diff --git a/CLAUDE.md b/CLAUDE.md
index 572c2c3..e18e45f 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -52,6 +52,7 @@ title-bar controls). The rules that matter most:
   `node tools/slack-mock.js 24716` (Slack; run ProdDash with `SLACK_API_BASE=http://127.0.0.1:24716/api`).
   `node tools/pco-band-mock.js 24710` (Planning Center for Band Lineup; run ProdDash with `BAND_LINEUP_API_BASE=http://127.0.0.1:24710`).
   `node tools/ableset-mock.js 39071` (AbleSet over OSC/UDP; point the AbleSet module at `127.0.0.1:39071`; `--stopped`, `--no-live`, `--speed 4`).
+  `node tools/overflow-tap-mock.js` (ProPresenter slide notes on `127.0.0.1:1602` + the Overflow Dashboard API on `127.0.0.1:24720`; run ProdDash with `OVERFLOW_TAP_API_BASE=http://127.0.0.1:24720`, any email/password signs in; `--fail-switch`, `--expire=20`, `--login=<email>:<password>`).
 
 ## Reference code (read-only forks — don't develop these here)
 
diff --git a/README.md b/README.md
index 2fe2a0f..b93d5c9 100644
--- a/README.md
+++ b/README.md
@@ -510,6 +510,27 @@ below. Nothing is installed without someone clicking.
   read from the account), and a folded **Timing** group for the poll
   intervals and a position trim.
   Tile settings: cue name, previous cue, playhead, cue list.
+- **Overflow Tap** — what Overflow's own "ProPresenter Integration" helper
+  app does, inside ProdDash, speaking the same Dashboard API it does: the
+  live slide's notes are read from ProPresenter (the presentation layer and
+  the announcement layer), and when they carry one of the keywords mapped in
+  the Overflow Dashboard, Overflow is told — and points that keyword's Tap
+  groups at its destination, so a tap on a disc follows what is on screen.
+  A slide with no keyword changes nothing. Keywords match as the helper
+  matches them: as a whole word of the notes, any case, punctuation around
+  it ignored (`give` fires on "Give!" and not on "forgiveness"). The tile is
+  one keyword, big: what Tap is on (and since when), its destination and the
+  groups moved, a chip saying whether the slide on screen carries a keyword,
+  and the last four switches with their times; a failed switch turns the
+  tile red with the reason, is retried, and — if switched on in admin —
+  flashes an alert channel. Admin config: the ProPresenter endpoint and an
+  **Overflow Dashboard login** (email and password; Google sign-in has no
+  password, so set one with "Forgot Your Password?"). The keywords, their
+  destinations and their Tap groups stay where Overflow keeps them —
+  Integrations › ProPresenter › Keyword Mappings in the Dashboard — and are
+  read from there on start, every few minutes, and on the tile's refresh
+  button. Tile settings are four switches: destination, groups, slide
+  match, history.
 - **Band Lineup** — the backstage stage board: everyone on stage in their mic
   slot with photo, name and mic/pack label, on one shared board that every
   screen sees the same way — whoever edits it changes it everywhere, over SSE.
@@ -560,8 +581,15 @@ timers + timecode on `127.0.0.1:1600`), `node tools/pco-mock.js`
 run ProdDash with `SLACK_API_BASE=http://127.0.0.1:24716/api`) and
 `node tools/pco-band-mock.js 24710` (Planning Center for the Band Lineup
 board — a plan, its team members, birthdays and photos — run ProdDash with
-`BAND_LINEUP_API_BASE=http://127.0.0.1:24710`). See the testing section of
-the [module guide](docs/MODULE-GUIDE.md).
+`BAND_LINEUP_API_BASE=http://127.0.0.1:24710`) and
+`node tools/overflow-tap-mock.js` (a ProPresenter whose slide notes carry
+keywords on `127.0.0.1:1602`, announcement layer included, plus the Overflow
+Dashboard API on `127.0.0.1:24720` — run ProdDash with
+`OVERFLOW_TAP_API_BASE=http://127.0.0.1:24720` and sign the module in with
+any email and password; `--fail-switch` refuses every switch,
+`--expire=20` makes sessions expire, `--login=<email>:<password>` accepts
+one login only). See the testing section of the
+[module guide](docs/MODULE-GUIDE.md).
 
 ## Install as a desktop web app
 
diff --git a/modules/overflow-tap/client.js b/modules/overflow-tap/client.js
new file mode 100644
index 0000000..dee1221
--- /dev/null
+++ b/modules/overflow-tap/client.js
@@ -0,0 +1,233 @@
+/* Overflow Tap — the tile.
+ *
+ * One fact matters across a booth: which keyword Tap is on right now, and
+ * whether the switch actually landed. That is the big line. Under it, the
+ * destination it maps to and the groups it moved; a small line says whether
+ * the slide on screen carries a keyword at all; and the last four switches
+ * sit at the bottom with their times, so a tech can see the service's trail.
+ *
+ * Everything comes from the server's `state` stream. The tile never talks to
+ * ProPresenter or Overflow itself.
+ */
+
+const HISTORY_SHOWN = 4;
+
+const ICON_REFRESH = '<svg viewBox="0 0 16 16" width="13" height="13" fill="none" stroke="currentColor" stroke-width="1.6" stroke-linecap="round" stroke-linejoin="round"><path d="M13.5 8a5.5 5.5 0 1 1-1.6-3.9"/><path d="M13.5 2.5v3h-3"/></svg>';
+
+export default function create({ root, moduleApi }) {
+  let state = null;
+  let stream = null;
+  let refreshBtn = null;
+  let streamDown = false; // the shared ProdDash stream dropped; cleared by the next state
+
+  const settings = () => moduleApi.instanceSettings || {};
+  const on = (key) => settings()[key] !== false;
+
+  function el(tag, className, text) {
+    const node = document.createElement(tag);
+    if (className) node.className = className;
+    if (text !== undefined && text !== null) node.textContent = text;
+    return node;
+  }
+
+  function clock(ms) {
+    if (!ms) return '';
+    try {
+      return new Date(ms).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit', second: '2-digit' });
+    } catch {
+      return '';
+    }
+  }
+
+  /** The one-line reason the tile cannot do its job, or '' when it can. */
+  function blocker() {
+    if (!state) return 'Waiting for ProdDash';
+    const pp = state.propresenter || {};
+    const of = state.overflow || {};
+    if (!pp.configured) return 'No ProPresenter host — set one in /admin';
+    if (!of.configured) return 'No Overflow login — add it in /admin';
+    if (of.reachable && !(state.keywords || []).length) return 'No keyword mappings in the Overflow Dashboard yet';
+    return '';
+  }
+
+  function render() {
+    root.textContent = '';
+    const box = el('div', 'ot-root');
+    root.append(box);
+
+    const stop = blocker();
+    if (stop) {
+      box.append(el('div', 'ot-empty', stop));
+      return;
+    }
+
+    const pp = state.propresenter || {};
+    const of = state.overflow || {};
+    const cur = state.current;
+    const offline = streamDown || !pp.reachable || !of.reachable;
+
+    if (offline) {
+      box.classList.add('is-offline');
+      const why = streamDown ? 'ProdDash connection lost'
+        : !of.reachable ? (of.error || 'Overflow unreachable')
+          : (pp.error ? `ProPresenter unreachable — ${pp.error}` : 'ProPresenter unreachable');
+      box.append(el('div', 'ot-offline', why));
+    }
+
+    const main = el('div', 'ot-main');
+    if (cur) {
+      // The label carries the state and, when there is one, the moment it
+      // became true; the small lines under the destination are the groups
+      // moved — or, when the switch failed, what went wrong, in their place
+      // (a tile has room for one or the other).
