Merge pull request 'Add OpenAI-compatible LLM client service (v0.19.0)' (#40) from feat/llm-client into main

Add OpenAI-compatible LLM client service (v0.19.0) (#40)

AGENTS.md

@@ -27,4 +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 reply string or void = no reply). First command: `#ping` → replies `#pong!`. Replies ride `COMMAND_CHANNEL`: directed DM back to the sender when present, else broadcast. A failing handler/send 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.
+- 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 reply string 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.
+- 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`).

CHANGELOG.md

@@ -1,5 +1,20 @@
 # Changelog
 
+## v0.19.0 — 2026-09-25 18:03
+
+- New LLM client module (`src/llm`): `LlmService` speaks the OpenAI-compatible chat-completions API of the local server at `LLM_API_BASE` (default `http://192.168.1.70:1111/v1`, no auth) using native fetch only — no new dependencies. Plain feature module (`LlmModule`), wired into `app.module.ts`; no Mesh/Schedule dependency.
+- Methods: `listModels()` (GET `/models` → `data[].id` strings), `chat(messages, opts?)` (POST `/chat/completions` with `{ model, messages, ...opts }` → `choices[0].message.content`; non-2xx throws an Error carrying the HTTP status and a short body snippet; malformed responses without content throw too), and `summarize(text)` — thin wrapper over `chat()` with system prompt "Summarize the following text concisely." (the stated primary use).
+- Env: `LLM_API_BASE` (default `http://192.168.1.70:1111/v1`), `LLM_MODEL` (default `qwen3.8-27b`), `LLM_TIMEOUT_MS` (default `60000` — the local 27B model can be slow; applied via `AbortSignal.timeout`).
+- Tests: +4 specs — listModels parses ids, chat passes model/messages/opts through and returns content, chat throws on non-2xx with status in the message, summarize sends system prompt + user text.
+
+## v0.18.1 — 2026-09-25 17:30
+
+- Command replies now ride `MeshService.respond(id, reply)` instead of direct `sendText` routing: when a handler returns a non-empty string and the trigger has a packet id, the reply is auto-routed (rx → DM back to the original sender unless the original was a broadcast; tx → its destination) on the **original message's channel** with `replyId = id`, so the recipient app renders it as a threaded quote of the triggering packet. `COMMAND_CHANNEL` is now only the trigger/listen gate — the reply channel comes from the record.
+- Defensive fallback: when the trigger has no packet id (never happens in production — `MeshService` always passes `pkt.id`), the legacy sendText routing on `COMMAND_CHANNEL` (directed DM or broadcast) still sends the reply out. Failure handling unchanged: a failing handler or respond only logs a warn, never crashes.
+- Tests: 121 → 124 specs — unit cases now mock `mesh.respond` (id present → `respond(id, reply)` with no sendText; id absent → legacy DM/broadcast fallback on the command channel), plus a failing-respond swallow case; e2e over the fake bridge asserts wire-level threading for both shapes: `#ping` broadcast on ch2 → `#pong!` broadcast on ch2 with `replyId` = ping packet id, and `#ping` DM → `#pong!` DM to the sender on ch2 with `replyId` set. All gate tests (case/whitespace/channel/env override) kept.
+- The wire-decode test helper `outboundPackets()` moved from `mesh.service.spec.ts` into `fake-bridge.ts` so both specs share it.
+- Docs: AGENTS.md "Other" bullet and MESHTASTIC.md describe the respond() auto-routing + threading; README env list unchanged (`COMMAND_CHANNEL` still exists, now meaning trigger channel only).
+
 ## v0.18.0 — 2026-09-25 17:08
 
 - New channel-index-2 auto-responder (`src/commands`): an event-driven `CommandService` reacts to decoded rx text on `COMMAND_CHANNEL` (env, default `2`) and dispatches exact `#command` matches (case-sensitive, surrounding whitespace trimmed) through a single-registration-point registry — handlers registered in the constructor via `register(name, fn)` receive `{ text, from?, id? }` and return a reply string or void (= no reply). First command: `#ping` → replies `#pong!`.

