diff --git a/internal/cloud/server-workbench-http.ts b/internal/cloud/server-workbench-http.ts
index dc226ee1..eb6e2c3e 100644
--- a/internal/cloud/server-workbench-http.ts
+++ b/internal/cloud/server-workbench-http.ts
@@ -1,5 +1,5 @@
 /*
- * SPEC: PJ2026-0104010803 Workbench唯一投影 draft-2026-06-19-p0-projector-resume; PJ2026-010403 API契约 draft-2026-06-18-r1; PJ2026-010401 Web工作台 draft-2026-06-18-r1; PJ2026-01060505 Workbench Performance draft-2026-06-17-p0
+ * SPEC: PJ2026-0104010803 Workbench唯一投影 draft-2026-06-19-p0-projector-resume; draft-2026-06-20-p1-zero-split-durable-realtime; PJ2026-010403 API契约 draft-2026-06-18-r1; PJ2026-010401 Web工作台 draft-2026-06-18-r1; PJ2026-01060505 Workbench Performance draft-2026-06-17-p0
  * 职责: Workbench REST read model。只读投影 session/message/turn/trace facts，不执行 AgentRun sync、billing finalize 或 workspace repair。
  */
 import { createHash } from "node:crypto";
@@ -126,33 +126,77 @@ export async function handleWorkbenchRealtimeHttp(request, response, url, option
     ?? null;
   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 unsubscribe = traceStore.subscribe(activeTraceId, (event, snapshot) => {
-      if (event) {
-        writeEvent("workbench.trace.event", {
-          type: "trace.event",
-          sessionId: streamSessionId,
-          threadId: streamThreadId,
-          traceId: activeTraceId,
-          event,
-          snapshot: { ...traceSnapshotSummary(snapshot), sessionId: streamSessionId, threadId: streamThreadId },
-          cursor: { traceSeq: eventSeq(event, Number(snapshot?.eventCount ?? 1) - 1) }
-        });
-      } else {
-        writeEvent("workbench.trace.snapshot", {
-          type: "trace.snapshot",
-          sessionId: streamSessionId,
-          threadId: streamThreadId,
-          traceId: activeTraceId,
-          reason: "trace-store-update",
-          snapshot: { ...traceSnapshotForRealtime(snapshot), sessionId: streamSessionId, threadId: streamThreadId },
-          cursor: { traceSeq: traceSnapshotLastSeq(snapshot) }
-        });
-      }
-      if (event?.terminal === true || TERMINAL_STATUSES.has(normalizeStatus(event?.status))) {
-        void writeTraceRealtimeSnapshot({ writeEvent, options, actor: auth.actor, traceId: activeTraceId, reason: "terminal" });
-      }
-    });
-    cleanup.push(unsubscribe);
+    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 pollOutbox = async () => {
+        if (closed || response.destroyed) return;
+        try {
+          const rows = await runtimeStore.readWorkbenchProjectionOutbox({ afterSeq: outboxCursor, limit: 50, traceId: activeTraceId });
+          for (const row of rows) {
+            if (closed || response.destroyed) break;
+            outboxCursor = row.outboxSeq;
+            if (row.commitType === "terminal") {
+              writeEvent("workbench.trace.snapshot", {
+                type: "trace.snapshot",
+                sessionId: row.sessionId ?? streamSessionId,
+                threadId: streamThreadId,
+                traceId: row.traceId ?? activeTraceId,
+                reason: "outbox-terminal",
+                cursor: { traceSeq: row.projectedSeq, outboxSeq: row.outboxSeq },
+                projectionStatus: { terminal: row.terminal, sealed: row.sealed }
+              });
+              void writeTraceRealtimeSnapshot({ writeEvent, options, actor: auth.actor, traceId: activeTraceId, reason: "terminal" });
+            } else {
+              writeEvent("workbench.trace.event", {
+                type: "trace.event",
+                sessionId: row.sessionId ?? streamSessionId,
+                threadId: streamThreadId,
+                traceId: row.traceId ?? activeTraceId,
+                cursor: { traceSeq: row.projectedSeq, outboxSeq: row.outboxSeq }
+              });
+            }
+          }
+        } catch (outboxError) {
+          writeEvent("workbench.error", {
