feat: wire gemma_cpp engine into discovery and optional imports

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/openjarvis/engine/__init__.py

@@ -15,7 +15,7 @@ from openjarvis.engine._base import (
 from openjarvis.engine._discovery import discover_engines, discover_models, get_engine
 
 # Optional engines — only register if their SDK deps are present
-for _optional in ("cloud", "litellm"):
+for _optional in ("cloud", "litellm", "gemma_cpp"):
     try:
         importlib.import_module(f".{_optional}", __name__)
     except ImportError:

src/openjarvis/engine/_discovery.py

@@ -25,12 +25,24 @@ _HOST_MAP: Dict[str, str | None] = {
     "apple_fm": "apple_fm_host",
     "cloud": None,
     "litellm": None,
+    "gemma_cpp": None,
 }
 
 
 def _make_engine(key: str, config: JarvisConfig) -> InferenceEngine:
     """Instantiate a registered engine with the appropriate config host."""
     cls = EngineRegistry.get(key)
+
+    # gemma_cpp: pass config fields instead of host
+    if key == "gemma_cpp":
+        cfg = config.engine.gemma_cpp
+        return cls(
+            model_path=cfg.model_path or None,
+            tokenizer_path=cfg.tokenizer_path or None,
+            model_type=cfg.model_type or None,
+            num_threads=cfg.num_threads,
+        )
+
     host_attr = _HOST_MAP.get(key)
     if host_attr is not None:
         host = getattr(config.engine, host_attr, None)

tests/engine/test_gemma_cpp.py

@@ -323,3 +323,37 @@ class TestGemmaCppConfigResolution:
         assert engine._tokenizer_path == ""
         assert engine._model_type == ""
         assert engine._num_threads == 0
+
+
+class TestGemmaCppDiscovery:
+    def test_host_map_contains_gemma_cpp(self) -> None:
+        from openjarvis.engine._discovery import _HOST_MAP
+        assert "gemma_cpp" in _HOST_MAP
+        assert _HOST_MAP["gemma_cpp"] is None
+
+    def test_make_engine_passes_config(self) -> None:
+        from openjarvis.core.config import GemmaCppEngineConfig, JarvisConfig
+        from openjarvis.core.registry import EngineRegistry
+        from openjarvis.engine._discovery import _make_engine
+        from openjarvis.engine.gemma_cpp import GemmaCppEngine
+
+        EngineRegistry.register_value("gemma_cpp", GemmaCppEngine)
+        config = JarvisConfig()
+        config.engine.gemma_cpp = GemmaCppEngineConfig(
+            model_path="/cfg/model.sbs",
+            tokenizer_path="/cfg/tokenizer.spm",
+            model_type="9b-it",
+            num_threads=4,
+        )
+        engine = _make_engine("gemma_cpp", config)
+        assert engine._model_path == "/cfg/model.sbs"
+        assert engine._tokenizer_path == "/cfg/tokenizer.spm"
+        assert engine._model_type == "9b-it"
+        assert engine._num_threads == 4
+
+    def test_registry_contains_gemma_cpp(self) -> None:
+        from openjarvis.core.registry import EngineRegistry
+        from openjarvis.engine.gemma_cpp import GemmaCppEngine
+
+        EngineRegistry.register_value("gemma_cpp", GemmaCppEngine)
+        assert EngineRegistry.contains("gemma_cpp")