MESHTASTIC.md

@@ -22,7 +22,7 @@ Rules for how mesh-bot communicates over Meshtastic and how the agent should rea
 
 - All bot sends ride channel index 3 ("test") by design (`MESH_SEND_CHANNEL`, default "3") — never the primary channel.
 - Broadcasts show up in `/api/messages` as `failed` / `NO_RESPONSE` on this firmware — known quirk, not a real failure; the message was transmitted.
-- Channel index 2 carries the bot's auto-responder (`COMMAND_CHANNEL`, default 2): exact `#command` texts (case-sensitive) get an automatic reply on that channel — directed back to the sender when present, else broadcast. Currently only `#ping` → `#pong!`. This is a mechanical echo for testing the mesh path; it is not the agent and does not mean the owner has seen anything.
+- Channel index 2 carries the bot's auto-responder (`COMMAND_CHANNEL`, default 2): exact `#command` texts (case-sensitive) on that channel get an automatic reply routed through `MeshService.respond()` — DM back to the original sender, broadcast when the original was a broadcast — riding the original message's channel as a threaded quote (`replyId` = the trigger packet id). Currently only `#ping` → `#pong!`. This is a mechanical echo for testing the mesh path; it is not the agent and does not mean the owner has seen anything.
 
 ## Notifications (mesh → agent)
 

README.md

@@ -125,6 +125,9 @@ Config lives in `.env` (gitignored) and is passed via compose environment — cr
 - `MESH_DB_PATH` (default `./data/mesh-bot.db`) — SQLite file backing the message history (parent dir created if missing; in Docker, mounted at `/app/data` via a named volume so it survives container recreation)
 - `MESH_POLL_MS` (default `1000`) — how often the poller re-upserts the message history into SQLite and prunes rows beyond the newest 1000
 - `PORT` (default `3000`) — HTTP listen port
+- `LLM_API_BASE` (default `http://192.168.1.70:1111/v1`) — OpenAI-compatible LLM server base URL used by the in-process `LlmService` (`src/llm`; no auth)
+- `LLM_MODEL` (default `qwen3.8-27b`) — model id sent to `/chat/completions`
+- `LLM_TIMEOUT_MS` (default `60000`) — per-request timeout for LLM calls (the local 27B model can be slow)
 
 Note: the serial bridge accepts only ONE client at a time — if another app is
 connected to the radio, this bot will not get a connection.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mesh-bot",
-  "version": "0.18.0",
+  "version": "0.19.0",
   "description": "",
   "author": "",
   "private": true,

src/app.module.ts

@@ -1,10 +1,17 @@
 import { Module } from '@nestjs/common';
 import { BatteryAlertModule } from './battery/battery.module.js';
 import { CommandModule } from './commands/command.module.js';
+import { LlmModule } from './llm/llm.module.js';
 import { MeshModule } from './mesh/mesh.module.js';
 import { WeatherModule } from './weather/weather.module.js';
 
 @Module({
-  imports: [MeshModule, WeatherModule, BatteryAlertModule, CommandModule],
+  imports: [
+    MeshModule,
+    WeatherModule,
+    BatteryAlertModule,
+    CommandModule,
+    LlmModule,
+  ],
 })
 export class AppModule {}

src/commands/command.service.spec.ts

@@ -4,6 +4,7 @@ import {
   startBridge,
   textPacketFrame,
   waitFor,
+  outboundPackets,
   KAMIL_NUM,
 } from '../mesh/fake-bridge.js';
 import type { MeshService } from '../mesh/mesh.service.js';
@@ -12,8 +13,12 @@ import { CommandService } from './command.service.js';
 
 function makeService(
   sendText?: ReturnType<typeof vi.fn>,
+  respond?: ReturnType<typeof vi.fn>,
 ): [CommandService, MeshService] {
-  const mesh = { sendText: sendText ?? vi.fn() } as unknown as MeshService;
+  const mesh = {
+    sendText: sendText ?? vi.fn(),
+    respond: respond ?? vi.fn().mockResolvedValue({ id: 1 }),
+  } as unknown as MeshService;
   return [new CommandService(mesh), mesh];
 }
 
