Void-Homelab/docs/superpowers/plans/2026-06-08-lan-device-discovery.md

LAN Device Discovery — Implementation Plan

For agentic workers: REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (- [ ]) syntax for tracking.

Goal: Replace the static devices.json with a persistent, MAC-keyed lan_devices store fed by an hourly arp-scan, with a "discovered → name/edit → promote" review flow and randomized-MAC auto-pruning.

Architecture: A decoupled scanner (lib/infra/scan.js, pure parser + injected exec) feeds a repo (lib/db/repos/lan_devices.js) keyed by MAC. An hourly cron runs scan→upsert→mark-absent→prune. An owner API (/api/devices) exposes the band + review/edit. The front-end band reads the DB and offers an add/edit panel.

Tech Stack: Node/Express, Postgres (pg), vanilla-ESM SPA, vitest+supertest+jsdom, arp-scan.

Spec: docs/superpowers/specs/2026-06-08-lan-device-discovery-design.md Branch: feat/lan-device-discovery (spec already committed there).

Conventions to mirror: repo = lib/db/repos/monitored_services.js; route = lib/api/routes/health.js (Router, asyncWrap, requireOwner from ../cap.js, validate from ../validate.js); repo test = tests/repos/monitored_services.test.js (resetDb()+migrateUp()); route test = tests/server.test.js (supertest, OWNER_TOKEN='test-token', Authorization: Bearer test-token); frontend test = tests/frontend/service_tile.test.js (jsdom). Run a single file: npm test -- <path>.

---

Task 1: Scanner module (pure parse + randomized detection + runScan)

Files:

• Create: lib/infra/scan.js

• Test: tests/infra/scan.test.js

• Step 1: Write the failing test

// tests/infra/scan.test.js
import { describe, it, expect } from 'vitest';
import { isRandomizedMac, parseArpScan, runScan } from '../../lib/infra/scan.js';

const SAMPLE = [
  'Interface: eth0, type: EN10MB, MAC: bc:24:11:9b:b7:3a, IPv4: 192.168.1.216',
  'Starting arp-scan 1.10.0',
  '192.168.1.13\tbc:a5:11:3e:06:88\tNetgear',
  '192.168.1.171\t5a:da:61:7a:0f:12\t(Unknown)',
  '192.168.1.1\t44:A5:6E:68:D0:E9\tNetgear Inc.',
  'garbage line that is not a host',
  '',
  '3 packets received by filter, 0 packets dropped'
].join('\n');

describe('scan parsing', () => {
  it('isRandomizedMac flags locally-administered MACs', () => {
    expect(isRandomizedMac('5a:da:61:7a:0f:12')).toBe(true);   // 0x5a & 0x02
    expect(isRandomizedMac('bc:a5:11:3e:06:88')).toBe(false);  // 0xbc & 0x02 == 0
    expect(isRandomizedMac('44:A5:6E:68:D0:E9')).toBe(false);
  });

  it('parseArpScan keeps only host lines, lowercases MAC, flags randomized', () => {
    const rows = parseArpScan(SAMPLE);
    expect(rows).toHaveLength(3);
    expect(rows[0]).toEqual({ ip: '192.168.1.13', mac: 'bc:a5:11:3e:06:88', vendor: 'Netgear', randomized: false });
    expect(rows[1]).toEqual({ ip: '192.168.1.171', mac: '5a:da:61:7a:0f:12', vendor: '(Unknown)', randomized: true });
    expect(rows[2].mac).toBe('44:a5:6e:68:d0:e9'); // lowercased
  });

  it('runScan parses the injected exec stdout', async () => {
    const rows = await runScan({ exec: async () => ({ stdout: SAMPLE }) });
    expect(rows.map(r => r.ip)).toEqual(['192.168.1.13', '192.168.1.171', '192.168.1.1']);
  });
});

• Step 2: Run it; verify it fails

Run: npm test -- tests/infra/scan.test.js Expected: FAIL — Cannot find module '../../lib/infra/scan.js'.

• Step 3: Create lib/infra/scan.js

// Decoupled LAN scanner: pure parser + a thin arp-scan runner (exec injected
// for tests). The repo/cron own persistence — this module only produces rows.
import { execFile } from 'node:child_process';
import { promisify } from 'node:util';

const pexec = promisify(execFile);

// A locally-administered (randomized) MAC has bit 0x02 set in its first octet.
export function isRandomizedMac(mac) {
  const first = parseInt(String(mac).split(':')[0], 16);
  return Number.isFinite(first) && (first & 0x02) === 0x02;
}

// Keep only "IP<ws>MAC<ws>[vendor]" lines; ignore banner/footer/garbage.
export function parseArpScan(text) {
  const re = /^(\d{1,3}(?:\.\d{1,3}){3})\s+([0-9a-fA-F]{2}(?::[0-9a-fA-F]{2}){5})\s*(.*)$/;
  const out = [];
  for (const line of String(text).split('\n')) {
    const m = line.match(re);
    if (!m) continue;
    const mac = m[2].toLowerCase();
    out.push({ ip: m[1], mac, vendor: m[3].trim(), randomized: isRandomizedMac(mac) });
  }
  return out;
}

// Run arp-scan on the local /24. `exec(file, args) -> {stdout}` injected for tests.
export async function runScan({ exec = pexec } = {}) {
  const { stdout } = await exec('arp-scan', ['--localnet', '--plain', '--retry=2']);
  return parseArpScan(stdout);
}

• Step 4: Run it; verify it passes

Run: npm test -- tests/infra/scan.test.js Expected: PASS (3 passed).

