diff --git a/app/mcp/query_service.py b/app/mcp/query_service.py
index 192c2c4..e5878a8 100644
--- a/app/mcp/query_service.py
+++ b/app/mcp/query_service.py
@@ -394,6 +394,9 @@ async def execute_query(
                 if hasattr(args, "field") and args.field not in units:
                     gaps.append(f"Unit metadata is unavailable for field {args.field}")
         else:
+            # Keep the selected field in durable evidence; `value` alone cannot
+            # distinguish raw observations from cleaned observations.
+            data = [{**row, args.field: row["value"]} if "value" in row else row for row in data]
             metadata = [
                 r
                 for device in ids
diff --git a/app/services/scada_presentation_coverage.py b/app/services/scada_presentation_coverage.py
index 5bc9d28..ea1d817 100644
--- a/app/services/scada_presentation_coverage.py
+++ b/app/services/scada_presentation_coverage.py
@@ -77,7 +77,8 @@ class ScadaObservations:
                 if "time" in row and "device_id" in row:
                     at = datetime.fromisoformat(row["time"])
                     if start <= at <= end:
-                        self.values[(str(row["device_id"]), at)] = row
+                        observed = self.values.setdefault((str(row["device_id"]), at), {})
+                        observed.update({field: row[field] for field in ("monitored_value", "cleaned_value") if field in row})
 
     def absent_reason(self, device: str, at: datetime) -> str | None:
         for ids, outside, start, end in self.windows:
@@ -206,6 +207,8 @@ def verify_chart(task: dict, chart: dict, evidence: list[dict], refs: list[str])
                         "历史散点只保留每日末三个对应时刻")
                 continue
             record = observations.values.get((device, at))
+            require(record is None or field in record, "SCADA_CHART_EVIDENCE_REQUIRED",
+                    f"设备 {device} 的证据未标明 {field}，请重新读取明确的监测字段", refs=[device])
             actual = record.get(field) if record is not None else None
             if actual is None:
                 absent = observations.absent_reason(device, at)
diff --git a/docs/investigation-progress-and-presentation.md b/docs/investigation-progress-and-presentation.md
index 2c8c267..f113b19 100644
--- a/docs/investigation-progress-and-presentation.md
+++ b/docs/investigation-progress-and-presentation.md
@@ -178,8 +178,10 @@ JSON 包含累计 `targets`、按 `chart_id` 保存的最新验证 `charts` 及
 历史读取不要求新字段，已完成报告不回写；旧 Agent 的无绑定图表仍可读，但不能通过新轮次的覆盖门禁。
 
 部署按[工作台数据库变更门禁](workbench-database-rollout.md)核实目标 BizDB、备份和回滚演练。
-先停止目标项目的任务写入并安排配套切换，在维护窗口应用
-[035 迁移](../resources/sql/035_scada_presentation_coverage.sql)，随后发布 Server、Agent 和前端。
+先部署已兼容内部清单读取的 Server，再暂停目标项目的任务写入并在维护窗口应用
+[035 迁移](../resources/sql/035_scada_presentation_coverage.sql)，核对读取与存储就绪后发布 Agent 和前端。
+不要在旧 Server 仍处理请求时新增该列：旧版整行 Run 投影会将内部字段传入严格响应模型。
+新 Server 在迁移前可读取历史任务，SCADA 写入明确返回 503；完成迁移后再恢复目标项目写入。
 迁移只为 Run 新增通用 JSON 产物清单，默认空对象；不会自动回填旧图或自动迁移其他项目。
 未应用迁移的 SCADA 写入与收尾返回明确的 503，历史读取保持可用。
 Run 读取投影显式排除内部清单，REST 与 MCP 原有 Run 结构保持一致。
diff --git a/tests/unit/test_mcp_query.py b/tests/unit/test_mcp_query.py
index a37d1c4..ecaeea1 100644
--- a/tests/unit/test_mcp_query.py
+++ b/tests/unit/test_mcp_query.py
@@ -1116,6 +1116,31 @@ def test_time_series_sql_is_bounded_and_field_names_cannot_inject_sql():
     asyncio.run(check())
 