@@ -22,15 +27,24 @@ beforeEach(() => {
 });
 
 describe('CommandService.onRx', () => {
-  it('answers #ping on the command channel with a directed DM back to the sender', async () => {
+  it('replies #ping via respond() — threaded quote of the trigger packet, no direct sendText', async () => {
     const [svc, mesh] = makeService();
     await svc.onRx(2, '#ping', 42, 7);
+    expect(mesh.respond).toHaveBeenCalledWith(7, '#pong!');
+    expect(mesh.sendText).not.toHaveBeenCalled();
+  });
+
+  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
+    expect(mesh.respond).not.toHaveBeenCalled();
     expect(mesh.sendText).toHaveBeenCalledWith(42, '#pong!', undefined, 2);
   });
 
-  it('broadcasts the reply when there is no sender', async () => {
+  it('falls back to a broadcast sendText on COMMAND_CHANNEL when the trigger has no packet id (no sender)', async () => {
     const [svc, mesh] = makeService();
-    await svc.onRx(2, '#ping');
+    await svc.onRx(2, '#ping'); // no from, no id — defensive path
+    expect(mesh.respond).not.toHaveBeenCalled();
     expect(mesh.sendText).toHaveBeenCalledWith(
       BROADCAST_ADDR,
       '#pong!',
@@ -43,6 +57,7 @@ describe('CommandService.onRx', () => {
     const [svc, mesh] = makeService();
     await svc.onRx(0, '#ping', 42);
     await svc.onRx(3, '#ping', 42);
+    expect(mesh.respond).not.toHaveBeenCalled();
     expect(mesh.sendText).not.toHaveBeenCalled();
   });
 
@@ -50,6 +65,7 @@ describe('CommandService.onRx', () => {
     const [svc, mesh] = makeService();
     await svc.onRx(2, 'hello there', 42);
     await svc.onRx(2, 'ping', 42); // no leading # — not a command trigger
+    expect(mesh.respond).not.toHaveBeenCalled();
     expect(mesh.sendText).not.toHaveBeenCalled();
   });
 
@@ -57,28 +73,31 @@ describe('CommandService.onRx', () => {
     const [svc, mesh] = makeService();
     await svc.onRx(2, '#Ping', 42);
     await svc.onRx(2, '#ping!', 42); // extra char — no partial matches
+    expect(mesh.respond).not.toHaveBeenCalled();
     expect(mesh.sendText).not.toHaveBeenCalled();
   });
 
   it('trims surrounding whitespace before matching', async () => {
     const [svc, mesh] = makeService();
-    await svc.onRx(2, '  #ping  ', 42);
-    expect(mesh.sendText).toHaveBeenCalledWith(42, '#pong!', undefined, 2);
+    await svc.onRx(2, '  #ping  ', 42, 9);
+    expect(mesh.respond).toHaveBeenCalledWith(9, '#pong!');
   });
 
   it('honors the COMMAND_CHANNEL env override', async () => {
     process.env.COMMAND_CHANNEL = '5';
     const [svc, mesh] = makeService();
     await svc.onRx(2, '#ping', 42); // old default no longer triggers
+    expect(mesh.respond).not.toHaveBeenCalled();
     expect(mesh.sendText).not.toHaveBeenCalled();
-    await svc.onRx(5, '#ping', 42);
-    expect(mesh.sendText).toHaveBeenCalledWith(42, '#pong!', undefined, 5);
+    await svc.onRx(5, '#ping', 42, 8);
+    expect(mesh.respond).toHaveBeenCalledWith(8, '#pong!');
   });
 
   it('sends nothing when a handler returns void', async () => {
     const [svc, mesh] = makeService();
     svc.register('silent', () => undefined);
     await svc.onRx(2, '#silent', 42);
+    expect(mesh.respond).not.toHaveBeenCalled();
     expect(mesh.sendText).not.toHaveBeenCalled();
   });
 
