Fix history filter dropping every message: model never saw user input

app.py

@@ -695,7 +695,11 @@ def _history_for_model(history: list) -> list[dict]:
     conversation = [{"role": "system", "content": SYSTEM_PROMPT}]
     for msg in history or []:
         role = msg.get("role", "user")
-        if role == "system" or msg.get("metadata"):
+        meta = msg.get("metadata") or {}
+        # Only skip thought/tool bubbles; Gradio attaches an empty metadata
+        # dict to ordinary messages, so a bare truthiness check drops them all.
+        is_thought = isinstance(meta, dict) and bool(meta.get("title"))
+        if role == "system" or is_thought:
             continue
         content = msg.get("content", "")
         if isinstance(content, list):