diff --git a/src/openjarvis/engine/cloud.py b/src/openjarvis/engine/cloud.py
index d5610f65..88c45bc6 100644
--- a/src/openjarvis/engine/cloud.py
+++ b/src/openjarvis/engine/cloud.py
@@ -893,6 +893,13 @@ class CloudEngine(InferenceEngine):
             "max_tokens": max_tokens,
             "temperature": temperature,
         }
+        # Forward tools / tool_choice (OpenRouter is OpenAI-compatible).
+        tools = kwargs.pop("tools", None)
+        if tools:
+            create_kwargs["tools"] = tools
+        tool_choice = kwargs.pop("tool_choice", None)
+        if tool_choice is not None:
+            create_kwargs["tool_choice"] = tool_choice
         t0 = time.monotonic()
         resp = self._openrouter_client.chat.completions.create(**create_kwargs)
         elapsed = time.monotonic() - t0
@@ -900,7 +907,7 @@ class CloudEngine(InferenceEngine):
         usage = resp.usage
         prompt_tokens = usage.prompt_tokens if usage else 0
         completion_tokens = usage.completion_tokens if usage else 0
-        return {
+        result: Dict[str, Any] = {
             "content": choice.message.content or "",
             "usage": {
                 "prompt_tokens": prompt_tokens,
@@ -911,6 +918,19 @@ class CloudEngine(InferenceEngine):
             "finish_reason": choice.finish_reason or "stop",
             "ttft": elapsed,
         }
+        if getattr(choice.message, "tool_calls", None):
+            result["tool_calls"] = [
+                {
+                    "id": tc.id,
+                    "type": tc.type,
+                    "function": {
+                        "name": tc.function.name,
+                        "arguments": tc.function.arguments,
+                    },
+                }
+                for tc in choice.message.tool_calls
+            ]
+        return result
 
     def _generate_minimax(
         self,
@@ -1195,6 +1215,13 @@ class CloudEngine(InferenceEngine):
             "temperature": temperature,
             "stream": True,
         }
+        # Forward tools / tool_choice (OpenRouter is OpenAI-compatible).
+        tools = kwargs.pop("tools", None)
+        if tools:
+            create_kwargs["tools"] = tools
+        tool_choice = kwargs.pop("tool_choice", None)
+        if tool_choice is not None:
+            create_kwargs["tool_choice"] = tool_choice
         resp = self._openrouter_client.chat.completions.create(**create_kwargs)
         for chunk in resp:
             delta = chunk.choices[0].delta if chunk.choices else None
diff --git a/tests/engine/test_cloud.py b/tests/engine/test_cloud.py
index ed9c22e2..a26671b8 100644
--- a/tests/engine/test_cloud.py
+++ b/tests/engine/test_cloud.py
@@ -381,3 +381,59 @@ class TestCodexGenerate:
         engine._codex_client = {"token": "t", "url": "http://test"}
         engine.close()
         assert engine._codex_client is None
+
+
+class TestOpenRouterToolForwarding:
+    """Regression for #511: the OpenRouter engine must forward tools/tool_choice
+    to the (OpenAI-compatible) API and parse tool_calls back out of the response.
+    Pre-fix, both were dropped, silently breaking function-calling via OpenRouter.
+    """
+
+    def test_generate_forwards_tools_and_parses_tool_calls(
+        self, monkeypatch: pytest.MonkeyPatch
+    ) -> None:
+        monkeypatch.delenv("OPENAI_API_KEY", raising=False)
+
+        fake_tc = SimpleNamespace(
+            id="call_1",
+            type="function",
+            function=SimpleNamespace(name="get_weather", arguments='{"city": "NYC"}'),
+        )
+        fake_choice = SimpleNamespace(
+            message=SimpleNamespace(content=None, tool_calls=[fake_tc]),
+            finish_reason="tool_calls",
+        )
+        fake_resp = SimpleNamespace(
+            choices=[fake_choice],
+            usage=SimpleNamespace(prompt_tokens=3, completion_tokens=2, total_tokens=5),
+            model="openai/gpt-4o",
+        )
+        fake_client = mock.MagicMock()
+        fake_client.chat.completions.create.return_value = fake_resp
+
+        EngineRegistry.register_value("cloud", CloudEngine)
+        engine = CloudEngine()
+        engine._openrouter_client = fake_client
+
+        tools = [
+            {
+                "type": "function",
+                "function": {"name": "get_weather", "parameters": {}},
+            }
+        ]
+        result = engine.generate(
+            [Message(role=Role.USER, content="weather in NYC?")],
+            model="openrouter/openai/gpt-4o",
+            tools=tools,
+            tool_choice="auto",
+        )
+
+        # tools / tool_choice are forwarded to the API call
+        sent = fake_client.chat.completions.create.call_args.kwargs
+        assert sent["tools"] == tools
+        assert sent["tool_choice"] == "auto"
+
+        # tool_calls from the response are parsed back into the result
+        assert result["tool_calls"][0]["id"] == "call_1"
+        assert result["tool_calls"][0]["function"]["name"] == "get_weather"
+        assert result["tool_calls"][0]["function"]["arguments"] == '{"city": "NYC"}'