+      let label = `TAP IS ON · since ${clock(cur.at)}`;
+      let tone = 'ok';
+      let note = '';
+      if (cur.pending) {
+        label = cur.attempts > 1 ? `SWITCHING · attempt ${cur.attempts}` : 'SWITCHING';
+        tone = 'muted';
+      } else if (!cur.ok) {
+        label = `NOT SWITCHED · ${clock(cur.at)}`;
+        tone = 'alert';
+        note = cur.error || '';
+      }
+      main.dataset.tone = tone;
+      main.append(el('div', 'ot-label', label));
+      main.append(el('div', 'ot-keyword', cur.keyword));
+      if (on('showDestination')) main.append(el('div', 'ot-dest', cur.destination || ''));
+      if (note) main.append(el('div', 'ot-error', note));
+      else if (on('showGroups') && cur.groups && cur.groups.length) main.append(el('div', 'ot-groups', cur.groups.join(' · ')));
+    } else {
+      main.dataset.tone = 'muted';
+      main.append(el('div', 'ot-label', 'NO KEYWORD YET'));
+      main.append(el('div', 'ot-keyword is-none', '—'));
+      main.append(el('div', 'ot-dest', 'Tap stays where Overflow left it'));
+    }
+    box.append(main);
+
+    if (on('showSlide')) {
+      const slide = state.slide || {};
+      const ann = state.announcement || {};
+      const slideKeys = Array.isArray(slide.keywords) ? slide.keywords : [];
+      const annKeys = Array.isArray(ann.keywords) ? ann.keywords : [];
+      let text;
+      let cls = 'ot-slide';
+      if (!pp.reachable) { text = 'ProPresenter: not answering'; cls += ' is-muted'; }
+      else if (!slide.live && !ann.live) { text = 'Nothing live in ProPresenter'; cls += ' is-muted'; }
+      else if (slideKeys.length || annKeys.length) {
+        const parts = [];
+        if (slideKeys.length) parts.push(`This slide: ${slideKeys.join(' + ')}`);
+        if (annKeys.length) parts.push(`Announcement: ${annKeys.join(' + ')}`);
+        text = parts.join(' · ');
+        cls += ' is-hit';
+      } else if (slide.live) { text = slide.hasNotes ? 'This slide: no keyword' : 'This slide: no notes'; cls += ' is-muted'; }
+      else { text = 'Announcement: no keyword'; cls += ' is-muted'; }
+      box.append(el('div', cls, text));
+    }
+
+    if (on('showHistory')) {
+      const rows = (state.history || []).slice(0, HISTORY_SHOWN);
+      const list = el('ol', 'ot-history');
+      if (!rows.length) {
+        list.append(el('li', 'ot-h-empty', cur ? 'No earlier switches' : 'No switches yet'));
+      }
+      for (const h of rows) {
+        const row = el('li', `ot-h-row${h.ok ? '' : ' is-failed'}`);
+        row.title = h.ok
+          ? `${h.keyword} → ${h.destination || ''}${h.groups && h.groups.length ? ` on ${h.groups.join(', ')}` : ''}`
+          : `${h.keyword}: ${h.error || 'failed'}`;
+        row.append(el('span', 'ot-h-time', clock(h.at)));
+        row.append(el('span', 'ot-h-kw', h.keyword));
+        row.append(el('span', 'ot-h-dest', h.destination || ''));
+        row.append(el('span', 'ot-h-mark', h.ok ? '✓' : '✕'));
+        list.append(row);
+      }
+      box.append(list);
+    }
+  }
+
+  function applyStatus() {
+    if (!state) return moduleApi.setStatus('connecting', 'Waiting for ProdDash');
+    const s = state.status === 'ok' || state.status === 'connecting' || state.status === 'error' ? state.status : 'connecting';
+    moduleApi.setStatus(s, state.message || '');
+  }
+
+  function handleState(e) {
+    try {
+      state = JSON.parse(e.data);
+    } catch {
+      return;
+    }
+    streamDown = false;
+    applyStatus();
+    render();
+  }
+
+  async function backfill() {
+    try {
+      const res = await moduleApi.fetch('/state');
+      if (!res.ok) return;
+      const body = await res.json();
+      if (!body || !body.state || !stream) return;
+      state = body.state;
+      streamDown = false;
+      applyStatus();
+      render();
+    } catch {
+      /* the stream will bring the next state */
+    }
+  }
+
+  async function refresh() {
+    if (!refreshBtn) return;
+    refreshBtn.classList.add('active');
+    try {
+      const res = await moduleApi.fetch('/refresh', { method: 'POST' });
+      if (!res.ok) {
+        let why = `Keyword refresh failed (${res.status})`;
+        try { why = (await res.json()).error || why; } catch { /* keep the status */ }
+        moduleApi.setStatus('error', why);
+      }
+    } catch (err) {
+      moduleApi.setStatus('error', `Keyword refresh failed: ${err && err.message ? err.message : err}`);
+    } finally {
+      refreshBtn.classList.remove('active');
+    }
+  }
+
+  return {
+    start() {
+      moduleApi.setStatus('connecting', 'Connecting');
+      refreshBtn = moduleApi.header.addButton({
+        icon: ICON_REFRESH,
+        title: 'Refresh keywords',
+        onClick: refresh,
+      });
+      stream = moduleApi.sse('/stream', {
+        // A fresh connection replays the state; a tile joining a stream the
+        // page already carries gets only `open`, and the server sends state
+        // on change alone — so backfill, or a second tile waits for the next
+        // switch to draw anything.
+        open() { backfill(); },
+        error() {
+          moduleApi.setStatus('error', 'Lost the connection to ProdDash');
+          streamDown = true;
+          render();
+        },
+        events: { state: handleState },
+      });
+      render();
+    },
+
+    stop() {
+      if (stream) stream.close();
+      stream = null;
+      refreshBtn = null;
+      root.textContent = '';
+    },
+
+    onConfigChange() {
+      render();
+    },
+  };
+}
diff --git a/modules/overflow-tap/keywords.js b/modules/overflow-tap/keywords.js
new file mode 100644
index 0000000..a9a8c49
--- /dev/null
+++ b/modules/overflow-tap/keywords.js
@@ -0,0 +1,66 @@
+'use strict';
+
+/**
+ * Keyword matching — which of Overflow's keywords a slide's notes carry.
+ *
+ * Pure functions, no I/O, so keywords.selftest.js can pin every rule down:
+ *
+ *   cleanNotes(raw)                 → the notes with ProPresenter's invisible padding removed
+ *   keywordMatches(notes, keyword)  → boolean
+ *   matchKeywords(notes, keywords)  → every keyword (in the order given) the notes carry
+ *   sameSet(a, b)                   → the two keyword lists hold the same keywords
+ *
+ * The rule is Overflow's own helper's: the notes are split into whitespace-
+ * separated words, each stripped of surrounding punctuation and lower-cased,
+ * and a keyword fires when it is one of those words. So `give` fires on
+ * "give", "Give!", "#give" and "(give)", and not on "forgiveness", "giveaway"
+ * or "give_now". Phrases work too, bounded the same way on both ends —
+ * something the helper cannot do, but nothing it would have matched is lost.
+ */
+
+const ZERO_WIDTH = /[​-‍⁠]/g;
+
+function cleanNotes(raw) {
+  return String(raw ?? '').replace(ZERO_WIDTH, '').replace(/\r\n?/g, '\n');
+}
+
+function norm(s) {
+  return String(s ?? '').trim().toLowerCase().replace(/\s+/g, ' ');
+}
+
+function escapeRe(s) {
+  return s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+}
+
+function keywordMatches(notes, keyword) {
+  const n = cleanNotes(notes);
+  const k = norm(keyword);
+  if (!k || !n.trim()) return false;
+  const flat = n.toLowerCase().replace(/\s+/g, ' ');
+  const re = new RegExp(`(?:^|[^\\p{L}\\p{N}_])${escapeRe(k)}(?=$|[^\\p{L}\\p{N}_])`, 'u');
+  return re.test(flat);
+}
+
+/** Every keyword the notes carry, in the order the list gives them, each once. Entries may be strings or objects with a `keyword`. */
+function matchKeywords(notes, keywords) {
+  const out = [];
+  const seen = new Set();
+  for (const raw of keywords || []) {
+    const k = typeof raw === 'string' ? raw : raw && raw.keyword;
+    const key = norm(k);
+    if (!key || seen.has(key)) continue;
+    if (keywordMatches(notes, k)) {
+      seen.add(key);
+      out.push(String(k).trim());
+    }
+  }
+  return out;
+}
+
+function sameSet(a, b) {
+  const x = [...(a || [])].map(norm).sort();
+  const y = [...(b || [])].map(norm).sort();
+  return x.length === y.length && x.every((v, i) => v === y[i]);
+}
+
+module.exports = { cleanNotes, norm, keywordMatches, matchKeywords, sameSet };
diff --git a/modules/overflow-tap/keywords.selftest.js b/modules/overflow-tap/keywords.selftest.js
new file mode 100644
index 0000000..4c71352
--- /dev/null
+++ b/modules/overflow-tap/keywords.selftest.js
@@ -0,0 +1,76 @@
+'use strict';
+
+/**
+ * Self-test for keywords.js — the matching rules, pinned.
+ *
+ *   node modules/overflow-tap/keywords.selftest.js
+ */
+
+const assert = require('node:assert/strict');
+const { keywordMatches, matchKeywords, sameSet, cleanNotes } = require('./keywords');
+
+let n = 0;
+function test(name, fn) {
+  n += 1;
+  try {
+    fn();
+    console.log(`ok   ${name}`);
+  } catch (err) {
+    console.log(`FAIL ${name}\n     ${err.message}`);
+    process.exitCode = 1;
+  }
+}
+
+test('a keyword fires as a word of the notes, whatever the case', () => {
+  assert.equal(keywordMatches('give', 'give'), true);
+  assert.equal(keywordMatches('Give', 'give'), true);
+  assert.equal(keywordMatches('please GIVE today', 'give'), true);
+});
+
+test('surrounding punctuation is ignored, as the helper strips it', () => {
+  assert.equal(keywordMatches('give!', 'give'), true);
+  assert.equal(keywordMatches('#give now', 'give'), true);
+  assert.equal(keywordMatches('go to (give) now', 'give'), true);
+  assert.equal(keywordMatches('"give"', 'give'), true);
+  assert.equal(keywordMatches('give.', 'give'), true);
+});
+
+test('a keyword inside another word does not fire', () => {
+  assert.equal(keywordMatches('a sermon on forgiveness', 'give'), false);
+  assert.equal(keywordMatches('giveaway', 'give'), false);
+  assert.equal(keywordMatches('give_now', 'give'), false);
+});
+
+test('a phrase keyword is bounded the same way', () => {
+  assert.equal(keywordMatches('Please fill out your Next   Steps card', 'next steps'), true);
+  assert.equal(keywordMatches('nextsteps', 'next steps'), false);
+});
+
+test('regex characters in a keyword are literal', () => {
+  assert.equal(keywordMatches('give.now', 'give.now'), true);
+  assert.equal(keywordMatches('giveXnow', 'give.now'), false);
+});
+
+test('empty notes never match; zero-width padding is ignored', () => {
+  assert.equal(keywordMatches('', 'give'), false);
+  assert.equal(keywordMatches('​', 'give'), false);
+  assert.equal(cleanNotes('​give'), 'give');
+  assert.equal(keywordMatches('​give', 'give'), true);
+});
+
+test('matchKeywords returns every hit, in list order, once each', () => {
+  const list = ['connect', 'give', 'prayer', { keyword: 'Events' }];
+  assert.deepEqual(matchKeywords('give and connect, then events', list), ['connect', 'give', 'Events']);
+  assert.deepEqual(matchKeywords('just worship', list), []);
+  assert.deepEqual(matchKeywords('give', []), []);
+  assert.deepEqual(matchKeywords('give give', ['give', 'GIVE']), ['give']);
+});
+
+test('sameSet compares keyword lists regardless of order and case', () => {
+  assert.equal(sameSet(['give', 'connect'], ['Connect', 'give']), true);
+  assert.equal(sameSet(['give'], ['give', 'connect']), false);
+  assert.equal(sameSet([], []), true);
+  assert.equal(sameSet(['give'], []), false);
+});
+
+console.log(`${n} tests, exit ${process.exitCode || 0}`);
diff --git a/modules/overflow-tap/module.json b/modules/overflow-tap/module.json
new file mode 100644
index 0000000..2c2ff78
--- /dev/null
+++ b/modules/overflow-tap/module.json
@@ -0,0 +1,112 @@
+{
+  "id": "overflow-tap",
+  "name": "Overflow Tap",
+  "version": "1.0.0",
+  "proddash": ">=1.11.0",
+  "description": "Switches Overflow Tap destinations from keywords in ProPresenter slide notes",
+  "permissions": [
+    {
+      "kind": "local-network",
+      "reason": "Reaching ProPresenter on this network"
+    }
+  ],
+  "client": "client.js",
+  "server": "server.js",
+  "style": "style.css",
+  "minSize": {
+    "w": 2,
+    "h": 2
+  },
+  "defaultSize": {
+    "w": 4,
+    "h": 3
+  },
+  "configGroups": {
+    "ProPresenter": {
+      "help": "The ProPresenter whose slide notes carry the keywords. Enable the network in ProPresenter's Preferences › Network and enter the host and port shown there. Only the live slide's notes (and the announcement layer's) are read — nothing on the stage screens changes."
