Adds a corner-overlay FPS readout gated on HERMES_TUI_FPS, fed by
ink's onFrame callback (so it's the REAL render rate, not a timer).
Displays fps, last-frame duration, and total frame count, colored by
threshold (green ≥50, yellow ≥30, red below).
Implementation:
* lib/fpsStore.ts — nanostore atom updated from a trackFrame()
sink. Ring buffer of last 30 frame timestamps; fps = 29/elapsed.
trackFrame is undefined when SHOW_FPS is off so ink's onFrame
short-circuits at the optional chain.
* components/fpsOverlay.tsx — tiny <Text> subscriber; returns null
when SHOW_FPS is off (React skips the subtree entirely).
* entry.tsx — composes onFrame from logFrameEvent (dev-perf) and
trackFrame (fps) so both flags can coexist. When both are off,
onFrame is undefined and ink never attaches the handler.
* appLayout.tsx — mounts the overlay as a flex-shrink=0 right-
aligned Box below the composer, conditional on SHOW_FPS.
Usage:
HERMES_TUI_FPS=1 hermes --tui
# bottom right: " 62.3fps · 0.8ms · #1234" (green/yellow/red)
Intended as a user-facing diagnostic during the scroll-perf tuning
pass — watch the counter drop while holding PageUp to see where
frames go silent, without having to run scripts/profile-tui.py in a
side terminal.
126 files post-compile with React Compiler; 352 tests still pass.
Extends HERMES_DEV_PERF to capture the complete render pipeline, not
just React commits. Adds scripts/profile-tui.py to drive repeatable
hold-PageUp stress tests against a real long session.
perfPane.tsx:
Wires ink's onFrame callback (already plumbed through the fork) into
the same perf.log as the React.Profiler samples. Captures per-phase
timing (yoga calculateLayout, renderNodeToOutput, screen diff, patch
optimize, stdout write) plus yoga counters (visited/measured/cache-
Hits/live) and patch counts per frame. Events are tagged
{src: 'react'|'frame'} so jq can split them. logFrameEvent is
undefined when HERMES_DEV_PERF is unset, so ink doesn't even attach
the callback.
entry.tsx:
Passes logFrameEvent into render().
types/hermes-ink.d.ts:
Declares FrameEvent + onFrame on RenderOptions so the ui-tui side
type-checks against the plumbed-through ink option.
scripts/profile-tui.py:
New harness. Launches the built TUI under a PTY with the longest
session in state.db resumed, holds PageUp/PageDown/etc at a
configurable Hz for N seconds, then parses perf.log and prints
per-phase p50/p95/p99/max plus yoga-counter summaries. Zero deps
beyond stdlib. Exit 2 if nothing was captured (wiring broken).
Initial findings (1106-msg session, 6s PageUp hold at 30Hz):
- Steady state: 10 fps; renderer phase p99=63ms, write p99=0.2ms
- 4/107 heavy frames (>=16ms), all dominated by renderNodeToOutput
- One pathological 97ms frame with yoga measuring 70,415 text cells
and Yoga visiting 225k nodes — the cold-unmeasured-region hit
- Ink's scroll fast-path (DECSTBM blit from prevScreen) is
disqualified because our spacer-based virtual history doesn't
keep heightDelta in sync with scroll.delta, so every PageUp step
falls through to a full 2000-4800 patch re-render instead of ~40
- 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
KISS/DRY sweep — drops ~90 LOC with no behavior change.
- circularBuffer: drop unused pushAll/toArray/size; fold toArray into drain
- gracefulExit: inline Cleanup type + failsafe const; signal→code as a
record instead of nested ternary; drop dead .catch on Promise.allSettled;
drop unused forceExit
- memory: inline heapDumpRoot() + writeSnapshot() (single-use); collapse
the two fd/smaps try/catch blocks behind one `swallow` helper; build
potentialLeaks functionally (array+filter) instead of imperative
push-chain; UNITS at file bottom
- memoryMonitor: inline DEFAULTS; drop unused onSnapshot; collapse
dumpedHigh/dumpedCritical bools to a single Set; single callback
dispatch line instead of duplicated if-chains
- entry.tsx: factor `dumpNotice` formatter (used twice by onHigh +
onCritical)
- useMainApp resize debounce: drop redundant `if (timer)` guards
(clearTimeout(undefined) is a no-op); init as undefined not null
- useVirtualHistory: trim wall-of-text comment to one-line intent; hoist
`const n = items.length`; split comma-declared lets; remove the
`;[start, end] = frozenRange` destructure in favor of direct Math.min
clamps; hoist `hi` init in upperBound for consistency
Validation: tsc clean (both configs), eslint clean on touched files,
vitest 102/102, build produces shebang-preserved dist/entry.js,
performHeapDump smoke-test still writes valid snapshot + diagnostics.
Long TUI sessions were crashing Node via V8 fatal-OOM once transcripts +
reasoning blobs crossed the default 1.5–4GB heap cap. This adds defense
in depth: a bigger heap, leak-proofing the RPC hot path, bounded
diagnostic buffers, automatic heap dumps at high-water marks, and
graceful signal / uncaught handlers.
## Changes
### Heap budget
- hermes_cli/main.py: `_launch_tui` now injects `NODE_OPTIONS=
--max-old-space-size=8192 --expose-gc` (appended — does not clobber
user-supplied NODE_OPTIONS). Covers both `node dist/entry.js` and
`tsx src/entry.tsx` launch paths.
