diff --git a/app/routers/runs.py b/app/routers/runs.py
index a951c9e..d3593db 100644
--- a/app/routers/runs.py
+++ b/app/routers/runs.py
@@ -157,17 +157,28 @@ async def get_run(
             except Exception as e:
                 logger.warning(f"Failed to load recipe for plan: {e}")
 
+        # Helper to convert simple type to MIME type prefix for template
+        def type_to_mime(simple_type: str) -> str:
+            if simple_type == "video":
+                return "video/mp4"
+            elif simple_type == "image":
+                return "image/jpeg"
+            elif simple_type == "audio":
+                return "audio/mpeg"
+            return None
+
         # Build artifacts list from output and inputs
         artifacts = []
         if run.get("output_hash"):
-            # Detect media type
+            # Detect media type using magic bytes
             output_hash = run["output_hash"]
             media_type = None
             try:
-                cache_path = get_cache_manager().get_path(output_hash)
+                from ..services.run_service import detect_media_type
+                cache_path = get_cache_manager().get_by_content_hash(output_hash)
                 if cache_path and cache_path.exists():
-                    import mimetypes
-                    media_type, _ = mimetypes.guess_type(str(cache_path))
+                    simple_type = detect_media_type(cache_path)
+                    media_type = type_to_mime(simple_type)
             except Exception:
                 pass
             artifacts.append({
@@ -179,14 +190,15 @@ async def get_run(
         # Build inputs list with media types
         run_inputs = []
         if run.get("inputs"):
-            import mimetypes
+            from ..services.run_service import detect_media_type
             cache_manager = get_cache_manager()
             for i, input_hash in enumerate(run["inputs"]):
                 media_type = None
                 try:
-                    cache_path = cache_manager.get_path(input_hash)
+                    cache_path = cache_manager.get_by_content_hash(input_hash)
                     if cache_path and cache_path.exists():
-                        media_type, _ = mimetypes.guess_type(str(cache_path))
+                        simple_type = detect_media_type(cache_path)
+                        media_type = type_to_mime(simple_type)
                 except Exception:
                     pass
                 run_inputs.append({