diff --git a/server/index.js b/server/index.js
index f62a4b7..96c91fc 100644
--- a/server/index.js
+++ b/server/index.js
@@ -45,6 +45,7 @@ module.exports = function register(ctx, api) {
 
   const shardStreams = require('./config/shardStreams')
   const townCrierLeg = require('./utils/shardAnnounce')
+  const teamProvider = require('./model/teamProvider/teamProvider.model')
   const boot = require('./boot')
   /* eslint-enable global-require */
 
@@ -86,6 +87,15 @@ module.exports = function register(ctx, api) {
   api.registerNotificationStreams(shardStreams.STREAMS)
   api.registerAnnounceLeg(townCrierLeg.leg)
 
+  // Teams: a UO guild is a Team, and this module is the authoritative source of
+  // them for this deployment (MODULE_API 1.6.0). Core asks the three questions;
+  // everything about what a guild IS stays here.
+  //
+  // Registration is a claim, not a call — nothing below runs until core
+  // reconciles, which is after `onBoot`. That matters because every method reads
+  // the database, and registration must not.
+  api.registerTeamProvider(teamProvider)
+
   api.onBoot(boot.onBoot)
   api.onShutdown(boot.onShutdown)
 
diff --git a/server/model/teamProvider/teamProvider.db.js b/server/model/teamProvider/teamProvider.db.js
new file mode 100644
index 0000000..49024cc
--- /dev/null
+++ b/server/model/teamProvider/teamProvider.db.js
@@ -0,0 +1,66 @@
+// SQL behind the Team provider — three questions core asks, answered from the
+// guild board and the roster Protocol 4 put there.
+//
+// Every statement reads only THIS module's tables. Core's Team tables are
+// core-internal (docs/website/TEAMS.md §10.3) and this module must never name
+// one, even though it is what fills them.
+
+const core = require('../../core')
+
+const query = (...args) => core.db.query(...args)
+
+/**
+ * The guild board — one row per guild the shard has told us about.
+ *
+ * `members`/`online` here are the COUNTS `guild.update` carries; the roster is a
+ * separate table (Protocol 4). Both are read, because a count is what the shard
+ * asserts and a roster is what it enumerated, and they can legitimately disagree
+ * for the moment between a membership change and the sweep that reports it.
+ */
+const listGuilds = () =>
+  query(
+    `SELECT id, name, abbr, alliance, members, online, leader_serial, leader_name, leader_acct
+     FROM shard_guilds ORDER BY name ASC`,
+  )
+
+const findGuild = (id) =>
+  query(
+    `SELECT id, name, abbr, alliance, members, online, leader_serial, leader_name, leader_acct
+     FROM shard_guilds WHERE id = ? LIMIT 1`,
+    [id],
+  )
+
+/**
+ * One guild's roster, with the site link and live presence folded in.
+ *
+ * Two LEFT JOINs, both deliberate:
+ *
+ *   - `shard_account_links` resolves `user_id` HERE rather than in core, because
+ *     this module owns that table and a core that read it would be core naming a
+ *     module's table by name (§2.3). It is also why a freshly linked account
+ *     appears as linked on the next reconcile rather than needing core to know
+ *     anything about linking.
+ *   - `shard_online` is how a member's `online` is answered at all. The roster
+ *     frame does not carry it — the wire's member is the standard actor object
+ *     (`serial`, `name`, `player`, `acct?`, `webId?`), and the board's `online` is
+ *     a count, not a set. Presence therefore comes from the online table, which
+ *     is the same source the public "who's online" surface already uses.
+ *
+ * `web_id` on the roster row is preferred over the link table when present: it is
+ * what the shard itself asserted at roster time, and the join is the fallback for
+ * a member whose row predates their link.
+ */
+const listGuildMembers = (guildId) =>
+  query(
+    `SELECT m.serial, m.name, m.acct, m.web_id, m.is_player,
+            l.user_id AS linked_user_id,
+            (o.serial IS NOT NULL) AS is_online
+     FROM shard_guild_members m
+     LEFT JOIN shard_account_links l ON l.account = m.acct
+     LEFT JOIN shard_online o ON o.serial = m.serial
+     WHERE m.guild_id = ?