+    },
+    "Overflow": {
+      "collapsed": "whenSet",
+      "help": "An Overflow Dashboard login with Tap access — what Overflow's own ProPresenter helper app signs in with. Google sign-in does not work here: the account needs a password (Forgot Your Password? on the Dashboard sets one). The keywords, their destinations and their Tap groups are managed in the Dashboard under Integrations › ProPresenter › Keyword Mappings and read from there; after changing them, press the tile's refresh button or wait a few minutes."
+    },
+    "Alerts": {
+      "toggle": "alertEnabled",
+      "collapsed": true,
+      "help": "Flash the dashboards listening on this channel when a switch fails — Overflow unreachable or refusing the change — so someone can fix Tap by hand before the moment passes."
+    }
+  },
+  "configSchema": {
+    "propresenter": {
+      "type": "endpoint",
+      "label": "ProPresenter",
+      "group": "ProPresenter",
+      "default": {
+        "host": "",
+        "port": 1025
+      }
+    },
+    "password": {
+      "type": "password",
+      "label": "API password",
+      "group": "ProPresenter",
+      "default": "",
+      "help": "Only if a password is set in ProPresenter's network preferences."
+    },
+    "overflowEmail": {
+      "type": "string",
+      "label": "Email",
+      "group": "Overflow",
+      "default": ""
+    },
+    "overflowPassword": {
+      "type": "password",
+      "label": "Password",
+      "group": "Overflow",
+      "default": ""
+    },
+    "nonprofitId": {
+      "type": "string",
+      "label": "Nonprofit ID",
+      "group": "Overflow",
+      "default": "",
+      "help": "Leave blank: a church login carries its own. Only an @overflow.co staff login needs one."
+    },
+    "alertEnabled": {
+      "type": "switch",
+      "label": "Alert when a switch fails",
+      "group": "Alerts",
+      "default": false
+    },
+    "alertChannel": {
+      "type": "number",
+      "label": "Channel",
+      "group": "Alerts",
+      "default": 1,
+      "min": 1,
+      "max": 6,
+      "help": "1–6; each dashboard chooses the channels it listens to in its Layouts menu."
+    }
+  },
+  "instanceSchema": {
+    "showDestination": {
+      "type": "switch",
+      "label": "Destination",
+      "default": true
+    },
+    "showGroups": {
+      "type": "switch",
+      "label": "Groups",
+      "default": true
+    },
+    "showSlide": {
+      "type": "switch",
+      "label": "Slide match",
+      "default": true
+    },
+    "showHistory": {
+      "type": "switch",
+      "label": "History",
+      "default": true
+    }
+  }
+}
diff --git a/modules/overflow-tap/overflow.js b/modules/overflow-tap/overflow.js
new file mode 100644
index 0000000..d2eb9e3
--- /dev/null
+++ b/modules/overflow-tap/overflow.js
@@ -0,0 +1,174 @@
+'use strict';
+
+/**
+ * Overflow Dashboard API — the calls Overflow's own "ProPresenter Integration"
+ * helper app (1.2.3) makes, read from its bundle on 2026-10-11. None of this is
+ * in Overflow's public API reference (which documents only reads for Tap): it
+ * is the Dashboard's own backend, used with a Dashboard login — the same
+ * email and password the helper asks for. Google sign-in does not work here;
+ * the account needs a password (Overflow's article says the same).
+ *
+ *   POST /nonprofit-dashboard/authentication/login/jwt
+ *          { email, password } → { token }      a JWT; its payload carries
+ *          email, nonprofitId, permissions [{ action, subject }] (subject TAP
+ *          or all is required), nonprofits [...], exp
+ *   GET  /nonprofit-dashboard/propresenter/nonprofits/{nonprofitId}/keywords
+ *          → [ { keyword, destinationName, tapGroups: [{ id, tapGroupName }], … } ]
+ *          the Dashboard's Integrations › ProPresenter › Keyword Mappings
+ *   POST /nonprofit-dashboard/propresenter/nonprofits/{nonprofitId}/keywords?syncNonprofit=true
+ *          { keywords: ["give"] } → the same list, updated      THE SWITCH:
+ *          Overflow points the keyword's groups at its destination
+ *   GET  /nonprofit-dashboard/propresenter/nonprofits?search=&limit=
+ *   POST /nonprofit-dashboard/propresenter/nonprofits/{nonprofitId}/select
+ *          only for an @overflow.co staff login, which has no nonprofit of its
+ *          own and must pick one first
+ *
+ * Bearer auth on everything after login. A 401 means the session is gone —
+ * sign in again. The helper's own wording for a refused login is kept here
+ * (401 invalid email or password, 429 too many attempts, 403 locked).
+ *
+ * OVERFLOW_TAP_API_BASE=http://127.0.0.1:24720 points the client at
+ * tools/overflow-tap-mock.js.
+ */
+
+const DEFAULT_API_BASE = 'https://server.overflow.co';
+const API_BASE = String(process.env.OVERFLOW_TAP_API_BASE || DEFAULT_API_BASE).replace(/\/+$/, '');
+const DASH = '/nonprofit-dashboard';
+const TIMEOUT_MS = 10000;
+const TRIGGER_TIMEOUT_MS = 15000;
+
+class OverflowError extends Error {
+  constructor(message, { status = 0, retryable = false, auth = false } = {}) {
+    super(message);
+    this.name = 'OverflowError';
+    this.status = status;
+    this.retryable = retryable;
+    this.auth = auth; // the session was refused: sign in again before retrying
+  }
+}
+
+/** The JWT's payload, or null when the token is not one. No signature check — we only read our own session. */
+function decodeJwt(token) {
+  const parts = String(token || '').split('.');
+  if (parts.length !== 3) return null;
+  try {
+    const b64 = parts[1].replace(/-/g, '+').replace(/_/g, '/');
+    return JSON.parse(Buffer.from(b64, 'base64').toString('utf8'));
+  } catch {
+    return null;
+  }
+}
+
+/** What the module needs to know about a session, from its token. */
+function describeSession(token) {
+  const p = decodeJwt(token) || {};
+  const email = String(p.email || '');
+  const perms = Array.isArray(p.permissions) ? p.permissions : [];
+  const nonprofits = Array.isArray(p.nonprofits)
+    ? p.nonprofits.map((n) => ({ id: String((n && n.id) || ''), name: String((n && n.name) || '') })).filter((n) => n.id)
+    : [];
+  return {
+    email,
+    staff: email.toLowerCase().endsWith('@overflow.co'),
+    nonprofitId: p.nonprofitId ? String(p.nonprofitId) : '',
+    nonprofits,
+    hasTap: perms.some((x) => x && (x.subject === 'TAP' || x.subject === 'all')),
+    expiresAt: Number.isFinite(Number(p.exp)) ? Number(p.exp) * 1000 : 0,
+  };
+}
+
+function createOverflowClient({ fetchImpl = globalThis.fetch } = {}) {
+  async function request(method, path, { query, body, token, timeout = TIMEOUT_MS } = {}) {
+    const url = new URL(API_BASE + path);
+    for (const [k, v] of Object.entries(query || {})) {
+      if (v === undefined || v === null || v === '') continue;
+      url.searchParams.set(k, String(v));
+    }
+    const headers = { Accept: 'application/json' };
+    if (token) headers.Authorization = `Bearer ${token}`;
+    if (body !== undefined) headers['Content-Type'] = 'application/json';
+    const ctl = new AbortController();
+    const timer = setTimeout(() => ctl.abort(), timeout);
+    let res;
+    try {
+      res = await fetchImpl(url, { method, headers, body: body === undefined ? undefined : JSON.stringify(body), signal: ctl.signal });
+    } catch (err) {
+      const aborted = err && err.name === 'AbortError';
+      const cause = err && err.cause && (err.cause.code || err.cause.message);
+      throw new OverflowError(
+        aborted ? `Overflow did not answer within ${timeout / 1000} s` : `Overflow unreachable: ${err.message}${cause ? ` (${cause})` : ''}`,
+        { retryable: true },
+      );
+    } finally {
+      clearTimeout(timer);
+    }
+    const text = await res.text();
+    let data = null;
+    if (text) {
+      try { data = JSON.parse(text); } catch { data = null; }
+    }
+    if (!res.ok) {
+      const detail = data && (data.message || data.error || data.detail);
+      const what = Array.isArray(detail) ? detail.join('; ') : (detail ? String(detail) : '');
+      throw new OverflowError(what ? `Overflow answered ${res.status}: ${what}` : `Overflow answered ${res.status} ${res.statusText}`.trim(), {
+        status: res.status,
+        auth: res.status === 401,
+        retryable: res.status === 429 || res.status >= 500,
+      });
+    }
+    return data;
+  }
+
+  return {
+    base: API_BASE,
+
+    /** Sign in with a Dashboard login; resolves to the JWT. */
+    async login(email, password) {
+      try {
+        const data = await request('POST', `${DASH}/authentication/login/jwt`, { body: { email, password } });
+        const token = data && data.token;
+        if (!token || typeof token !== 'string') throw new OverflowError('Overflow sign-in answered without a token');
+        return token;
+      } catch (err) {
+        if (!(err instanceof OverflowError) || !err.status) throw err;
+        if (err.status === 401) throw new OverflowError('Overflow refused the sign-in: invalid email or password', { status: 401 });
+        if (err.status === 429) throw new OverflowError('Overflow refused the sign-in: too many attempts — wait a while', { status: 429, retryable: true });
+        if (err.status === 403) throw new OverflowError('Overflow refused the sign-in: account locked', { status: 403 });
+        throw err;
+      }
+    },
+
+    /** The Keyword Mappings for a nonprofit, as the Dashboard holds them. */
+    async listKeywords(token, nonprofitId) {
+      const data = await request('GET', `${DASH}/propresenter/nonprofits/${encodeURIComponent(nonprofitId)}/keywords`, { token });
+      return Array.isArray(data) ? data : [];
+    },
+
+    /** Tell Overflow these keywords are on screen; it moves their groups. Resolves to the updated list when one comes back. */
+    async trigger(token, nonprofitId, keywords) {
+      const data = await request('POST', `${DASH}/propresenter/nonprofits/${encodeURIComponent(nonprofitId)}/keywords`, {
+        query: { syncNonprofit: 'true' },
+        body: { keywords },
+        token,
+        timeout: TRIGGER_TIMEOUT_MS,
+      });
+      return Array.isArray(data) ? data : null;
+    },
+
+    /** Staff logins only: the nonprofits this login may act for. */
+    async searchNonprofits(token, search = '', limit = 10) {
+      const data = await request('GET', `${DASH}/propresenter/nonprofits`, { token, query: { search, limit } });
+      const list = (data && data.data && data.data.nonprofits) || (data && data.nonprofits) || (data && data.data) || data;
+      return Array.isArray(list)
+        ? list.map((n) => ({ id: String((n && n.id) || ''), name: String((n && n.name) || ''), slug: String((n && n.slug) || '') }))
+        : [];
+    },
+
+    /** Staff logins only: bind the session to one nonprofit before reading its keywords. */
+    selectNonprofit(token, nonprofitId) {
+      return request('POST', `${DASH}/propresenter/nonprofits/${encodeURIComponent(nonprofitId)}/select`, { token, body: {} });
+    },
+  };
+}
+
+module.exports = { createOverflowClient, OverflowError, decodeJwt, describeSession, API_BASE, DEFAULT_API_BASE };
diff --git a/modules/overflow-tap/server.js b/modules/overflow-tap/server.js
new file mode 100644
index 0000000..3036a76
--- /dev/null
+++ b/modules/overflow-tap/server.js
@@ -0,0 +1,648 @@
+'use strict';
+
+/**
+ * Overflow Tap — server entry.
