Lite MCP tools disclose a truncated query-stats window (#4231)

Darling/Darling.Tests/McpPayloadContractCensusTests.cs

@@ -1512,8 +1512,8 @@ public static readonly (string Key, string[] Files, string WhatWasCut)[] SecondB
 
     public static readonly (string Key, string[] Files, string WhatItExplains)[] CutNoteKeys =
     [
-        ("truncation_note", ["DarlingMcpDataTools.cs", "DarlingMcpQueryStoreClutterTools.cs", "DarlingMcpTools.cs", "McpAnalysisTools.cs"],
-            "the prose beside the flag: on get_analysis_findings (both SKUs) beside truncated, the WindowCoveringLimit read cap observed off a cap + 1 fetch; on get_query_store_top and get_query_store_clutter beside window_truncated, the #2364 window floor — the store's raw retention did not reach the whole requested window (on the clutter view, for the two arms that read the raw tier)"),
+        ("truncation_note", ["DarlingMcpDataTools.cs", "DarlingMcpQueryStoreClutterTools.cs", "DarlingMcpTools.cs", "McpAnalysisTools.cs", "McpQueryTools.cs"],
+            "the prose beside the flag: on get_analysis_findings (both SKUs) beside truncated, the WindowCoveringLimit read cap observed off a cap + 1 fetch; on get_query_store_top and get_query_store_clutter beside window_truncated, the #2364 window floor — the store's raw retention did not reach the whole requested window (on the clutter view, for the two arms that read the raw tier); on Lite's get_top_queries_by_cpu / get_top_procedures_by_cpu / get_query_store_top (#4231), the same window-floor note, from LocalDataService.GetQueryWindowFloorAsync"),
         ("findings_truncated_note", ["DarlingMcpTools.cs", "McpAnalysisTools.cs"],
             "#4198: the prose beside findings_truncated — how many diagnostic chains were active in the window and that raising limit or narrowing hours_back would show more of them"),
     ];
@@ -1763,6 +1763,10 @@ disclosure over query_stats and procedure_stats. */
         ("DarlingMcpTrendTools.cs", "envelope", 1),
         ("DarlingMcpTrendTools.cs", "initializer", 1),
         ("McpQueryTools.cs", "envelope", 1),
+        /* #4231: Lite's own get_query_store_top initializer (mirroring DarlingMcpDataTools.cs's 2, but Lite's
+           get_query_store_top has no module_name-miss hint block of its own, so 1), plus get_top_queries_by_cpu
+           and get_top_procedures_by_cpu, newly given the same raw-tier disclosure. */
+        ("McpQueryTools.cs", "initializer", 4),
     ];
 
     public static readonly (string File, string Tool)[] WindowFloorTools =
@@ -1778,7 +1782,10 @@ public static readonly (string File, string Tool)[] WindowFloorTools =
         ("McpQueryTools.cs", "get_procedure_duration_trend"),
         ("McpQueryTools.cs", "get_query_duration_trend"),
         ("McpQueryTools.cs", "get_query_store_duration_trend"),
+        ("McpQueryTools.cs", "get_query_store_top"),
         ("McpQueryTools.cs", "get_query_trend"),
+        ("McpQueryTools.cs", "get_top_procedures_by_cpu"),
+        ("McpQueryTools.cs", "get_top_queries_by_cpu"),
     ];
 
     /// <summary>The reach key: the one neighbour only the window floor has.</summary>
@@ -2003,23 +2010,8 @@ a caller needs to read the payload (the key, and that it is a retention floor, n
                is a guardrail and must be served in the head. Unconverted, the head is the whole description. */
             Assert.Contains(clause, description!, StringComparison.Ordinal);
             var head = McpToolGuide.Split(description!).Head;
-            if (tool is "get_top_queries_by_cpu" or "get_top_procedures_by_cpu")
-            {
-                /* #4231: these two are shared with Lite, and D6's twin pin
-                   (McpToolGuideTests.EverySharedToolName_CarriesTheMarkerOnBothSkus_OrNeither_WithByteIdenticalHeads)
-                   requires their served head stay byte-identical to Lite's until Lite's own #4279 ships the
-                   same disclosure — a Darling-only head guardrail would fail that pin regardless of merge
-                   order. Both facts still ride the wire today, in the tail's WindowTruncatedDescription
-                   clause, so read them from the full description here rather than the head. A follow-up PR
-                   can move one identical sentence into both SKUs' heads once #4279 merges. */
-                Assert.Contains(WindowFloorKey, description!, StringComparison.Ordinal);
-                Assert.Contains("not a page cut", description!, StringComparison.Ordinal);
-            }
-            else
-            {
-                Assert.Contains(WindowFloorKey, head, StringComparison.Ordinal);
-                Assert.Contains("not a page cut", head, StringComparison.Ordinal);
-            }
+            Assert.Contains(WindowFloorKey, head, StringComparison.Ordinal);
+            Assert.Contains("not a page cut", head, StringComparison.Ordinal);
             Assert.DoesNotContain("read truncated", description!, StringComparison.Ordinal);
         }
     }

