diff --git a/app/main.py b/app/main.py
index 16aa2ea..ac1b93a 100644
--- a/app/main.py
+++ b/app/main.py
@@ -129,9 +129,10 @@ def create_app() -> FastAPI:
 
     # Templates
     import json as _json
+    from markupsafe import Markup as _Markup
     templates_dir = Path(__file__).parent / "templates"
     templates = Jinja2Templates(directory=str(templates_dir))
-    templates.env.filters["tojson"] = _json.dumps
+    templates.env.filters["tojson"] = lambda v: _Markup(_json.dumps(v))
 
     # Register UI routes (must come before API to avoid catch-all conflicts)
     from .ui.routes import router as ui_router, setup_templates