cursor_info

Instructions

Implementation Reference

• src/cursor.ts:3-10 (schema)

  CursorInfo interface defining the shape returned by cursor_info: x, y, monitor, foregroundWindow, windowUnderCursor.

  export interface CursorInfo {
    x: number;
    y: number;
    monitor?: number;
    foregroundWindow?: string;
    /** Title of the window under the cursor when available. */
    windowUnderCursor?: string;
  }

• src/cursor.ts:17-25 (handler)

  getCursorInfo() - main handler that dispatches to Windows-specific implementation or returns a stub on other platforms.

  export async function getCursorInfo(): Promise<CursorInfo> {
    if (process.platform === "win32") {
      return getCursorInfoWindows();
    }
    /* On other platforms we keep a stub - position lookup needs platform-specific
     * code that is out of scope for the first release. Callers should treat the
     * absence of x/y as "unknown". */
    return { x: -1, y: -1 };
  }

• src/cursor.ts:27-84 (handler)

  getCursorInfoWindows() - PowerShell-based Windows implementation that gets cursor position, foreground window title, and window under cursor via Win32 APIs.

  async function getCursorInfoWindows(): Promise<CursorInfo> {
    const ps = `
  Add-Type -AssemblyName System.Windows.Forms
  Add-Type -TypeDefinition @"
  using System;
  using System.Runtime.InteropServices;
  using System.Text;
  public class W {
    [DllImport("user32.dll")] public static extern IntPtr GetForegroundWindow();
    [DllImport("user32.dll")] public static extern int GetWindowText(IntPtr hWnd, StringBuilder text, int count);
    [DllImport("user32.dll")] public static extern IntPtr WindowFromPoint(POINT p);
    [DllImport("user32.dll")] public static extern IntPtr GetAncestor(IntPtr hWnd, uint flags);
    [StructLayout(LayoutKind.Sequential)] public struct POINT { public int x; public int y; }
  }
  "@
  $pos = [System.Windows.Forms.Cursor]::Position
  $fg = [W]::GetForegroundWindow()
  $sb = New-Object System.Text.StringBuilder 512
  [void][W]::GetWindowText($fg, $sb, 512)
  $fgTitle = $sb.ToString()
  $pt = New-Object W+POINT
  $pt.x = $pos.X
  $pt.y = $pos.Y
  $wnd = [W]::WindowFromPoint($pt)
  $root = [W]::GetAncestor($wnd, 2)
  $sb2 = New-Object System.Text.StringBuilder 512
  [void][W]::GetWindowText($root, $sb2, 512)
  $undTitle = $sb2.ToString()
  $out = @{ x = $pos.X; y = $pos.Y; fg = $fgTitle; under = $undTitle }
  $out | ConvertTo-Json -Compress
  `;
    return new Promise((resolve, reject) => {
      const child = spawn(
        "powershell.exe",
        ["-NoProfile", "-NonInteractive", "-Command", ps],
        { windowsHide: true }
      );
      let out = "";
      let err = "";
      child.stdout.on("data", (d) => (out += d.toString()));
      child.stderr.on("data", (d) => (err += d.toString()));
      child.on("error", reject);
      child.on("close", (code) => {
        if (code !== 0) return reject(new Error(`cursor probe failed: ${err}`));
        try {
          const j = JSON.parse(out.trim());
          resolve({
            x: j.x,
            y: j.y,
            foregroundWindow: j.fg || undefined,
            windowUnderCursor: j.under || undefined,
          });
        } catch (e) {
          reject(new Error(`cursor probe parse error: ${(e as Error).message} :: ${out}`));
        }
      });
    });
  }

• src/index.ts:72-79 (registration)

  Tool registration for cursor_info in the ListToolsRequestSchema handler: defines the tool name, description, and empty input schema.

  {
    name: "cursor_info",
    description:
      "Return the current mouse cursor position, the foreground window title, and the " +
      "title of the window directly under the cursor (Windows only; other platforms " +
      "report position only when available).",
    inputSchema: { type: "object", properties: {} },
  },

• src/index.ts:185-188 (registration)

  CallToolRequestSchema handler dispatches 'cursor_info' case: calls getCursorInfo() and returns the result as text.

  case "cursor_info": {
    const ci = await getCursorInfo();
    return text(ci);
  }