Merge pull request 'Add #help command with short list of all commands (v0.21.6)' (#49) from fix/help-command into main

Owner request: 'now add #help with short list of all command'. Registered in
the CommandService constructor next to #ping; returns a SINGLE multi-line
string (one packet, ~203 chars) — not an array, which would drip-feed one
spaced packet per line through the v0.21.5 MESH_MULTI_SEND_DELAY_MS loop.

Also hardened the v0.21.5 multi-send-spacing spec: its wall-clock assertion
('first send < 8 ms after t0') flaked under full-suite load — replaced with
fake timers, which assert deterministically that line 1 is out before any time
elapses and lines 2-3 land exactly one delay apart.

AGENTS.md

@@ -12,7 +12,7 @@
 ## Verification
 
 1. **Local checks** — `npm run build` (nest build) and `npm test` (vitest; no e2e suite yet). Both must pass before a PR is opened.
-2. **Docker** — `docker compose build`, then after `docker compose up -d`: `curl -s -H "Host: bot.dev.kkhost.pl" http://localhost/api/status` returns JSON (`{ connected, myNodeNum, host, port }`). `"connected":false` is normal while the bridge/device is down — the service retries every 5 s.
+2. **Docker** — `docker compose build`, then after `docker compose up -d`: `curl -s -H "Host: bot.dev.kkhost.pl" http://localhost/api/status` returns JSON (`{ connected, myNodeNum, host, port }`). `"connected":false` is normal while the bridge/device is down — the service retries every 5 s. An idle watchdog also force-reconnects an ESTABLISHED-but-silent connection (zombie bridge: outbound works, inbound dead) when no DECODED FRAME arrives from the bridge for `MESH_IDLE_TIMEOUT_MS` ms (default 60000 = 1 min; checked every 30 s — raw non-frame bytes do NOT count), an undecoded frame buffer over `MESH_MAX_FRAME_BUFFER` bytes (default 256000) forces a reconnect as a stream-desync backstop, and the socket has TCP keepalive enabled (30 s). A lazy periodic autoreconnect additionally unconditionally re-establishes every `MESH_RECONNECT_INTERVAL_MS` ms (default 300000 = 5 min) for a fresh sync.
 
