Function FocusSession

internal/kitty/kitty.go:124–143

FocusSession tries to focus the kitty window currently running `binary` with the given session UUID. The `binary` arg is the harness's executable name (e.g. "claude", "codex", "gemini") used to filter windows. Returns (true, nil) on focus, (false, nil) if no window across any kitty OS window matches

(sessionID, binary string)

// If remote control is disabled, `kitty @ ls` exits non-zero and the
// error is surfaced wrapped.
func FocusSession(sessionID, binary string) (bool, error) {
	if sessionID == "" {
		return false, nil
	}
	out, err := RunnerOutput([]string{"@", "ls"})
	if err != nil {
		return false, fmt.Errorf("kitty @ ls: %w", err)
	}
	winID, ok, err := windowIDForHarnessSession(out, sessionID, binary)
	if err != nil {
		return false, err
	}
	if !ok {
		return false, nil
	}
	if err := Runner([]string{"@", "focus-window", fmt.Sprintf("--match=id:%d", winID)}); err != nil {
		return false, fmt.Errorf("kitty @ focus-window: %w", err)
	}
	return true, nil
}

// kittyOSWindow / kittyTab / kittyWindow / kittyFGProc are the minimal
// subset of the `kitty @ ls` JSON schema we care about. The full schema