Add GGUF detection with friendly error; clarify scope in UI

app.py

@@ -208,13 +208,16 @@ with gr.Blocks(
     # 🧬 ModelDNA
     ### The DNA test for AI models — verify provenance before you download
     *Powered by ModelAtlas · a RadicalNotion product*
+
+    > **Works with:** standard HuggingFace checkpoints (safetensors / PyTorch bin).
+    > **Not yet supported:** GGUF quantized models, private/gated models. No weight download needed — Stage 1 reads config.json only.
     ---
     """)
 
     with gr.Row():
         model_input = gr.Textbox(
-            label="HuggingFace Model ID",
-            placeholder="e.g. Qwen/Qwen3.5-27B or paste a HF URL",
+            label="HuggingFace Model ID or URL",
+            placeholder="e.g. Qwen/Qwen3.5-27B  (not GGUF — use the original checkpoint)",
             scale=4,
         )
         scan_btn = gr.Button("🔬 Scan", variant="primary", scale=1)

scan.py

@@ -315,6 +315,22 @@ def generate_verdict(
 def scan(model_id: str) -> dict:
     """Full Stage 1 scan. Entry point."""
     t0 = time.time()
+
+    # Detect unsupported formats before attempting config fetch
+    name_lower = model_id.lower()
+    if "gguf" in name_lower:
+        return {
+            "model_id": model_id,
+            "error": (
+                "GGUF models pack weights into a single file and don't have a standard config.json. "
+                "Stage 1 scanning works with standard HuggingFace checkpoints (safetensors/PyTorch). "
+                "Try the original (non-quantized) model instead — e.g. the unsloth/Qwen3.6-35B-A3B "
+                "base would be Qwen/Qwen2.5-... or the upstream source. "
+                "GGUF support is on the roadmap."
+            ),
+            "scanned_at": datetime.now(timezone.utc).isoformat(),
+        }
+
     config = fetch_config(model_id)
     if not config:
         return {