Darling/Darling.Tests/McpToolGuideHeads.CollectionLog.cs

@@ -35,7 +35,6 @@ private static readonly (string Tool, string Fact)[] HeadFacts =
         ("get_collection_log", "an unknown value is refused, never silently empty"),
         ("get_query_store_top", "window_truncated"),
         ("get_query_store_top", "not a page cut"),
-        ("get_query_store_top", "Lite: no such floor"),
     ];
 
     [Fact]
@@ -67,13 +66,16 @@ public void CollectionLogTail_CarriesTheThreeHeldBackParameterRemainders()
         Assert.Contains("status: THE FAILURE FILTER", tail, StringComparison.Ordinal);
     }
 
-    /// <summary>get_query_store_top's window-floor clause (#2364/#3653) is Darling-only; the head says so in one
-    /// clause rather than asserting it's true for Lite too (D6), and Lite's own tail never claims it.</summary>
+    /// <summary>#4231: get_query_store_top's window-floor clause (#2364/#3653) is now one shared, byte-identical
+    /// head across both SKUs -- neither the old "Darling: " qualifier nor the false "Lite: no such floor" line
+    /// survives.</summary>
     [Fact]
-    public void QueryStoreTop_WindowFloorClause_IsScopedToDarlingInTheHead()
+    public void QueryStoreTop_WindowFloorClause_IsSharedAcrossBothSkusInTheHead()
     {
         var served = McpToolGuideTests.Served("get_query_store_top");
-        Assert.Contains("Darling: window_truncated", served.Served, StringComparison.Ordinal);
-        Assert.Contains("Lite: no such floor", served.Served, StringComparison.Ordinal);
+        Assert.Contains("window_truncated", served.Served, StringComparison.Ordinal);
+        Assert.Contains("not a page cut", served.Served, StringComparison.Ordinal);
+        Assert.DoesNotContain("Darling: window_truncated", served.Served, StringComparison.Ordinal);
+        Assert.DoesNotContain("Lite: no such floor", served.Served, StringComparison.Ordinal);
     }
 }

Darling/Darling.Tests/McpToolGuideHeads.Data.cs

@@ -43,8 +43,12 @@ private static readonly (string Tool, string Fact)[] HeadFacts =
         ("get_perfmon_stats", "LATEST IS A TIME: the newest snapshot, not a window"),
         ("get_server_properties", "LATEST IS A TIME: the newest snapshot, not a window"),
         ("get_top_procedures_by_cpu", "LIFETIME extremes, not windowed"),
+        ("get_top_procedures_by_cpu", "window_truncated"),
+        ("get_top_procedures_by_cpu", "not a page cut"),
         ("get_top_queries_by_cpu", "LIFETIME extremes, not windowed"),
         ("get_top_queries_by_cpu", "an empty page under it is the window's real answer, not a miss"),
+        ("get_top_queries_by_cpu", "window_truncated"),
+        ("get_top_queries_by_cpu", "not a page cut"),
         ("get_wait_stats", "Bounded by limit"),
         ("list_servers", "Darling has no live connection to monitored servers"),
         ("list_servers", "Lite's status IS a live connection check"),

Darling/Darling.Tests/McpToolsListBudget/DarlingMcpDataTools.txt

@@ -44,7 +44,7 @@ param get_perfmon_stats.counter_name 61
 param get_perfmon_stats.instance_name 57
 param get_perfmon_stats.server_name 28
 
-tool get_query_store_top 422
+tool get_query_store_top 351
 param get_query_store_top.as_of 167
 param get_query_store_top.database_name 30
 param get_query_store_top.execution_type 72
@@ -63,14 +63,14 @@ param get_tempdb_trend.bucket_minutes 55
 param get_tempdb_trend.hours_back 29
 param get_tempdb_trend.server_name 28
 
-tool get_top_procedures_by_cpu 406
+tool get_top_procedures_by_cpu 532
 param get_top_procedures_by_cpu.as_of 167
 param get_top_procedures_by_cpu.database_name 30
 param get_top_procedures_by_cpu.hours_back 29
 param get_top_procedures_by_cpu.server_name 28
 param get_top_procedures_by_cpu.top 37
 
-tool get_top_queries_by_cpu 474
+tool get_top_queries_by_cpu 600
 param get_top_queries_by_cpu.as_of 167
 param get_top_queries_by_cpu.database_name 30
 param get_top_queries_by_cpu.group_by 167

Darling/Darling.Tests/McpToolsListBudgetTests.cs

@@ -171,7 +171,11 @@ shared 32 KB budget and is not a served description either. */
        #4231 branched from); combined total unchanged from the merge base since #4231 added no head bytes. */
     /* #4231 (merge after #4273): re-measured after merging origin/dev (dev now includes #4272+#4273); #4231
        still adds no head bytes, so the total is dev's own. */
-    private const int TotalCeilingBytes = 174_373;
+    /* #4279 (Lite half of #4231 ships): the exemption above no longer applies once Lite's own head carries the
+       same disclosure. get_query_store_top's head drops the old Darling/Lite split for the shared sentence
+       (422 -> 351, banking 71 bytes); get_top_queries_by_cpu and get_top_procedures_by_cpu each gain that same
+       sentence (474 -> 600 and 406 -> 532, +126 bytes apiece). Net +181, matching Lite's twin change exactly. */
+    private const int TotalCeilingBytes = 174_554;
 
 
     private const int ConvertedHeadCap = 1_000;