 ## API
 
@@ -27,5 +27,5 @@
 
 - MESHTASTIC.md — rules for Meshtastic communication (owner authority, language, response protocol); read before acting on mesh messages.
 - Hourly cron weather report job (`src/weather`): fetches Open-Meteo current conditions and broadcasts a one-line report to the mesh on the pinned send channel; env `WEATHER_CRON`/`WEATHER_LAT`/`WEATHER_LON`/`WEATHER_CITY`.
-- Channel-2 auto-responder (`src/commands`): event-driven — `CommandService.onRx()` is called by `MeshService` for every decoded rx text (right after the notify gate) and dispatches exact, case-sensitive `#command` matches on `COMMAND_CHANNEL` (env, default 2) through a single-registration-point registry (handlers registered in the constructor via `register(name, fn)`; handler gets `{ text, from?, id? }`, returns a reply string — or an array of lines, sent as one message per line through the same routing — or void = no reply). First command: `#ping` → replies `#pong!`. Replies go through `MeshService.respond(id, reply)`: auto-routed (rx → DM back to the original sender unless the original was a broadcast; tx → its destination), riding the original record's channel with `replyId = id` so the recipient app renders it as a threaded quote — `COMMAND_CHANNEL` is only the trigger/listen gate. Only when the trigger has no packet id does it fall back to legacy sendText routing on `COMMAND_CHANNEL`. A failing handler/respond only logs a warn. DI: provided by `CommandModule`'s factory (injects `MeshService`, attaches itself via `attachCommands()`) — no constructor-level cycle; `forwardRef` was tried and left one side null in NestJS 12's injector. Prefix dispatch (`registerPrefix(name, fn)`) lets one handler own a whole family: the `#rss` subcommands live in `src/rss` (`RssService.handle`, registered as prefix `'rss'` from the CommandModule factory — exact matches still win over prefixes). Subcommands: `#rss help`; `#rss add <url> <name>` (validates URL, fetches with 15 s timeout, requires ≥1 titled item, rejects duplicate names case-insensitively; LLM generates 2-4 lowercase tags from up to 8 latest titles — on LLM failure the source is added with empty tags and the reply says so); `#rss remove <name>`; `#rss tags` (all distinct tags); `#rss sources`; `#rss get <name|#tag>` (LLM headline summary as 3-5 SEPARATE mesh messages: prompt asks for exactly 3-5 lines, one item per line, `<short header>: <one or two short sentences>` with ≤20-char header, no intro/outro/numbering; reply parsed into items — drop empty/separator-less lines, cap at 5, fewer than 3 → send what we got (no retry), zero → no message; each item sent via its own respond() threaded to the trigger packet id, per-line backstop `fitOneLine()` hard-cuts >185-char lines at a word boundary near 180 so every item fits one packet; maxTokens 2500 is headroom because the LLM server's reasoning tokens count against it — see rss.service.ts comment; `#tag` collects items across ALL sources carrying that tag — one dead feed does not sink the summary). Storage: `rss_sources(name TEXT PRIMARY KEY, url, tags, created_at)` table in the EXISTING MESH_DB_PATH file via a second node:sqlite connection (names matched case-insensitively); feed parsing via `fast-xml-parser` (RSS 2.0 + Atom; malformed/no-items → "not a valid feed"); LLM via injected `LlmService.chat()` with explicit maxTokens (50 tags / 2500 summary headroom).
-- LLM client (`src/llm`): `LlmService` wraps the local OpenAI-compatible server (default `http://192.168.1.70:1111/v1`, no auth) with native fetch — plain feature module, no Mesh/Schedule dependency. Methods: `listModels()` → `data[].id`; `chat(messages, { maxTokens?, temperature? })` → `choices[0].message.content` (non-2xx throws with status + body snippet); `summarize(text)` = chat() with system prompt "Summarize the following text concisely." Env: `LLM_API_BASE`, `LLM_MODEL` (default `qwen3.8-27b`), `LLM_TIMEOUT_MS` (default 60000, via `AbortSignal.timeout`).
+- Channel-2 auto-responder (`src/commands`): event-driven — `CommandService.onRx()` is called by `MeshService` for every decoded rx text (right after the notify gate) and dispatches exact, case-sensitive `#command` matches on `COMMAND_CHANNEL` (env, default 2) through a single-registration-point registry (handlers registered in the constructor via `register(name, fn)`; handler gets `{ text, from?, id? }`, returns a reply string — or an array of lines, sent as one message per line through the same routing, spaced `MESH_MULTI_SEND_DELAY_MS` ms apart (default 5000) so each packet has time to land in RF — or void = no reply). First commands: `#ping` → replies `#pong!`; `#help` → short single-message list of all available commands. Replies go through `MeshService.respond(id, reply)`: auto-routed (rx → DM back to the original sender unless the original was a broadcast; tx → its destination), riding the original record's channel with `replyId = id` so the recipient app renders it as a threaded quote — `COMMAND_CHANNEL` is only the trigger/listen gate. Only when the trigger has no packet id does it fall back to legacy sendText routing on `COMMAND_CHANNEL`. A failing handler/respond only logs a warn. DI: provided by `CommandModule`'s factory (injects `MeshService`, attaches itself via `attachCommands()`) — no constructor-level cycle; `forwardRef` was tried and left one side null in NestJS 12's injector. Prefix dispatch (`registerPrefix(name, fn)`) lets one handler own a whole family: the `#rss` subcommands live in `src/rss` (`RssService.handle`, registered as prefix `'rss'` from the CommandModule factory — exact matches still win over prefixes). Subcommands: `#rss help`; `#rss add <url> <name>` (validates URL, fetches with 15 s timeout, requires ≥1 titled item, rejects duplicate names case-insensitively; LLM generates 2-4 lowercase tags from up to 8 latest titles — on LLM failure the source is added with empty tags and the reply says so); `#rss remove <name>`; `#rss tags` (all distinct tags); `#rss sources`; `#rss get <name|#tag>` (LLM headline summary as 3-5 SEPARATE mesh messages: prompt asks for exactly 3-5 lines, one item per line, `<short header>: <one or two short sentences>` with ≤20-char header, no intro/outro/numbering; reply parsed into items — drop empty/separator-less lines, cap at 5, fewer than 3 → send what we got (no retry), zero → no message; each item sent via its own respond() threaded to the trigger packet id, per-line backstop `fitOneLine()` hard-cuts >185-char lines at a word boundary near 180 so every item fits one packet; maxTokens 2500 is headroom because the LLM server's reasoning tokens count against it — see rss.service.ts comment; `#tag` collects items across ALL sources carrying that tag — one dead feed does not sink the summary). Storage: `rss_sources(name TEXT PRIMARY KEY, url, tags, created_at)` table in the EXISTING MESH_DB_PATH file via a second node:sqlite connection (names matched case-insensitively); feed parsing via `fast-xml-parser` (RSS 2.0 + Atom; malformed/no-items → "not a valid feed"); LLM via injected `LlmService.chat()` with explicit maxTokens (50 tags / 2500 summary headroom).
+- LLM client (`src/llm`): `LlmService` wraps the local OpenAI-compatible server (default `http://192.168.1.70:1111/v1`, no auth) with native fetch — plain feature module, no Mesh/Schedule dependency. Methods: `listModels()` → `data[].id`; `chat(messages, { maxTokens?, temperature? })` → `choices[0].message.content` (non-2xx throws with status + body snippet); `summarize(text)` = chat() with system prompt "Summarize the following text concisely." Env: `LLM_API_BASE`, `LLM_MODEL` (default `qwen3.8-27b`), `LLM_TIMEOUT_MS` (default 180000, via `AbortSignal.timeout`).