+ *
+ * Does what Overflow's "ProPresenter Integration" helper app does, inside
+ * ProdDash: watches the live slide in ProPresenter (the presentation layer
+ * and the announcement layer), and when its notes carry one of the keywords
+ * mapped in the Overflow Dashboard, tells Overflow — which points that
+ * keyword's Tap groups at its destination, so what people reach when they
+ * tap a disc follows what is on screen. A slide with no keyword changes
+ * nothing; the last destination stays until the next keyworded slide.
+ *
+ *   GET  /state      → the view-model every tile draws
+ *   GET  /stream     → SSE, `state` events on every change (heartbeated)
+ *   POST /refresh    → re-read the keyword mappings from the Dashboard now
+ *   GET  /keywords   → the mappings as read, for a look while setting up
+ *
+ * ProPresenter is polled (GET /v1/status/slide for the presentation layer,
+ * GET /v1/announcement/slide_index for announcements, once a second each —
+ * small requests, nothing heavier) because its chunked update stream is the
+ * thing that goes quiet without saying so. Overflow is the Dashboard's own
+ * API, signed in with a Dashboard login — the calls, and where they come
+ * from, are at the top of overflow.js. Keyword mappings are read on start,
+ * every few minutes after that, on /refresh, and from every trigger's answer.
+ *
+ * OVERFLOW_TAP_API_BASE=http://127.0.0.1:24720 points the module at
+ * tools/overflow-tap-mock.js, which also plays a ProPresenter on :1602.
+ */
+
+const crypto = require('crypto');
+const { createOverflowClient, OverflowError, describeSession } = require('./overflow');
+const { matchKeywords, sameSet, cleanNotes, norm } = require('./keywords');
+
+const POLL_MS = 1000;                  // ProPresenter, while it answers
+const RETRY_MS = 3000;                 // ProPresenter, while it does not
+const PP_TIMEOUT_MS = 4000;
+const HEARTBEAT_MS = 15000;
+const KEYWORDS_REFRESH_MS = 5 * 60 * 1000;
+const OVERFLOW_RETRY_MS = 30 * 1000;
+const LOGIN_MIN_GAP_MS = 20 * 1000;    // a refused sign-in is not retried sooner (429 = "too many attempts")
+const SESSION_MARGIN_MS = 60 * 1000;   // sign in again this long before the token expires
+const SWITCH_RETRY_MS = 10 * 1000;
+const SWITCH_RETRIES = 3;
+const HISTORY_MAX = 8;                 // the tile shows four; a few more for the hover
+const ALERT_SECONDS = 30;
+
+/** Set by init(), read by routes() — both are rebuilt together on a config save. */
+let current = null;
+
+/**
+ * The signed-in session, kept across re-inits for the same login: an admin
+ * saving config five times in a minute must not become five sign-ins
+ * (Overflow refuses that with 429). Keyed on a hash of the login, so a
+ * changed email or password starts fresh; the token itself never leaves the
+ * server process.
+ */
+let sessionCache = null; // { key, token, expiresAt, email, nonprofitId }
+
+function json(res, code, body) {
+  res.writeHead(code, { 'Content-Type': 'application/json; charset=utf-8', 'Cache-Control': 'no-store' });
+  res.end(JSON.stringify(body));
+}
+
+/** One line for a log or a tile; a fetch failure names its cause (ECONNREFUSED, ENOTFOUND…). */
+function describe(err) {
+  if (err instanceof OverflowError) return err.message;
+  if (err && err.name === 'AbortError') return 'timed out';
+  const msg = err && err.message ? err.message : String(err);
+  const cause = err && err.cause && (err.cause.code || err.cause.message);
+  return cause && !msg.includes(String(cause)) ? `${msg} (${cause})` : msg;
+}
+
+function unique(list) {
+  const seen = new Set();
+  const out = [];
+  for (const v of list) {
+    const k = norm(v);
+    if (!k || seen.has(k)) continue;
+    seen.add(k);
+    out.push(v);
+  }
+  return out;
+}
+
+/** The destination and group names Overflow attached to a keyword mapping, whatever the field names turn out to be. */
+function destinationOf(entry) {
+  return String((entry && (entry.destinationName || (entry.destination && entry.destination.name))) || '');
+}
+function groupsOf(entry) {
+  const list = entry && Array.isArray(entry.tapGroups) ? entry.tapGroups : [];
+  return list.map((g) => String((g && (g.tapGroupName || g.name || g.id)) || '')).filter(Boolean);
+}
+
+module.exports = {
+  init({ config, log, shell }) {
+    /* ── config ────────────────────────────────────────────────────── */
+    const ep = config.propresenter && typeof config.propresenter === 'object' ? config.propresenter : {};
+    const host = String(ep.host || '').trim();
+    const port = Number(ep.port) || 1025;
+    const ppPassword = String(config.password || '');
+    const email = String(config.overflowEmail || '').trim();
+    const ofPassword = String(config.overflowPassword || '');
+    const staffNonprofit = String(config.nonprofitId || '').trim();
+    const configured = Boolean(email && ofPassword);
+    const alertEnabled = Boolean(config.alertEnabled);
+    const alertChannel = Math.min(6, Math.max(1, Math.round(Number(config.alertChannel) || 1)));
+    const sessionKey = crypto.createHash('sha256').update(`${email}\n${ofPassword}`).digest('hex');
+
+    const overflow = createOverflowClient();
+
+    /* ── state ─────────────────────────────────────────────────────── */
+    const streams = new Set();
+    const timers = new Set();
+    let stopped = false;
+    let lastFrame = '';
+
+    let keywordCache = new Map(); // norm(keyword) → the Dashboard's entry
+    let session = null;           // { token, expiresAt, email, nonprofitId }
+    let lastLoginAt = 0;
+    let lastLoginError = null;
+    let wanted = null;            // the keywords Tap should be on: { keywords, keyword, destination, groups }
+    let inFlight = false;
+    let retriesLeft = 0;
+    let retryTimer = null;
+    let alertRaised = false;
+
+    // Presentation layer: the slide /v1/status/slide reports.
+    let lastSlideKey = null;
+    let lastSlide = null;
+    let lastPresKeywords = [];
+    // Announcement layer: the slide /v1/announcement/slide_index points at, read from /v1/announcement/active.
