diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2d9f577e..21156b4d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -104,6 +104,7 @@ Status of the `main` branch. Changes prior to the next official version change w
     thread (#2038)
 
 * Language Servers:
+  - Fix: Dart analysis server no longer receives rootUri/rootPath, which added the monorepo root as an extra analysis root and could pin a CPU core at idle (#2045)
   - Fix: The C# language server opened every `.csproj` found anywhere under the repository root,
     without consulting the project's ignore settings. On repositories that vendor third-party or
     sample C# projects, this loads projects the server cannot restore on every start, and their
diff --git a/src/solidlsp/initialize_params.py b/src/solidlsp/initialize_params.py
index f71f6e5d..87fd36d3 100644
--- a/src/solidlsp/initialize_params.py
+++ b/src/solidlsp/initialize_params.py
@@ -40,10 +40,11 @@ class InitializeParamsBuilder(ABC):
 
 
 class DefaultInitializeParamsBuilder(InitializeParamsBuilder):
-    def __init__(self, ls: "SolidLanguageServer", set_workspace_folders: bool = True):
+    def __init__(self, ls: "SolidLanguageServer", set_workspace_folders: bool = True, set_root_uri: bool = True):
         super().__init__()
         self._ls = ls
         self._set_workspace_folders = set_workspace_folders
+        self._set_root_uri = set_root_uri
 
     @staticmethod
     def _create_workspace_folder_entry(path: str) -> WorkspaceFolder:
@@ -54,10 +55,22 @@ class DefaultInitializeParamsBuilder(InitializeParamsBuilder):
         root_abs_path = self._ls.repository_root_path
 
         self._set("processId", os.getpid())
-        self._set("rootPath", root_abs_path)
-        self._set("rootUri", pathlib.Path(root_abs_path).as_uri())
         self._set("clientInfo", {"name": "Serena"})
 
+        # Some language servers treat rootUri as an additional analysis root on top of
+        # workspaceFolders, with no de-duplication, which can cause unbounded indexing.
+        # When set_root_uri is False, rootUri/rootPath are omitted so that workspaceFolders
+        # alone determine the analysis roots.
+        if self._set_root_uri:
+            self._set("rootPath", root_abs_path)
+            self._set("rootUri", pathlib.Path(root_abs_path).as_uri())
+        else:
+            # Some servers reject initialize when the key is absent
+            # ("params.rootUri must not be undefined"). Send explicit null so the
+            # field is present but not used as an analysis root (#2045).
+            self._set("rootPath", None)
+            self._set("rootUri", None)
+
         if self._set_workspace_folders:
             abs_workspace_paths = self._ls.config.get_absolute_workspace_folders(root_abs_path)
             log.info("Workspace folders: %s", abs_workspace_paths)
diff --git a/src/solidlsp/language_servers/dart_language_server.py b/src/solidlsp/language_servers/dart_language_server.py
index 6bd890e9..c668d8ba 100644
--- a/src/solidlsp/language_servers/dart_language_server.py
+++ b/src/solidlsp/language_servers/dart_language_server.py
@@ -7,6 +7,7 @@ from collections.abc import Hashable
 
 from overrides import override
 
+from solidlsp.initialize_params import DefaultInitializeParamsBuilder, InitializeParamsBuilder
 from solidlsp.ls import RawDocumentSymbol, SolidLanguageServer
 from solidlsp.lsp_protocol_handler.server import ProcessLaunchInfo
 from solidlsp.settings import SolidLSPSettings
@@ -73,6 +74,13 @@ class DartLanguageServer(SolidLanguageServer):
         # via either notification it sends for this (see _start_server).
         self.analysis_complete = threading.Event()
 
+    def _create_initialize_params_builder(self) -> InitializeParamsBuilder:
+        # The Dart analysis server treats rootUri as an additional analysis root on top of
+        # workspaceFolders, with no de-duplication, so on a monorepo root that is not a Dart
+        # package the whole tree is analysed and the server burns CPU at idle (oraios/serena#2045).
+        # Omit rootUri/rootPath and rely on workspaceFolders alone.
+        return DefaultInitializeParamsBuilder(self, set_root_uri=False)
+
     @override
     def _document_symbols_cache_fingerprint(self) -> Hashable:
         normalize_symbol_name_version = 1
diff --git a/test/solidlsp/test_dart_root_uri.py b/test/solidlsp/test_dart_root_uri.py
new file mode 100644
index 00000000..46d6f4d6
--- /dev/null
+++ b/test/solidlsp/test_dart_root_uri.py
@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: MIT
+
+import tempfile
+from pathlib import Path
+
+from solidlsp.language_servers.dart_language_server import DartLanguageServer
+
+
+def _make_dart_ls() -> DartLanguageServer:
+    ls = object.__new__(DartLanguageServer)
+    ls._custom_settings = {}
+    # Windows: as_uri() rejects drive-less paths like "/tmp/..."
+    project_dir = Path(tempfile.mkdtemp(prefix="fake-dart-project-")) / "project"
+    project_dir.mkdir(parents=True, exist_ok=True)
+    ls.repository_root_path = str(project_dir)
+
+    class _Cfg:
+        @staticmethod
+        def get_absolute_workspace_folders(root):
+            return [root]
+
+        @staticmethod
+        def get_absolute_additional_workspace_folders(root):
+            return []
+
+    ls.config = _Cfg()
+    # custom_settings property reads from _custom_settings on SolidLanguageServer
+    return ls
+
+
+def test_dart_omits_root_uri():
+    builder = _make_dart_ls()._create_initialize_params_builder()
+    params = builder.build()
+    # rootUri must be present (some servers reject an undefined key) but null, so that only
+    # workspaceFolders determine the analysis roots (oraios/serena#2045).
+    assert params["rootUri"] is None
+    assert params["rootPath"] is None
+    assert params["workspaceFolders"]
diff --git a/test/solidlsp/test_initialize_params_root_uri.py b/test/solidlsp/test_initialize_params_root_uri.py
new file mode 100644
index 00000000..7ab80c98
--- /dev/null
+++ b/test/solidlsp/test_initialize_params_root_uri.py
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: MIT
+
+import tempfile
+from pathlib import Path
+
+from solidlsp.initialize_params import DefaultInitializeParamsBuilder
+
+
+class _FakeLS:
+    # Windows: as_uri() rejects drive-less paths like "/tmp/..."
+    repository_root_path = str(Path(tempfile.mkdtemp(prefix="fake-project-")) / "root")
+
+    class config:
+        @staticmethod
+        def get_absolute_workspace_folders(root):
+            return [root]
+
+        @staticmethod
+        def get_absolute_additional_workspace_folders(root):
+            return []
+
+    custom_settings: dict = {}
+
+
+def test_default_builder_sets_root_uri():
+    builder = DefaultInitializeParamsBuilder(_FakeLS())
+    params = builder.build()
+    assert "rootUri" in params
+    assert "rootPath" in params
+
+
+def test_builder_sends_null_root_uri_when_disabled():
+    builder = DefaultInitializeParamsBuilder(_FakeLS(), set_root_uri=False)
+    params = builder.build()
+    # keys must be present (some servers reject an undefined rootUri); values are null
+    assert params["rootUri"] is None
+    assert params["rootPath"] is None
+    assert params["processId"] is not None
+    assert params["clientInfo"] == {"name": "Serena"}