CHANGELOG.md

@@ -1,5 +1,37 @@
 # Changelog
 
+## v0.21.6 — 2026-09-26 10:37
+
+- New `#help` command (owner request): replies with a short list of all available commands as ONE multi-line message (single packet, not one spaced packet per line) — `#ping`, the `#rss help/add/remove/get/sources/tags` family. Registered in the CommandService constructor next to `#ping`.
+- Tests: 173 → 174 — `#help` dispatches through respond() exactly once with text containing both `#ping` and `#rss`. (Also hardened the v0.21.5 multi-send-spacing spec, which flaked under full-suite load: it now uses fake timers to assert deterministically that line 1 goes out before any time elapses and lines 2-3 land exactly one delay apart.)
+
+## v0.21.5 — 2026-09-26 10:26
+
+- Multi-line command replies are now spaced apart: `CommandService.onRx` waits `MESH_MULTI_SEND_DELAY_MS` (new env, default **5000** = 5 s, read at construction) between consecutive lines of an array reply — no delay before the first line. Production incident: `#rss get lublin` sent its items back-to-back within the same second and 3 of 4 were dropped in RF (the owner saw only the last one); each packet now gets time to land.
+- Tests: 172 → 173 — a 3-line reply with an overridden short delay asserts all lines are sent, the first goes out immediately (no pre-delay), and each subsequent line lands ≥ the configured gap after the previous one; existing specs pin `MESH_MULTI_SEND_DELAY_MS=0` in `beforeEach` so they stay fast.
+
+## v0.21.4 — 2026-09-26 09:51
+
+- `LLM_TIMEOUT_MS` default raised from 60000 (60 s) to **180000** (3 min): production incident — `#rss get lublin` at 9:41 AM failed with "The operation was aborted due to timeout" because the local OpenAI-compatible server (qwen3.8-27b, uncontrollable reasoning tokens) was slow/busy on that call; the same endpoint answers a trivial prompt in ~1 s when idle, so this is latency variance, not a dead endpoint. Still env-overridable (`LLM_TIMEOUT_MS`), only the fallback changed.
+
+## v0.21.3 — 2026-09-26 09:31
+
+- Idle timeout default lowered from 10 min to **1 min** (`MESH_IDLE_TIMEOUT_MS` fallback `600000` → `60000`) — the v0.21.2 frame-based watchdog works in production (it fired today and the reconnect delivered queued packets), but the bridge/radio side at 192.168.1.4 keeps killing inbound RX within ~20 min of a fresh sync, so a shorter detection window is wanted.
+- New **lazy periodic autoreconnect**: `MESH_RECONNECT_INTERVAL_MS` (new env, default **300000** = 5 min, read at construction) — an interval that unconditionally logs ("periodic reconnect — MESH_RECONNECT_INTERVAL_MS elapsed") and destroys the socket so the existing close→scheduleReconnect loop re-establishes with a fresh sync on schedule. When not connected at tick time, destroy is a no-op and the retry loop owns recovery (no special-casing). Started in `onModuleInit`, cleared in `onModuleDestroy`.
+- Tests: 171 → 172 — periodic reconnect observed end-to-end with an overridden short interval (fake bridge disconnect + re-establish); existing watchdog tests pass unchanged, comments updated to the new 60 s default.
+
+## v0.21.2 — 2026-09-26 08:47
+
+- Idle watchdog now tracks DECODED FRAMES, not raw bytes (fixes a second production zombie that slipped past v0.21.1): text+telemetry RX was dead for >1 h while TX worked and the watchdog never fired — /proc/net/snmp showed InSegs delta = 2 segments per 30 s, i.e. the bridge peer keeps dribbling small NON-frame bytes (~every 15 s) that kept resetting `lastPacketAt` on every socket chunk even though zero valid Meshtastic frames decoded. The `'data'` handler no longer updates `lastPacketAt` per chunk; it is updated only when `extractFrames` yields ≥1 valid packet (the reset in the `'connect'` handler is unchanged), so a stream that decodes nothing trips the watchdog after `MESH_IDLE_TIMEOUT_MS` even while raw bytes keep arriving.
+- Buffer-overflow backstop: if the undecoded frame buffer exceeds `MESH_MAX_FRAME_BUFFER` (new env, default **256000** = 250 KB) the service logs ERROR ("frame buffer overflow — stream desync, forcing reconnect") and destroys the socket → existing close→scheduleReconnect self-heals a desynced stream. The undecoded buffer is also reset on every (re)connect so leftover garbage from a dead session can't re-trigger the backstop or corrupt the first frames of a healthy new stream.
+- Tests: 169 → 171 — raw non-frame bytes do NOT keep the watchdog alive (garbage-only stream forces disconnect + reconnect, exactly today's incident shape), and an undecoded chunk over `MESH_MAX_FRAME_BUFFER` triggers destroy + a fresh session that decodes normally. The existing valid-frames-reset-the-clock test now exercises frame-based tracking unchanged.
+
+## v0.21.1 — 2026-09-26 06:47
+
+- Bridge zombie-connection fix (production incident: outbound sends kept working ~10 h while inbound packets stopped entirely and `/api/status` stayed `connected:true`). New **idle watchdog**: the service tracks `lastPacketAt`, updated on EVERY chunk received from the bridge in the lowest-level socket `'data'` path (any frame kind, decodable or not) and reset when a connection successfully starts. A 30 s interval checks: if connected AND no inbound traffic for `MESH_IDLE_TIMEOUT_MS` (new env, default **600000** = 10 min), it logs WARN ("no bridge traffic for X ms — forcing reconnect") and destroys the socket — the EXISTING connect/retry loop (`MESH_RECONNECT_MS`) then re-establishes with a fresh sync. No changes to connect-error retry/backoff behavior; this only adds detection for established-but-silent connections.
+- TCP keepalive on the bridge socket: `socket.setKeepAlive(true, 30_000)` — cheap insurance against dead peers at the TCP level, complementing the application-level watchdog.
+- Tests: 165 → 169 — silence past an overridden timeout forces disconnect + reconnect (fake bridge), inbound traffic keeps resetting the idle clock so no false trigger, default timeout does not fire in a test window, and `setKeepAlive(true, 30_000)` is asserted on the socket.
+
 ## v0.21.0 — 2026-09-25 19:59
 
