Fix explicit null validation for optional MCP tool inputs

src/dbtools-mcp-server/dbtools-mcp-server.py

@@ -805,7 +805,7 @@ def bootstrap_reports(dbtools_connection_display_name: str) -> str:
         })
 
 @mcp.tool()
-def create_report(dbtools_connection_display_name: str, name: str, sql_query: str, description: str = None, bind_parameters: list = None) -> str:
+def create_report(dbtools_connection_display_name: str, name: str, sql_query: str, description: str | None = None, bind_parameters: list | None = None) -> str:
     """
     Create a new report definition in the report_definitions table.
 
@@ -914,7 +914,7 @@ def create_report(dbtools_connection_display_name: str, name: str, sql_query: st
     })
 
 @mcp.tool()
-def execute_report(dbtools_connection_display_name: str, report_name: str, bind_values: dict = None) -> str:
+def execute_report(dbtools_connection_display_name: str, report_name: str, bind_values: dict | None = None) -> str:
     """
     Execute a report by its name with optional bind parameter values.
 

src/dbtools-mcp-server/test_null_inputs.py

@@ -0,0 +1,70 @@
+"""
+Copyright (c) 2026, Oracle and/or its affiliates.
+Licensed under the Universal Permissive License v1.0 as shown at
+https://oss.oracle.com/licenses/upl.
+"""
+
+import importlib.util
+import sys
+import unittest
+from contextlib import ExitStack
+from pathlib import Path
+from unittest.mock import patch
+
+from fastmcp import Client
+from fastmcp.exceptions import ToolError
+from jsonschema import Draft202012Validator
+
+
+class TestNullInputs(unittest.IsolatedAsyncioTestCase):
+    @classmethod
+    def setUpClass(cls):
+        # The script creates OCI clients at import; keep those external boundaries offline.
+        config = dict.fromkeys(("tenancy", "user", "fingerprint", "key_file", "pass_phrase"), "sample")
+        with ExitStack() as stack:
+            stack.enter_context(patch("oci.config.from_file", return_value=config))
+            for target in (
+                "oci.identity.IdentityClient", "oci.resource_search.ResourceSearchClient",
+                "oci.database.DatabaseClient", "oci.database_tools.DatabaseToolsClient",
+                "oci.vault.VaultsClient", "oci.secrets.SecretsClient",
+                "oci.object_storage.ObjectStorageClient", "oci.signer.Signer",
+            ):
+                stack.enter_context(patch(target))
+            spec = importlib.util.spec_from_file_location(
+                "dbtools_null_inputs", Path(__file__).with_name("dbtools-mcp-server.py")
+            )
+            cls.server = importlib.util.module_from_spec(spec)
+            sys.modules[spec.name] = cls.server
+            spec.loader.exec_module(cls.server)
+
+    @classmethod
+    def tearDownClass(cls):
+        sys.modules.pop("dbtools_null_inputs", None)
+
+    async def test_null_defaults_are_accepted_by_advertised_schemas(self):
+        async with Client(self.server.mcp) as client:
+            for tool in await client.list_tools():
+                validator = Draft202012Validator(tool.inputSchema)
+                for name, schema in tool.inputSchema["properties"].items():
+                    if "default" in schema and schema["default"] is None:
+                        self.assertTrue(validator.evolve(schema=schema).is_valid(None), f"{tool.name}.{name}")
+
+    async def test_optional_report_inputs(self):
+        cases = [
+            ("create_report", {"dbtools_connection_display_name": "sample", "name": "sample",
+                               "sql_query": "SELECT 1"}, "description", "Sample report"),
+            ("create_report", {"dbtools_connection_display_name": "sample", "name": "sample",
+                               "sql_query": "SELECT 1"}, "bind_parameters", ["id"]),
+            ("execute_report", {"dbtools_connection_display_name": "sample", "report_name": "sample"},
+             "bind_values", {"id": 1}),
+        ]
+        with patch.object(self.server, "_resolve_connection_or_error", return_value=(None, '{"error": "Offline test"}')):
+            async with Client(self.server.mcp) as client:
+                for name, required, parameter, valid in cases:
+                    with self.subTest(tool=name, parameter=parameter):
+                        omitted = await client.call_tool(name, required)
+                        for value in (None, valid):
+                            result = await client.call_tool(name, {**required, parameter: value})
+                            self.assertEqual(result.content, omitted.content)
+                        with self.assertRaisesRegex(ToolError, "validation error"):
+                            await client.call_tool(name, {**required, parameter: 7})