• Step 5: Commit

git add lib/infra/scan.js tests/infra/scan.test.js
git commit -m "feat(devices): arp-scan parser + randomized-MAC detection"

---

Task 2: Migration 024_lan_devices (table + seed)

Files:

• Create: lib/db/migrations/024_lan_devices.sql

• Test: covered by the repo test in Task 3 (seed assertions). This task is verified by running migrations.

• Step 1: Create the migration

-- 024_lan_devices.sql
-- LAN device inventory keyed by MAC, fed by the hourly arp-scan. Separate from
-- network_hosts (homelab guests). New MACs land status='new' for owner review.
CREATE TABLE IF NOT EXISTS lan_devices (
  mac         text PRIMARY KEY,
  ip          text,
  vendor      text,
  name        text,
  grp         text,
  note        text,
  status      text NOT NULL DEFAULT 'new',     -- new | known | ignored
  randomized  boolean NOT NULL DEFAULT false,
  flagged     boolean NOT NULL DEFAULT false,
  first_seen  timestamptz NOT NULL DEFAULT now(),
  last_seen   timestamptz NOT NULL DEFAULT now(),
  present     boolean NOT NULL DEFAULT true
);

-- Seed from the curated devices.json (MACs lowercased). Named devices -> 'known';
-- the unidentified ASUS box -> 'new'. present=false until the first live scan.
INSERT INTO lan_devices (mac, ip, vendor, name, grp, status, flagged, randomized, present) VALUES
  ('48:43:dd:fc:2f:84','192.168.1.3','Amazon','Amazon Echo','Smart Home','known',false,false,false),
  ('14:0a:c5:6d:15:6e','192.168.1.4','Amazon','Amazon Echo','Smart Home','known',false,false,false),
  ('c8:47:8c:01:17:70','192.168.1.6','Beken','Smart device','Smart Home','known',false,false,false),
  ('d4:a6:51:12:36:92','192.168.1.23','Tuya','Smart device','Smart Home','known',false,false,false),
  ('ec:4d:3e:36:ef:e1','192.168.1.20','Xiaomi','Xiaomi device','Smart Home','known',false,false,false),
  ('1c:53:f9:bb:32:24','192.168.1.12','Google','Google / Nest','Entertainment','known',false,false,false),
  ('d4:f5:47:95:33:93','192.168.1.14','Google','Google Nest Mini','Entertainment','known',false,false,false),
  ('ec:4d:3e:37:38:8f','192.168.1.18','Google','Google / Nest','Entertainment','known',false,false,false),
  ('48:70:1e:01:4f:7b','192.168.1.29','StreamMagic','Cambridge Audio','Entertainment','known',false,false,false),
  ('08:66:98:b9:cf:f2','192.168.1.43','Apple','Apple TV / HomePod','Entertainment','known',false,false,false),
  ('1c:86:9a:4c:f0:ec','192.168.1.24','Samsung','Samsung TV','Entertainment','known',false,false,false),
  ('5a:da:61:7a:0f:12','192.168.1.171','Samsung','Galaxy Tab S4','Personal','known',false,true,false),
  ('1c:57:dc:70:e8:2d','192.168.1.133','Apple','Apple device','Personal','known',false,false,false),
  ('a0:d0:5b:04:70:96','192.168.1.61','Samsung','Samsung device','Personal','known',false,false,false),
  ('14:eb:b6:40:7e:93','192.168.1.10','TP-Link','TP-Link device','Personal','known',false,false,false),
  ('44:a5:6e:68:d0:e9','192.168.1.1','Netgear','Gateway / Router','Network','known',false,false,false),
  ('bc:a5:11:3e:06:88','192.168.1.13','Netgear (Orbi mesh)','Orbi Satellite','Network','known',false,false,false),
  ('24:4b:fe:8e:09:a4','192.168.1.15','ASUSTek','ASUS device','Flagged','new',true,false,false)
ON CONFLICT (mac) DO NOTHING;

• Step 2: Run migrations against the test DB to verify the SQL is valid

Run: node -e "import('./lib/db/migrate.js').then(m=>m.migrateUp()).then(()=>{console.log('migrated');process.exit(0)}).catch(e=>{console.error(e);process.exit(1)})" Expected: prints migrated (no SQL error). (Uses the env DATABASE_URL; in dev this is the test/dev DB.)

