- drop unused TUI helpers, test-only layout scaffolding, and stale public debug exports
- remove an unused profiler import and trim test-only coverage for deleted helpers
Keep history metadata consistent with lineage replay, globally order replayed lineage messages, and make Ink cache eviction report post-eviction sizes. Also keys TUI config cache by path to avoid cross-home test leakage.
- stringWidth: true LRU on cache hit (touch-on-read via delete+set) so
hot strings stay resident under long sessions; was insertion-order
FIFO before
- virtualHeights: include todos, panel sections, and intro version in
messageHeightKey so height-cache reuse correctly invalidates when
todo content / panel sections change
- virtualHeights: estimate trail+todos rows at todos.length+2 (or 2
collapsed) instead of the generic ~1-line fallback, so initial
virtualization offsets are closer to reality
- useInputHandlers: clearTimeout on unmount for scrollIdleTimer so
pending relaxStreaming() never fires after teardown
- render-node-to-output: drop unused declined.noHint counter from
scrollFastPathStats; it was always 0 (the "hint missing" branch is
outside the diagnostics block)
- perfPane / hermes-ink.d.ts: follow the noHint removal
- wheelAccel: replace ~/claude-code path comment with generic
attribution that doesn't reference a developer-local checkout
Adds an `evictInkCaches(level)` API that prunes the four hot module-level
caches (`widthCache`, `wrapCache`, `sliceCache`, `lineWidthCache`) with
either a half-keep LRU pass or a full clear. Wired into:
- memoryMonitor: half-prune on 'high', full drop on 'critical', before
the heap dump / auto-restart path. Gives long sessions a shot at
recovering RSS instead of hard-exiting.
- useSessionLifecycle.resetSession: half-prune so a /new session starts
with a half-warm pool and the prior session can resume cheaply.
Also: lineWidthCache now uses LRU half-eviction on overflow instead of a
full `cache.clear()`, matching the other three caches.
Comparison vs claude-code: both forks now share the same `prevScreen`
blit + dirty-cascade machinery in render-node-to-output. Their smoothness
came from sibling-memo discipline (every chrome pane memo'd so dirty
cascade doesn't disable transcript blit) — already in place in our
appLayout.tsx (TranscriptPane / ComposerPane / StatusRulePane all memo'd).
Alt-screen is not the cause; both use it. The remaining gap was per-row
CPU on width/wrap/slice, which the previous commit closed.
CPU profile (Apr 2026, real-user scroll on 11k-line session) showed three
hot loops in the per-frame render path:
Output.get() per-frame walk: 24% total
└─ sliceAnsi(line, from, to) per write: 18% total
stringWidth(line) chain (cached + JS): 14% total
All three were re-doing identical work every frame: same string → same
clipped slice → same width.
Fixes:
1. Memoize stringWidth (8k-entry LRU) for non-ASCII strings; ASCII fast-path
skips the cache (inline scan beats Map.get for short ASCII, the >90%
case). String.charCodeAt scan up to 64 chars is cheaper than the regex
fallback.
2. Memoize wrapText (4k-entry LRU keyed by maxWidth|wrapType|text) — wrapAnsi
is pure and the same content reflows identically every frame.
3. Memoize sliceAnsi (4k-entry LRU keyed by start|end|str) for the
end-defined hot path used by Output.get().
4. Skip the slice entirely in Output.get() when the line already fits the
clip box (startsBefore=false && endsAfter=false). Most transcript lines
never exceed their container width, and tokenizing them just to slice
(line, 0, width) was pure overhead. This single fast-path drops
sliceAnsi from 18% → ~0% in the profile.
Also tighten virtualization constants (MAX_MOUNTED 260→120, OVERSCAN 40→20,
SLIDE_STEP 25→12) and cap historical-message render at 800 chars / 16
lines via HISTORY_RENDER_MAX_*; messages inside the FULL_RENDER_TAIL_ITEMS
window still render in full so reading-zone behavior is unchanged.
