Constant PTY_SHELL_READ_TOOL 

pub(crate) const PTY_SHELL_READ_TOOL: &str = r#"{
  "name": "PtyShellRead",
  "description": "Read back a PtyShell()'s output tail (default last 200 lines). This is a raw text log, not a rendered screen — a full-screen program that redraws in place (progress bars, cursor-addressed UIs) won't read back exactly as it visually renders, but line-oriented prompts (the common case) read back cleanly.",
  "inputSchema": {
    "type": "object",
    "properties": {
      "shell_id":   { "type": "string", "description": "The shell_id returned by a prior PtyShell() call" },
      "tail_lines": { "type": "integer", "description": "Number of trailing lines to return (default 200)" }
    },
    "required": ["shell_id"]
  }
}"#;