• Step 3: Commit

git add lib/db/migrations/024_lan_devices.sql
git commit -m "feat(devices): lan_devices table + seed from curated devices.json"

---

Task 3: lan_devices repo (upsert / absent / prune / promote)

Files:

• Create: lib/db/repos/lan_devices.js

• Test: tests/repos/lan_devices.test.js

• Step 1: Write the failing test

// tests/repos/lan_devices.test.js
import { describe, it, expect, beforeAll, beforeEach } from 'vitest';
import { resetDb } from '../helpers/db.js';
import { migrateUp } from '../../lib/db/migrate.js';
import { pool } from '../../lib/db/pool.js';
import * as repo from '../../lib/db/repos/lan_devices.js';

beforeAll(async () => { await resetDb(); await migrateUp(); });
beforeEach(async () => { await resetDb(); await migrateUp(); });

describe('lan_devices repo', () => {
  it('seed: 17 known, 1 discovered (ASUS)', async () => {
    expect(await repo.listKnown()).toHaveLength(17);
    const disc = await repo.listDiscovered();
    expect(disc).toHaveLength(1);
    expect(disc[0].mac).toBe('24:4b:fe:8e:09:a4');
    expect(disc[0].flagged).toBe(true);
  });

  it('upsertScan inserts unseen as new, updates known IP without clobbering name', async () => {
    await repo.upsertScan([
      { mac: 'aa:bb:cc:dd:ee:ff', ip: '192.168.1.99', vendor: 'NewCo', randomized: false }, // new
      { mac: 'bc:a5:11:3e:06:88', ip: '192.168.1.77', vendor: 'Netgear', randomized: false } // known Orbi, IP changed
    ]);
    const orbi = await repo.get('bc:a5:11:3e:06:88');
    expect(orbi.ip).toBe('192.168.1.77');        // ip updated
    expect(orbi.name).toBe('Orbi Satellite');    // name preserved
    expect(orbi.status).toBe('known');           // status preserved
    expect(orbi.present).toBe(true);
    const fresh = await repo.get('aa:bb:cc:dd:ee:ff');
    expect(fresh.status).toBe('new');
  });

  it('markAbsent flips present for unseen; empty list is a no-op', async () => {
    await repo.upsertScan([{ mac: 'aa:bb:cc:dd:ee:ff', ip: '192.168.1.99', vendor: '', randomized: false }]);
    await repo.markAbsent(['aa:bb:cc:dd:ee:ff']); // only this one seen
    expect((await repo.get('bc:a5:11:3e:06:88')).present).toBe(false); // seeded device now absent
    expect((await repo.get('aa:bb:cc:dd:ee:ff')).present).toBe(true);
    const before = (await repo.get('aa:bb:cc:dd:ee:ff')).present;
    expect(await repo.markAbsent([])).toBe(0);    // guard: no-op
    expect((await repo.get('aa:bb:cc:dd:ee:ff')).present).toBe(before);
  });

  it('prune deletes stale new+absent (randomized >24h, others >14d); keeps known', async () => {
    await pool.query(`INSERT INTO lan_devices (mac, status, randomized, present, last_seen)
      VALUES ('11:11:11:11:11:11','new',true,false, now()-interval '2 days'),
             ('22:22:22:22:22:22','new',false,false, now()-interval '20 days'),
             ('33:33:33:33:33:33','new',true,false, now()-interval '1 hour'),
             ('44:44:44:44:44:44','known',true,false, now()-interval '99 days')`);
    const n = await repo.prune();
    expect(n).toBe(2);                                   // the two stale 'new'
    expect(await repo.get('33:33:33:33:33:33')).not.toBeNull(); // recent kept
    expect(await repo.get('44:44:44:44:44:44')).not.toBeNull(); // known kept
  });

  it('update promotes + names a discovered device', async () => {
    await repo.update('24:4b:fe:8e:09:a4', { name: 'ASUS RT-AX88U', grp: 'Network', status: 'known', flagged: false });
    expect(await repo.listDiscovered()).toHaveLength(0);
    const d = await repo.get('24:4b:fe:8e:09:a4');
    expect(d.name).toBe('ASUS RT-AX88U');
    expect(d.status).toBe('known');
  });
});

• Step 2: Run it; verify it fails

Run: npm test -- tests/repos/lan_devices.test.js Expected: FAIL — Cannot find module '../../lib/db/repos/lan_devices.js'.

