feat(assistant): #91 etapes enrichies (sous-sections Reflechon/Sources, chevrons, indicateur anime, suppression barre de chargement)

backend/tools/web.py

@@ -150,12 +150,29 @@ def web_search(ctx, params: WebSearchInput) -> dict[str, Any]:
                 "score": item.get("score"),
             }
         )
-    return {
+    unresponsive = [
+        name for entry in (data.get("unresponsive_engines") or [])
+        for name in ([entry[0]] if isinstance(entry, (list, tuple)) and entry else [entry])
+        if isinstance(name, str)
+    ]
+    payload: dict[str, Any] = {
         "query": query,
         "engine": "searxng",
         "results": results,
         "count": len(results),
     }
+    if unresponsive:
+        payload["unresponsive_engines"] = unresponsive[:8]
+    if not results:
+        # An instance whose upstream engines are all blocked (CAPTCHA / rate
+        # limit) answers 200 with an empty list. Without an explicit hint the
+        # model retries the same search until it burns its tool quota.
+        payload["warning"] = (
+            "Aucun résultat : les moteurs de recherche de l'instance SearXNG sont "
+            f"indisponibles ({', '.join(unresponsive[:5]) or 'inconnus'}). "
+            "Ne relance pas la même recherche — dis-le à l'utilisateur."
+        )
+    return payload
 
 
 @tool(