 - `#rss get <name|#tag>` now replies with **3–5 SEPARATE mesh messages** instead of one small summary (owner request: the single-message summary was too small). Each item is its own packet, so no fragmentation — and each rides the trigger's channel threaded as a quote of the command packet.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mesh-bot",
-  "version": "0.21.0",
+  "version": "0.21.6",
   "description": "",
   "author": "",
   "private": true,

src/commands/command.service.spec.ts

@@ -30,6 +30,7 @@ function makeService(
 
 beforeEach(() => {
   delete process.env.COMMAND_CHANNEL; // default channel 2 under test
+  process.env.MESH_MULTI_SEND_DELAY_MS = '0'; // no spacing under test unless a test opts in — the real default (5000) would slow the suite down
 });
 
 describe('CommandService.onRx', () => {
@@ -40,6 +41,15 @@ describe('CommandService.onRx', () => {
     expect(mesh.sendText).not.toHaveBeenCalled();
   });
 
+  it('replies #help with a short single-message list of all commands', async () => {
+    const [svc, mesh] = makeService();
+    await svc.onRx(2, '#help', 42, 7);
+    expect(mesh.respond).toHaveBeenCalledTimes(1); // one packet — not one per line
+    const text = mesh.respond.mock.calls[0][1];
+    expect(text).toContain('#ping');
+    expect(text).toContain('#rss');
+  });
+
   it('falls back to a directed sendText on COMMAND_CHANNEL when the trigger has no packet id (DM)', async () => {
     const [svc, mesh] = makeService();
     await svc.onRx(2, '#ping', 42); // from present but no id — defensive path
@@ -124,6 +134,37 @@ describe('CommandService.onRx', () => {
     expect(mesh.sendText).not.toHaveBeenCalled();
   });
 
+  it('spaces consecutive multi-line sends by MESH_MULTI_SEND_DELAY_MS — no delay before the first line', async () => {
+    process.env.MESH_MULTI_SEND_DELAY_MS = '50'; // short so the test stays fast
+    let sends = 0;
+    const respond = vi.fn(async () => {
+      sends++;
+      return { id: 1 };
+    });
+    vi.useFakeTimers();
+    try {
+      const [svc, mesh] = makeService(undefined, respond);
+      svc.register('multi3', () => ['a: one', 'b: two', 'c: three']);
+
+      const p = svc.onRx(2, '#multi3', 42, 9);
+      // flush microtasks without advancing time — the first line must already be out (no delay before it)
+      await vi.advanceTimersByTimeAsync(0);
+      expect(sends).toBe(1);
+
+      // each subsequent line waits exactly MESH_MULTI_SEND_DELAY_MS after the previous one landed
+      await vi.advanceTimersByTimeAsync(50);
+      expect(sends).toBe(2);
+      await vi.advanceTimersByTimeAsync(50);
+      expect(sends).toBe(3);
+
+      await p;
+      expect(mesh.respond).toHaveBeenCalledTimes(3);
+    } finally {
+      vi.useRealTimers();
+      delete process.env.MESH_MULTI_SEND_DELAY_MS;
+    }
+  });
+
   it('sends each line of an array reply via the legacy sendText fallback when there is no packet id', async () => {
     const [svc, mesh] = makeService();
     svc.register('multi', () => ['one: first item', 'two: second item']);