• Step 3: Create lib/db/repos/lan_devices.js

import { pool } from '../pool.js';

const COLS = 'mac, ip, vendor, name, grp, note, status, randomized, flagged, first_seen, last_seen, present';

export async function listKnown() {
  const { rows } = await pool.query(
    `SELECT ${COLS} FROM lan_devices WHERE status='known' ORDER BY grp, name NULLS LAST, ip`);
  return rows;
}

export async function listDiscovered() {
  const { rows } = await pool.query(
    `SELECT ${COLS} FROM lan_devices WHERE status='new' ORDER BY last_seen DESC`);
  return rows;
}

export async function get(mac) {
  const { rows: [r] } = await pool.query(`SELECT ${COLS} FROM lan_devices WHERE mac=$1`, [mac]);
  return r || null;
}

// Insert unseen MACs as status='new'; for existing, refresh ip/vendor/last_seen/present
// WITHOUT touching owner-curated name/grp/status/flagged.
export async function upsertScan(rows) {
  for (const r of rows) {
    await pool.query(
      `INSERT INTO lan_devices (mac, ip, vendor, randomized, status, present, first_seen, last_seen)
       VALUES ($1,$2,$3,$4,'new',true,now(),now())
       ON CONFLICT (mac) DO UPDATE SET
         ip = EXCLUDED.ip,
         vendor = COALESCE(NULLIF(EXCLUDED.vendor,''), lan_devices.vendor),
         last_seen = now(), present = true`,
      [r.mac, r.ip ?? null, r.vendor ?? null, !!r.randomized]);
  }
  return rows.length;
}

// Mark devices not in the latest scan as absent. Empty input is a no-op so a
// failed/empty scan can never blanket-mark everything offline.
export async function markAbsent(seenMacs) {
  if (!seenMacs || !seenMacs.length) return 0;
  const { rowCount } = await pool.query(
    `UPDATE lan_devices SET present=false WHERE present=true AND NOT (mac = ANY($1::text[]))`,
    [seenMacs]);
  return rowCount;
}

// Reap unreviewed + absent rows past their TTL. Never touches known/ignored.
export async function prune() {
  const { rowCount } = await pool.query(
    `DELETE FROM lan_devices WHERE status='new' AND present=false AND (
        (randomized AND last_seen < now() - interval '24 hours') OR
        (NOT randomized AND last_seen < now() - interval '14 days'))`);
  return rowCount;
}

const PATCHABLE = ['name', 'grp', 'note', 'status', 'flagged'];
export async function update(mac, patch) {
  const sets = [], vals = [];
  for (const k of PATCHABLE) {
    if (patch[k] !== undefined) { vals.push(patch[k]); sets.push(`${k}=$${vals.length}`); }
  }
  if (!sets.length) return get(mac);
  vals.push(mac);
  const { rows: [r] } = await pool.query(
    `UPDATE lan_devices SET ${sets.join(', ')} WHERE mac=$${vals.length} RETURNING ${COLS}`, vals);
  return r || null;
}

export async function remove(mac) {
  const { rowCount } = await pool.query(`DELETE FROM lan_devices WHERE mac=$1`, [mac]);
  return rowCount > 0;
}

• Step 4: Run it; verify it passes

Run: npm test -- tests/repos/lan_devices.test.js Expected: PASS (6 passed).

• Step 5: Commit

git add lib/db/repos/lan_devices.js tests/repos/lan_devices.test.js
git commit -m "feat(devices): lan_devices repo (upsert/absent/prune/promote)"

---

Task 4: Scan-cycle orchestration + cron wiring

Files:

• Create: lib/infra/scan_cycle.js

• Modify: lib/cron/index.js

• Test: tests/infra/scan_cycle.test.js

• Step 1: Write the failing test

// tests/infra/scan_cycle.test.js
import { describe, it, expect, vi } from 'vitest';
import { runDeviceScanCycle } from '../../lib/infra/scan_cycle.js';

function fakeRepo() {
  return {
    calls: [],
    upsertScan: vi.fn(async r => r.length),
    markAbsent: vi.fn(async () => 1),
    prune: vi.fn(async () => 2)
  };
}

describe('runDeviceScanCycle', () => {
  it('scan→upsert→markAbsent→prune on a non-empty scan', async () => {
    const repo = fakeRepo();
    const scan = vi.fn(async () => [{ mac: 'aa:bb:cc:dd:ee:ff', ip: '1.2.3.4', vendor: 'x', randomized: false }]);
    const res = await runDeviceScanCycle({ scan, repo });
    expect(repo.upsertScan).toHaveBeenCalledOnce();
    expect(repo.markAbsent).toHaveBeenCalledWith(['aa:bb:cc:dd:ee:ff']);
    expect(repo.prune).toHaveBeenCalledOnce();
    expect(res).toEqual({ seen: 1, pruned: 2 });
  });

  it('skips upsert/prune when the scan returns nothing', async () => {
    const repo = fakeRepo();
    const res = await runDeviceScanCycle({ scan: async () => [], repo });
    expect(repo.upsertScan).not.toHaveBeenCalled();
    expect(repo.prune).not.toHaveBeenCalled();
    expect(res).toEqual({ seen: 0 });
  });
});

• Step 2: Run it; verify it fails

Run: npm test -- tests/infra/scan_cycle.test.js Expected: FAIL — module not found.