Validation, real-user CPU profile, page-up scroll on 11k-line session:
Output.get() self-time: 24% → 0.3%
sliceAnsi total: 18% → not in top 25
stringWidth family: 14% → ~3%
idle: 60.7% → 77.3%
Frame timings (synthetic page-up profile harness):
dur p95: ~10ms → 4.87ms
dur p99: 25ms+ → 12.80ms
yoga p99: ~20ms → 1.87ms
The remaining CPU in the profile is Yoga layoutNode + React commit,
which is the irreducible work for this UI tree size.
Replaces the static WHEEL_SCROLL_STEP=1 multiplier on wheel events
with an adaptive accel state machine that infers user intent from
inter-event timing.
Algorithm ported straight from claude-code's
src/components/ScrollKeybindingHandler.tsx. All tuning constants,
the native/xterm.js path split, the encoder-bounce detection, the
trackpad-burst signature → all theirs. This file is a mechanical
port into our module structure.
What it does:
precision click (>500ms gap) 1 row/event (deliberate scan)
sustained mouse (40-200ms) 2-6 rows (decay curve)
detected wheel bounce ramps to 15 (sticky wheel-mode)
trackpad flick (5+ <5ms) 1 row/event (burst detect)
direction reversal reset to base
Two implementation paths:
* native terminals (ghostty, iTerm2, Kitty, WezTerm) — linear
window-ramp + optional wheel-mode curve triggered by detected
encoder bounce. SGR proportional reporting handled via the
burst-count guard.
* xterm.js (VS Code / Cursor / browser terminals) — pure
exponential-decay curve with fractional carry. Events arrive
1-per-notch with no pre-amplification, so the curve is more
aggressive.
Selected at construction via isXtermJs() from @hermes/ink (now
exported). Per-user tune via HERMES_TUI_SCROLL_SPEED (alias
CLAUDE_CODE_SCROLL_SPEED for portability).
13 unit tests covering direction flip/bounce/reversal, idle
disengage, trackpad-burst disengage, frac invariants, and the
native vs xterm.js branches.
Profiled under --rate 30 (stress test) and --rate 10 (realistic
sustained scroll): accel ramps to cap=6 at 30Hz burst, decays to
1-3 rows at sparse 10Hz clicks. Perf is comparable to baseline
because accel IS multiplying step — the win is perceptual (fast
flicks cover distance, slow clicks keep precision), not raw fps.
Companion to the earlier WHEEL_SCROLL_STEP=1 change: that set the
base; this modulates around it.
Adds four fields to FrameEvent.phases and the matching profile
summary:
optimizedPatches post-optimize patch count (what's actually
written to stdout; the .patches field is
pre-optimize)
writeBytes UTF-8 byte count of the write this frame
backpressure true when Node's stdout.write returned false
(Writable buffer full — outer terminal can't
keep up)
prevFrameDrainMs end-to-end drain time of the PREVIOUS frame's
write, captured from stdout.write's 2-arg
callback. Reported on the next frame so the
measurement reflects "time until OS flushed
the bytes to the terminal fd", not "time until
queued in Node".
writeDiffToTerminal() now returns { bytes, backpressure } and
accepts an optional onDrain callback. Only attached on TTY with
diff; piped/non-TTY stdout bypasses flow control so the callback
would fire synchronously anyway.
Initial measurements under hold-wheel_up against 1106-msg session
(30Hz for 6s):
patches total 28,888
optimized total 16,700 (ratio 0.58 — optimizer cuts ~42%)
writeBytes 42 KB / 10s = 4.2 KB/s throughput
drainMs p50 0.14 ms terminal accepts bytes instantly
drainMs p99 0.85 ms
backpressure 0% of frames
This rules out the terminal-parse hypothesis — Cursor's xterm.js
drains our output in sub-millisecond time at only 4 KB/s. The
remaining lag has to be in the render pipeline, not the wire.
Profile output now includes the bytes+drain+backpressure lines to
keep this visible on every subsequent iteration.
Adds scrollFastPathStats counters to render-node-to-output.ts: captures
every time a ScrollBox's DECSTBM scroll hint is generated, records
whether the fast path took it (blit+shift from prevScreen) or declined,
and why. Exposed through hermes-ink's public exports and snapshotted on
every FrameEvent so the profiler harness can correlate decline reasons
with the actual patch/renderer cost per frame.