+    let annSupported = true;
+    let lastAnnKey = null;
+    let annNotes = '';
+    let annLive = false;
+    let lastAnnKeywords = [];
+
+    const state = {
+      status: 'connecting',
+      message: '',
+      propresenter: { configured: Boolean(host), reachable: false, error: '', host, port },
+      overflow: { configured, reachable: false, error: '', keywords: 0, loadedAt: 0 },
+      keywords: [],
+      slide: { live: false, keywords: [], hasNotes: false },
+      announcement: { live: false, keywords: [] },
+      current: null,
+      history: [],
+      updatedAt: 0,
+    };
+
+    /* ── timers that die with the handle ───────────────────────────── */
+
+    function later(fn, ms) {
+      const t = setTimeout(() => {
+        timers.delete(t);
+        if (!stopped) fn();
+      }, ms);
+      t.unref?.();
+      timers.add(t);
+      return t;
+    }
+
+    /* ── health, shared by the admin line and the tiles ────────────── */
+
+    function assess(forAdmin = false) {
+      const pp = state.propresenter;
+      const of = state.overflow;
+      if (!pp.configured) return ['error', 'No ProPresenter host configured — set one in /admin'];
+      if (!of.configured) return ['error', 'Overflow login not set — add the email and password in /admin'];
+      if (!of.reachable) return ['error', of.error || 'Signing in to Overflow…'];
+      if (!pp.reachable) return ['error', pp.error ? `ProPresenter unreachable: ${pp.error}` : 'Reaching ProPresenter…'];
+      if (!state.keywords.length) return ['error', 'No keyword mappings in the Overflow Dashboard (Integrations › ProPresenter)'];
+      if (state.current && !state.current.pending && !state.current.ok) {
+        return ['error', `Tap not switched to ${state.current.keyword} — ${state.current.error}`];
+      }
+      if (state.current && state.current.pending) return ['connecting', `Switching Tap to ${state.current.keyword}…`];
+      const n = state.keywords.length;
+      const who = forAdmin && session && session.email ? `${session.email}, ` : '';
+      return ['ok', `Following ${host}:${port} · Overflow: ${who}${n} keyword${n === 1 ? '' : 's'}`];
+    }
+
+    function publish() {
+      if (stopped) return;
+      [state.status, state.message] = assess(false);
+      const { updatedAt, ...rest } = state;
+      let frame;
+      try {
+        frame = JSON.stringify(rest);
+      } catch {
+        return;
+      }
+      if (frame === lastFrame) return;
+      lastFrame = frame;
+      state.updatedAt = Date.now();
+      const payload = `event: state\ndata: ${JSON.stringify(state)}\n\n`;
+      for (const res of streams) {
+        try {
+          res.write(payload);
+        } catch {
+          streams.delete(res);
+        }
+      }
+    }
+
+    /* ── the Overflow session ──────────────────────────────────────── */
+
+    async function ensureSession() {
+      const now = Date.now();
+      if (session && now < session.expiresAt - SESSION_MARGIN_MS) return session;
+      if (sessionCache && sessionCache.key === sessionKey && now < sessionCache.expiresAt - SESSION_MARGIN_MS) {
+        session = sessionCache;
+        return session;
+      }
+      if (lastLoginError && now - lastLoginAt < LOGIN_MIN_GAP_MS) throw lastLoginError;
+      lastLoginAt = now;
+      let token;
+      try {
+        token = await overflow.login(email, ofPassword);
+      } catch (err) {
+        lastLoginError = err;
+        throw err;
+      }
+      lastLoginError = null;
+      const info = describeSession(token);
+      if (!info.hasTap) throw new OverflowError('This Overflow login has no Tap permission — use one with the Organization Admin or Tap Only role');
+      let nonprofitId = info.nonprofitId || (info.nonprofits.length === 1 ? info.nonprofits[0].id : '');
+      if (info.staff) {
+        if (!staffNonprofit) throw new OverflowError('An @overflow.co login has no nonprofit of its own — enter the Nonprofit ID in /admin');
+        await overflow.selectNonprofit(token, staffNonprofit);
+        nonprofitId = staffNonprofit;
+      } else if (!nonprofitId) {
+        nonprofitId = staffNonprofit;
+      }
+      if (!nonprofitId) throw new OverflowError('This Overflow login carries no nonprofit — enter the Nonprofit ID in /admin');
+      session = { token, expiresAt: info.expiresAt || now + 12 * 3600 * 1000, email: info.email || email, nonprofitId };
+      sessionCache = { key: sessionKey, ...session };
+      log(`signed in to Overflow as ${session.email} (nonprofit ${nonprofitId})`);
+      return session;
+    }
+
+    function dropSession() {
+      session = null;
+      if (sessionCache && sessionCache.key === sessionKey) sessionCache = null;
+    }
+
+    /** Run a signed-in call; when the session is refused, sign in again once and retry. */
+    async function withSession(fn) {
+      const s = await ensureSession();
+      try {
+        return await fn(s);
+      } catch (err) {
+        if (!(err instanceof OverflowError) || !err.auth) throw err;
+        dropSession();
+        const again = await ensureSession();
+        return fn(again);
+      }
+    }
+
+    /* ── the keyword mappings ──────────────────────────────────────── */
+
+    function rebuildKeywordView() {
+      state.keywords = [...keywordCache.values()].map((e) => ({
+        keyword: String(e.keyword).trim(),
+        destination: destinationOf(e),
+        groups: groupsOf(e),
+      }));
+      state.overflow.keywords = state.keywords.length;
+    }
+
+    /** Replace the cache with the Dashboard's list (`merge` folds a partial answer into it instead). */
+    function applyKeywordList(list, merge = false) {
+      const next = merge ? new Map(keywordCache) : new Map();
+      for (const entry of list || []) {
+        if (!entry || typeof entry !== 'object') continue;
+        const k = norm(entry.keyword);
+        if (!k) continue;
+        if (entry.active === false || entry.enabled === false || entry.isActive === false) {
+          next.delete(k);
+          continue;
+        }
+        next.set(k, entry);
+      }
+      keywordCache = next;
+      rebuildKeywordView();
+    }
+
+    let loading = null;
+    let refreshTimer = null;
+
+    async function loadKeywords() {
+      if (stopped || !configured) return;
+      if (loading) return loading;
+      loading = (async () => {
+        try {
+          const list = await withSession((s) => overflow.listKeywords(s.token, s.nonprofitId));
+          applyKeywordList(list);
+          state.overflow.reachable = true;
+          state.overflow.error = '';
+          state.overflow.loadedAt = Date.now();
+          reconsider(); // a slide already up when the mappings arrive takes effect now
+        } catch (err) {
+          state.overflow.reachable = false;
+          state.overflow.error = describe(err);
+          log(`Overflow: ${state.overflow.error}`);
+        }
+        publish();
+      })();
+      try {
+        await loading;
+      } finally {
+        loading = null;
+      }
+      if (stopped) return;
+      if (refreshTimer) {
+        clearTimeout(refreshTimer);
+        timers.delete(refreshTimer);
+      }
+      refreshTimer = later(loadKeywords, state.overflow.reachable ? KEYWORDS_REFRESH_MS : OVERFLOW_RETRY_MS);
+    }
+
+    /* ── the switch ────────────────────────────────────────────────── */
+
+    function describeTarget(keys) {
+      const entries = keys.map((k) => keywordCache.get(norm(k))).filter(Boolean);
+      return {
+        keywords: keys,
+        keyword: keys.join(' + '),
+        destination: unique(entries.map(destinationOf).filter(Boolean)).join(' + '),
+        groups: unique(entries.flatMap(groupsOf)),
+      };
+    }
+
+    function pushHistory(entry) {
+      const { pending, ...rest } = entry;
+      state.history.unshift(rest);
+      if (state.history.length > HISTORY_MAX) state.history.length = HISTORY_MAX;
+    }
+
+    function raiseAlert(keyword) {
+      if (!alertEnabled || !shell || typeof shell.alert !== 'function') return;
+      alertRaised = true;
+      Promise.resolve(shell.alert({ channel: alertChannel, level: 'medium', text: `Tap not switched: ${keyword}`, duration: ALERT_SECONDS }))
+        .catch((err) => log(`alert refused: ${describe(err)}`));
+    }
+
+    function clearAlert() {
+      if (!alertRaised || !shell || typeof shell.clearAlert !== 'function') return;
+      alertRaised = false;
+      Promise.resolve(shell.clearAlert(alertChannel)).catch(() => {});
+    }
+
+    function requestSwitch(target) {
+      wanted = target;
+      retriesLeft = SWITCH_RETRIES;
+      if (retryTimer) {
+        clearTimeout(retryTimer);
+        timers.delete(retryTimer);
+        retryTimer = null;
+      }
+      runSwitch();
+    }
+
+    async function runSwitch() {
+      if (stopped || inFlight || !wanted) return;
+      const target = wanted;
+      const cur = state.current;
+      const sameTarget = cur && sameSet(cur.keywords, target.keywords);
+      if (sameTarget && cur.ok) return; // already there
+      inFlight = true;
+      let entry;
+      if (sameTarget) {
+        entry = cur; // another go at the same switch
+      } else {
+        if (cur) pushHistory(cur);
+        entry = {
+          keyword: target.keyword,
+          keywords: target.keywords,
+          destination: target.destination,
+          groups: target.groups,
+          at: Date.now(),
+          ok: false,
+          pending: true,
+          error: '',
+          attempts: 0,
+        };
+        state.current = entry;
+      }
+      entry.pending = true;
+      entry.attempts += 1;
+      publish();
+      try {
+        const answer = await withSession((s) => overflow.trigger(s.token, s.nonprofitId, target.keywords));
+        if (answer) {
+          applyKeywordList(answer, true);
+          const fresh = describeTarget(target.keywords);
+          entry.destination = fresh.destination || entry.destination;
+          entry.groups = fresh.groups.length ? fresh.groups : entry.groups;
+        }
+        entry.ok = true;
+        entry.error = '';
+        entry.at = Date.now();
+        clearAlert();
+        log(`Tap → ${entry.destination || '?'} (${target.keyword})${entry.groups.length ? ` on ${entry.groups.join(', ')}` : ''}`);
+      } catch (err) {
+        if (stopped) return;
+        entry.ok = false;
+        entry.error = describe(err);
+        log(`Tap not switched to ${target.keyword}: ${entry.error}`);
+        if (retriesLeft > 0) {
+          retriesLeft -= 1;
+          retryTimer = later(() => {
+            retryTimer = null;
+            runSwitch();
+          }, SWITCH_RETRY_MS);
+        }
+        raiseAlert(target.keyword);
+      } finally {
+        entry.pending = false;
+        inFlight = false;
+        publish();
+        if (!stopped && wanted !== target) runSwitch(); // a newer keyword arrived meanwhile
+      }
+    }
+
+    /* ── what is on screen, and what to do about it ────────────────── */
+
+    /**
+     * The helper's rule, per layer: when the set of keywords the layer's
+     * slide carries changes to a non-empty set, send it. Returning to a
+     * keyword after a slide without one sends it again; staying on the same
+     * keyword across slides sends nothing.