• Step 3: Create lib/infra/scan_cycle.js

// One discovery cycle: scan → upsert → mark-absent → prune. Deps injected for
// tests. Prune only runs after a successful, non-empty scan, so a failed scan
// can never reap rows.
import { runScan } from './scan.js';
import * as devices from '../db/repos/lan_devices.js';
import { log } from '../log.js';

export async function runDeviceScanCycle({ scan = runScan, repo = devices } = {}) {
  const rows = await scan();
  if (!rows.length) {
    log.warn('device scan returned no hosts; skipping upsert/prune');
    return { seen: 0 };
  }
  await repo.upsertScan(rows);
  await repo.markAbsent(rows.map(r => r.mac));
  const pruned = await repo.prune();
  log.info({ seen: rows.length, pruned }, 'device scan cycle complete');
  return { seen: rows.length, pruned };
}

• Step 4: Run it; verify it passes

Run: npm test -- tests/infra/scan_cycle.test.js Expected: PASS (2 passed).

• Step 5: Wire the hourly cron

In lib/cron/index.js, add the import near the other imports:

import { runDeviceScanCycle } from '../infra/scan_cycle.js';

Then inside startCron(), before the final log.info('cron started'), add:

  // Hourly LAN device scan (staggered off the :00 speedtest)
  cron.schedule('7 * * * *', async () => {
    try { await runDeviceScanCycle(); }
    catch (e) { log.error({ err: e }, 'device scan cycle failed'); }
  });

• Step 6: Sanity-check + commit

Run: node --check lib/cron/index.js Expected: clean (exit 0).

git add lib/infra/scan_cycle.js lib/cron/index.js tests/infra/scan_cycle.test.js
git commit -m "feat(devices): hourly scan-cycle orchestration + cron"

---

Task 5: API route /api/devices

Files:

• Create: lib/api/routes/devices.js

• Modify: lib/api/index.js (import + mount)

• Test: tests/api/devices.test.js

• Step 1: Write the failing test

// tests/api/devices.test.js
import { describe, it, expect, beforeAll, beforeEach } from 'vitest';
import request from 'supertest';
import { createApp } from '../../server.js';
import { resetDb } from '../helpers/db.js';
import { migrateUp } from '../../lib/db/migrate.js';

let app;
const owner = r => r.set('Authorization', 'Bearer test-token');
beforeAll(async () => { process.env.OWNER_TOKEN = 'test-token'; app = createApp(); });
beforeEach(async () => { await resetDb(); await migrateUp(); });

describe('/api/devices', () => {
  it('GET / returns known devices grouped', async () => {
    const res = await request(app).get('/api/devices');
    expect(res.status).toBe(200);
    const names = res.body.groups.map(g => g.name);
    expect(names).toContain('Network');
    const net = res.body.groups.find(g => g.name === 'Network');
    expect(net.devices.some(d => d.name === 'Orbi Satellite')).toBe(true);
  });

  it('GET /discovered requires owner and lists new devices', async () => {
    expect((await request(app).get('/api/devices/discovered')).status).toBe(401);
    const res = await owner(request(app).get('/api/devices/discovered'));
    expect(res.status).toBe(200);
    expect(res.body.some(d => d.mac === '24:4b:fe:8e:09:a4')).toBe(true);
  });

  it('PATCH /:mac promotes + names (owner)', async () => {
    const res = await owner(request(app).patch('/api/devices/24:4b:fe:8e:09:a4'))
      .send({ name: 'ASUS Router', grp: 'Network', status: 'known' });
    expect(res.status).toBe(200);
    expect(res.body.name).toBe('ASUS Router');
    expect((await owner(request(app).get('/api/devices/discovered'))).body).toHaveLength(0);
  });

  it('PATCH rejects a bad MAC', async () => {
    expect((await owner(request(app).patch('/api/devices/not-a-mac')).send({ name: 'x' })).status).toBe(400);
  });
});

• Step 2: Run it; verify it fails

Run: npm test -- tests/api/devices.test.js Expected: FAIL — route not mounted (404s / module missing).

• Step 3: Create lib/api/routes/devices.js

import { Router } from 'express';
import { z } from 'zod';
import { asyncWrap } from '../errors.js';
import { requireOwner } from '../cap.js';
import { validate } from '../validate.js';
import * as devices from '../../db/repos/lan_devices.js';

export const router = Router();
const GROUP_ORDER = ['Smart Home', 'Entertainment', 'Personal', 'Network', 'Flagged'];

// GET /devices — known devices grouped for the band (open within the app, like /services).
router.get('/', asyncWrap(async (_req, res) => {
  const byGrp = new Map();
  for (const d of await devices.listKnown()) {
    const g = d.grp || 'Flagged';
    if (!byGrp.has(g)) byGrp.set(g, []);
    byGrp.get(g).push(d);
  }
  const order = [...GROUP_ORDER, ...[...byGrp.keys()].filter(g => !GROUP_ORDER.includes(g))];
  res.json({ groups: order.filter(g => byGrp.has(g)).map(name => ({ name, devices: byGrp.get(name) })) });
}));

