      "workbench.sse.lifecycle": "failed",
+      "error.code": classified.code,
+      "error.layer": "workbench.realtime"
+    };
+  }
+  logWorkbenchReadModelFailure(options.logger ?? console, {
+    event: "workbench_realtime_route_failed",
+    ok: false,
+    route: "/v1/workbench/events",
+    statusCode: classified.statusCode,
+    errorCode: classified.code,
+    errorName: error?.name ?? "Error",
+    message: error instanceof Error ? error.message : String(error ?? "unknown"),
+    valuesRedacted: true
+  });
+  if (response.headersSent && !response.destroyed) {
+    try {
+      response.write(`event: workbench.error\n`);
+      response.write(`data: ${JSON.stringify({ contractVersion: "workbench-events-v1", serverSentAt: new Date().toISOString(), type: "error", error: { code: classified.code, message: classified.message, valuesRedacted: true } })}\n\n`);
+      response.end();
+    } catch {
+      try { response.destroy(); } catch {}
+    }
+    return;
+  }
+  if (!response.destroyed) sendJson(response, classified.statusCode, workbenchError(classified.code, classified.message, { route: "/v1/workbench/events", errorName: error?.name ?? "Error" }));
+}
+
 function realtimeEventCreatedAt(payload) {
   const candidates = [payload?.event?.createdAt, payload?.snapshot?.lastEvent?.createdAt, payload?.turn?.updatedAt];
   for (const value of candidates) {
diff --git a/internal/cloud/server.ts b/internal/cloud/server.ts
index 7d9fe89c..f20dee58 100644
--- a/internal/cloud/server.ts
+++ b/internal/cloud/server.ts
@@ -595,7 +595,7 @@ async function handleRestAdapter(request, response, url, options) {
     const [dbProbe, codeAgent, runtime] = await Promise.all([
       observeHttpRoutePhase(request, options, "v1.db_readiness", () => buildDbRuntimeReadiness(options.env ?? process.env, dbProbeOptions)),
       observeHttpRoutePhase(request, options, "v1.code_agent_availability", () => describeCodeAgentAvailability(options.env ?? process.env, options)),
-      observeHttpRoutePhase(request, options, "v1.runtime_readiness", () => runtimeReadiness(options.runtimeStore))
+      observeHttpRoutePhase(request, options, "v1.runtime_readiness", () => runtimeReadinessSnapshot(options.runtimeStore))
     ]);
     const db = applyRuntimeDbReadinessLayers(dbProbe, runtime);
     const readiness = buildCloudApiReadiness({ db, codeAgent, runtime });