Add /debug endpoint and accurate /health model reporting

main.py

@@ -50,6 +50,7 @@ esen_backbone_hook = None  # forward hook on backbone to capture node_embedding
 mm_model = None
 ofm_model = None
 models_loaded = False
+load_errors = {}  # {model_name: error_string} for diagnostics
 
 
 class BackboneHook:
@@ -85,6 +86,7 @@ class EmbedResponse(BaseModel):
 class HealthResponse(BaseModel):
     status: str
     models_loaded: bool
+    available_models: list[str]
     vector_dims: dict[str, int]
 
 
@@ -128,6 +130,8 @@ def load_models():
 
         print(f"  eSEN loaded successfully! (dataset: {esen_dataset})")
     except Exception as e:
+        import traceback
+        load_errors["esen"] = f"{e}\n{traceback.format_exc()}"
         print(f"  Warning: Could not load eSEN: {e}")
         print("  eSEN embeddings will not be available.")
 
@@ -143,6 +147,8 @@ def load_models():
 
         print("  l-MM and l-OFM loaded successfully!")
     except Exception as e:
+        import traceback
+        load_errors["megnet"] = f"{e}\n{traceback.format_exc()}"
         print(f"  Warning: Could not load MEGNet featurizers: {e}")
 
     models_loaded = True
@@ -187,14 +193,37 @@ async def startup_event():
 
 @app.get("/health", response_model=HealthResponse)
 async def health_check():
-    """Health check endpoint."""
+    """Health check endpoint — reports which models actually loaded."""
+    available = []
+    dims = {}
+    if esen_predictor is not None:
+        available.append("esen")
+        dims["esen"] = ESEN_DIM
+    if mm_model is not None:
+        available.append("l_mm")
+        dims["l_mm"] = MM_DIM
+    if ofm_model is not None:
+        available.append("l_ofm")
+        dims["l_ofm"] = OFM_DIM
     return HealthResponse(
         status="healthy" if models_loaded else "loading",
         models_loaded=models_loaded,
-        vector_dims={"esen": ESEN_DIM, "l_mm": MM_DIM, "l_ofm": OFM_DIM},
+        available_models=available,
+        vector_dims=dims,
     )
 
 
+@app.get("/debug")
+async def debug_info():
+    """Diagnostic endpoint showing model load status and errors."""
+    return {
+        "esen_loaded": esen_predictor is not None,
+        "mm_loaded": mm_model is not None,
+        "ofm_loaded": ofm_model is not None,
+        "load_errors": load_errors,
+    }
+
+
 @app.post("/embed", response_model=EmbedResponse)
 async def embed_structure(req: CifRequest):
     """