@@ -86,7 +105,7 @@ describe('CommandService.onRx', () => {
     const [svc, mesh] = makeService();
     svc.register('status', (ctx) => `up from ${ctx.from ?? 'broadcast'}`);
     await svc.onRx(2, '#status', 99, 5);
-    expect(mesh.sendText).toHaveBeenCalledWith(99, 'up from 99', undefined, 2);
+    expect(mesh.respond).toHaveBeenCalledWith(5, 'up from 99');
   });
 
   it('swallows a failing handler (a bad command must not crash the app)', async () => {
@@ -95,19 +114,28 @@ describe('CommandService.onRx', () => {
       throw new Error('kaboom');
     });
     await expect(svc.onRx(2, '#boom', 42)).resolves.toBeUndefined();
+    expect(mesh.respond).not.toHaveBeenCalled();
     expect(mesh.sendText).not.toHaveBeenCalled();
   });
 
+  it('swallows a failing respond (unknown id / bridge down) without throwing', async () => {
+    const [svc] = makeService(
+      undefined,
+      vi.fn().mockRejectedValue(new Error('no message with id 7')),
+    );
+    await expect(svc.onRx(2, '#ping', 42, 7)).resolves.toBeUndefined();
+  });
+
   it('swallows a failing send (mesh down) without throwing', async () => {
     const [svc] = makeService(
       vi.fn().mockRejectedValue(new Error('no bridge')),
     );
-    await expect(svc.onRx(2, '#ping', 42)).resolves.toBeUndefined();
+    await expect(svc.onRx(2, '#ping', 42)).resolves.toBeUndefined(); // no id → legacy path
   });
 });
 
 describe('MeshService wiring (event-driven trigger)', () => {
-  it('calls onRx for decoded rx text and answers #ping over the wire', async () => {
+  it('answers a #ping DM on ch2 with a directed #pong! back to the sender, same channel, threaded quote', async () => {
     const bridge = await startBridge();
     process.env.MESH_HOST = '127.0.0.1';
     process.env.MESH_PORT = String(bridge.port);
@@ -120,6 +148,10 @@ describe('MeshService wiring (event-driven trigger)', () => {
         () => bridge.sockets.length === 1 && svc.status().connected,
       );
 
+      const out: Uint8Array[] = [];
+      bridge.sockets[0].on('data', (c) => out.push(c));
+
+      // rx DM from KAMIL to node 42 on channel 2 (packet id 1)
       bridge.sockets[0].write(textPacketFrame(KAMIL_NUM, 42, '#ping', 2));
 
