Two long-standing prompt_toolkit bugs in the base hermes CLI:
1. Resize duplication. Column-shrink resize used to push 40+ rows of
duplicate chrome (status bar, input rules) into terminal scrollback
every resize. Same wall as pt issues #29 (open since 2014), #1675,
#1933 — aider/xonsh/ipython all use alt-screen to dodge it.
Root cause (verified by reading prompt_toolkit/renderer.py):
_output_screen_diff (renderer.py L232-242) deliberately moves the
cursor to the bottom of the canvas after every paint 'to make sure
the terminal scrolls up'. In non-fullscreen mode this scrolls chrome
content into terminal scrollback on every render — not just on
resize.
Fix: monkey-patch prompt_toolkit.renderer._output_screen_diff to
bypass the reserve-vertical-space cursor move. When pt's logic checks
'if current_height > previous_screen.height', we inflate the previous
screen height so the branch falls through. ~30-line wrapper, no fork
of pt, no alt-screen, no DECSTBM scroll region.
Verified empirically in real Terminal.app: 10 resizes (mixed
shrinks/widens 1300→500→1400) during streaming produced ZERO
scrollback delta, full agent response preserved, status bar pinned
at bottom, no visible duplicates. pt is pinned to ==3.0.52 so the
private-function patch is safe; future pt bumps will need to
re-verify the signature matches.
2. Light-mode terminal visibility. Hardcoded skin colors (#FFF8DC
cornsilk, #FFD700 gold, #B8860B dark goldenrod) are tuned for dark
Terminal.app — invisible on light/cream backgrounds.
Port ui-tui/src/theme.ts detectLightMode() to Python so the base CLI
adapts. Detection priority: HERMES_LIGHT/HERMES_TUI_LIGHT env →
HERMES_TUI_THEME=light|dark → HERMES_TUI_BACKGROUND=#RRGGBB →
COLORFGBG env (xterm/Konsole/urxvt) → OSC 11 query
(\x1b]11;?\x1b\\) with 100ms timeout → default dark. OSC 11 is
tty-gated so gateway/cron/batch/subagent code paths don't pay the
timeout cost.
When light mode is detected, dark-mode colors auto-remap to readable
equivalents (#FFF8DC → #1A1A1A, #FFD700 → #9A6B00, etc). Hooked at
three points:
- _hex_to_ansi() — auto-remaps any color emitted via the ANSI helper
- _build_tui_style_dict() — rewrites pt style strings (chrome bg/fg)
- SkinConfig.get_color() — wrapped at module load so Rich Panel
borders/body text get the remap too
Status-bar foreground colors (#C0C0C0, #888888, etc.) are explicitly
skipped because they're paired with a dark navy bg — remapping them
would make them invisible in dark mode.
3. Other visibility fixes: [thinking] reasoning preview now uses ANSI
dim+italic (\x1b[2;3m) instead of #B8860B so it inherits terminal
default fg color. Input/prompt area defaults to terminal default fg
(was #FFF8DC cornsilk → invisible on cream).
Co-authored-by: Brooklyn Nicholson <brooklyn.bb.nicholson@gmail.com>
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