src/mysql-mcp-server/oracle/mysql_mcp_server/server.py

@@ -246,7 +246,7 @@ def list_all_connections() -> str:
 
 @mcp.tool()
 def execute_sql_tool_by_connection_id(
-    connection_id: str, sql_script: str, params: list = None
+    connection_id: str, sql_script: str, params: Optional[list] = None
 ) -> str:
     """
     Execute a SQL script on the specified database connection.
@@ -1021,7 +1021,7 @@ def _get_compartment_by_name(
 
 @mcp.tool()
 def object_storage_list_buckets(
-    compartment_name: str = None, compartment_id: str = None
+    compartment_name: Optional[str] = None, compartment_id: Optional[str] = None
 ) -> str:
     """
     [MCP Tool] List all accessible Object Storage buckets in a compartment.

src/mysql-mcp-server/oracle/mysql_mcp_server/tests/test_null_inputs.py

@@ -0,0 +1,50 @@
+"""
+Copyright (c) 2026, Oracle and/or its affiliates.
+Licensed under the Universal Permissive License v1.0 as shown at
+https://oss.oracle.com/licenses/upl.
+"""
+
+import importlib
+import unittest
+from unittest.mock import patch
+
+from fastmcp import Client
+from fastmcp.exceptions import ToolError
+from jsonschema import Draft202012Validator
+
+
+class TestNullInputs(unittest.IsolatedAsyncioTestCase):
+    @classmethod
+    def setUpClass(cls):
+        from oracle.mysql_mcp_server import utils
+
+        with patch.object(utils, "load_mysql_config", side_effect=RuntimeError("Offline test")), \
+                patch.object(utils, "OciInfo", side_effect=RuntimeError("Offline test")):
+            cls.server = importlib.import_module("oracle.mysql_mcp_server.server")
+
+    async def test_null_defaults_are_accepted_by_advertised_schemas(self):
+        async with Client(self.server.mcp) as client:
+            for tool in await client.list_tools():
+                validator = Draft202012Validator(tool.inputSchema)
+                for name, schema in tool.inputSchema["properties"].items():
+                    if "default" in schema and schema["default"] is None:
+                        self.assertTrue(validator.evolve(schema=schema).is_valid(None), f"{tool.name}.{name}")
+
+    async def test_optional_inputs(self):
+        cases = [
+            ("execute_sql_tool_by_connection_id", {"connection_id": "sample", "sql_script": "SELECT 1"},
+             "params", [1]),
+            ("object_storage_list_buckets", {}, "compartment_name", "sample"),
+            ("object_storage_list_buckets", {}, "compartment_id", "sample"),
+        ]
+        with patch.object(self.server, "_get_db_connection", side_effect=RuntimeError("Offline test")), \
+                patch.object(self.server, "oci_error_msg", '{"error": "Offline test"}'):
+            async with Client(self.server.mcp) as client:
+                for name, required, parameter, valid in cases:
+                    with self.subTest(tool=name, parameter=parameter):
+                        omitted = await client.call_tool(name, required)
+                        for value in (None, valid):
+                            result = await client.call_tool(name, {**required, parameter: value})
+                            self.assertEqual(result.content, omitted.content)
+                        with self.assertRaisesRegex(ToolError, "validation error"):
+                            await client.call_tool(name, {**required, parameter: 7})

src/oci-cloud-guard-mcp-server/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Fixed
+
+- Allow explicit null for the optional comment in update_problem_status, matching omission.
+
 ### Security
 