 
+@pytest.mark.parametrize("field", ["monitored_value", "cleaned_value"])
+def test_scada_detail_preserves_the_requested_field_with_its_value_alias(monkeypatch, field):
+    at = datetime.now(timezone.utc)
+    monkeypatch.setattr(query_service, "permissions_for_context", lambda ctx: PERMISSIONS)
+    monkeypatch.setattr(query_service.reads, "series_rows", AsyncMock(return_value=[{
+        "device_id": "D1", "time": at, "value": 32.0,
+    }]))
+    monkeypatch.setattr(query_service.reads, "scada_devices", AsyncMock(return_value=[{
+        "device_id": "D1", "measurement_unit": "m",
+    }]))
+
+    class Scope:
+        project = object()
+        connection = Connection()
+
+        @asynccontextmanager
+        async def timescale(self):
+            yield self.connection
+
+    args = ScadaInput(context_handle="a" * 43, device_ids=["D1"], field=field,
+                      start=at - timedelta(hours=3), end=at)
+    result = asyncio.run(query_service.execute_query(Scope(), binding(), TOOLS["query_scada_readings"], args))
+    assert result.data[0][field] == result.data[0]["value"] == 32.0
+
+
 def test_analysis_preserves_run_units_and_reports_inference(monkeypatch):
     from app.mcp.models import AnalysisValuesInput
     from unittest.mock import AsyncMock
diff --git a/tests/unit/test_scada_presentation_coverage.py b/tests/unit/test_scada_presentation_coverage.py
index 2014324..4854b03 100644
--- a/tests/unit/test_scada_presentation_coverage.py
+++ b/tests/unit/test_scada_presentation_coverage.py
@@ -1,5 +1,6 @@
 """SCADA display coverage is independent of whether a device supports a conclusion."""
 from datetime import datetime, timedelta, timezone
+from copy import deepcopy
 from uuid import uuid4
 
 import pytest
@@ -16,6 +17,44 @@ END = datetime(2026, 7, 16, tzinfo=timezone.utc)
 START = END - timedelta(hours=3)
 
 
+@pytest.mark.anyio
+async def test_value_only_detail_evidence_cannot_claim_missing_observations():
+    from app.services.scada_presentation_coverage import verify_chart
+    task, repository, _, evidence_id = await investigation()
+    detail = deepcopy(repository.evidence[evidence_id])
+    detail["evidence_id"] = "detail-values"
+    rows = detail["data_snapshot"]["data"]["data"]["readings"]
+    detail["data_snapshot"]["data"]["data"] = [
+        {"device_id": row["device_id"], "time": row["time"], "value": row["monitored_value"]}
+        for row in rows
+    ]
+    value = chart(devices=["524529"])
+    value["series"][0].update(data=[None] * 13, sample_times=[None] * 13)
+    with pytest.raises(DomainError) as failure:
+        verify_chart(task, value, [repository.evidence[evidence_id], detail], ["detail-values"])
+    assert failure.value.code == "SCADA_CHART_EVIDENCE_REQUIRED"
+
+
+@pytest.mark.anyio
+@pytest.mark.parametrize("field", ["monitored_value", "cleaned_value"])
+async def test_detail_fields_do_not_discard_other_observed_fields(field):
+    from app.services.scada_presentation_coverage import verify_chart
+    task, repository, _, evidence_id = await investigation()
+    detail = deepcopy(repository.evidence[evidence_id])
+    detail["evidence_id"] = "detail-cleaned"
+    rows = detail["data_snapshot"]["data"]["data"]["readings"]
+    detail["data_snapshot"]["data"]["data"] = [
+        {"device_id": row["device_id"], "time": row["time"], "value": row["cleaned_value"] + 10,
+         "cleaned_value": row["cleaned_value"] + 10} for row in rows
+    ]
+    value = chart(devices=["524529"])
+    value["scada"]["value_field"] = field
+    if field == "cleaned_value":
+        value["series"][0]["data"] = [point + 10 for point in value["series"][0]["data"]]
+    result = verify_chart(task, value, [repository.evidence[evidence_id], detail], [evidence_id, "detail-cleaned"])
+    assert result["gaps"] == []
+
+
 @pytest.fixture
 def anyio_backend():
     return "asyncio"