src/commands/command.service.ts

@@ -27,6 +27,11 @@ export class CommandService {
     process.env.COMMAND_CHANNEL ?? '2',
     10,
   );
+  // spacing between consecutive multi-line reply messages — back-to-back packets get dropped in RF on a real mesh; each packet needs time to land. Read at construction like the other env config.
+  private readonly multiSendDelayMs = parseInt(
+    process.env.MESH_MULTI_SEND_DELAY_MS ?? '5000',
+    10,
+  );
   // single registration point: the constructor registers every built-in command — add the next one there (or via register())
   private readonly commands = new Map<string, CommandHandler>();
   // prefix handlers own a whole family (`#rss`, `#rss add ...`) instead of one exact name
@@ -38,6 +43,17 @@ export class CommandService {
     rss?: RssService,
   ) {
     this.register('ping', () => '#pong!');
+    // single multi-line string = ONE packet — not an array, which would drip-feed one spaced packet per line
+    this.register('help', () =>
+      [
+        '#ping - alive check',
+        '#rss help - rss subcommands',
+        '#rss add <url> <name> - add feed with AI tags',
+        '#rss remove <name> - drop feed',
+        '#rss get <name|#tag> - news summary',
+        '#rss sources / #rss tags - list feeds/tags',
+      ].join('\n'),
+    );
     if (rss) this.registerPrefix('rss', (ctx) => rss.handle(ctx));
   }
 
@@ -83,8 +99,15 @@ export class CommandService {
     try {
       const reply = await handler({ text: trimmed, from, id });
       if (reply === undefined || reply === null) return; // void = no reply
-      // an array reply sends one message per line, all threaded to the same trigger packet id
-      for (const line of Array.isArray(reply) ? reply : [reply]) {
+      // an array reply sends one message per line, all threaded to the same trigger packet id — spaced so each packet has time to land in RF (no delay before the first line)
+      const lines = Array.isArray(reply) ? reply : [reply];
+      for (let i = 0; i < lines.length; i++) {
+        if (i > 0 && this.multiSendDelayMs > 0) {
+          await new Promise((resolve) =>
+            setTimeout(resolve, this.multiSendDelayMs),
+          );
+        }
+        const line = lines[i];
         if (id !== undefined && this.mesh) {
           // respond() auto-routes each line: rides the original record's channel with replyId = id (threaded quote)
           await this.mesh.respond(id, line);

src/llm/llm.service.ts

@@ -12,9 +12,9 @@ export class LlmService {
   private readonly apiBase =
     process.env.LLM_API_BASE ?? 'http://192.168.1.70:1111/v1';
   private readonly model = process.env.LLM_MODEL ?? 'qwen3.8-27b';
-  // local 27B model can be slow — generous default
+  // local 27B model can be slow (uncontrollable reasoning tokens) — generous default: 3 min headroom for slow reasoning periods
   private readonly timeoutMs = parseInt(
-    process.env.LLM_TIMEOUT_MS ?? '60000',
+    process.env.LLM_TIMEOUT_MS ?? '180000',
     10,
   );
 

src/mesh/mesh.service.spec.ts

@@ -1,6 +1,7 @@
 import { create, fromBinary, toBinary } from '@bufbuild/protobuf';
 import * as P from '@meshtastic/protobufs';
 import { BadRequestException, NotFoundException } from '@nestjs/common';
+import * as net from 'node:net';
 import { DatabaseSync } from 'node:sqlite';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { BROADCAST_ADDR, extractFrames, frame } from './codec.js';
@@ -249,6 +250,195 @@ describe('MeshService connect', () => {
   });
 });
 