       // rx record + the directed #pong! reply on channel 2 (newest first — the reply is [0])
@@ -130,6 +162,60 @@ describe('MeshService wiring (event-driven trigger)', () => {
         text: '#pong!',
         channel: 2,
       });
+
+      // wire-level: DM back to the sender on ch2 with replyId = the ping packet id (threaded quote)
+      await waitFor(() => outboundPackets(out).length >= 1);
+      const pkt = outboundPackets(out)[0]!;
+      expect(pkt.to).toBe(KAMIL_NUM);
+      expect(pkt.channel).toBe(2);
+      const data =
+        pkt.payloadVariant?.case === 'decoded'
+          ? pkt.payloadVariant.value
+          : undefined;
+      expect(data?.replyId).toBe(1);
+    } finally {
+      svc.onModuleDestroy();
+      bridge.close();
+    }
+  });
+
+  it('answers a #ping broadcast on ch2 with a #pong! broadcast, same channel, threaded quote', async () => {
+    const bridge = await startBridge();
+    process.env.MESH_HOST = '127.0.0.1';
+    process.env.MESH_PORT = String(bridge.port);
+    const svc = new RealMeshService();
+    try {
+      svc.attachCommands(new CommandService(svc));
+      svc.onModuleInit();
+      await waitFor(
+        () => bridge.sockets.length === 1 && svc.status().connected,
+      );
+
+      const out: Uint8Array[] = [];
+      bridge.sockets[0].on('data', (c) => out.push(c));
+
+      // rx broadcast from KAMIL on channel 2 (packet id 1)
+      bridge.sockets[0].write(
+        textPacketFrame(KAMIL_NUM, BROADCAST_ADDR, '#ping', 2),
+      );
+
+      await waitFor(() => svc.messages().length === 2);
+      expect(svc.messages()[0]).toMatchObject({
+        dir: 'tx',
+        to: BROADCAST_ADDR, // broadcast original → broadcast reply
+        text: '#pong!',
+        channel: 2,
+      });
+
+      await waitFor(() => outboundPackets(out).length >= 1);
+      const pkt = outboundPackets(out)[0]!;
+      expect(pkt.to).toBe(BROADCAST_ADDR);
+      expect(pkt.channel).toBe(2);
+      const data =
+        pkt.payloadVariant?.case === 'decoded'
+          ? pkt.payloadVariant.value
+          : undefined;
+      expect(data?.replyId).toBe(1); // threaded quote of the ping packet (id 1)
     } finally {
       svc.onModuleDestroy();
       bridge.close();

src/commands/command.service.ts

@@ -42,8 +42,10 @@ export class CommandService {
   /**
    * Event-driven entry point called by MeshService for every decoded rx text.
    * No-op unless on COMMAND_CHANNEL with an exact `#command` match (case-sensitive).
-   * Replies ride COMMAND_CHANNEL: directed DM back to the sender when present, else broadcast.
-   * Never throws — a failed command must not crash the app.
+   * Replies go through MeshService.respond(id, reply): auto-routed to the original message's
+   * destination and channel as a threaded quote (replyId = id). Only when the trigger has no packet
+   * id does it fall back to legacy sendText routing on COMMAND_CHANNEL. Never throws — a failed
+   * command must not crash the app.
    */
   async onRx(
     channel: number,
@@ -59,12 +61,18 @@ export class CommandService {
     try {
       const reply = await handler({ text: trimmed, from, id });
       if (reply === undefined || reply === null) return; // void = no reply
-      await this.mesh?.sendText(
-        from ?? BROADCAST_ADDR,
-        reply,
-        undefined,
-        this.commandChannel,
-      );
+      if (id !== undefined && this.mesh) {
+        // respond() auto-routes the reply: rides the original record's channel with replyId = id (threaded quote)
+        await this.mesh.respond(id, reply);
+      } else {
+        // defensive fallback when the trigger has no packet id: legacy routing on COMMAND_CHANNEL
+        await this.mesh?.sendText(
+          from ?? BROADCAST_ADDR,
+          reply,
+          undefined,
+          this.commandChannel,
+        );
+      }
     } catch (err) {
       this.logger.warn(
         `[commands] '${trimmed}' failed: ${(err as Error).message}`,

src/llm/llm.module.ts

@@ -0,0 +1,8 @@
+import { Module } from '@nestjs/common';
+import { LlmService } from './llm.service.js';
+
+@Module({
+  providers: [LlmService],
+  exports: [LlmService],
+})
+export class LlmModule {}

