Herdr v0.6.0 SGR mouse escape sequence leak

Thesis

Herdr v0.6.0 enables SGR extended mouse mode (DECSET 1006) on the outer terminal, but under certain conditions the raw SGR escape sequences (<5;X;YM) leak through as visible text in panes instead of being consumed by Herdr’s TUI event handler. The leak occurs because escape sequences sent from inside a pane are consumed by Herdr’s virtual terminal emulation layer and never reach the outer terminal, so printf '\x1b[?1000l\x1b[?1006l' inside a pane cannot disable SGR at the terminal level.

Evidence

• Observed patterns: 5;52;14M, 35;109;23M, 1;22M, 8M, [<35;109;24M — all SGR extended mode (DECSET 1006) mouse events where ESC[ prefix is consumed but parameters render as text
• 5 = scroll wheel down (standard xterm button code)
• Coordinates span multiple positions across the TUI (pane areas + sidebar)
• Occurs in ALL panes, not specific to any one app
• Setting mouse_capture = false in Herdr config breaks pane selection but does NOT stop the leak (config reload doesn’t re-initialize terminal SGR mode)
• Setting tmux set -g mouse off has no effect (tmux runs INSIDE Herdr panes for OmniPulse, not as the host)
• printf '\x1b[?1000l\x1b[?1006l' from inside a Herdr pane is consumed by Herdr’s pty layer — never reaches outer terminal

Root cause analysis

The outer terminal emulator (SSH client side) has SGR mouse mode enabled by Herdr’s startup initialization. When mouse events arrive:

1. Herdr normally consumes them for its TUI
2. Under certain conditions (race, buffer overflow, mode conflict), the raw sequences bypass Herdr’s handler
3. The ESC[ prefix is consumed but the parameter body (5;X;YM) renders as visible text

The mouse_capture setting in Herdr’s config controls whether Herdr REACTS to mouse events for pane selection/resizing, but does NOT control whether SGR mode is ENABLED on the outer terminal.

Tried fixes (none worked)

• mouse_capture = false in config.toml — breaks pane selection, leak continues
• tmux set -g mouse off — irrelevant (tmux is inside Herdr’s panes, not hosting Herdr)
• printf '\x1b[?1000l\x1b[?1006l' in a pane — consumed by Herdr’s pty, never reaches terminal
• herdr kill — invalid command (correct command: herdr server stop)

Untried potential fixes

1. Proper server stop (herdr server stop) — should trigger terminal cleanup (SGR disable) on server shutdown, then restart clean
2. TERM=vt100 herdr — force terminal type without SGR mouse support to prevent Herdr from enabling SGR mode
3. --no-session flag — run monolithically, might bypass SGR initialization path

Implications

• Herdr’s terminal initialization sets SGR mode but its cleanup path when config-reloading doesn’t disable it
• The mouse_capture config option name is misleading — it controls mouse UI interaction, not SGR mode enabling
• This is likely a Herdr v0.6.0 bug worth reporting (SGR mode should be toggled based on mouse_capture setting at startup, or a separate enable_sgr_mouse config option should exist)