From da0766dc67ef55705a44a7cd8a78e8e50435a6e3 Mon Sep 17 00:00:00 2001
From: Yufeng He <40085740+he-yufeng@users.noreply.github.com>
Date: Mon, 8 Jun 2026 02:13:37 +0800
Subject: [PATCH] fix: handle boolean MCP schema leaves

---
 google/genai/_mcp_utils.py                    |  8 ++++--
 .../tests/mcp/test_mcp_to_gemini_tools.py     | 28 +++++++++++++++++++
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/google/genai/_mcp_utils.py b/google/genai/_mcp_utils.py
index cc7a1642b..8b17da4b9 100644
--- a/google/genai/_mcp_utils.py
+++ b/google/genai/_mcp_utils.py
@@ -24,7 +24,6 @@
 import google.auth
 from google.auth.transport.requests import Request
 
-from . import _common
 from . import types
 from ._api_client import _MULTI_REGIONAL_LOCATIONS
 
@@ -124,9 +123,12 @@ def set_mcp_usage_header(headers: dict[str, str]) -> None:
 
 
 def _filter_to_supported_schema(
-    schema: _common.StringDict,
-) -> _common.StringDict:
+    schema: Any,
+) -> Any:
   """Filters the schema to only include fields that are supported by JSONSchema."""
+  if not isinstance(schema, dict):
+    return schema
+
   supported_fields: set[str] = set(types.JSONSchema.model_fields.keys())
 
   supported_fields.update([
diff --git a/google/genai/tests/mcp/test_mcp_to_gemini_tools.py b/google/genai/tests/mcp/test_mcp_to_gemini_tools.py
index 61d64102c..37d4eff2e 100644
--- a/google/genai/tests/mcp/test_mcp_to_gemini_tools.py
+++ b/google/genai/tests/mcp/test_mcp_to_gemini_tools.py
@@ -285,6 +285,34 @@ def test_update_endpoint_labels_conversion():
     assert 'additionalProperties' in labels_schema
 
 
+def test_mcp_boolean_additional_properties_conversion():
+  """Test MCP schemas with boolean additionalProperties values."""
+  mcp_tools = [
+      mcp_types.Tool(
+          name='tool',
+          description='tool-description',
+          inputSchema={
+              'type': 'object',
+              'properties': {
+                  'payload': {
+                      'type': 'object',
+                      'additionalProperties': False,
+                  }
+              },
+          },
+      ),
+  ]
+
+  result = _mcp_utils.mcp_to_gemini_tools(mcp_tools)
+  payload_schema = (
+      result[0]
+      .function_declarations[0]
+      .parameters.properties['payload']
+  )
+
+  assert payload_schema.type == 'OBJECT'
+
+
 def test_agent_platform_preserves_unknown_fields():
     """Test that Agent Platform translation passes all schema fields directly
     to the backend.