src/llm/llm.service.spec.ts

@@ -0,0 +1,104 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import type { ChatMessage } from './llm.service.js';
+import { LlmService } from './llm.service.js';
+
+const BASE = 'http://192.168.1.70:1111/v1';
+
+function json(body: unknown): Response {
+  return { ok: true, status: 200, json: async () => body } as Response;
+}
+
+/** Fresh service with a clean env (explicit base/model/timeout). */
+function makeService(): LlmService {
+  process.env.LLM_API_BASE = BASE;
+  process.env.LLM_MODEL = 'qwen3.8-27b';
+  process.env.LLM_TIMEOUT_MS = '60000';
+  return new LlmService();
+}
+
+describe('LlmService', () => {
+  let fetchMock: ReturnType<typeof vi.fn>;
+
+  beforeEach(() => {
+    fetchMock = vi.fn();
+    vi.stubGlobal('fetch', fetchMock);
+  });
+
+  afterEach(() => {
+    vi.unstubAllGlobals();
+    for (const k of ['LLM_API_BASE', 'LLM_MODEL', 'LLM_TIMEOUT_MS'])
+      delete process.env[k];
+  });
+
+  it('listModels returns the data[].id strings from GET /models', async () => {
+    const svc = makeService();
+    fetchMock.mockResolvedValueOnce(
+      json({
+        data: [
+          { id: 'qwen3.8-27b' },
+          { id: 'text-embedding-nomic-embed-text-v1.5' },
+        ],
+      }),
+    );
+
+    await expect(svc.listModels()).resolves.toEqual([
+      'qwen3.8-27b',
+      'text-embedding-nomic-embed-text-v1.5',
+    ]);
+    expect(fetchMock).toHaveBeenCalledTimes(1);
+    expect(fetchMock.mock.calls[0][0]).toBe(`${BASE}/models`);
+  });
+
+  it('chat posts model+messages and returns choices[0].message.content', async () => {
+    const svc = makeService();
+    fetchMock.mockResolvedValueOnce(
+      json({ choices: [{ message: { content: 'hello back' } }] }),
+    );
+
+    const messages: ChatMessage[] = [
+      { role: 'system', content: 'be brief' },
+      { role: 'user', content: 'hi' },
+    ];
+    await expect(
+      svc.chat(messages, { maxTokens: 50, temperature: 0.2 }),
+    ).resolves.toBe('hello back');
+
+    const [url, init] = fetchMock.mock.calls[0];
+    expect(url).toBe(`${BASE}/chat/completions`);
+    expect(init.method).toBe('POST');
+    expect(JSON.parse(init.body)).toEqual({
+      model: 'qwen3.8-27b',
+      messages,
+      maxTokens: 50,
+      temperature: 0.2,
+    });
+  });
+
+  it('chat throws on non-2xx with the HTTP status in the message', async () => {
+    const svc = makeService();
+    fetchMock.mockResolvedValueOnce({
+      ok: false,
+      status: 503,
+      text: async () => 'upstream down',
+    } as Response);
+
+    await expect(svc.chat([{ role: 'user', content: 'hi' }])).rejects.toThrow(
+      /HTTP 503.*upstream down/,
+    );
+  });
+
+  it('summarize calls chat with the system prompt plus the user text', async () => {
+    const svc = makeService();
+    fetchMock.mockResolvedValueOnce(
+      json({ choices: [{ message: { content: 'the summary' } }] }),
+    );
+
+    await expect(svc.summarize('a long text')).resolves.toBe('the summary');
+
+    const [, init] = fetchMock.mock.calls[0];
+    expect(JSON.parse(init.body).messages).toEqual([
+      { role: 'system', content: 'Summarize the following text concisely.' },
+      { role: 'user', content: 'a long text' },
+    ]);
+  });
+});