+     ORDER BY m.name ASC`,
+    [guildId],
+  )
+
+module.exports = { listGuilds, findGuild, listGuildMembers }
diff --git a/server/model/teamProvider/teamProvider.model.js b/server/model/teamProvider/teamProvider.model.js
new file mode 100644
index 0000000..a18888f
--- /dev/null
+++ b/server/model/teamProvider/teamProvider.model.js
@@ -0,0 +1,182 @@
+// ── module-uo's Team provider ──────────────────────────────────────────────
+//
+// The three questions core asks this module about Teams
+// (docs/website/MODULE_API.md — `api.registerTeamProvider`, and TEAMS.md §2.3).
+// A UO guild is a Team; this file is the whole of the translation.
+//
+// **Every method returns an envelope, and answering `{ ok: false }` is a normal
+// outcome, not a failure to handle.** Core's contract is that module
+// unavailability becomes staleness and never emptiness, and the only way this
+// module can say "I cannot answer" is to say so — an empty array would be read as
+// an authoritative "there are none", which during a cold start is how every
+// roster on the site gets emptied. So the guard below is the most important code
+// in the file, and it is deliberately conservative: **an unreachable or
+// never-connected sidecar refuses, rather than reporting the board it happens to
+// still hold.**
+//
+// The board IS durable and would survive a sidecar outage, which is exactly what
+// makes this tempting to get wrong. The reason to refuse anyway: core cannot tell
+// a board that is five minutes stale from one that is five days stale, and it
+// makes destructive decisions — archiving Teams, departing members — from a
+// complete answer. Reporting a stale board as authoritative would license those.
+
+const core = require('../../core')
+const db = require('./teamProvider.db')
+const uoLinkConfig = require('../uoLinkConfig/uoLinkConfig.model')
+const uoLinkSocket = require('../../utils/uoLinkSocket')
+
+const log = core.logger('teams')
+
+/** A refusal, in the shape core reads (§2.3). */
+const refuse = (reason) => ({ ok: false, reason })
+
+/**
+ * Is the bridge in a state where the board can be trusted as current?
+ *
+ * The board is only as good as the socket that fills it. Three states refuse, and
+ * they are asked in this order because each is a different thing being wrong:
+ *
+ *   - **no uo-link configured** — there is no shard behind this website at all;
+ *   - **the integration is disabled** — an admin turned it off, and the board is
+ *     frozen at whatever it held;
+ *   - **the socket is not connected** — the board is a snapshot of unknown age.
+ *
+ * The in-process socket state is preferred over the persisted status column,
+ * which is written on transitions: a process that has just started has not
+ * transitioned yet, so the column can still say `connected` from the last run
+ * while this process has never opened a socket.
+ */
+async function boardIsCurrent() {
+  const config = await uoLinkConfig.getSafe()
+  if (!config || !config.baseUrl) return { ok: false, reason: 'no uo-link configured' }
+  if (!config.enabled) return { ok: false, reason: 'the uo-link integration is disabled' }
+
+  const state = uoLinkSocket.getState()
+  if (!state || !state.connected) {
+    return { ok: false, reason: 'the uo-link socket is not connected; the guild board may be stale' }
+  }
+  return { ok: true }
+}
+
+/**
+ * `getTeams()` — every guild on the board.
+ *
+ * `externalId` is the ServUO `Guild.Id`, which survives a rename: renaming a
+ * guild in-game keeps the id, so core sees "an id whose name changed" and applies
+ * its rename rule (archive plus create). That mapping is this module's to make —
+ * only the game knows what identity survives what (§10.5).
+ *
+ * `meta` carries the alliance, opaquely. Core stores and displays it and never
+ * branches on it, which is what lets a UO concept reach a Team page without core
+ * acquiring an opinion about alliances.
