Fix MCP pagination review findings (#1727 #1729)

Author: Widthdom

src/CodeIndex/Database/DbReader.References.cs

@@ -25,7 +25,9 @@ public List<ReferenceResult> SearchReferences(string? query = null, int limit =
             return SearchReferencesCore(query, limit, lang, referenceKind, pathPatterns, excludePathPatterns, excludeTests, exact, offset, maxLineWidth, excludeSelfReferences);
 
         var rawLimit = Math.Max(limit, CSharpUsingStaticReferenceFilterChunkSize);
-        var rawOffset = Math.Max(0, offset);
+        var rawOffset = 0;
+        var acceptedBeforePage = Math.Max(0, offset);
+        var accepted = 0;
         var filtered = new List<ReferenceResult>();
         while (filtered.Count < limit)
         {
@@ -38,6 +40,13 @@ public List<ReferenceResult> SearchReferences(string? query = null, int limit =
                 if (ShouldSuppressCSharpUsingStaticConstantPatternReference(result))
                     continue;
 
+                if (accepted < acceptedBeforePage)
+                {
+                    accepted++;
+                    continue;
+                }
+
+                accepted++;
                 filtered.Add(result);
                 if (filtered.Count >= limit)
                     break;

src/CodeIndex/Mcp/McpToolDefinitions.cs

@@ -27,8 +27,7 @@ private JsonNode HandleToolsList(JsonNode? id)
                     ["properties"] = new JsonObject
                     {
                         ["query"] = new JsonObject { ["type"] = "string", ["description"] = "Search query text. Append `*` to a token to make that token a prefix phrase (`計算*` matches `計算する`)." },
-                        ["limit"] = new JsonObject { ["type"] = "integer", ["description"] = "Max results (default: 20). Responses include `truncated`, `more_available`, and `next_offset` when more rows exist.", ["default"] = 20 },
-                        ["offset"] = new JsonObject { ["type"] = "integer", ["description"] = "Zero-based result offset for pagination; use `next_offset` from a truncated response.", ["default"] = 0, ["minimum"] = 0 },
+                        ["limit"] = new JsonObject { ["type"] = "integer", ["description"] = "Max results (default: 20). Responses include `truncated` and `more_available` when more rows exist.", ["default"] = 20 },
                         ["lang"] = new JsonObject { ["type"] = "string", ["description"] = "Filter by language (e.g. csharp, python, javascript)" },
                         ["snippetLines"] = new JsonObject { ["type"] = "integer", ["description"] = "Max snippet lines per result (default: 8, max: 20)", ["default"] = 8, ["minimum"] = 1, ["maximum"] = SearchSnippetFormatter.MaxSnippetLines },
                         ["maxLineWidth"] = new JsonObject { ["type"] = "integer", ["description"] = "Clamp very long single-line snippets per line (default: 512; 0 disables clamping). Match lines are clamped around the first match; non-match lines are clamped from the head. Each clamp inserts a `...(+N)...` marker showing how many chars were elided.", ["default"] = LineWidthFormatter.DefaultMaxLineWidth, ["minimum"] = 0, ["maximum"] = LineWidthFormatter.MaxAllowedLineWidth },

tests/CodeIndex.Tests/DbReaderTests.cs

@@ -10245,11 +10245,12 @@ class Demo
         // call site.
         const int suppressedReferenceCount = 64;
         const int callReferenceLine = suppressedReferenceCount + 10;
+        const int secondCallReferenceLine = callReferenceLine + 1;
 
         using (var updateFileCmd = _db.Connection.CreateCommand())
         {
             updateFileCmd.CommandText = "UPDATE files SET lines = @lines WHERE path = 'src/Use.cs'";
-            updateFileCmd.Parameters.AddWithValue("@lines", callReferenceLine + 5);
+            updateFileCmd.Parameters.AddWithValue("@lines", secondCallReferenceLine + 5);
             updateFileCmd.ExecuteNonQuery();
         }
 
@@ -10307,13 +10308,29 @@ LIMIT 1
             ContainerKind = "function",
             ContainerName = "Match",
         });
+        syntheticReferences.Add(new ReferenceRecord
+        {
+            FileId = useFileId,
+            SymbolName = "Red",
+            ReferenceKind = "call",
+            Line = secondCallReferenceLine,
+            Column = 9,
+            Context = "        Red();",
+            ContainerKind = "function",
+            ContainerName = "Match",
+        });
         _writer.InsertReferences(syntheticReferences);
 
         var result = Assert.Single(_reader.SearchReferences("Red", limit: 1, lang: "csharp", exact: true, pathPatterns: ["src/Use.cs"]));
         Assert.Equal("call", result.ReferenceKind);
         Assert.Equal(callReferenceLine, result.Line);
-        Assert.Equal(1, _reader.CountSearchReferences("Red", limit: 1, lang: "csharp", exact: true, pathPatterns: ["src/Use.cs"]));
-        Assert.Equal(new QueryCountResult(1, 1), _reader.CountSearchReferencesTotal("Red", lang: "csharp", exact: true, pathPatterns: ["src/Use.cs"]));
+
+        var nextPage = Assert.Single(_reader.SearchReferences("Red", limit: 1, lang: "csharp", exact: true, pathPatterns: ["src/Use.cs"], offset: 1));
+        Assert.Equal("call", nextPage.ReferenceKind);
+        Assert.Equal(secondCallReferenceLine, nextPage.Line);
+
+        Assert.Equal(2, _reader.CountSearchReferences("Red", limit: 2, lang: "csharp", exact: true, pathPatterns: ["src/Use.cs"]));
+        Assert.Equal(new QueryCountResult(2, 1), _reader.CountSearchReferencesTotal("Red", lang: "csharp", exact: true, pathPatterns: ["src/Use.cs"]));
     }
 
     [Fact]