rc:Toolbar=false
hides the toolbar. If the value of this parameter is false, all remaining options are ignored. If you omit this parameter, the toolbar is automatically displayed for rendering formats that support it. The default of this parameter is true.
You can hide the toolbar in Report Server by URL as below:
http://<ServerName>/reportserver?/Sales/YearlySalesSummary&rs:Command=Render&rs:Format=HTML4.0&rc:Toolbar=false
Please refer here for more details.