diff --git a/apps/api/src/services/awoooi_priority_work_order_readback.py b/apps/api/src/services/awoooi_priority_work_order_readback.py
index 30e3347e5..1785e38e9 100644
--- a/apps/api/src/services/awoooi_priority_work_order_readback.py
+++ b/apps/api/src/services/awoooi_priority_work_order_readback.py
@@ -3079,6 +3079,7 @@ def _enrich_from_current_readbacks(
         or reboot_slo.get("safe_next_step")
         or ""
     )
+    state["active_p0_projection_source"] = "reboot_auto_recovery_slo_scorecard"
     state["active_p0_readiness_percent"] = _int(
         reboot_slo.get("readiness_percent")
         or workbench_readback.get("current_p0_readiness_percent")
@@ -4021,6 +4022,9 @@ def _set_rollups_and_summary(
         "active_p0_next_safe_action": str(
             state.get("active_p0_next_safe_action") or ""
         ),
+        "active_p0_projection_source": str(
+            state.get("active_p0_projection_source") or ""
+        ),
         "controlled_service_data_backup_readback_present": (
             state.get("controlled_service_data_backup_readback_present") is True
         ),
@@ -4143,6 +4147,9 @@ def _set_rollups_and_summary(
         "active_p0_next_safe_action": str(
             state.get("active_p0_next_safe_action") or ""
         ),
+        "active_p0_projection_source": str(
+            state.get("active_p0_projection_source") or ""
+        ),
         "active_p0_live_active_blockers": active_blockers,
         "controlled_service_data_backup_readback_present": (
             state.get("controlled_service_data_backup_readback_present") is True
diff --git a/apps/api/tests/test_awoooi_priority_work_order_readback_api.py b/apps/api/tests/test_awoooi_priority_work_order_readback_api.py
index 21ad0b886..bc911ef20 100644
--- a/apps/api/tests/test_awoooi_priority_work_order_readback_api.py
+++ b/apps/api/tests/test_awoooi_priority_work_order_readback_api.py
@@ -665,6 +665,10 @@ def test_awoooi_priority_work_order_readback_routes_closed_backup_to_host_boot_a
     assert state["active_p0_next_safe_action"] == (
         "rerun_reboot_event_detector_and_host_probe_verify_only_no_reboot"
     )
+    assert (
+        state["active_p0_projection_source"]
+        == "reboot_auto_recovery_slo_scorecard"
+    )
     assert state["next_executable_mainline_state"] == (
         "blocked_reboot_slo_scorecard_host_boot_and_windows99_verify_"
         "collection_not_ready"
@@ -683,9 +687,17 @@ def test_awoooi_priority_work_order_readback_routes_closed_backup_to_host_boot_a
     assert payload["summary"]["active_p0_next_safe_action"] == (
         "rerun_reboot_event_detector_and_host_probe_verify_only_no_reboot"
     )
+    assert (
+        payload["summary"]["active_p0_projection_source"]
+        == "reboot_auto_recovery_slo_scorecard"
+    )
     assert payload["rollups"]["active_p0_slo_active_blocker_count"] == len(
         in_progress["evidence"]["active_blockers"]
     )
+    assert (
+        payload["rollups"]["active_p0_projection_source"]
+        == "reboot_auto_recovery_slo_scorecard"
+    )
     assert payload["summary"]["next_executable_mainline_state"] == (
         "blocked_reboot_slo_scorecard_host_boot_and_windows99_verify_"
         "collection_not_ready"
diff --git a/docs/LOGBOOK.md b/docs/LOGBOOK.md
index e29d02f2d..e841f14dc 100644
--- a/docs/LOGBOOK.md
+++ b/docs/LOGBOOK.md
@@ -54159,6 +54159,7 @@ production browser smoke:
 **完成內容**：
 - `awoooi-priority-work-order-readback` 已在 source 層補齊 P0-006 active blocker count、primary blocker、current phase、ETA / wait reason 與 next safe action projection；第一次 main push `12af61a58` 已進 Gitea main，但 CD `#4559` 被後續 metadata-only commit 取代，production readback 尚未出現新增欄位。
 - 本段以最小 API source touch 固定 `active_p0_live_active_blocker_count` 以 live blocker list 為 canonical，避免 stale top-level count 遮蔽 priority work order 的下一步欄位，並重新觸發 production build/deploy。
+- 第二輪補上 `active_p0_projection_source=reboot_auto_recovery_slo_scorecard`，讓 production readback 可直接證明 active P0 欄位來自 reboot SLO scorecard projection。
 
 **本地驗證結果**：
 - `DATABASE_URL=postgresql+asyncpg://test:test@localhost/test PYTHONPATH=apps/api python3.11 -m pytest apps/api/tests/test_awoooi_priority_work_order_readback_api.py apps/api/tests/test_reboot_auto_recovery_slo_scorecard_api.py -q -p no:cacheprovider`：`38 passed`。