Constant LAYOUT_TOOL 

pub(crate) const LAYOUT_TOOL: &str = r#"{
  "name": "Layout",
  "description": "Read the AgentMux UI structure around you. `query` selects what to return: \"layout\" (the full tree — every window with its workspace, tabs, and panes [block_id, view, title], and which tab is active), \"windows\" (window_id, display name, assigned workspace), \"workspaces\" (workspace_id, name, tab count, active tab), or \"tabs\" (tabs in your own workspace: tab_id, name, pane count). Read-only; use before naming or focusing things. For your OWN ids (block/tab/window/workspace), use WhoAmI instead.",
  "inputSchema": {
    "type": "object",
    "properties": {
      "query": { "type": "string", "enum": ["layout", "windows", "workspaces", "tabs"], "description": "What to return (default: layout)" }
    }
  }
}"#;