* fix(tui): append gateway stderr tail to start_timeout activity
`gateway.start_timeout` previously published only `cwd` + `python`,
which made TUI startup failures hard to disambiguate. The user saw
`gateway startup timed out · /path/to/python /repo · /logs to inspect`
with no signal whether the actual cause was a wrong python interpreter,
a missing dependency, or a config parse failure.
Plumb a 20-line stderr tail through the event so the most useful lines
land directly in the TUI activity feed, capped to the last 8 non-empty
lines for readability:
* `gatewayClient.ts` — collect `getLogTail(20)` when the readyTimer
fires and attach it as `payload.stderr_tail`.
* `gatewayTypes.ts` — extend the `gateway.start_timeout` event union
with the new optional field.
* `createGatewayEventHandler.ts` — emit the trimmed lines after the
existing `gateway startup timed out` activity entry, classified
`error`.
Tests: regression test in `createGatewayEventHandler.test.ts` checks
that `ModuleNotFoundError` / `FileNotFoundError` lines from the tail
land in `getTurnState().activity` so they show up in the UI immediately.
Validation: `npm run type-check` clean, `npm test --run` 390/390.
* review(copilot): filter blanks before slice and cap stderr tail at 120 chars
Six small fixes, all valid review feedback:
- gatewayClient: onTimeout is now a class-field arrow so setTimeout gets a
stable reference — no per-request bind allocation (the whole point of
the original refactor).
- memory: growth rate was lifetime average of rss/uptime, which reports
phantom growth for stable processes. Now computed as delta since a
module-load baseline (STARTED_AT). Sanity-checked: 0.00 MB/hr at
steady-state, non-zero after an allocation.
- hermes_cli: NODE_OPTIONS merge is now token-aware — respects a
user-supplied --max-old-space-size (don't downgrade a deliberate 16GB
setting) and avoids duplicating --expose-gc.
- useVirtualHistory: if items shrink past the frozen range's start
mid-freeze (/clear, compaction), drop the freeze and fall through to
the normal range calc instead of collapsing to an empty mount.
- circularBuffer: throw on non-positive capacity instead of silently
producing NaN indices.
- debug slash help: /heapdump mentions HERMES_HEAPDUMP_DIR override
instead of hardcoding the default path.
Validation: tsc clean, eslint clean, vitest 102/102, growth-rate smoke
test confirms baseline=0 → post-alloc>0.
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
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).
- 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