+const sleep = (ms: number) => new Promise((r) => setTimeout(r, ms));
+
+describe('MeshService idle watchdog', () => {
+  it('forces a reconnect when an established connection goes silent past MESH_IDLE_TIMEOUT_MS', async () => {
+    const bridge = await startBridge();
+    process.env.MESH_HOST = '127.0.0.1';
+    process.env.MESH_PORT = String(bridge.port);
+    process.env.MESH_RECONNECT_MS = '50'; // fast retry so the re-establishment is observable
+    process.env.MESH_IDLE_TIMEOUT_MS = '100'; // override — the default (60000) would never fire in a test
+    const svc = new MeshService();
+    try {
+      svc.onModuleInit();
+      await waitFor(
+        () => bridge.sockets.length === 1 && svc.status().connected,
+      );
+
+      // zombie case: connected but no inbound traffic at all — wait past the timeout, then drive a watchdog tick
+      await sleep(250);
+      svc.checkIdle();
+
+      // socket torn down → existing connect/retry loop re-establishes with a fresh session
+      await waitFor(() => bridge.sockets.length >= 2 && svc.status().connected);
+    } finally {
+      delete process.env.MESH_RECONNECT_MS;
+      delete process.env.MESH_IDLE_TIMEOUT_MS;
+      svc.onModuleDestroy();
+      bridge.close();
+    }
+  });
+
+  it('raw non-frame bytes do NOT keep the watchdog alive — a garbage-only stream forces a reconnect', async () => {
+    const bridge = await startBridge();
+    process.env.MESH_HOST = '127.0.0.1';
+    process.env.MESH_PORT = String(bridge.port);
+    process.env.MESH_RECONNECT_MS = '50'; // fast retry so the re-establishment is observable
+    process.env.MESH_IDLE_TIMEOUT_MS = '100'; // override — the default (60000) would never fire in a test
+    const svc = new MeshService();
+    try {
+      svc.onModuleInit();
+      await waitFor(
+        () => bridge.sockets.length === 1 && svc.status().connected,
+      );
+
+      // today's incident: the peer keeps dribbling small non-frame bytes (keepalive noise / desynced stream) — raw chunks must not reset the idle clock
+      const garbage = Buffer.from('zz-no-frames-here'); // pure ASCII — never forms a 0x94 0xc3 frame header
+      for (let i = 0; i < 6; i++) {
+        await sleep(50); // ~300 ms wall time, well past the timeout
+        bridge.sockets[0].write(garbage);
+      }
+
+      svc.checkIdle();
+      await waitFor(() => bridge.sockets.length >= 2 && svc.status().connected);
+    } finally {
+      delete process.env.MESH_RECONNECT_MS;
+      delete process.env.MESH_IDLE_TIMEOUT_MS;
+      svc.onModuleDestroy();
+      bridge.close();
+    }
+  });
+
+  it('forces a reconnect when the undecoded frame buffer exceeds MESH_MAX_FRAME_BUFFER', async () => {
+    const bridge = await startBridge();
+    process.env.MESH_HOST = '127.0.0.1';
+    process.env.MESH_PORT = String(bridge.port);
+    process.env.MESH_RECONNECT_MS = '50'; // fast retry so the re-establishment is observable
+    process.env.MESH_MAX_FRAME_BUFFER = '100'; // tiny cap — Node delivers socket data in ~64 KB events, far below the 256_000 default
+    const svc = new MeshService();
+    try {
+      svc.onModuleInit();
+      await waitFor(
+        () => bridge.sockets.length === 1 && svc.status().connected,
+      );
+
+      // non-frame bytes (0x42 is not part of any frame header) — a desynced stream that never forms frames; the first ~64 KB data event alone exceeds the cap
+      bridge.sockets[0].write(Buffer.alloc(300_000, 0x42));
+
+      // overflow forced a reconnect — fresh session
+      await waitFor(() => bridge.sockets.length >= 2 && svc.status().connected);
+
+      // the new socket starts with a clean buffer and decodes valid frames normally (the myInfo frame is well under the cap)
+      const fr = create(P.Mesh.FromRadioSchema, {
+        payloadVariant: { case: 'myInfo', value: { myNodeNum: 777 } },
+      });
+      bridge.sockets[1].write(frame(toBinary(P.Mesh.FromRadioSchema, fr)));
+      await waitFor(() => svc.status().myNodeNum === 777);
+    } finally {
+      delete process.env.MESH_RECONNECT_MS;
+      delete process.env.MESH_MAX_FRAME_BUFFER;
+      svc.onModuleDestroy();
+      bridge.close();
+    }
+  });
+
+  it('inbound traffic keeps resetting the idle clock — no false trigger while packets arrive', async () => {
+    const bridge = await startBridge();
+    process.env.MESH_HOST = '127.0.0.1';
+    process.env.MESH_PORT = String(bridge.port);
+    process.env.MESH_IDLE_TIMEOUT_MS = '100';
+    const svc = new MeshService();
+    try {
+      svc.onModuleInit();
+      await waitFor(
+        () => bridge.sockets.length === 1 && svc.status().connected,
+      );
+
+      // steady drip of inbound frames for well over the timeout in wall time — each chunk resets lastPacketAt
+      for (let i = 0; i < 5; i++) {
+        await sleep(60);
+        bridge.sockets[0].write(nodeInfoFrame(42, kamilNodeInfo()));
+      }
+
+      svc.checkIdle(); // wall time is past the timeout, but traffic kept resetting it
+      await sleep(100); // enough for a destroy to surface as 'close' (connected would flip false)
+      expect(svc.status().connected).toBe(true);
+      expect(bridge.sockets.length).toBe(1);
+    } finally {
+      delete process.env.MESH_IDLE_TIMEOUT_MS;
+      svc.onModuleDestroy();
+      bridge.close();
+    }
+  });
+
+  it('does not trigger under the default timeout (MESH_IDLE_TIMEOUT_MS unset)', async () => {
+    const bridge = await startBridge();
+    process.env.MESH_HOST = '127.0.0.1';
+    process.env.MESH_PORT = String(bridge.port);
+    delete process.env.MESH_IDLE_TIMEOUT_MS; // default 60000 — a test can't wait that long, so silence must NOT fire
+    const svc = new MeshService();
+    try {
+      svc.onModuleInit();
+      await waitFor(
+        () => bridge.sockets.length === 1 && svc.status().connected,
+      );
+
+      await sleep(250); // silent, but far under the default budget
+      svc.checkIdle();
+
+      expect(svc.status().connected).toBe(true);
+      expect(bridge.sockets.length).toBe(1);
+    } finally {
+      delete process.env.MESH_IDLE_TIMEOUT_MS;
+      svc.onModuleDestroy();
+      bridge.close();
+    }
+  });
+
+  it('enables TCP keepalive on the bridge socket', async () => {
+    const setKeepAlive = vi.spyOn(net.Socket.prototype, 'setKeepAlive');
+    const bridge = await startBridge();
+    process.env.MESH_HOST = '127.0.0.1';
+    process.env.MESH_PORT = String(bridge.port);
+    const svc = new MeshService();
+    try {
+      svc.onModuleInit();
+      await waitFor(() => svc.status().connected);
+      expect(setKeepAlive).toHaveBeenCalledWith(true, 30_000);
+    } finally {
+      setKeepAlive.mockRestore();
+      svc.onModuleDestroy();
+      bridge.close();
+    }
+  });
+});
+
+describe('MeshService periodic autoreconnect', () => {
+  it('unconditionally reconnects when MESH_RECONNECT_INTERVAL_MS elapses', async () => {
+    const bridge = await startBridge();
+    process.env.MESH_HOST = '127.0.0.1';
+    process.env.MESH_PORT = String(bridge.port);
+    process.env.MESH_RECONNECT_MS = '50'; // fast retry so the re-establishment is observable
+    process.env.MESH_RECONNECT_INTERVAL_MS = '100'; // override — the default (300000) would never elapse in a test
+    const svc = new MeshService();
+    try {
+      svc.onModuleInit();
+      await waitFor(
+        () => bridge.sockets.length === 1 && svc.status().connected,
+      );
+
+      // interval fires → destroy → existing close/retry loop re-establishes with a fresh session
+      await waitFor(() => bridge.sockets.length >= 2 && svc.status().connected);
+    } finally {
+      delete process.env.MESH_RECONNECT_MS;
+      delete process.env.MESH_RECONNECT_INTERVAL_MS;
+      svc.onModuleDestroy();
+      bridge.close();
+    }
+  });
+});
+
 describe('MeshService send', () => {
   it('sends on the test channel (index 3) by default, never primary', async () => {
     const bridge = await startBridge();