src/llm/llm.service.ts

@@ -0,0 +1,68 @@
+import { Injectable } from '@nestjs/common';
+
+/** A single chat message in OpenAI chat-completions shape. */
+export interface ChatMessage {
+  role: string;
+  content: string;
+}
+
+@Injectable()
+export class LlmService {
+  // read at construction, like other services' env config
+  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
+  private readonly timeoutMs = parseInt(
+    process.env.LLM_TIMEOUT_MS ?? '60000',
+    10,
+  );
+
+  /** GET {base}/models → the `data[].id` strings. */
+  async listModels(): Promise<string[]> {
+    const res = await fetch(`${this.apiBase}/models`, {
+      signal: AbortSignal.timeout(this.timeoutMs),
+    });
+    if (!res.ok) {
+      throw new Error(
+        `listModels failed: HTTP ${res.status} ${(await res.text()).slice(0, 200)}`,
+      );
+    }
+    const body = (await res.json()) as { data?: { id: string }[] };
+    return (body.data ?? []).map((m) => m.id);
+  }
+
+  /** POST {base}/chat/completions → `choices[0].message.content`. */
+  async chat(
+    messages: ChatMessage[],
+    opts?: { maxTokens?: number; temperature?: number },
+  ): Promise<string> {
+    const res = await fetch(`${this.apiBase}/chat/completions`, {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({ model: this.model, messages, ...opts }),
+      signal: AbortSignal.timeout(this.timeoutMs),
+    });
+    if (!res.ok) {
+      throw new Error(
+        `chat failed: HTTP ${res.status} ${(await res.text()).slice(0, 200)}`,
+      );
+    }
+    const body = (await res.json()) as {
+      choices?: { message?: { content?: string } }[];
+    };
+    const content = body.choices?.[0]?.message?.content;
+    if (typeof content !== 'string') {
+      throw new Error('chat failed: no choices[0].message.content in response');
+    }
+    return content;
+  }
+
+  /** Thin wrapper over chat(): the stated primary use of this service. */
+  async summarize(text: string): Promise<string> {
+    return this.chat([
+      { role: 'system', content: 'Summarize the following text concisely.' },
+      { role: 'user', content: text },
+    ]);
+  }
+}

src/mesh/fake-bridge.ts

@@ -1,8 +1,8 @@
-import { create, toBinary } from '@bufbuild/protobuf';
+import { create, fromBinary, toBinary } from '@bufbuild/protobuf';
 import * as P from '@meshtastic/protobufs';
 import * as net from 'node:net';
 import type { AddressInfo } from 'node:net';
-import { frame } from './codec.js';
+import { extractFrames, frame } from './codec.js';
 
 /** In-process TCP stand-in for the meshtastic-serial-bridge; hands out accepted sockets. */
 export function startBridge(
@@ -176,6 +176,21 @@ export function textPacketFrame(
   );
 }
 
+/** Outbound text packets written to the bridge, in order (want_config frames skipped). */
+export function outboundPackets(out: Uint8Array[]): P.Mesh.MeshPacket[] {
+  const merged = new Uint8Array(out.reduce((n, c) => n + c.length, 0));
+  let off = 0;
+  for (const c of out) {
+    merged.set(c, off);
+    off += c.length;
+  }
+  return extractFrames(merged).packets.flatMap((p) => {
+    const tr = fromBinary(P.Mesh.ToRadioSchema, p);
+    if (tr.payloadVariant?.case === 'packet') return [tr.payloadVariant.value];
+    return [];
+  });
+}
+
 export const KAMIL_NUM = 123456789;
 
 export function kamilNodeInfo(): NodeInfoFields {

src/mesh/mesh.service.spec.ts

@@ -11,6 +11,7 @@ import {
   metadataFrame,
   moduleConfigSectionFrame,
   nodeInfoFrame,
+  outboundPackets,
   startBridge,
   telemetryPacketFrame,
   textPacketFrame,
@@ -667,21 +668,6 @@ describe('MeshService message history', () => {
   });
 });
 
-// outbound text packets written to the bridge, in order (want_config frames skipped)
-function outboundPackets(out: Uint8Array[]): P.Mesh.MeshPacket[] {
-  const merged = new Uint8Array(out.reduce((n, c) => n + c.length, 0));
-  let off = 0;
-  for (const c of out) {
-    merged.set(c, off);
-    off += c.length;
-  }
-  return extractFrames(merged).packets.flatMap((p) => {
-    const tr = fromBinary(P.Mesh.ToRadioSchema, p);
-    if (tr.payloadVariant?.case === 'packet') return [tr.payloadVariant.value];
-    return [];
-  });
-}
-
 describe('MeshService respond', () => {
   it('replies to an rx DM as a directed send back to the sender on the original channel with replyId = messageId', async () => {
     const bridge = await startBridge();