// GET /devices/discovered — review queue (owner).
router.get('/discovered', requireOwner, asyncWrap(async (_req, res) => {
  res.json(await devices.listDiscovered());
}));

const macParam = z.object({ mac: z.string().regex(/^[0-9a-f]{2}(:[0-9a-f]{2}){5}$/i) });
const patchBody = z.object({
  name: z.string().max(120).optional(),
  grp: z.enum(['Smart Home', 'Entertainment', 'Personal', 'Network', 'Flagged']).optional(),
  status: z.enum(['new', 'known', 'ignored']).optional(),
  note: z.string().max(500).optional(),
  flagged: z.boolean().optional()
});

// PATCH /devices/:mac — name / edit / promote (owner). This is "add from discovered".
router.patch('/:mac', requireOwner, validate({ params: macParam, body: patchBody }), asyncWrap(async (req, res) => {
  const updated = await devices.update(req.params.mac.toLowerCase(), req.body);
  if (!updated) return res.status(404).json({ error: { code: 'not_found' } });
  res.json(updated);
}));

// DELETE /devices/:mac (owner).
router.delete('/:mac', requireOwner, validate({ params: macParam }), asyncWrap(async (req, res) => {
  if (!(await devices.remove(req.params.mac.toLowerCase()))) return res.status(404).json({ error: { code: 'not_found' } });
  res.status(204).end();
}));

// POST /devices/scan — run a scan now (owner).
router.post('/scan', requireOwner, asyncWrap(async (_req, res) => {
  const { runDeviceScanCycle } = await import('../../infra/scan_cycle.js');
  res.json(await runDeviceScanCycle());
}));

• Step 4: Mount it in lib/api/index.js

Add with the other route imports:

import { router as devicesRouter } from './routes/devices.js';

Add with the other api.use(...) mounts:

  api.use('/devices', devicesRouter);

• Step 5: Run it; verify it passes

Run: npm test -- tests/api/devices.test.js Expected: PASS (4 passed).

• Step 6: Commit

git add lib/api/routes/devices.js lib/api/index.js tests/api/devices.test.js
git commit -m "feat(devices): /api/devices band + discovered review/edit endpoints"

---

Task 6: Front-end — DB-backed band + discovered review/add/edit

Files:

• Modify: public/views/devices_band.js (rewrite the data source + add review panel)

• Modify: public/style.css (badges/panel styles)

• Test: tests/frontend/devices_band.test.js (create)

• Step 1: Write the failing test

// tests/frontend/devices_band.test.js
import { describe, it, expect, vi, beforeAll, afterAll } from 'vitest';
import { JSDOM } from 'jsdom';

vi.mock('../../public/api.js', () => ({
  api: {
    get: vi.fn(async (p) => {
      if (p === '/api/devices') return { groups: [ { name: 'Network', devices: [
        { mac: 'bc:a5:11:3e:06:88', ip: '192.168.1.13', name: 'Orbi Satellite', vendor: 'Netgear', randomized: false, present: true } ] } ] };
      if (p === '/api/devices/discovered') return [
        { mac: '24:4b:fe:8e:09:a4', ip: '192.168.1.15', vendor: 'ASUSTek', randomized: false, present: true } ];
      return {};
    }),
    patch: vi.fn(async () => ({}))
  }
}));

let renderDevicesBand;
beforeAll(async () => {
  const dom = new JSDOM('<!doctype html><html><body><div id="h"></div></body></html>', { url: 'http://localhost/' });
  global.window = dom.window; global.document = dom.window.document; global.Node = dom.window.Node;
  ({ renderDevicesBand } = await import('../../public/views/devices_band.js'));
});
afterAll(() => { delete global.window; delete global.document; delete global.Node; });

describe('devices band', () => {
  it('renders known devices from the API with MAC, and a discovered count', async () => {
    const host = document.getElementById('h');
    await renderDevicesBand(host);
    await new Promise(r => setTimeout(r, 0));
    expect(host.textContent).toContain('Orbi Satellite');
    expect(host.querySelector('.dv-mac').textContent).toBe('bc:a5:11:3e:06:88');
    expect(host.querySelector('.dv-discovered')).not.toBeNull();   // review affordance present
    expect(host.textContent).toMatch(/Discovered/i);
  });
});

• Step 2: Run it; verify it fails

Run: npm test -- tests/frontend/devices_band.test.js Expected: FAIL — band still fetches /devices.json (uses fetch, not api) and has no .dv-discovered.