+     */
+    function reconsider() {
+      const list = [...keywordCache.values()];
+      const presNotes = lastSlide ? cleanNotes(lastSlide.notes) : '';
+      const presKeys = lastSlide ? matchKeywords(presNotes, list) : [];
+      state.slide = { live: Boolean(lastSlide), keywords: presKeys, hasNotes: Boolean(presNotes.trim()) };
+      const presChanged = !sameSet(presKeys, lastPresKeywords);
+      if (presChanged) lastPresKeywords = presKeys;
+
+      const annKeys = annLive ? matchKeywords(annNotes, list) : [];
+      state.announcement = { live: annLive, keywords: annKeys };
+      const annChanged = !sameSet(annKeys, lastAnnKeywords);
+      if (annChanged) lastAnnKeywords = annKeys;
+
+      const batch = [];
+      if (presChanged && presKeys.length) batch.push(...presKeys);
+      if (annChanged && annKeys.length) batch.push(...annKeys);
+      if (batch.length) requestSwitch(describeTarget(unique(batch)));
+    }
+
+    /* ── ProPresenter ──────────────────────────────────────────────── */
+
+    function ppUrl(target) {
+      const u = new URL(`http://${host}:${port}${target}`);
+      if (ppPassword) u.searchParams.set('password', ppPassword);
+      return u;
+    }
+
+    async function ppJson(target) {
+      const ctl = new AbortController();
+      const timer = setTimeout(() => ctl.abort(), PP_TIMEOUT_MS);
+      try {
+        const res = await fetch(ppUrl(target), { headers: { Accept: 'application/json' }, signal: ctl.signal });
+        if (!res.ok) {
+          const err = new Error(`ProPresenter ${res.status} ${res.statusText}`);
+          err.status = res.status;
+          throw err;
+        }
+        const text = await res.text();
+        return text ? JSON.parse(text) : null;
+      } finally {
+        clearTimeout(timer);
+      }
+    }
+
+    /** The presentation layer: /v1/status/slide names the live slide and carries its notes. */
+    async function pollSlide() {
+      const data = await ppJson('/v1/status/slide');
+      const cur = data && data.current && typeof data.current === 'object' ? data.current : null;
+      const key = cur ? `${cur.uuid || ''}\u0000${cur.text || ''}\u0000${cur.notes || ''}` : '';
+      if (key === lastSlideKey) return false;
+      lastSlideKey = key;
+      lastSlide = cur;
+      return true;
+    }
+
+    /**
+     * The announcement layer: its slide index names the document and the
+     * slide; the document's slides (every group's, in order, disabled ones
+     * included — that is the index's space) carry the notes. An older
+     * ProPresenter without this API answers 404 once and is left alone.
+     */
+    async function pollAnnouncement() {
+      if (!annSupported) return false;
+      let idx;
+      try {
+        idx = await ppJson('/v1/announcement/slide_index');
+      } catch (err) {
+        if (err && err.status === 404) {
+          annSupported = false;
+          log('this ProPresenter has no announcement layer API — following the presentation layer only');
+          return false;
+        }
+        throw err;
+      }
+      const node = idx && idx.announcement_index;
+      if (!node || !Number.isInteger(node.index)) {
+        if (lastAnnKey === '') return false;
+        lastAnnKey = '';
+        annLive = false;
+        annNotes = '';
+        return true;
+      }
+      const id = node.presentation_id || {};
+      const key = `${id.uuid || ''}\u0000${id.name || ''}\u0000${node.index}`;
+      if (key === lastAnnKey) return false;
+      const doc = await ppJson('/v1/announcement/active');
+      const ann = doc && doc.announcement;
+      const slides = [];
+      for (const g of (ann && Array.isArray(ann.groups) ? ann.groups : [])) {
+        for (const s of (g && Array.isArray(g.slides) ? g.slides : [])) slides.push(s);
+      }
+      const slide = slides[node.index];
+      annNotes = slide ? cleanNotes(slide.notes) : '';
+      annLive = true;
+      lastAnnKey = key;
+      return true;
+    }
+
+    async function pollTick() {
+      if (stopped) return;
+      let ok = false;
+      let changed = false;
+      try {
+        changed = await pollSlide();
+        state.propresenter.reachable = true;
+        state.propresenter.error = '';
+        ok = true;
+        try {
+          if (await pollAnnouncement()) changed = true;
+        } catch {
+          /* the presentation poll already said ProPresenter answers; a hiccup here waits for the next tick */
+        }
+      } catch (err) {
+        state.propresenter.reachable = false;
+        state.propresenter.error = err && err.name === 'AbortError' ? 'timed out' : describe(err);
+      }
+      if (changed) reconsider();
+      publish();
+      later(pollTick, ok ? POLL_MS : RETRY_MS);
+    }
+
+    /* ── go ────────────────────────────────────────────────────────── */
+
+    if (host) {
+      pollTick();
+      log(`following ProPresenter at ${host}:${port}`);
+    } else {
+      log('no ProPresenter host configured — set one in /admin');
+    }
+    if (configured) {
+      loadKeywords();
+      log(`Overflow at ${overflow.base}`);
+    } else {
+      log('Overflow login not set — add the email and password in /admin');
+    }
+    publish();
+
+    const heartbeat = setInterval(() => {
+      for (const res of streams) {
+        try {
+          res.write(': ping\n\n');
+        } catch {
+          streams.delete(res);
+        }
+      }
+    }, HEARTBEAT_MS);
+    heartbeat.unref?.();
+
+    const handle = {
+      streams,
+      configured,
+      getState: () => state,
+      refresh: () => loadKeywords(),
+    };
+    current = handle;
+
+    return {
+      stop() {
+        stopped = true;
+        clearInterval(heartbeat);
+        for (const t of timers) clearTimeout(t);
+        timers.clear();
+        clearAlert();
+        for (const res of streams) {
+          try { res.end(); } catch { /* already gone */ }
+        }
+        streams.clear();
+        if (current === handle) current = null;
+      },
+      health() {
+        const [status, message] = assess(true);
+        return { status, message };
+      },
+    };
+  },
+
+  routes() {
+    return {
+      'GET /state': (req, res) => {
+        if (!current) return json(res, 503, { error: 'Overflow Tap is not running.' });
+        json(res, 200, { state: current.getState() });
+      },
+
+      'GET /stream': (req, res) => {
+        res.writeHead(200, {
+          'Content-Type': 'text/event-stream; charset=utf-8',
+          'Cache-Control': 'no-cache, no-transform',
+          Connection: 'keep-alive',
+          'X-Accel-Buffering': 'no',
+        });
+        res.write('retry: 3000\n\n');
+        if (!current) return void res.end();
+        res.write(`event: state\ndata: ${JSON.stringify(current.getState())}\n\n`);
+        try { req.socket.setKeepAlive(true, 15000); } catch { /* gone */ }
+        current.streams.add(res);
+        req.on('close', () => current && current.streams.delete(res));
+      },
+
+      'POST /refresh': async (req, res) => {
+        if (!current) return json(res, 503, { error: 'Overflow Tap is not running.' });
+        if (!current.configured) return json(res, 400, { error: 'Overflow login is not set.' });
+        await current.refresh();
+        const st = current.getState();
+        if (!st.overflow.reachable) return json(res, 502, { error: st.overflow.error || 'Overflow unreachable.' });
+        json(res, 200, { ok: true, keywords: st.overflow.keywords });
+      },
+
+      'GET /keywords': (req, res) => {
+        if (!current) return json(res, 503, { error: 'Overflow Tap is not running.' });
+        const st = current.getState();
+        json(res, 200, { keywords: st.keywords, loadedAt: st.overflow.loadedAt, error: st.overflow.error });
+      },
+    };
+  },
+};
diff --git a/modules/overflow-tap/style.css b/modules/overflow-tap/style.css
new file mode 100644
index 0000000..9a43d86
--- /dev/null
+++ b/modules/overflow-tap/style.css
@@ -0,0 +1,213 @@
+/* Overflow Tap — scoped under its tile via [data-module="overflow-tap"] and
+   styled with the shell's variables only. Sizes hang off the tile (container
+   units) so the keyword reads from across a booth on a big tile and still
+   fits a 2×2. */
+
+[data-module="overflow-tap"] {
+  container-type: size;
+}
+
+[data-module="overflow-tap"] .ot-root {
+  position: absolute;
+  inset: 0;
+  display: flex;
+  flex-direction: column;
+  align-items: stretch;
+  padding: clamp(4px, 4cqmin, 18px);
+  gap: clamp(2px, 1.8cqmin, 10px);
+  overflow: hidden;
+  color: var(--text);
+  user-select: none;
+  -webkit-user-select: none;
+}
+
+[data-module="overflow-tap"] .ot-offline {
+  flex-shrink: 0;
+  font-size: clamp(0.6rem, 4.6cqmin, 0.9rem);
+  font-weight: 700;
+  color: var(--danger);
+  text-transform: uppercase;