 - Updated locked AnyIO to 4.15.1; updated locked multidict to 6.9.1; updated PyJWT to 2.15.1 and urllib3 to 2.8.0; updated `cryptography` to 50.0.1 to prevent PKCS#7 EnvelopedData decryption from exposing a Bleichenbacher oracle through distinguishable errors and timing (CVE-2026-69247).

src/oci-cloud-guard-mcp-server/oracle/oci_cloud_guard_mcp_server/server.py

@@ -156,7 +156,7 @@ def update_problem_status(
         "OPEN",
         description="Action taken by user. Allowed values are: OPEN, RESOLVED, DISMISSED, CLOSED",
     ),
-    comment: str = Field(None, description="A comment from the user"),
+    comment: Optional[str] = Field(None, description="A comment from the user"),
 ) -> Problem:
     updated_problem_status = oci.cloud_guard.models.UpdateProblemStatusDetails(status=status, comment=comment)
     response = get_cloud_guard_client().update_problem_status(

src/oci-cloud-guard-mcp-server/oracle/oci_cloud_guard_mcp_server/tests/test_null_inputs.py

@@ -0,0 +1,49 @@
+"""
+Copyright (c) 2026, Oracle and/or its affiliates.
+Licensed under the Universal Permissive License v1.0 as shown at
+https://oss.oracle.com/licenses/upl.
+"""
+
+from unittest.mock import MagicMock
+
+import oci
+import pytest
+from fastmcp import Client
+from fastmcp.exceptions import ToolError
+from jsonschema import Draft202012Validator
+
+from oracle.oci_cloud_guard_mcp_server import server
+
+
+@pytest.mark.asyncio
+async def test_null_defaults_are_accepted_by_advertised_schemas():
+    async with Client(server.mcp) as client:
+        for tool in await client.list_tools():
+            validator = Draft202012Validator(tool.inputSchema)
+            for name, schema in tool.inputSchema["properties"].items():
+                if "default" in schema and schema["default"] is None:
+                    assert validator.evolve(schema=schema).is_valid(None), f"{tool.name}.{name}"
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("comment_args", [{}, {"comment": None}, {"comment": "Investigated"}])
+async def test_update_problem_accepts_optional_comment(monkeypatch, comment_args):
+    sdk = MagicMock()
+    sdk.update_problem_status.return_value.data = oci.cloud_guard.models.Problem(
+        id="sample", lifecycle_detail="OPEN", comment=comment_args.get("comment")
+    )
+    monkeypatch.setattr(server, "get_cloud_guard_client", lambda: sdk)
+
+    async with Client(server.mcp) as client:
+        result = await client.call_tool("update_problem_status", {"problem_id": "sample", **comment_args})
+        assert result.structured_content["id"] == "sample"
+        assert result.structured_content["comment"] == comment_args.get("comment")
+        details = sdk.update_problem_status.call_args.kwargs["update_problem_status_details"]
+        assert details.comment == comment_args.get("comment")
+
+
+@pytest.mark.asyncio
+async def test_update_problem_rejects_invalid_comment():
+    async with Client(server.mcp) as client:
+        with pytest.raises(ToolError, match="valid string"):
+            await client.call_tool("update_problem_status", {"problem_id": "sample", "comment": 7})

src/oci-database-mcp-server/CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to OCI Database MCP Server are documented in this file.
 
 ## Unreleased
 
+### Fixed
+
+- Allow explicit null for optional region arguments so calls use the configured default region, matching omission.
+
 ### Security
 
 - Updated locked AnyIO to 4.15.1; updated locked multidict to 6.9.1; updated PyJWT to 2.15.1 and urllib3 to 2.8.0; updated `cryptography` to 50.0.1 to prevent PKCS#7 EnvelopedData decryption from exposing a Bleichenbacher oracle through distinguishable errors and timing (CVE-2026-69247).