• Step 3: Rewrite public/views/devices_band.js

// Network Devices band — DB-backed (GET /api/devices). Shows IP+MAC+vendor,
// a randomized-MAC badge, and an owner "Discovered" review panel to name/promote
// newly-seen devices. Kept SEPARATE from Little Blue's homelab-service band.
import { el, mount, clear } from '../dom.js';
import { api } from '../api.js';

let host;
const GROUPS = ['Smart Home', 'Entertainment', 'Personal', 'Network', 'Flagged'];

function tile(d) {
  return el('div', { class: 'dv-tile' + (d.flagged ? ' flag' : '') + (d.present === false ? ' absent' : '') },
    el('span', { class: 'dv-nm' }, d.name || 'Unknown'),
    el('span', { class: 'dv-ip' }, d.ip || ''),
    d.mac ? el('span', { class: 'dv-mac' }, d.mac) : null,
    el('span', { class: 'dv-vendor' },
      (d.vendor || '') + (d.randomized ? ' · randomized' : '') + (d.present === false ? ' · absent' : '')));
}

function discoveredRow(d, onDone) {
  const nameI = el('input', { class: 'dv-edit-name', placeholder: d.vendor || 'name', value: d.name || '' });
  const grpS = el('select', { class: 'dv-edit-grp' }, ...GROUPS.map(g => el('option', { value: g }, g)));
  const add = el('button', { class: 'dv-add' }, 'Add');
  add.onclick = async () => {
    await api.patch('/api/devices/' + d.mac, { name: nameI.value.trim() || null, grp: grpS.value, status: 'known', flagged: false });
    onDone();
  };
  const ignore = el('button', { class: 'ghost dv-ignore' }, 'Ignore');
  ignore.onclick = async () => { await api.patch('/api/devices/' + d.mac, { status: 'ignored' }); onDone(); };
  return el('div', { class: 'dv-disc-row' },
    el('span', { class: 'dv-ip' }, d.ip || ''),
    el('span', { class: 'dv-mac' }, d.mac + (d.randomized ? ' · randomized' : '')),
    el('span', { class: 'dv-vendor' }, d.vendor || ''),
    nameI, grpS, add, ignore);
}

async function load() {
  if (!host) return;
  let data, discovered = [];
  try { data = await api.get('/api/devices'); } catch { mount(host, el('div', { class: 'dv-note' }, 'Devices unavailable')); return; }
  try { discovered = await api.get('/api/devices/discovered'); } catch { /* owner-only; ignore for non-owner */ }

  const total = data.groups.reduce((n, g) => n + g.devices.length, 0);
  const sections = data.groups.map(g =>
    el('div', { class: 'dv-section' },
      el('div', { class: 'dv-group' },
        el('span', { class: 'gname' }, g.name),
        el('span', { class: 'gcount' }, String(g.devices.length)),
        el('span', { class: 'line' })),
      el('div', { class: 'dv-tiles' }, g.devices.map(tile))));

  const discPanel = discovered.length
    ? el('div', { class: 'dv-discovered' },
        el('div', { class: 'dv-disc-hd' }, `Discovered · ${discovered.length} awaiting review`),
        ...discovered.map(d => discoveredRow(d, load)))
    : null;

  clear(host);
  mount(host,
    el('div', { class: 'dv-hd' },
      el('div', { class: 'dv-title' }, 'Network · Devices'),
      el('span', { class: 'dv-count' }, `${total} known${discovered.length ? ` · ${discovered.length} new` : ''}`)),
    discPanel,
    ...sections);
}

export function renderDevicesBand(root) { host = root; return load(); }
export function stopDevicesBand() { host = null; }

• Step 4: Add styles in public/style.css

After the existing .dv-tile .dv-mac { … } line (added earlier), add:

.dv-tile.absent { opacity: .5; }
.dv-discovered { border: 1px solid var(--accent-dim); border-radius: 6px; padding: 10px 12px; margin: 10px 0; background: var(--accent-soft); }
.dv-disc-hd { font-family: var(--font-display); font-size: 12px; text-transform: uppercase; letter-spacing: .1em; color: var(--accent); margin-bottom: 8px; }
.dv-disc-row { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; padding: 5px 0; }
.dv-disc-row .dv-edit-name { flex: 1 1 120px; }
.dv-disc-row .dv-add { background: var(--accent-dim); color: var(--text); border: 1px solid var(--accent); border-radius: 3px; padding: 4px 10px; cursor: pointer; font-family: var(--font-ui); font-size: 12px; }
.dv-disc-row .dv-add:hover { background: var(--accent); color: var(--bg); }
.dv-disc-row .ghost { background: transparent; color: var(--muted); border: 1px solid var(--border); border-radius: 3px; padding: 4px 10px; cursor: pointer; font-size: 12px; }

• Step 5: Run it; verify it passes

Run: npm test -- tests/frontend/devices_band.test.js Expected: PASS.