+ */
+async function getTeams() {
+  const ready = await boardIsCurrent()
+  if (!ready.ok) return refuse(ready.reason)
+
+  try {
+    const rows = await db.listGuilds()
+    return {
+      ok: true,
+      complete: true,
+      teams: rows.map((row) => ({
+        externalId: String(row.id),
+        name: row.name,
+        abbr: row.abbr || null,
+        meta: row.alliance ? { alliance: row.alliance } : null,
+      })),
+    }
+  } catch (err) {
+    log.warn('getTeams failed', { message: err.message })
+    return refuse(`guild board unreadable: ${err.message}`)
+  }
+}
+
+/**
+ * `getTeamMembers(externalId)` — one guild's roster.
+ *
+ * **A guild with no roster rows is refused, not reported empty**, unless the board
+ * itself says the guild has no members. Protocol 4's roster arrives on its own
+ * frames, separately from the `guild.update` that creates the board row, so there
+ * is a real window — a fresh guild, or a website that connected between the two —
+ * where core would otherwise be told authoritatively that a 155-member guild has
+ * nobody in it. The board's own `members` count is what distinguishes the two,
+ * and it is the only thing that can.
+ */
+async function getTeamMembers(externalId) {
+  const ready = await boardIsCurrent()
+  if (!ready.ok) return refuse(ready.reason)
+
+  try {
+    const [guild] = await db.findGuild(externalId)
+    if (!guild) return refuse(`guild ${externalId} is not on the board`)
+
+    const rows = await db.listGuildMembers(externalId)
+    if (!rows.length && guild.members > 0) {
+      return refuse(`roster for guild ${externalId} has not arrived yet (board says ${guild.members} members)`)
+    }
+
+    const leaderSerial = guild.leader_serial || null
+    return {
+      ok: true,
+      complete: true,
+      members: rows.map((row) => ({
+        memberKey: row.serial,
+        displayName: row.name || null,
+        // Not on the wire. The roster member is the standard actor object, which
+        // carries no guild rank — see the note at the bottom of this file.
+        rankLabel: null,
+        leader: Boolean(leaderSerial && row.serial === leaderSerial),
+        online: Boolean(row.is_online),
+        userId: resolveUserId(row),
+      })),
+    }
+  } catch (err) {
+    log.warn('getTeamMembers failed', { externalId, message: err.message })
+    return refuse(`roster unreadable: ${err.message}`)
+  }
+}
+
+/**
+ * `getTeamLeaders(externalId)` — who leads the guild.
+ *
+ * **One leader, because that is all the wire carries.** TEAMS.md §2.5 expects
+ * multiple leaders to be the normal case, from `PlayerMobile.GuildRank.Rank >= 4`,
+ * and core supports them — but Protocol 4's roster member is the standard actor
+ * object with no rank field, so the only leadership this module can see is the
+ * board's single `leader_serial` from `guild.update`. Reporting a guessed second
+ * leader would be worse than reporting one honestly.
+ *
+ * Raising this to the full set is a protocol change (rank on the actor object),
+ * not something this file can fix.
+ */
+async function getTeamLeaders(externalId) {
+  const ready = await boardIsCurrent()
+  if (!ready.ok) return refuse(ready.reason)
+
+  try {
+    const [guild] = await db.findGuild(externalId)
+    if (!guild) return refuse(`guild ${externalId} is not on the board`)
+    return { ok: true, leaders: guild.leader_serial ? [guild.leader_serial] : [] }
+  } catch (err) {
+    log.warn('getTeamLeaders failed', { externalId, message: err.message })
+    return refuse(`leadership unreadable: ${err.message}`)
+  }
+}
+
+/**
+ * The site account behind a character, or null.
+ *
+ * `web_id` is what the shard itself asserted when it emitted the roster; the
+ * account-link join is the fallback for a member whose roster row predates their
+ * link. Both are coerced through the same check, because `web_id` arrives from
+ * the wire as a string.
