feat: add Nebius AI provider support

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - **Tavily Search provider** — `tavily/basic` and `tavily/advanced` as Router paths. Returns web search results wrapped in an OpenAI-compatible ChatCompletion shim so Thompson Sampling can compete Tavily against LLMs on web research goals. Set `TAVILY_API_KEY` env var.
+- **Nebius AI provider** — `nebius/` prefix routes to Nebius AI Studio (OpenAI-compatible). Set `NEBIUS_API_KEY` env var. Supported models: `nebius/meta-llama/Llama-3.3-70B-Instruct`, `nebius/Qwen/Qwen2.5-72B-Instruct`, `nebius/mistralai/Mistral-Nemo-Instruct-2407`.
 
 ## [1.9.3] - 2026-03-29
 

kalibr/router.py

@@ -931,6 +931,7 @@ def _call_deepgram_stt(
         "google/": "google",
         "deepseek/": "deepseek",
         "tavily/": "tavily",
+        "nebius/": "nebius",
     }
 
     def _dispatch(
@@ -962,6 +963,8 @@ def _dispatch(
                     return self._call_deepseek(bare_model, messages, tools, **kwargs)
                 elif vendor == "tavily":
                     return self._call_tavily(bare_model, messages, tools, **kwargs)
+                elif vendor == "nebius":
+                    return self._call_nebius(bare_model, messages, tools, **kwargs)
 
         # Standard prefix checks for bare model IDs
         if model_id.startswith(("gpt-", "o1-", "o3-")):
@@ -1017,6 +1020,28 @@ def _call_deepseek(self, model: str, messages: List[Dict], tools: Any, **kwargs)
         call_kwargs = {"model": model, "messages": messages, **kwargs}
         return client.chat.completions.create(**call_kwargs)
 
+    def _call_nebius(self, model: str, messages: List[Dict], tools: Any, **kwargs) -> Any:
+        """Call Nebius AI API using OpenAI-compatible client with Nebius base URL."""
+        try:
+            from openai import OpenAI
+        except ImportError:
+            raise ImportError("Install 'openai' package: pip install openai")
+
+        api_key = os.environ.get("NEBIUS_API_KEY")
+        if not api_key:
+            raise EnvironmentError(
+                "NEBIUS_API_KEY environment variable not set.\n"
+                "Get your API key from: https://studio.nebius.ai"
+            )
+
+        client = OpenAI(
+            api_key=api_key,
+            base_url="https://api.studio.nebius.ai/v1/",
+        )
+
+        call_kwargs = {"model": model, "messages": messages, **kwargs}
+        return client.chat.completions.create(**call_kwargs)
+
     def _call_anthropic(self, model: str, messages: List[Dict], tools: Any, **kwargs) -> Any:
         """Call Anthropic API and convert response to OpenAI format."""
         try:

tests/test_router.py

@@ -107,6 +107,35 @@ def test_tavily_response_shape(self, mock_post):
         os.environ.pop("TAVILY_API_KEY", None)
 
 
+class TestNebiusRouting:
+    @patch("kalibr.router.Router._call_nebius")
+    def test_routes_nebius_prefix(self, mock_nebius):
+        mock_nebius.return_value = MagicMock()
+        router = Router(goal="test", paths=["nebius/meta-llama/Llama-3.3-70B-Instruct"], auto_register=False)
+        router._dispatch("nebius/meta-llama/Llama-3.3-70B-Instruct", [{"role": "user", "content": "hi"}], None)
+        mock_nebius.assert_called_once()
+        assert mock_nebius.call_args[0][0] == "meta-llama/Llama-3.3-70B-Instruct"
+
+    @patch("kalibr.router.Router._call_nebius")
+    def test_routes_nebius_qwen(self, mock_nebius):
+        mock_nebius.return_value = MagicMock()
+        router = Router(goal="test", paths=["nebius/Qwen/Qwen2.5-72B-Instruct"], auto_register=False)
+        router._dispatch("nebius/Qwen/Qwen2.5-72B-Instruct", [{"role": "user", "content": "hi"}], None)
+        mock_nebius.assert_called_once()
+        assert mock_nebius.call_args[0][0] == "Qwen/Qwen2.5-72B-Instruct"
+
+    def test_nebius_missing_api_key(self):
+        import os
+        router = Router(goal="test", paths=["nebius/meta-llama/Llama-3.3-70B-Instruct"], auto_register=False)
+        env_backup = os.environ.pop("NEBIUS_API_KEY", None)
+        try:
+            with pytest.raises(EnvironmentError, match="NEBIUS_API_KEY"):
+                router._call_nebius("meta-llama/Llama-3.3-70B-Instruct", [{"role": "user", "content": "hi"}], None)
+        finally:
+            if env_backup:
+                os.environ["NEBIUS_API_KEY"] = env_backup
+
+
 class TestRouterReport:
     def test_double_report_warning(self):
         router = Router(goal="test", auto_register=False)