diff --git a/generator/plugins/python/utils.py b/generator/plugins/python/utils.py
index 9c2eaa7..e616af9 100644
--- a/generator/plugins/python/utils.py
+++ b/generator/plugins/python/utils.py
@@ -22,7 +22,19 @@
 SPECIAL_ENUMS = ["LanguageKind", "ErrorCodes", "LSPErrorCodes"]
 
 
+def customizations(spec: model.LSPModel) -> model.LSPModel:
+    # https://github.com/microsoft/lsprotocol/issues/344
+    # Allow CompletionItemKind to support custom values
+    for enum in spec.enumerations:
+        if enum.name == "CompletionItemKind":
+            enum.supportsCustomValues = True
+            break
+
+    return spec
+
+
 def generate_from_spec(spec: model.LSPModel, output_dir: str, test_dir: str) -> None:
+    spec = customizations(spec)
     code = TypesCodeGenerator(spec).get_code()
 
     output_path = pathlib.Path(output_dir, PACKAGE_NAME)
diff --git a/packages/python/lsprotocol/_hooks.py b/packages/python/lsprotocol/_hooks.py
index e505bfe..6bf869b 100644
--- a/packages/python/lsprotocol/_hooks.py
+++ b/packages/python/lsprotocol/_hooks.py
@@ -745,6 +745,15 @@ def _text_edit_hook(
             return converter.structure(object_, lsp_types.AnnotatedTextEdit)
         return converter.structure(object_, lsp_types.TextEdit)
 
+    def _completion_item_kind_hook(
+        object_: Any, _: type
+    ) -> Union[lsp_types.CompletionItemKind, OptionalPrimitive]:
+        if object_ is None:
+            return None
+        if isinstance(object_, (bool, int, str, float)):
+            return object_
+        return converter.structure(object_, lsp_types.CompletionItemKind)
+
     structure_hooks = [
         (
             Optional[
@@ -1098,6 +1107,14 @@ def _text_edit_hook(
             ],
             _text_edit_hook,
         ),
+        (
+            Optional[Union[lsp_types.CompletionItemKind, int]],
+            _completion_item_kind_hook,
+        ),
+        (
+            Union[lsp_types.CompletionItemKind, int],
+            _completion_item_kind_hook,
+        ),
     ]
     for type_, hook in structure_hooks:
         converter.register_structure_hook(type_, hook)
diff --git a/packages/python/lsprotocol/types.py b/packages/python/lsprotocol/types.py
index 443f61e..b6dbb62 100644
--- a/packages/python/lsprotocol/types.py
+++ b/packages/python/lsprotocol/types.py
@@ -3239,7 +3239,7 @@ class CompletionItem:
     @since 3.17.0"""
     # Since: 3.17.0
 
-    kind: Optional[CompletionItemKind] = attrs.field(default=None)
+    kind: Optional[Union[CompletionItemKind, int]] = attrs.field(default=None)
     """The kind of this completion item. Based of the kind
     an icon is chosen by the editor."""
 
@@ -9125,7 +9125,9 @@ class ClientCompletionItemOptionsKind:
 
     # Since: 3.18.0
 
-    value_set: Optional[Sequence[CompletionItemKind]] = attrs.field(default=None)
+    value_set: Optional[Sequence[Union[CompletionItemKind, int]]] = attrs.field(
+        default=None
+    )
     """The completion item kind values the client supports. When this
     property exists the client also guarantees that it will
     handle values outside its set gracefully and falls back