diff --git a/internal/cloud/server-workbench-http.ts b/internal/cloud/server-workbench-http.ts
index 0f3eae12..62f935da 100644
--- a/internal/cloud/server-workbench-http.ts
+++ b/internal/cloud/server-workbench-http.ts
@@ -144,34 +144,45 @@ export async function handleWorkbenchRealtimeHttp(request, response, url, option
   emitWorkbenchRealtimeAcceptedOtelSpan(request, options.env);
   if (activeTraceId) {
     await (perf ? perf.measure("workbench_initial_trace", () => writeTraceRealtimeSnapshotSafe({ writeEvent, options, actor: auth.actor, traceId: activeTraceId, reason: "initial" })) : writeTraceRealtimeSnapshotSafe({ writeEvent, options, actor: auth.actor, traceId: activeTraceId, reason: "initial" }));
-    const runtimeStore = options.runtimeStore ?? null;
-    const outboxPollMs = parsePositiveInteger(options.env?.HWLAB_WORKBENCH_SSE_OUTBOX_POLL_MS, 2000);
-    let outboxCursor = 0;
-    if (typeof runtimeStore?.readWorkbenchProjectionOutbox === "function") {
+  }
+  const runtimeStore = options.runtimeStore ?? null;
+  const outboxPollMs = parsePositiveInteger(options.env?.HWLAB_WORKBENCH_SSE_OUTBOX_POLL_MS, 2000);
+  let outboxCursor = 0;
+  const outboxTraceSnapshots = new Set(activeTraceId ? [activeTraceId] : []);
+  if (typeof runtimeStore?.readWorkbenchProjectionOutbox === "function" && (streamSessionId || activeTraceId)) {
       const pollOutbox = async () => {
         if (closed || response.destroyed) return;
         try {
-          const rows = await runtimeStore.readWorkbenchProjectionOutbox({ afterSeq: outboxCursor, limit: 50, traceId: activeTraceId });
+          const query = { afterSeq: outboxCursor, limit: 50 };
+          if (streamSessionId) query.sessionId = streamSessionId;
+          else query.traceId = activeTraceId;
+          const rows = await runtimeStore.readWorkbenchProjectionOutbox(query);
           for (const row of rows) {
             if (closed || response.destroyed) break;
             outboxCursor = row.outboxSeq;
+            const rowTraceId = safeTraceId(row.traceId) ?? activeTraceId;
+            const rowSessionId = safeSessionId(row.sessionId ?? streamSessionId) ?? streamSessionId;
+            if (rowTraceId && !outboxTraceSnapshots.has(rowTraceId)) {
+              outboxTraceSnapshots.add(rowTraceId);
+              await writeTraceRealtimeSnapshotSafe({ writeEvent, options, actor: auth.actor, traceId: rowTraceId, reason: "outbox-session" });
+            }
             if (row.commitType === "terminal") {
               writeEvent("workbench.trace.snapshot", {
                 type: "trace.snapshot",
-                sessionId: row.sessionId ?? streamSessionId,
+                sessionId: rowSessionId,
                 threadId: streamThreadId,
-                traceId: row.traceId ?? activeTraceId,
+                traceId: rowTraceId,
                 reason: "outbox-terminal",
                 cursor: { traceSeq: row.projectedSeq, outboxSeq: row.outboxSeq },
                 projectionStatus: { terminal: row.terminal, sealed: row.sealed }
               });
-              void writeTraceRealtimeSnapshotSafe({ writeEvent, options, actor: auth.actor, traceId: activeTraceId, reason: "terminal" });
+              if (rowTraceId) void writeTraceRealtimeSnapshotSafe({ writeEvent, options, actor: auth.actor, traceId: rowTraceId, reason: "terminal" });
             } else {
               writeEvent("workbench.trace.event", {
                 type: "trace.event",
-                sessionId: row.sessionId ?? streamSessionId,
+                sessionId: rowSessionId,
                 threadId: streamThreadId,
-                traceId: row.traceId ?? activeTraceId,
+                traceId: rowTraceId,
                 cursor: { traceSeq: row.projectedSeq, outboxSeq: row.outboxSeq }
               });
             }
@@ -186,7 +197,7 @@ export async function handleWorkbenchRealtimeHttp(request, response, url, option
       await pollOutbox();
       const outboxTimer = setInterval(() => { void pollOutbox(); }, Math.max(500, outboxPollMs));
       cleanup.push(() => clearInterval(outboxTimer));
-    } else {
+    } else if (activeTraceId) {
       const unsubscribe = traceStore.subscribe(activeTraceId, (event, snapshot) => {
         if (event) {
           writeEvent("workbench.trace.event", {