fix(mcp): hide system.* collections from find/count, log and redact the schema resource (#1774, #1775)

lib/core/mcp/mcp_mongo_service.dart

@@ -185,11 +185,7 @@ class McpMongoService {
 
   Future<List<String>> listCollections(int connectionId) {
     return _withSession(connectionId, (session) async {
-      final names = await session.listCollections();
-      return [
-        for (final n in names)
-          if (!n.startsWith('system.')) n,
-      ]..sort();
+      return (await _visibleCollections(session)).toList()..sort();
     });
   }
 
@@ -243,9 +239,16 @@ class McpMongoService {
     }
   }
 
+  /// The collections the model may see and name; `system.*` ones (profile,
+  /// views) hold past queries and stay hidden from every tool.
+  Future<Iterable<String>> _visibleCollections(McpMongoSession session) async {
+    final names = await session.listCollections();
+    return names.where((n) => !n.startsWith('system.'));
+  }
+
   /// The collection must exist, so model input never names one unchecked.
   Future<String> _knownCollection(McpMongoSession session, String name) async {
-    final names = await session.listCollections();
+    final names = (await _visibleCollections(session)).toList();
     if (names.contains(name)) return name;
     final lower = name.toLowerCase();
     final loose = names.where((n) => n.toLowerCase() == lower).toList();

lib/core/mcp/querya_mcp_server.dart

@@ -344,7 +344,20 @@ base class QueryaMcpServer extends MCPServer with ToolsSupport, ResourcesSupport
     if (!request.uri.startsWith(prefix)) return null;
     final id = int.tryParse(request.uri.substring(prefix.length));
     if (id == null) return null;
-    final tables = await service.schemaOverview(id);
+    final started = DateTime.now();
+    final sw = Stopwatch()..start();
+    final List<McpTableDescription> tables;
+    try {
+      tables = await service.schemaOverview(id);
+    } on McpToolException catch (e) {
+      _report('schema', started, sw.elapsed, id, null, null, e.message, e.rule);
+      rethrow;
+    } catch (e) {
+      final message = McpRedaction.redact('Internal error: $e');
+      _report('schema', started, sw.elapsed, id, null, null, message, null);
+      throw McpToolException(message);
+    }
+    _report('schema', started, sw.elapsed, id, null, tables.length, null, null);
     return ReadResourceResult(contents: [
       TextResourceContents(
         uri: request.uri,

test/core/mcp/mcp_mongo_service_test.dart

@@ -113,6 +113,23 @@ void main() {
     opened = 0;
   });
 
+  test('system.* collections are neither listed nor readable (#1774)',
+      () async {
+    final svc = service();
+    expect(await svc.listCollections(1), ['orders', 'users']);
+    await expectLater(
+      svc.find(1, 'system.views'),
+      throwsA(isA<McpToolException>()
+          .having((e) => e.message, 'message', contains('Collection not found'))),
+    );
+    await expectLater(
+      svc.count(1, 'system.views'),
+      throwsA(isA<McpToolException>()
+          .having((e) => e.message, 'message', contains('Collection not found'))),
+    );
+    expect(session.calls, isEmpty);
+  });
+
   group('McpMongoGuard', () {
     test('plain filters pass', () {
       expect(

test/core/mcp/mcp_security_test.dart

@@ -66,9 +66,17 @@ SqlExecutionResult _catalog(String sql) {
 }
 
 /// Client and server over an in-memory channel.
-Future<(ServerConnection, QueryaMcpServer)> _connect(McpQueryService service) async {
+Future<(ServerConnection, QueryaMcpServer)> _connect(
+  McpQueryService service, {
+  void Function(McpCallRecord)? onCall,
+}) async {
   final pair = StreamChannelController<String>();
-  final server = QueryaMcpServer(pair.local, service: service, version: 't');
+  final server = QueryaMcpServer(
+    pair.local,
+    service: service,
+    version: 't',
+    onCall: onCall,
+  );
   final client = MCPClient(Implementation(name: 'attacker', version: '1'));
   final conn = client.connectServer(pair.foreign);
   await conn.initialize(InitializeRequest(
@@ -371,6 +379,55 @@ void main() {
     });
   });
 
+  group('the schema resource (#1775)', () {
+    test('is logged like a tool call', () async {
+      final calls = <McpCallRecord>[];
+      final (conn, server) = await _connect(
+        McpQueryService(
+          createDelegate: (row, dialect) =>
+              FakeSqlExecutionDelegate()..onExecute = _catalog,
+          access: _Access({1}),
+          loadConnections: () async => [_row(1, 'postgresql')],
+        ),
+        onCall: calls.add,
+      );
+      addTearDown(server.shutdown);
+
+      await conn.readResource(ReadResourceRequest(uri: 'schema://1'));
+
+      expect(calls.single.tool, 'schema');
+      expect(calls.single.connectionId, 1);
+      expect(calls.single.error, isNull);
+    });
+
+    test('masks secrets in a failing driver error and logs it', () async {
+      final calls = <McpCallRecord>[];
+      final (conn, server) = await _connect(
+        McpQueryService(
+          createDelegate: (row, dialect) => throw StateError(
+              'connect postgresql://admin:$_pw@db.internal/shop failed'),
+          access: _Access({1}),
+          loadConnections: () async => [_row(1, 'postgresql')],
+        ),
+        onCall: calls.add,
+      );
+      addTearDown(server.shutdown);
+
+      Object? caught;
+      try {
+        await conn.readResource(ReadResourceRequest(uri: 'schema://1'));
+      } catch (e) {
+        caught = e;
+      }
+
+      expect(caught, isNotNull);
+      expect('$caught', isNot(contains(_pw)));
+      expect(calls.single.tool, 'schema');
+      expect(calls.single.error, isNotNull);
+      expect(calls.single.error, isNot(contains(_pw)));
+    });
+  });
+
   test('a connection that is not shared is invisible to every tool', () async {
     var created = 0;
     final (conn, server) = await _connect(McpQueryService(