+  letter-spacing: 0.04em;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+[data-module="overflow-tap"] .ot-root.is-offline .ot-main,
+[data-module="overflow-tap"] .ot-root.is-offline .ot-slide,
+[data-module="overflow-tap"] .ot-root.is-offline .ot-history {
+  opacity: 0.45;
+  filter: grayscale(0.6);
+}
+
+/* ── the live keyword ───────────────────────────────────────────── */
+
+[data-module="overflow-tap"] .ot-main {
+  --tone: var(--accent);
+  flex: 1 1 auto;
+  min-height: 0;
+  container-type: size;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: 0;
+  text-align: center;
+  overflow: hidden;
+}
+[data-module="overflow-tap"] .ot-main[data-tone="ok"] { --tone: var(--accent); }
+[data-module="overflow-tap"] .ot-main[data-tone="warn"] { --tone: var(--warn); }
+[data-module="overflow-tap"] .ot-main[data-tone="alert"] { --tone: var(--danger); }
+[data-module="overflow-tap"] .ot-main[data-tone="muted"] { --tone: var(--muted); }
+
+[data-module="overflow-tap"] .ot-label {
+  color: var(--tone);
+  font-size: clamp(0.5rem, 9cqh, 0.95rem);
+  font-weight: 700;
+  letter-spacing: 0.14em;
+  line-height: 1.2;
+  max-width: 100%;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  font-variant-numeric: tabular-nums;
+}
+
+[data-module="overflow-tap"] .ot-keyword {
+  color: var(--tone);
+  font-size: min(clamp(1rem, 38cqh, 7rem), 18cqw);
+  font-weight: 750;
+  line-height: 1.15;
+  max-width: 100%;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+[data-module="overflow-tap"] .ot-keyword.is-none { color: var(--muted); }
+[data-module="overflow-tap"] .ot-main[data-tone="muted"] .ot-keyword {
+  animation: ot-pulse 1.2s ease-in-out infinite;
+}
+@keyframes ot-pulse {
+  0%, 100% { opacity: 1; }
+  50% { opacity: 0.45; }
+}
+
+[data-module="overflow-tap"] .ot-dest {
+  color: var(--text);
+  font-size: min(clamp(0.7rem, 16cqh, 1.9rem), 8cqw);
+  font-weight: 600;
+  line-height: 1.2;
+  max-width: 100%;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+[data-module="overflow-tap"] .ot-main[data-tone="muted"] .ot-dest { color: var(--muted); font-weight: 500; }
+
+[data-module="overflow-tap"] .ot-groups {
+  color: var(--muted);
+  font-size: clamp(0.5rem, 9cqh, 0.95rem);
+  line-height: 1.3;
+  flex-shrink: 0;
+  max-width: 100%;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+[data-module="overflow-tap"] .ot-error {
+  color: var(--danger);
+  font-size: clamp(0.5rem, 9cqh, 0.95rem);
+  line-height: 1.3;
+  max-width: 100%;
+  overflow: hidden;
+  display: -webkit-box;
+  -webkit-line-clamp: 2;
+  -webkit-box-orient: vertical;
+}
+[data-module="overflow-tap"] .ot-error.is-warn { color: var(--warn); }
+
+/* ── this slide ─────────────────────────────────────────────────── */
+
+[data-module="overflow-tap"] .ot-slide {
+  flex-shrink: 0;
+  text-align: center;
+  font-size: clamp(0.55rem, 4.8cqmin, 0.95rem);
+  color: var(--text);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  padding: 0.25em 0.6em;
+  border-radius: 999px;
+  background: color-mix(in srgb, var(--text) 7%, transparent);
+  align-self: center;
+  max-width: 100%;
+}
+[data-module="overflow-tap"] .ot-slide.is-muted { color: var(--muted); }
+[data-module="overflow-tap"] .ot-slide.is-hit {
+  color: var(--accent-text);
+  background: color-mix(in srgb, var(--accent) 80%, transparent);
+  font-weight: 650;
+}
+[data-module="overflow-tap"] .ot-slide.is-warn {
+  color: var(--warn);
+  background: color-mix(in srgb, var(--warn) 16%, transparent);
+}
+
+/* ── the trail ──────────────────────────────────────────────────── */
+
+[data-module="overflow-tap"] .ot-history {
+  flex-shrink: 0;
+  list-style: none;
+  margin: 0;
+  padding: 0.3em 0 0;
+  border-top: 1px solid var(--border);
+  font-size: clamp(0.55rem, 4.6cqmin, 0.95rem);
+  display: flex;
+  flex-direction: column;
+  gap: 0.1em;
+}
+
+[data-module="overflow-tap"] .ot-h-row {
+  display: grid;
+  grid-template-columns: auto minmax(0, 1fr) minmax(0, 1.4fr) auto;
+  align-items: baseline;
+  gap: 0 0.7em;
+  color: var(--text);
+}
+[data-module="overflow-tap"] .ot-h-row.is-failed .ot-h-kw,
+[data-module="overflow-tap"] .ot-h-row.is-failed .ot-h-mark { color: var(--danger); }
+[data-module="overflow-tap"] .ot-h-time {
+  color: var(--muted);
+  font-variant-numeric: tabular-nums;
+}
+[data-module="overflow-tap"] .ot-h-kw { font-weight: 650; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+[data-module="overflow-tap"] .ot-h-dest { color: var(--muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+[data-module="overflow-tap"] .ot-h-mark { color: var(--accent); font-weight: 700; }
+[data-module="overflow-tap"] .ot-h-empty { color: var(--muted); text-align: center; }
+
+/* On a short tile the trail would crowd the keyword out: keep the
+   keyword, drop the trail. Inside the keyword block the same rule: when
+   it is short, the small lines go before the keyword does. */
+@container (max-height: 120px) {
+  [data-module="overflow-tap"] .ot-history { display: none; }
+}
+@container (max-height: 70px) {
+  [data-module="overflow-tap"] .ot-groups,
+  [data-module="overflow-tap"] .ot-error { display: none; }
+}
+@container (max-height: 46px) {
+  [data-module="overflow-tap"] .ot-dest,
+  [data-module="overflow-tap"] .ot-label { display: none; }
+}
+
+[data-module="overflow-tap"] .ot-empty {
+  position: absolute;
+  inset: 0;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 6%;
+  color: var(--muted);
+  text-align: center;
+  font-size: clamp(0.65rem, 5.5cqmin, 1rem);
+}
diff --git a/tools/overflow-tap-mock.js b/tools/overflow-tap-mock.js
new file mode 100644
index 0000000..fa1d54b
--- /dev/null
+++ b/tools/overflow-tap-mock.js
@@ -0,0 +1,255 @@
+/**
+ * Mock ProPresenter slide status + mock Overflow Dashboard API, for developing
+ * the overflow-tap module without a live ProPresenter or an Overflow account.
+ *
+ *   node tools/overflow-tap-mock.js [--pp=1602] [--overflow=24720] [--step=4000]
+ *                                   [--login=<email>:<password>] [--expire=<seconds>]
+ *                                   [--fail-switch] [--slow] [--no-announcements]
+ *
+ * ProPresenter side (127.0.0.1:1602 by default) — the routes the module uses,
+ * with a service that advances every --step ms:
+ *   GET /version                      reachability probe
+ *   GET /v1/status/slide              { current: { uuid, text, notes }, next }, cycling
+ *                                     through slides whose notes carry keywords
+ *                                     ("give", "Next steps: connect", "prayer"),
+ *                                     slides with other notes ("forgiveness" —
+ *                                     must NOT fire "give"), a slide whose
+ *                                     keyword is not mapped on the account, and
+ *                                     a stretch with nothing live.
+ *   GET /v1/announcement/slide_index  the announcement layer: a three-slide
+ *                                     document whose index advances every third
+ *                                     step; its middle slide carries "events".
+ *   GET /v1/announcement/active       that document, groups → slides → notes.
+ *                                     --no-announcements answers 404 to both,
+ *                                     like an older ProPresenter.
+ *
+ * Overflow side (127.0.0.1:24720 by default; run ProdDash with
+ * OVERFLOW_TAP_API_BASE=http://127.0.0.1:24720) — the Dashboard API the
+ * module speaks (see modules/overflow-tap/overflow.js):
+ *   POST /nonprofit-dashboard/authentication/login/jwt      any non-empty email +
+ *        password signs in (--login=<email>:<password> demands that pair,
+ *        answering 401 otherwise); the token expires after --expire seconds
+ *        (3600 by default — set 20 to exercise the sign-in-again path). An
+ *        @overflow.co email gets a staff token with no nonprofit of its own.
+ *   GET  /nonprofit-dashboard/propresenter/nonprofits          staff: the nonprofits
+ *   POST /nonprofit-dashboard/propresenter/nonprofits/{id}/select
+ *   GET  /nonprofit-dashboard/propresenter/nonprofits/{id}/keywords   four mappings:
+ *        give → Give Online (every group), connect → Connect Card (Lobby),
+ *        prayer → Prayer Request (every group), events → Events (Lobby, Kids
+ *        Wing). "baptism" is deliberately unmapped.
+ *   POST /nonprofit-dashboard/propresenter/nonprofits/{id}/keywords?syncNonprofit=true
+ *        { keywords } — moves the groups and answers the updated list.
+ *        --fail-switch answers 500 instead, to exercise the failure path.
+ * Every signed-in call needs a Bearer token this mock issued and has not
+ * expired, or it answers 401. --slow adds a two-second delay to every Overflow
+ * answer.
+ *
+ * Every incoming request is logged so we can confirm what the module does.