- ui-tui/src/entry.tsx: shebang rewritten to
`#!/usr/bin/env -S node --max-old-space-size=8192 --expose-gc` as a
fallback when the binary is invoked directly.
### GatewayClient (ui-tui/src/gatewayClient.ts)
- `setMaxListeners(0)` — silences spurious warnings from React hook
subscribers.
- `logs` and `bufferedEvents` replaced with fixed-capacity
CircularBuffer — O(1) push, no splice(0, …) copies under load.
- RPC timeout refactor: `setTimeout(this.onTimeout.bind(this), …, id)`
replaces the inline arrow closure that captured `method`/`params`/
`resolve`/`reject` for the full 120 s request timeout. Each Pending
record now stores its own timeout handle, `.unref()`'d so stuck
timers never keep the event loop alive, and `rejectPending()` clears
them (previously leaked the timer itself).
### Memory diagnostics (new)
- ui-tui/src/lib/memory.ts: `performHeapDump()` +
`captureMemoryDiagnostics()`. Writes heap snapshot + JSON diag
sidecar to `~/.hermes/heapdumps/` (override via
`HERMES_HEAPDUMP_DIR`). Diagnostics are written first so we still get
useful data if the snapshot crashes on very large heaps.
Captures: detached V8 contexts (closure-leak signal), active
handles/requests (`process._getActiveHandles/_getActiveRequests`),
Linux `/proc/self/fd` count + `/proc/self/smaps_rollup`, heap growth
rate (MB/hr), and auto-classifies likely leak sources.
- ui-tui/src/lib/memoryMonitor.ts: 10 s interval polling heapUsed. At
1.5 GB writes an auto heap dump (trigger=`auto-high`); at 2.5 GB
writes a final dump and exits 137 before V8 fatal-OOMs so the user
can restart cleanly. Handle is `.unref()`'d so it never holds the
process open.
### Graceful exit (new)
- ui-tui/src/lib/gracefulExit.ts: SIGINT/SIGTERM/SIGHUP run registered
cleanups through a 4 s failsafe `setTimeout` that hard-exits if
cleanup hangs.
`uncaughtException` / `unhandledRejection` are logged to stderr
instead of crashing — a transient TUI render error should not kill
an in-flight agent turn.
### Slash commands (new)
- ui-tui/src/app/slash/commands/debug.ts:
- `/heapdump` — manual snapshot + diagnostics.
- `/mem` — live heap / rss / external / array-buffer / uptime panel.
- Registered in `ui-tui/src/app/slash/registry.ts`.
### Utility (new)
- ui-tui/src/lib/circularBuffer.ts: small fixed-capacity ring buffer
with `push` / `tail(n)` / `drain()` / `clear()`. Replaces the ad-hoc
`array.splice(0, len - MAX)` pattern.
## Validation
- tsc `--noEmit` clean
- `vitest run`: 15 files, 102 tests passing
- eslint clean on all touched/new files
- build produces executable `dist/entry.js` with preserved shebang
- smoke-tested: `HERMES_HEAPDUMP_DIR=… performHeapDump('manual')`
writes both a valid `.heapsnapshot` and a `.diagnostics.json`
containing detached-contexts, active-handles, smaps_rollup.
## Env knobs
- `HERMES_HEAPDUMP_DIR` — override snapshot output dir
- `HERMES_HEAPDUMP_ON_START=1` — dump once at boot
- existing `NODE_OPTIONS` is respected and appended, not replaced
Dynamic-importing @hermes/ink + App costs ~170ms on cold start — during
that window the terminal was blank. Now `entry.tsx` writes a raw-ANSI
banner to stdout immediately after the TTY check, using hardcoded
DEFAULT_THEME colors. Ink's `<AlternateScreen>` wipes the normal-screen
buffer when it mounts, so the boot banner is replaced seamlessly by the
real React render a moment later — no double-banner, no flash.
T=2ms banner visible (vs. ~170ms before)
T=~170ms React + Ink mounts
T=~200ms alt screen takes over, Banner component repaints
Palette drift between `bootBanner.ts` and the live theme is harmless —
the live render overrides after ~200ms. Narrow terminals (cols < 98)
fall back to the one-line "⚕ NOUS HERMES" marker.
Before: entry.tsx imports @hermes/ink (394KB bundle) + App + GatewayClient
in declaration order, then calls `gw.start()` at ~T=220ms. Python fork +
server.py import starts then.
After: only `GatewayClient` is statically imported (5ms, node builtins
only). `gw.start()` fires at ~T=5ms. @hermes/ink + App load in parallel
via `Promise.all(import(...))`. Python gets ~215ms of free runway to do
its own module import before node even finishes loading.
Net: session.info arrives ~150ms earlier in cold start. First React frame
timing is unchanged (still ~240ms — still gated by ink+app imports).
Removed a previously-tried warm-thread in server.py that pre-imported
`run_agent` in the background. Measured variance showed occasional
5-10s outliers (GIL thrashing); median gain was <100ms. Not worth the
non-determinism.
- Switch tsconfig to nodenext module resolution for Node 22 (used by
installer script)
- Add shebang to entry.tsx, preserved into index.js
- Add HERMES_ROOT env var fallback for repo root resolution