+            type: "error",
+            error: { code: "workbench_outbox_poll_failed", message: outboxError?.message ?? "Workbench outbox poll failed." }
+          });
+        }
+      };
+      await pollOutbox();
+      const outboxTimer = setInterval(() => { void pollOutbox(); }, Math.max(500, outboxPollMs));
+      cleanup.push(() => clearInterval(outboxTimer));
+    } else {
+      const unsubscribe = traceStore.subscribe(activeTraceId, (event, snapshot) => {
+        if (event) {
+          writeEvent("workbench.trace.event", {
+            type: "trace.event",
+            sessionId: streamSessionId,
+            threadId: streamThreadId,
+            traceId: activeTraceId,
+            event,
+            snapshot: { ...traceSnapshotSummary(snapshot), sessionId: streamSessionId, threadId: streamThreadId },
+            cursor: { traceSeq: eventSeq(event, Number(snapshot?.eventCount ?? 1) - 1) }
+          });
+        } else {
+          writeEvent("workbench.trace.snapshot", {
+            type: "trace.snapshot",
+            sessionId: streamSessionId,
+            threadId: streamThreadId,
+            traceId: activeTraceId,
+            reason: "trace-store-update",
+            snapshot: { ...traceSnapshotForRealtime(snapshot), sessionId: streamSessionId, threadId: streamThreadId },
+            cursor: { traceSeq: traceSnapshotLastSeq(snapshot) }
+          });
+        }
+        if (event?.terminal === true || TERMINAL_STATUSES.has(normalizeStatus(event?.status))) {
+          void writeTraceRealtimeSnapshot({ writeEvent, options, actor: auth.actor, traceId: activeTraceId, reason: "terminal" });
+        }
+      });
+      cleanup.push(unsubscribe);
+    }
   }
 
   const heartbeat = setInterval(async () => {
diff --git a/internal/cloud/workbench-facts-store.ts b/internal/cloud/workbench-facts-store.ts
index 1f890a87..75ad4e9f 100644
--- a/internal/cloud/workbench-facts-store.ts
+++ b/internal/cloud/workbench-facts-store.ts
@@ -1,5 +1,5 @@
 /*
- * SPEC: PJ2026-0104010803 Workbench唯一投影 draft-2026-06-18-p0-unique-projection; PJ2026-010403 API契约 draft-2026-06-18-r1.
+ * SPEC: PJ2026-0104010803 Workbench唯一投影 draft-2026-06-18-p0-unique-projection; draft-2026-06-20-p1-zero-split-durable-realtime; PJ2026-010403 API契约 draft-2026-06-18-r1.
  * 职责: Workbench durable facts store adapter。统一读取 session/message/turn/trace projection facts，不在 GET 中推进 AgentRun facts。
  */
 import { defaultCodeAgentTraceStore } from "./code-agent-trace-store.ts";
@@ -124,6 +124,31 @@ export function createWorkbenchFactsStore(options = {}, actor = null) {
     return traceStore.subscribe(traceId, listener);
   }
 
+  function subscribeDurableProjection(traceId, listener, pollOptions = {}) {
+    const runtimeStore = options.runtimeStore ?? null;
+    if (typeof runtimeStore?.readWorkbenchProjectionOutbox !== "function") return () => {};
+    const pollMs = Math.max(500, Number(pollOptions.pollMs ?? 2000));
+    let cursor = 0;
+    let stopped = false;
+    const poll = async () => {
+      if (stopped) return;
+      try {
+        const rows = await runtimeStore.readWorkbenchProjectionOutbox({ afterSeq: cursor, limit: 50, traceId });
+        for (const row of rows) {
+          if (stopped) break;
+          cursor = row.outboxSeq;
+          listener(row);
+        }
+      } catch { /* durable projection poll errors are non-fatal for SSE consumers */ }
+    };
+    void poll();
+    const timer = setInterval(() => { void poll(); }, pollMs);
+    return () => {
+      stopped = true;
+      clearInterval(timer);
+    };
+  }
+
   return {
     queryFacts,
     getSessionById,
@@ -134,6 +159,7 @@ export function createWorkbenchFactsStore(options = {}, actor = null) {
     traceSnapshot,
     traceSnapshotSync,
     subscribeTrace,
+    subscribeDurableProjection,
     canReadOwner: (ownerUserId) => canActorReadOwner(ownerUserId, actor)
   };
 }