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Debugging

Mosaico provides several tools for inspecting and troubleshooting the window manager.

mosaico doctor

The doctor command performs a comprehensive health check:

mosaico doctor

It checks:

  1. Config directory exists
  2. All configuration files are valid TOML
  3. All keybinding key names resolve to valid key codes
  4. Daemon status (running, stopped, or stale)
  5. Monitor enumeration and dimensions

Issues are reported with colored tags: [ok], [warn], [fail], or [fixed].

mosaico debug list

Lists all visible windows on the desktop:

mosaico debug list

The output is a formatted table showing:

ColumnDescription
HWNDWindow handle in hex
ManagedWhether the window is tiled
MonitorWhich monitor the window is on
TitleWindow title
ClassWindow class name
PositionX, Y coordinates
SizeWidth and height
Border OffsetInvisible frame compensation values

This is useful for finding window class names when writing window rules.

mosaico debug events

Streams window events in real time:

mosaico debug events

Shows events like window creation, destruction, focus changes, moves, minimize/restore, and title changes. Press Ctrl+C to stop.

This is useful for understanding how Mosaico reacts to window changes and diagnosing timing issues.

mosaico debug move

Moves a specific window to exact coordinates:

mosaico debug move 0x1A2B3C 100 200 800 600

Arguments: <hwnd> <x> <y> <width> <height>. The HWND can be in decimal or 0x hex format (use debug list to find it).