+ */
+'use strict';
+
+const http = require('http');
+const crypto = require('crypto');
+
+const args = process.argv.slice(2);
+const opt = (name, dflt) => {
+  const a = args.find((x) => x.startsWith(`--${name}=`));
+  return a ? a.slice(name.length + 3) : dflt;
+};
+const PP_PORT = Number.parseInt(opt('pp', '1602'), 10);
+const OF_PORT = Number.parseInt(opt('overflow', '24720'), 10);
+const STEP_MS = Number.parseInt(opt('step', '4000'), 10);
+const LOGIN = opt('login', '');
+const EXPIRE_S = Number.parseInt(opt('expire', '3600'), 10);
+const FAIL_SWITCH = args.includes('--fail-switch');
+const SLOW = args.includes('--slow');
+const NO_ANN = args.includes('--no-announcements');
+
+function sendJson(res, code, body, extra = {}) {
+  res.writeHead(code, { 'Content-Type': 'application/json', ...extra });
+  res.end(body === undefined ? '' : JSON.stringify(body));
+}
+
+/* ── ProPresenter ────────────────────────────────────────────────── */
+
+const SLIDES = [
+  { uuid: 'S1', text: 'Welcome to Waters Church', notes: '' },
+  { uuid: 'S2', text: 'Give online', notes: 'give' },
+  { uuid: 'S3', text: 'Amazing grace, how sweet the sound', notes: 'Chorus x2' },
+  { uuid: 'S4', text: 'Fill out a Connect Card', notes: 'Next steps: connect' },
+  { uuid: 'S5', text: 'A sermon on forgiveness', notes: 'forgiveness — do not switch on this' },
+  { uuid: 'S6', text: 'Pray with us', notes: 'prayer' },
+  { uuid: 'S7', text: 'Baptism Sunday', notes: 'baptism' },
+  null, // nothing live
+  { uuid: 'S8', text: 'Give online (again)', notes: 'give' },
+  { uuid: 'S9', text: 'See you next week', notes: '' },
+];
+const ANNOUNCEMENT = {
+  id: { uuid: 'ANN-1', name: 'Announcements', index: 0 },
+  presentation_path: 'Announcements',
+  groups: [
+    { name: 'Loop', slides: [
+      { enabled: true, notes: '', text: 'Welcome', label: '' },
+      { enabled: true, notes: 'events', text: 'Upcoming events', label: '' },
+      { enabled: true, notes: '', text: 'Thanks for coming', label: '' },
+    ] },
+  ],
+};
+let step = 0;
+setInterval(() => { step += 1; }, STEP_MS).unref();
+const slideIdx = () => step % SLIDES.length;
+const annIdx = () => Math.floor(step / 3) % ANNOUNCEMENT.groups[0].slides.length;
+
+function slidePayload() {
+  const cur = SLIDES[slideIdx()];
+  const nxt = SLIDES[(slideIdx() + 1) % SLIDES.length];
+  return {
+    current: cur ? { uuid: cur.uuid, text: cur.text, notes: cur.notes } : null,
+    next: nxt ? { uuid: nxt.uuid, text: nxt.text, notes: nxt.notes } : null,
+  };
+}
+
+http.createServer((req, res) => {
+  const url = new URL(req.url, `http://${req.headers.host}`);
+  const p = url.pathname;
+  console.log(`[pp] ${req.method} ${p}`);
+  if (p === '/version') return sendJson(res, 200, { name: 'Overflow mock', platform: 'mac', host_description: 'ProPresenter 21 (mock)', api_version: 'v1' });
+  if (p === '/v1/status/slide') return sendJson(res, 200, slidePayload());
+  if (p === '/v1/status/layers') return sendJson(res, 200, { slide: Boolean(SLIDES[slideIdx()]), media: false, announcements: !NO_ANN });
+  if (p === '/v1/announcement/slide_index') {
+    if (NO_ANN) return sendJson(res, 404, { error: 'not found' });
+    return sendJson(res, 200, { announcement_index: { index: annIdx(), presentation_id: ANNOUNCEMENT.id } });
+  }
+  if (p === '/v1/announcement/active') {
+    if (NO_ANN) return sendJson(res, 404, { error: 'not found' });
+    return sendJson(res, 200, { announcement: ANNOUNCEMENT });
+  }
+  sendJson(res, 404, { error: 'not found' });
+}).listen(PP_PORT, '127.0.0.1', () => {
+  console.log(`[pp] mock ProPresenter on http://127.0.0.1:${PP_PORT} (slide every ${STEP_MS} ms${NO_ANN ? ', no announcement layer' : ''})`);
+});
+
+/* ── Overflow Dashboard ──────────────────────────────────────────── */
+
+const NONPROFIT = { id: '6710f34fd5061afeec3eab00', name: 'Waters Church (mock)', slug: 'waters-church' };
+const DESTINATIONS = {
+  give: { id: '6710f34fd5061afeec3eab01', name: 'Give Online' },
+  connect: { id: '6710f34fd5061afeec3eab02', name: 'Connect Card' },
+  prayer: { id: '6710f34fd5061afeec3eab03', name: 'Prayer Request' },
+  events: { id: '6710f34fd5061afeec3eab04', name: 'Events' },
+};
+const GROUPS = [
+  { id: '6710f34fd5061afeec3eab11', tapGroupName: 'Auditorium', destinationId: DESTINATIONS.events.id },
+  { id: '6710f34fd5061afeec3eab12', tapGroupName: 'Lobby', destinationId: DESTINATIONS.events.id },
+  { id: '6710f34fd5061afeec3eab13', tapGroupName: 'Kids Wing', destinationId: DESTINATIONS.connect.id },
+];
+const groupRef = (g) => ({ id: g.id, tapGroupName: g.tapGroupName });
+const KEYWORDS = [
+  { id: 'kw1', keyword: 'give', destinationId: DESTINATIONS.give.id, destinationName: DESTINATIONS.give.name, tapGroups: GROUPS.map(groupRef), active: true },
+  { id: 'kw2', keyword: 'connect', destinationId: DESTINATIONS.connect.id, destinationName: DESTINATIONS.connect.name, tapGroups: [groupRef(GROUPS[1])], active: true },
+  { id: 'kw3', keyword: 'prayer', destinationId: DESTINATIONS.prayer.id, destinationName: DESTINATIONS.prayer.name, tapGroups: GROUPS.map(groupRef), active: true },
+  { id: 'kw4', keyword: 'events', destinationId: DESTINATIONS.events.id, destinationName: DESTINATIONS.events.name, tapGroups: [groupRef(GROUPS[1]), groupRef(GROUPS[2])], active: true },
+];
+const stampedKeywords = () => KEYWORDS.map((k) => ({ ...k, nonprofitId: NONPROFIT.id, updatedAt: new Date().toISOString() }));
+
+const tokens = new Map(); // token → { email, exp, nonprofitId }
+
+function issueToken(email) {
+  const staff = email.toLowerCase().endsWith('@overflow.co');
+  const now = Math.floor(Date.now() / 1000);
+  const payload = {
+    id: 'user-1',
+    email,
+    fullName: 'Mock User',
+    role: staff ? 'overflowSupport' : 'orgAdmin',
+    permissions: [{ action: 'manage', subject: 'TAP' }],
+    nonprofits: staff ? [] : [{ id: NONPROFIT.id, name: NONPROFIT.name, slug: NONPROFIT.slug }],
+    iat: now,
+    exp: now + EXPIRE_S,
+  };
+  if (!staff) payload.nonprofitId = NONPROFIT.id;
+  const b64 = (o) => Buffer.from(JSON.stringify(o)).toString('base64url');
+  const token = `${b64({ alg: 'HS256', typ: 'JWT' })}.${b64(payload)}.${crypto.randomBytes(16).toString('base64url')}`;
+  tokens.set(token, { email, exp: payload.exp, nonprofitId: staff ? '' : NONPROFIT.id });
+  return token;
+}
+
+function bearer(req) {
+  const m = /^Bearer\s+(.+)$/.exec(String(req.headers.authorization || ''));
+  if (!m) return null;
+  const t = tokens.get(m[1]);
+  if (!t) return null;
+  if (Date.now() / 1000 >= t.exp) return null;
+  return t;
+}
+
+function readBody(req) {
+  return new Promise((resolve) => {
+    let body = '';
+    req.on('data', (c) => (body += c));
+    req.on('end', () => {
+      try { resolve(JSON.parse(body || '{}')); } catch { resolve(null); }
+    });
+  });
+}
+
+http.createServer(async (req, res) => {
+  const url = new URL(req.url, `http://${req.headers.host}`);
+  const p = url.pathname;
+  const answer = (code, body) => {
+    const go = () => sendJson(res, code, body);
+    if (SLOW) setTimeout(go, 2000);
+    else go();
+  };
+  console.log(`[overflow] ${req.method} ${p}${url.search}`);
+
+  if (req.method === 'POST' && p === '/nonprofit-dashboard/authentication/login/jwt') {
+    const body = await readBody(req);
+    const email = String((body && body.email) || '').trim();
+    const password = String((body && body.password) || '');
+    if (!email || !password) return answer(400, { statusCode: 400, message: 'email and password are required' });
+    if (LOGIN && `${email}:${password}` !== LOGIN) return answer(401, { statusCode: 401, message: 'Invalid email or password' });
+    console.log(`[overflow]   signed in ${email} (token expires in ${EXPIRE_S} s)`);
+    return answer(200, { token: issueToken(email) });
+  }
+
+  const session = bearer(req);
+  if (!session) return answer(401, { statusCode: 401, message: 'Unauthorized' });
+
+  if (req.method === 'GET' && p === '/nonprofit-dashboard/propresenter/nonprofits') {
+    return answer(200, { data: { nonprofits: [NONPROFIT] } });
+  }
+  const sel = /^\/nonprofit-dashboard\/propresenter\/nonprofits\/([^/]+)\/select$/.exec(p);
+  if (req.method === 'POST' && sel) {
+    if (sel[1] !== NONPROFIT.id) return answer(404, { statusCode: 404, message: 'Nonprofit not found' });
+    session.nonprofitId = NONPROFIT.id;
+    return answer(204);
+  }
+  const kw = /^\/nonprofit-dashboard\/propresenter\/nonprofits\/([^/]+)\/keywords$/.exec(p);
+  if (kw) {
+    if (kw[1] !== NONPROFIT.id || session.nonprofitId !== NONPROFIT.id) return answer(403, { statusCode: 403, message: 'Forbidden' });
+    if (req.method === 'GET') return answer(200, stampedKeywords());
+    if (req.method === 'POST') {
+      const body = await readBody(req);
+      const keys = body && Array.isArray(body.keywords) ? body.keywords.map((k) => String(k).toLowerCase().trim()) : [];
+      if (!keys.length) return answer(400, { statusCode: 400, message: 'keywords is required' });
+      if (FAIL_SWITCH) return answer(500, { statusCode: 500, message: 'Internal server error' });
+      for (const k of keys) {
+        const entry = KEYWORDS.find((x) => x.keyword === k);
+        if (!entry) {
+          console.log(`[overflow]   "${k}" is not a mapped keyword — ignored`);
+          continue;
+        }
+        for (const g of entry.tapGroups) {
+          const group = GROUPS.find((x) => x.id === g.id);
+          if (group) group.destinationId = entry.destinationId;
+        }
+        console.log(`[overflow]   ${entry.tapGroups.map((g) => g.tapGroupName).join(', ')} → ${entry.destinationName} (${k})`);
+      }
+      return answer(200, stampedKeywords());
+    }
+  }
+  answer(404, { statusCode: 404, message: `Cannot ${req.method} ${p}` });
+}).listen(OF_PORT, '127.0.0.1', () => {
+  console.log(`[overflow] mock Overflow Dashboard API on http://127.0.0.1:${OF_PORT}${FAIL_SWITCH ? ' (every switch answers 500)' : ''}${LOGIN ? ' (one login accepted)' : ''}${EXPIRE_S < 3600 ? ` (tokens expire after ${EXPIRE_S} s)` : ''}`);
+});