Fix: agents.defaults.model at top level, not under gateway

start.sh

@@ -146,9 +146,11 @@ CONFIG_JSON=$(cat <<'CONFIGEOF'
 CONFIGEOF
 )
 
-# Gateway token + model
+# Gateway token
 CONFIG_JSON=$(echo "$CONFIG_JSON" | jq ".gateway.auth.token = \"$GATEWAY_TOKEN\"")
-CONFIG_JSON=$(echo "$CONFIG_JSON" | jq ".gateway.agents = {\"defaults\": {\"model\": \"$LLM_MODEL\"}}")
+
+# Model configuration at top level
+CONFIG_JSON=$(echo "$CONFIG_JSON" | jq ".agents.defaults.model = \"$LLM_MODEL\"")
 
 # Control UI origin (allow HF Space URL for web UI access)
 if [ -n "$SPACE_HOST" ]; then