+ */
+function resolveUserId(row) {
+  const fromRoster = Number.parseInt(row.web_id, 10)
+  if (Number.isInteger(fromRoster) && fromRoster > 0) return fromRoster
+  const fromLink = Number.parseInt(row.linked_user_id, 10)
+  return Number.isInteger(fromLink) && fromLink > 0 ? fromLink : null
+}
+
+module.exports = { getTeams, getTeamMembers, getTeamLeaders, boardIsCurrent }
diff --git a/server/test/_fakes.js b/server/test/_fakes.js
index 3f13c62..8aaee4d 100644
--- a/server/test/_fakes.js
+++ b/server/test/_fakes.js
@@ -95,6 +95,7 @@ function fakeApi() {
     extensions: [],
     streams: null,
     legs: [],
+    teamProvider: null,
     hooks: {},
   }
   const called = new Set()
@@ -107,6 +108,10 @@ function fakeApi() {
     registerExtension(slot, router) { record.extensions.push({ slot, router }) },
     registerNotificationStreams(streams) { once('registerNotificationStreams'); record.streams = streams },
     registerAnnounceLeg(leg) { record.legs.push(leg) },
+    // MODULE_API 1.6.0. `once` because core holds a single provider per
+    // deployment — a second registration is a collision there, so it has to be
+    // one here too, or this suite would pass a shape core rejects at load.
+    registerTeamProvider(provider) { once('registerTeamProvider'); record.teamProvider = provider },
     onBoot(fn) { once('onBoot'); record.hooks.onBoot = fn },
     onShutdown(fn) { once('onShutdown'); record.hooks.onShutdown = fn },
   }
diff --git a/server/test/entry.test.js b/server/test/entry.test.js
index cc4ee2d..91b9249 100644
--- a/server/test/entry.test.js
+++ b/server/test/entry.test.js
@@ -85,6 +85,35 @@ test('every registered stream is namespaced or grandfathered', () => {
   }
 })
 
+test('registers a Team provider with all three methods', () => {
+  // Core requires all three: a provider that could list Teams but not their
+  // members would leave core holding Teams it can never populate, which is not
+  // the same as a call that fails. Asserted here so a refactor that drops one
+  // fails in this suite rather than at load on an operator's install.
+  const api = fakeApi()
+  register(fakeCtx(), api)
+
+  const provider = api.record.teamProvider
+  assert.ok(provider, 'a UO guild is a Team; something has to answer for them')
+  for (const method of ['getTeams', 'getTeamMembers', 'getTeamLeaders']) {
+    assert.strictEqual(typeof provider[method], 'function', `${method} is missing`)
+  }
+})
+
+test('registration does not call the provider, or touch the database', async () => {
+  // register() runs while core's app.js is still being required, with the pool
+  // pointed at a dead port — routeManifest.js and swagger.js both depend on that.
+  // Registration is a CLAIM; core does not ask anything until it reconciles,
+  // which is after onBoot.
+  const ctx = fakeCtx()
+  let queried = false
+  const frozen = Object.freeze({ ...ctx, db: Object.freeze({ query: async () => { queried = true; return [] } }) })
+  const api = fakeApi()
+
+  register(frozen, api)
+  assert.equal(queried, false, 'a query at registration time would hang the manifest and the spec build')
+})
+
 test('takes a frozen ctx and does not try to write to it', () => {
   const ctx = fakeCtx()
   assert.ok(Object.isFrozen(ctx))
diff --git a/server/test/teamProvider.test.js b/server/test/teamProvider.test.js
new file mode 100644
index 0000000..4780b15
--- /dev/null
+++ b/server/test/teamProvider.test.js
@@ -0,0 +1,246 @@
+// module-uo's Team provider (docs/website/TEAMS.md §2.3, MODULE_API.md 1.6.0).
+//
+// The tests that matter here are the REFUSALS. Core's contract is that module
+// unavailability becomes staleness and never emptiness, and this module is the
+// only thing that can honour it — an empty array from here is read as an
+// authoritative "there are none", and core makes destructive decisions from an
+// authoritative answer. Every state where this module cannot honestly claim to
+// know is asserted below, because each one is a plausible place for someone to
+// later "simplify" the guard away and get a plausible-looking empty list.
