Constant UI_SCREENSHOT_TOOL 

pub(crate) const UI_SCREENSHOT_TOOL: &str = r#"{
  "name": "UIScreenshot",
  "description": "Capture a screenshot of your OWN AgentMux pane's UI — clipped to just that pane, not the whole shared window (can't see other panes/agents). Returns a file path; use the Read tool on that path to view the image yourself, or OpenMedia to show it to the user. Use this to visually verify a UI change (e.g. after UIClick-ing a button). Pass pane (from OpenBrowser) to act on a browser pane you opened; without it this acts on your own pane.",
  "inputSchema": { "type": "object", "properties": { "pane": { "type": "string", "description": "Optional: the pane id OpenBrowser returned, to act on a browser pane you opened instead of your own pane. Only panes you opened are accepted." } } }
}"#;