From dcf70fec4ca6817b199ece9fbf5e088e904b50d0 Mon Sep 17 00:00:00 2001
From: Stepan Filonov <stepanfilonov@gmail.com>
Date: Mon, 9 Feb 2026 04:56:37 +0800
Subject: [PATCH] Feat: strict definition openai

---
 mcphero/adapters/openai.py   | 21 ++++++++++++++++++---
 tests/test_openai_adapter.py | 20 +++++++++++++++++++-
 2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/mcphero/adapters/openai.py b/mcphero/adapters/openai.py
index f96fdab..7406f90 100644
--- a/mcphero/adapters/openai.py
+++ b/mcphero/adapters/openai.py
@@ -37,8 +37,23 @@ class MCPToolAdapterOpenAI(
     """
 
     @staticmethod
-    def _to_openai_tool(tool: MCPToolDefinition) -> ChatCompletionToolParam:
+    def _to_openai_tool(
+        tool: MCPToolDefinition, *, strict: bool = True
+    ) -> ChatCompletionToolParam:
         """Convert MCPToolDefinition to OpenAI format."""
+        if strict:
+            return {
+                "type": "function",
+                "function": {
+                    "name": tool.name,
+                    "description": tool.description,
+                    "strict": True,
+                    "parameters": {
+                        **tool.input_schema,
+                        "additionalProperties": False,
+                    },
+                },
+            }
         return {
             "type": "function",
             "function": {
@@ -49,11 +64,11 @@ def _to_openai_tool(tool: MCPToolDefinition) -> ChatCompletionToolParam:
         }
 
     async def get_tool_definitions(
-        self, *, parallel: bool = True
+        self, *, parallel: bool = True, strict: bool = True
     ) -> list[ChatCompletionToolParam]:
         """Fetch tools and return OpenAI-compatible definitions."""
         tools = await self.discover_tools(parallel=parallel)
-        return [self._to_openai_tool(t) for t in tools]
+        return [self._to_openai_tool(t, strict=strict) for t in tools]
 
     async def _execute_single_tool_call(
         self, tool_call: ChatCompletionMessageToolCall, *, return_errors: bool
diff --git a/tests/test_openai_adapter.py b/tests/test_openai_adapter.py
index 636d647..076a7ba 100644
--- a/tests/test_openai_adapter.py
+++ b/tests/test_openai_adapter.py
@@ -32,7 +32,11 @@ async def test_converts_mcp_tools_to_openai_format(
             tools[0]["function"]["description"]
             == "Get the current weather for a location"
         )
-        assert tools[0]["function"]["parameters"] == sample_mcp_tools[0]["inputSchema"]
+        assert tools[0]["function"]["strict"] is True
+        assert tools[0]["function"]["parameters"] == {
+            **sample_mcp_tools[0]["inputSchema"],
+            "additionalProperties": False,
+        }
 
     @respx.mock
     async def test_handles_missing_input_schema(
@@ -51,8 +55,22 @@ async def test_handles_missing_input_schema(
         assert tools[0]["function"]["parameters"] == {
             "type": "object",
             "properties": {},
+            "additionalProperties": False,
         }
 
+    @respx.mock
+    async def test_strict_false_omits_strict_fields(self, base_url, sample_mcp_tools):
+        respx.post(base_url).mock(
+            return_value=httpx.Response(200, json=_tools_response(sample_mcp_tools))
+        )
+
+        adapter = MCPToolAdapterOpenAI(MCPServerConfig(url=base_url, init_mode="none"))
+        tools = await adapter.get_tool_definitions(strict=False)
+
+        assert tools[0]["function"]["parameters"] == sample_mcp_tools[0]["inputSchema"]
+        assert "strict" not in tools[0]["function"]
+        assert "additionalProperties" not in tools[0]["function"]["parameters"]
+
     @respx.mock
     async def test_handles_empty_tools(self, base_url):
         respx.post(base_url).mock(