This is pure observation — no behaviour change. Preparing for the
virtual-history rewrite: the hypothesis was that our topSpacer/
bottomSpacer scheme disqualifies every scroll via heightDelta
mismatch, but the data shows the fast path is actually taken on most
scrolls (19/23 over a 6s PageUp hold through 1100 messages) — the
remaining steady-state renderer cost is Yoga tree traversal, not
the per-frame full redraw I initially suspected.
Declines that do happen correlate with React commits that changed the
mounted range mid-scroll (heightDelta=±3 to ±35). Those are the rarer
cases the virtualization rewrite still needs to address.
No test diffs — instrumentation-only. Build verified: `tsc --noEmit`
plus the full `npm run build` compiler post-pass pass cleanly.
Follow-up on #16020 salvage. Three corrections:
1. Truth signal for /copy
Before: success was 'OSC 52 sequence was emitted to stdout'. That's
false on local Linux inside tmux (emitSequence=false), so /copy kept
printing 'clipboard copy failed' to users whose xclip/wl-copy had
already succeeded fire-and-forget.
Fix: setClipboard() now returns { sequence, success } where success =
native-fired OR tmux-buffer-loaded OR osc52-emitted. copyNative()
returns a boolean telling setClipboard whether a native attempt was
made. /copy only shows 'failed' when literally no path was taken.
2. Dashboard keybinding
Before: Ctrl+C for copy on non-Mac (Ctrl+Shift+C for paste).
That swallows SIGINT when a stale selection is present and breaks
the xterm/gnome-terminal/konsole/Windows-Terminal convention where
Ctrl+C in a terminal emulator is always SIGINT. The real bug was
that clipboard writes lost user-gesture through OSC-52 round-trips,
which the direct writeText already fixes.
Fix: revert copyModifier to Ctrl+Shift+C on non-Mac. Direct
writeText in the keydown handler preserves user gesture. term.write
Escape replaced with term.clearSelection() (works without relying
on TUI input mode).
3. Error toast text
Before: 'see HERMES_TUI_DEBUG_CLIPBOARD' — tells users how to
debug but not how to fix.
Fix: point users at HERMES_TUI_FORCE_OSC52=1 first (the actual
escape hatch), mention the debug var second.
- Dashboard copy: direct Clipboard API on Ctrl+C/Cmd+C (user gesture);
send Escape to TUI to clear selection; Ctrl+Shift+C kept as fallback.
- TUI /copy: copySelection() async; only reports success if OSC52 emitted.
- Add HERMES_TUI_FORCE_OSC52 env var to override native-tool detection.
- Fixes "copied N chars" false-positive when clipboard backend absent.
Changes:
web/src/pages/ChatPage.tsx — direct navigator.clipboard.writeText
ui-tui/packages/hermes-ink/src/ink/ink.tsx — async copySelection
ui-tui/packages/hermes-ink/src/ink/termio/osc.ts — HERMES_TUI_FORCE_OSC52
ui-tui/src/app/slash/commands/core.ts — async /copy with honest feedback
Problem: Ctrl+C in Hermes TUI shows 'copied' but clipboard often empty.
Root causes:
- Native Linux tools (xclip, wl-copy) require DISPLAY/WAYLAND_DISPLAY; in
headless Docker/SSH they fail or hang.
- OSC 52 fallback requires terminal emulator support; when absent, sequence
is dropped silently.
- Dashboard OSC 52 → Clipboard API path fails due to missing user gesture;
errors were silently caught.
- User feedback 'copied selection' was shown unconditionally, regardless of
success.
Solution implemented:
- Short-circuit Linux native clipboard probing when no display server is
present (no DISPLAY and no WAYLAND_DISPLAY). Avoids futile attempts and
timeouts.
- Add HERMES_TUI_DEBUG_CLIPBOARD env var (1/true). When set, TUI logs to
stderr which clipboard path is used, probe results on Linux, and whether
OSC 52 was emitted. Greatly improves diagnosability.
- Improve dashboard clipboard error handling: replace empty catch blocks
with console.warn messages for OSC 52 decode/Write failures and direct
copy/paste errors. Makes browser permission/user-gesture failures visible
in DevTools.