src/mesh/mesh.service.ts

@@ -81,6 +81,8 @@ export interface TelemetryRecord {
 const HISTORY_LIMIT = 100;
 /** Rows kept in SQLite across restarts; older rows are pruned on every poller tick. */
 const DB_RETENTION = 1000;
+// how often the idle watchdog checks for a silent-but-connected bridge (ms)
+const IDLE_CHECK_MS = 30_000;
 
 // one row per MessageRecord, keyed by packet id (tx ids and injected ids are random uint32, rx uses the wire id)
 export const MESSAGES_DDL = `CREATE TABLE IF NOT EXISTS messages(
@@ -208,6 +210,21 @@ export class MeshService implements OnModuleInit, OnModuleDestroy {
   );
   // how often the poller re-upserts the history buffer into SQLite (ms)
   private readonly pollMs = parseInt(process.env.MESH_POLL_MS ?? '1000', 10);
+  // idle watchdog: force a reconnect when an ESTABLISHED connection stops decoding frames — the zombie-bridge case where outbound sends keep working but inbound frame flow is dead (raw non-frame bytes do NOT reset the clock). Read at construction like the other env config.
+  private readonly idleTimeoutMs = parseInt(
+    process.env.MESH_IDLE_TIMEOUT_MS ?? '60000',
+    10,
+  );
+  // lazy periodic autoreconnect: unconditionally destroy + re-establish every N ms so a fresh sync happens on schedule — the bridge/radio side tends to kill inbound RX within ~20 min of a fresh sync. Read at construction like the other env config.
+  private readonly reconnectIntervalMs = parseInt(
+    process.env.MESH_RECONNECT_INTERVAL_MS ?? '300000',
+    10,
+  );
+  // cap on undecoded frame buffer: a desynced stream that never forms frames would grow it without bound — force a reconnect instead. Env-overridable so tests can trigger it (Node caps socket 'data' events at ~64 KB).
+  private readonly maxFrameBuffer = parseInt(
+    process.env.MESH_MAX_FRAME_BUFFER ?? '256000',
+    10,
+  );
 
   /** SQLite database backing the message history; null = persistence disabled (tests construct without one). */
   private db: DatabaseSync | null = null;
@@ -255,6 +272,10 @@ export class MeshService implements OnModuleInit, OnModuleDestroy {
   // telemetry history (newest kept, capped at HISTORY_LIMIT)
   private telemetryHistory: TelemetryRecord[] = [];
   private reconnectTimer: NodeJS.Timeout | null = null;
+  /** epoch ms when the last valid frame was decoded from the bridge; reset on connect — idle watchdog baseline */
+  private lastPacketAt = Date.now();
+  private idleTimer: NodeJS.Timeout | null = null;
+  private periodicReconnectTimer: NodeJS.Timeout | null = null;
   private shuttingDown = false;
 