• Step 6: Commit

git add public/views/devices_band.js public/style.css tests/frontend/devices_band.test.js
git commit -m "feat(devices): DB-backed devices band + discovered review/add/edit UI"

---

Task 7: Retire devices.json, version bump, CHANGELOG

Files:

• Delete: public/devices.json

• Modify: package.json, server.js, CHANGELOG.md

• Step 1: Remove the static file

git rm public/devices.json

• Step 2: Bump version to 2.1.0

• package.json: "version": "2.1.0"

• server.js: const VERSION = '2.1.0';

• Step 3: CHANGELOG entry

Prepend under the Format: line in CHANGELOG.md:

## 2.1.0 — LAN device discovery
- **`lan_devices` store + hourly `arp-scan`** (`migration 024`, `lib/infra/scan.js`,
  `lib/db/repos/lan_devices.js`, `lib/cron`): the Devices band is now DB-backed and
  self-updating. New MACs land in a **Discovered** review queue; the owner names/
  groups/promotes them (`/api/devices`). Devices are keyed by MAC (IP is mutable);
  unreviewed + absent rows auto-prune (randomized >24h, others >14d) so randomized
  MACs can't bloat the table. Replaces the static `public/devices.json` (now seeded
  into the table by the migration).

• Step 4: Run the full suite

Run: npm test Expected: all green (existing + the new device tests).

• Step 5: Commit

git add -A
git commit -m "chore(release): 2.1.0 — LAN device discovery; retire static devices.json"

---

Task 8: Infra setup + deploy

Files: none in-repo beyond deploy/README.md. Live infra on CT 311 (void-app, 192.168.1.216).

• Step 1: Install arp-scan + grant raw-socket capability (so the void user can scan)

ssh root@192.168.1.216 "apt-get update -qq && apt-get install -y arp-scan && \
  setcap cap_net_raw,cap_net_admin+eip \$(readlink -f \$(command -v arp-scan)) && \
  echo '--- verify as void user ---' && sudo -u void arp-scan --localnet --plain --retry=2 | head -5"

Expected: a few IP<tab>MAC<tab>vendor lines printed as the void user (proves the capability works without root).

• Step 2: Document it in deploy/README.md

Append a short "LAN device scan" section noting the apt install arp-scan + setcap cap_net_raw,cap_net_admin+eip /usr/sbin/arp-scan requirement (re-apply after an arp-scan package upgrade), then:

git add deploy/README.md && git commit -m "docs(deploy): arp-scan + setcap for device discovery"

• Step 3: Snapshot + deploy

ssh root@192.168.1.124 "pct snapshot 311 pre_2_1_0 --description 'before LAN device discovery'"
cd /project/src/void-v2 && ./deploy/push.sh

Expected: Deployed 2.1.0 — healthy. ✓ (migration 024 runs as part of deploy).

• Step 4: Trigger a scan and verify

TOK=$(ssh root@192.168.1.216 "grep -m1 '^OWNER_TOKEN=' /opt/void-server/.env | cut -d= -f2- | tr -d '\"'")
curl -s -X POST -H "Authorization: Bearer $TOK" http://192.168.1.216:3000/api/devices/scan
curl -s http://192.168.1.216:3000/api/devices | python3 -c "import sys,json;d=json.load(sys.stdin);print('groups:',[g['name'] for g in d['groups']])"
curl -s -H "Authorization: Bearer $TOK" http://192.168.1.216:3000/api/devices/discovered | python3 -c "import sys,json;print('discovered:',len(json.load(sys.stdin)))"

Expected: scan returns {"seen":N,...}; band shows the seeded groups; discovered count ≥ 0 (new MACs found on the live LAN beyond the seed appear here).

• Step 5: Browser check (webapp-testing)

Open void.hynesy.com, find the Devices band (Sacred Valley): confirm devices show IP+MAC, randomized devices show the badge, and the Discovered panel lets you name + Add a device (it then moves into a group).

---

Self-review notes

• Spec coverage: MAC-keyed store + seed (T2,T3) · decoupled arp-scan + randomized flag (T1) · hourly cron scan→upsert→mark-absent→prune (T4) · discovered/review/name/edit/promote API (T5) + UI (T6) · prune/retention for randomized bloat (T3 prune, T4 wiring) · DB-backed band replacing devices.json (T6,T7) · setcap/arp-scan infra (T8). All spec sections map to a task.
• Type/name consistency: lan_devices columns (mac,ip,vendor,name,grp,note,status,randomized,flagged,first_seen,last_seen,present) are identical across migration (T2), repo (T3), API (T5), and UI (T6). Repo methods upsertScan/markAbsent/prune/listKnown/listDiscovered/get/update/remove match their callers in scan_cycle.js (T4) and the route (T5). runScan({exec}) / runDeviceScanCycle({scan,repo}) injection shapes match their tests.
• Out of scope (not planned, per spec): port/service fingerprinting, SNMP/LLDP, multi-VLAN, push notifications, stable identity across MAC rotations.