- Add comprehensive clipboard troubleshooting documentation to README and
AGENTS, covering OSC 52 verification, tmux config, Docker/headless
constraints, env vars, dashboard caveats, and fallback strategies.
Technical details:
- in ui-tui/packages/hermes-ink/src/ink/termio/osc.ts:
- Early return on Linux if both DISPLAY and WAYLAND_DISPLAY unset.
- Refactor probe sequence to async with 500ms timeout,
caching result; subsequent copies use cached tool immediately.
- Emit debug logs when HERMES_TUI_DEBUG_CLIPBOARD=1.
- in ink.tsx: log when OSC 52 not emitted (native
or tmux path in use) in debug mode.
- : OSC 52 handler and Ctrl+Shift+C handler now
log warnings to console on Clipboard API rejection with error message.
- Documentation: new 'Clipboard Troubleshooting' section in README; new
'Clipboard environment variables and pitfalls' subsection in AGENTS.md
(Known Pitfalls).
Tests: full ui-tui test suite (292 tests) passes; clipboard and OSC tests
unaffected. No breaking changes.
Files changed:
- ui-tui/packages/hermes-ink/src/ink/termio/osc.ts
- ui-tui/packages/hermes-ink/src/ink/ink.tsx
- web/src/pages/ChatPage.tsx
- README.md
- AGENTS.md
- CHANGELOG.md (new)
- editor.ts: collapse two private helpers into one flatMap-driven lookup,
keep `isExecutable` as the only named primitive, document the fallback
chain with prompt_toolkit parity
- editor.test.ts: hoist the `exe` helper out of `describe`, drop the
empty afterEach + dead mkdir branch, materialize expected paths before
the resolveEditor call so argument evaluation order doesn't bite
- useComposerState.openEditor: rmSync the mkdtemp dir (was leaking),
early-return on bad exit / empty buffer, run cleanup in finally
- useInputHandlers: cheap `ch.toLowerCase() === 'g'` guard before the
modifier check
- hermes-ink/screen.ts: pick up `npm run fix` import-sort cleanup so
lint passes
- add a written-cell bitmap so selection can distinguish rendered spaces from blank padding
- preserve code indentation without markdown-specific rendering hacks
- clamp selection highlight to real row content so blank drag margins do not render or copy
- keep successful copy actions quiet while preserving usage and failure feedback
- add reusable overlay key and help-text helpers for picker-style overlays
- make model, session, skills, and pager hints consistently support Esc/q close behavior
- run the requested ui-tui lint+format pass and include resulting formatting updates
- guard text-measure cache eviction key in hermes-ink so ui-tui type-check stays green
On Windows WSL2, ConPTY implicitly enables mouse event injection when
the alternate screen buffer (DEC 1049) is entered, causing raw escape
sequences to appear in the transcript as ghost characters.
Fix (two parts):
1. ConPTY fix: send DISABLE_MOUSE_TRACKING immediately after entering
alt screen when mouse tracking is off (AlternateScreen.tsx)
2. Runtime toggle: add /mouse [on|off|toggle] slash command with config
persistence (display.tui_mouse) so users can manage this at runtime
The env var HERMES_TUI_DISABLE_MOUSE continues to work as the initial
default, but can now be overridden via /mouse and persisted to config.
Closes: upstream ConPTY mouse injection issue
Credits: OutThisLife / PR #13716 for the toggle concept
- disable ANSI dim on VTE terminals by default so dark-background reasoning and accents stay readable
- suppress local multiplexer OSC52 echo while preserving remote passthrough and add regression coverage
Adds a per-ink-text measurement cache keyed by width|widthMode to avoid
re-squashing and re-wrapping the same text when yoga calls measureFunc
multiple times per frame with different widths during flex layout re-pass.
Trim comment noise, remove redundant typing, normalize sticky prompt viewport args to top→bottom order, and reuse one sticky viewport helper instead of duplicating the math.
Renderer-driven follow-to-bottom was restoring the viewport to the tail without notifying ScrollBox subscribers, so StickyPromptTracker could stay stale-visible. Notify on render-time scroll/sticky changes and treat near-bottom as bottom for prompt hiding.
Broaden the settle repaint from xterm.js-only to all alt-screen terminals. Ink upstream and ConPTY/xterm reports point to resize/reflow desync as a general stale-cell class, not a host-specific quirk.