   onModuleInit(): void {
@@ -264,6 +285,15 @@ export class MeshService implements OnModuleInit, OnModuleDestroy {
       // ponytail: full re-upsert of the ≤100-row buffer every tick — trivial load, zero bookkeeping
       this.pollTimer = setInterval(() => this.flushHistory(), this.pollMs);
     }
+    // idle watchdog: catches established-but-silent connections (zombie bridge) that the connect/retry loop never sees
+    this.idleTimer = setInterval(() => this.checkIdle(), IDLE_CHECK_MS);
+    // lazy periodic autoreconnect: unconditional fresh sync on a fixed schedule; when not connected, destroy is a no-op and the retry loop owns recovery
+    this.periodicReconnectTimer = setInterval(() => {
+      this.logger.log(
+        'periodic reconnect — MESH_RECONNECT_INTERVAL_MS elapsed',
+      );
+      this.socket?.destroy();
+    }, this.reconnectIntervalMs);
     this.connect();
   }
 
@@ -271,6 +301,8 @@ export class MeshService implements OnModuleInit, OnModuleDestroy {
     this.shuttingDown = true;
     if (this.reconnectTimer) clearTimeout(this.reconnectTimer);
     if (this.pollTimer) clearInterval(this.pollTimer);
+    if (this.idleTimer) clearInterval(this.idleTimer);
+    if (this.periodicReconnectTimer) clearInterval(this.periodicReconnectTimer);
     this.socket?.destroy();
     this.db?.close();
   }
@@ -641,11 +673,17 @@ export class MeshService implements OnModuleInit, OnModuleDestroy {
   private connect(): void {
     if (this.shuttingDown) return;
     const socket = net.createConnection({ host: this.host, port: this.port });
+    // TCP-level keepalive: cheap insurance against a dead peer that the idle watchdog (application level) complements
+    socket.setKeepAlive(true, 30_000);
     this.socket = socket;
     socket.on('connect', () => {
       this.connected = true;
+      // fresh connection — reset the idle clock so it can't self-trigger before any traffic arrives
+      this.lastPacketAt = Date.now();
       // fresh sync on every (re)connect — drop stale channels/nodes/device info/telemetry from the old session;
-      // message history is NOT reset: it's an append-only log backed by SQLite and survives reconnects
+      // message history is NOT reset: it's an append-only log backed by SQLite and survives reconnects.
+      // The undecoded frame buffer goes too: leftover desync garbage must not re-trigger the overflow backstop on a healthy new stream.
+      this.buffer = new Uint8Array(0);
       this.channelMap = new Map();
       this.nodeMap = new Map();
       this.metadata = null;
@@ -666,9 +704,19 @@ export class MeshService implements OnModuleInit, OnModuleDestroy {
       const merged = new Uint8Array(this.buffer.length + chunk.length);
       merged.set(this.buffer, 0);
       merged.set(chunk, this.buffer.length);
+      // buffer-overflow backstop: a desynced stream that never forms frames would grow the buffer without bound — cap it and self-heal via reconnect
+      if (merged.length > this.maxFrameBuffer) {
+        this.logger.error(
+          'frame buffer overflow — stream desync, forcing reconnect',
+        );
+        socket.destroy();
+        return;
+      }
       this.buffer = merged;
       const { packets, rest } = extractFrames(this.buffer);
       this.buffer = rest;
+      // the watchdog tracks DECODED FRAMES, not raw bytes: non-frame noise (keepalives, desynced streams) must not keep a dead connection alive
+      if (packets.length) this.lastPacketAt = Date.now();
       for (const p of packets) {
         decodeFromRadio(p)
           .then((fr) => this.handleFromRadio(fr))
@@ -694,6 +742,25 @@ export class MeshService implements OnModuleInit, OnModuleDestroy {
     this.reconnectTimer = setTimeout(() => this.connect(), this.reconnectMs);
   }
 
+  /**
+   * Idle watchdog tick: force a reconnect when an ESTABLISHED connection has decoded no frames from
+   * the bridge for MESH_IDLE_TIMEOUT_MS — the zombie case where outbound sends keep working but inbound
+   * frame flow is dead (raw non-frame bytes arriving on the socket do not count). Destroying the socket
+   * routes through 'close' → onDown → scheduleReconnect, so the existing connect/retry loop re-establishes
+   * with a fresh sync; no new retry machinery here. Public so tests can drive a tick without waiting for
+   * the real interval (like flushHistory()).
+   */
+  checkIdle(): void {
+    if (!this.connected) return; // disconnected state is owned by the connect/retry loop
+    const idle = Date.now() - this.lastPacketAt;
+    if (idle > this.idleTimeoutMs) {
+      this.logger.warn(
+        `no decoded bridge frames for ${idle} ms — forcing reconnect`,
+      );
+      this.socket?.destroy();
+    }
+  }
+
   private async handleFromRadio(
     fr: import('@meshtastic/protobufs').Mesh.FromRadio,
   ): Promise<void> {