fix(agent): skip reasoning extra_body for unsupported OpenRouter models (#1485)

* fix(agent): skip reasoning extra_body for models that don't support it

Sending reasoning config to models like MiniMax or Nvidia via OpenRouter
causes a 400 BadRequestError. Previously, reasoning extra_body was sent
to all OpenRouter and Nous models unconditionally.

Fix: only send reasoning extra_body when the model slug starts with a
known reasoning-capable prefix (deepseek/, anthropic/, openai/, x-ai/,
google/gemini-2, qwen/qwen3) or when using Nous Portal directly.

Applies to both the main API call path (_build_api_kwargs) and the
conversation summary path.

Fixes #1083

* test(agent): cover reasoning extra_body gating

---------

Co-authored-by: ygd58 <buraysandro9@gmail.com>

run_agent.py

@@ -3302,8 +3302,7 @@ class AIAgent:
             extra_body["provider"] = provider_preferences
         _is_nous = "nousresearch" in self.base_url.lower()
 
-        _is_mistral = "api.mistral.ai" in self.base_url.lower()
+        if self._supports_reasoning_extra_body():
-        if (_is_openrouter or _is_nous) and not _is_mistral:
             if self.reasoning_config is not None:
                 rc = dict(self.reasoning_config)
                 # Nous Portal requires reasoning enabled — don't send
@@ -3327,6 +3326,32 @@ class AIAgent:
 
         return api_kwargs
 
+    def _supports_reasoning_extra_body(self) -> bool:
+        """Return True when reasoning extra_body is safe to send for this route/model.
+
+        OpenRouter forwards unknown extra_body fields to upstream providers.
+        Some providers/routes reject `reasoning` with 400s, so gate it to
+        known reasoning-capable model families and direct Nous Portal.
+        """
+        base_url = (self.base_url or "").lower()
+        if "nousresearch" in base_url:
+            return True
+        if "openrouter" not in base_url:
+            return False
+        if "api.mistral.ai" in base_url:
+            return False
+
+        model = (self.model or "").lower()
+        reasoning_model_prefixes = (
+            "deepseek/",
+            "anthropic/",
+            "openai/",
+            "x-ai/",
+            "google/gemini-2",
+            "qwen/qwen3",
+        )
+        return any(model.startswith(prefix) for prefix in reasoning_model_prefixes)
+
     def _build_assistant_message(self, assistant_message, finish_reason: str) -> dict:
         """Build a normalized assistant message dict from an API response message.
 
@@ -4265,9 +4290,8 @@ class AIAgent:
                     api_messages.insert(sys_offset + idx, pfm.copy())
 
             summary_extra_body = {}
-            _is_openrouter = "openrouter" in self.base_url.lower()
             _is_nous = "nousresearch" in self.base_url.lower()
-            if _is_openrouter or _is_nous:
+            if self._supports_reasoning_extra_body():
                 if self.reasoning_config is not None:
                     summary_extra_body["reasoning"] = self.reasoning_config
                 else:

tests/test_run_agent.py

@@ -612,6 +612,25 @@ class TestBuildApiKwargs:
         kwargs = agent._build_api_kwargs(messages)
         assert kwargs["extra_body"]["reasoning"] == {"enabled": False}
 
+    def test_reasoning_not_sent_for_unsupported_openrouter_model(self, agent):
+        agent.model = "minimax/minimax-m2.5"
+        messages = [{"role": "user", "content": "hi"}]
+        kwargs = agent._build_api_kwargs(messages)
+        assert "reasoning" not in kwargs.get("extra_body", {})
+
+    def test_reasoning_sent_for_supported_openrouter_model(self, agent):
+        agent.model = "qwen/qwen3.5-plus-02-15"
+        messages = [{"role": "user", "content": "hi"}]
+        kwargs = agent._build_api_kwargs(messages)
+        assert kwargs["extra_body"]["reasoning"]["effort"] == "medium"
+
+    def test_reasoning_sent_for_nous_route(self, agent):
+        agent.base_url = "https://inference-api.nousresearch.com/v1"
+        agent.model = "minimax/minimax-m2.5"
+        messages = [{"role": "user", "content": "hi"}]
+        kwargs = agent._build_api_kwargs(messages)
+        assert kwargs["extra_body"]["reasoning"]["effort"] == "medium"
+
     def test_max_tokens_injected(self, agent):
         agent.max_tokens = 4096
         messages = [{"role": "user", "content": "hi"}]
@@ -942,6 +961,19 @@ class TestHandleMaxIterations:
         assert "error" in result.lower()
         assert "API down" in result
 
+    def test_summary_skips_reasoning_for_unsupported_openrouter_model(self, agent):
+        agent.model = "minimax/minimax-m2.5"
+        resp = _mock_response(content="Summary")
+        agent.client.chat.completions.create.return_value = resp
+        agent._cached_system_prompt = "You are helpful."
+        messages = [{"role": "user", "content": "do stuff"}]
+
+        result = agent._handle_max_iterations(messages, 60)
+
+        assert result == "Summary"
+        kwargs = agent.client.chat.completions.create.call_args.kwargs
+        assert "reasoning" not in kwargs.get("extra_body", {})
+
 
 class TestRunConversation:
     """Tests for the main run_conversation method.