Copilot flagged the variable as unused. LogUpdate.render only sees prev/next, so a simulated "physical terminal" has no hook in the public API. Kept the narrative in the comment and tightened the assertion to demonstrate the test's actual invariant: identical prev/next emits no heal patches.
Replace 28-line guard + nested queueMicrotask + pendingResizeRender flag-reuse with a named canAltScreenRepaint predicate and a single flat paint. setTimeout already drained the burst coalescer; the nested defer and flag dance were paranoia.
- run the xterm.js settle-heal pass through a full render commit instead of diff-only scheduleRender
- guard against overlapping resize renders and clear settle timers on unmount
- force full alt-screen damage in xterm.js hosts to avoid stale glyph artifacts
- skip incremental scroll optimization there and repaint from a cleared screen atomically
- entry.tsx no longer writes bootBanner() to the main screen before the
alt-screen enters. The <Banner> renders inside the alt screen via the
seeded intro row, so nothing is lost — just the flash that preceded it.
Fixes the torn first frame reported on Alacritty (blitz row 5 #17) and
shaves the 'starting agent' hang perception (row 5 #1) since the UI
paints straight into the steady-state view
- AlternateScreen prefixes ERASE_SCROLLBACK (\x1b[3J) to its entry so
strict emulators start from a pristine grid; named constants replace
the inline sequences for clarity
- bootBanner.ts deleted — dead code
- normalizeStatusBar collapses to one ternary expression
- /statusbar slash hoists the toggle value and flattens the branch tree
- shift-tab yolo comment reduced to one line
- cursorLayout/offsetFromPosition lose paragraph-length comments
- appLayout collapses the three {!overlay.agents && …} into one fragment
- StatusRule drops redundant flexShrink={0} (Yoga default)
- server.py uses a walrus + frozenset and trims the compat helper
Net -43 LoC. 237 vitest + 46 pytest green, layouts unchanged.
- input wrap: add <Text wrap="wrap-char"> mode that drives wrap-ansi with
wordWrap:false, and align cursorLayout/offsetFromPosition to that same
boundary (w=cols, trailing-cell overflow). Word-wrap's whitespace
reshuffle was causing the cursor to jump a word left/right on each
keystroke near the right edge — blitz row 9
- shift-tab: toggle per-session yolo without submitting a turn (mirrors
Claude Code's in-place dangerously-approve); slash /yolo still works
for discoverability — blitz row 5 sub-item 11
- statusline: lift StatusRule out of ComposerPane to a new StatusRulePane
anchored at the bottom of AppLayout, below the input — blitz row 5
sub-item 12
Selected rows in the model/session/skills pickers and approval/clarify
prompts only changed from dim gray to cornsilk, which reads as low
contrast on lighter themes and LCDs (reported during TUI v2 blitz).
Switch the selected row to `inverse bold` with the brand accent color
across modelPicker, sessionPicker, skillsHub, and prompts so the
highlight is terminal-portable and unambiguous. Unselected rows stay
dim. Also extends the sessionPicker middle meta column (which was
always dim) to inherit the row's selection state.
Guards four unbounded growth paths reachable at idle — the shape matches
reports of the TUI hitting V8's 2GB heap limit after ~1m of idle with 0
tokens used (Mark-Compact freed ~6MB of 2045MB → pure retention).
- `GatewayClient.logs` + `gateway.stderr` events: 200-line cap is bytes-
uncapped; a chatty Python child emitting multi-MB lines (traceback,
dumped config, unsplit JSON) retains everything. Truncate at 4KB/line.
- `GatewayClient.bufferedEvents`: unbounded until `drain()` fires. Cap
at 2000 so a pre-mount event storm can't pin memory indefinitely.
- `useMainApp` gateway `exit` handler: didn't reset `turnController`, so
a mid-stream crash left `bufRef`/`reasoningText` alive forever.
- `pasteSnips` count-capped (32) but byte-uncapped. Add a 4MB total cap
and clear snips in `clearIn` so submitted pastes don't linger.
- `StylePool.transitionCache`: uncapped `Map<number,string>`. Full-clear
at 32k entries (mirrors `charCache` pattern).