+process.env.DB_HOST = '127.0.0.1'
+process.env.DB_PORT = '59999'
+
+const { test, beforeEach, afterEach } = require('node:test')
+const assert = require('node:assert/strict')
+
+const core = require('../core')
+
+// The provider reaches the database through core, which is initialised with a ctx
+// in production. A minimal one is enough here — the db layer is stubbed anyway.
+core.init({
+  db: { query: async () => [] },
+  log: () => ({ error() {}, warn() {}, info() {}, debug() {} }),
+  moduleId: 'uo',
+})
+
+const db = require('../model/teamProvider/teamProvider.db')
+const uoLinkConfig = require('../model/uoLinkConfig/uoLinkConfig.model')
+const uoLinkSocket = require('../utils/uoLinkSocket')
+const provider = require('../model/teamProvider/teamProvider.model')
+
+const saved = []
+function patch(mod, name, fn) {
+  saved.push([mod, name, mod[name]])
+  mod[name] = fn
+}
+
+// The healthy default: configured, enabled, connected. Each test then breaks only
+// the thing it is about.
+function healthy() {
+  patch(uoLinkConfig, 'getSafe', async () => ({ baseUrl: 'http://127.0.0.1:7787', enabled: true }))
+  patch(uoLinkSocket, 'getState', () => ({ connected: true, running: true }))
+}
+
+const guild = (extra = {}) => ({
+  id: 1, name: 'The Silver Hand', abbr: 'TSH', alliance: null,
+  members: 2, online: 1, leader_serial: '0x1', leader_name: 'Aldric', leader_acct: 'aldric', ...extra,
+})
+
+const member = (extra = {}) => ({
+  serial: '0x1', name: 'Aldric', acct: 'aldric', web_id: null, is_player: 1,
+  linked_user_id: null, is_online: 0, ...extra,
+})
+
+beforeEach(healthy)
+afterEach(() => {
+  while (saved.length) {
+    const [mod, name, fn] = saved.pop()
+    mod[name] = fn
+  }
+})
+
+// ── The refusals ───────────────────────────────────────────────────────────
+
+test('no uo-link configured refuses, on all three methods', async () => {
+  patch(uoLinkConfig, 'getSafe', async () => ({ baseUrl: null, enabled: false }))
+  patch(db, 'listGuilds', async () => { throw new Error('must not be read') })
+
+  for (const answer of [await provider.getTeams(), await provider.getTeamMembers('1'), await provider.getTeamLeaders('1')]) {
+    assert.equal(answer.ok, false)
+    assert.match(answer.reason, /no uo-link configured/)
+    assert.equal(answer.teams, undefined)
+    assert.equal(answer.members, undefined)
+  }
+})
+
+test('a disabled integration refuses rather than reporting a frozen board', async () => {
+  patch(uoLinkConfig, 'getSafe', async () => ({ baseUrl: 'http://x', enabled: false }))
+  const answer = await provider.getTeams()
+  assert.equal(answer.ok, false)
+  assert.match(answer.reason, /disabled/)
+})
+
+test('a disconnected socket refuses, even though the board is still there', async () => {
+  // The tempting mistake, stated as a test: the board is durable and survives an
+  // outage, so serving it looks harmless. Core cannot tell a board five minutes
+  // stale from one five days stale, and it archives Teams and departs members
+  // from a complete answer.
+  patch(uoLinkSocket, 'getState', () => ({ connected: false, running: true }))
+  patch(db, 'listGuilds', async () => [guild()])
+
+  const answer = await provider.getTeams()
+  assert.equal(answer.ok, false)
+  assert.match(answer.reason, /not connected/)
+  assert.equal(answer.teams, undefined, 'a stale board must not arrive as authoritative')
+})
+
+test('a database error refuses instead of throwing at core', async () => {
+  patch(db, 'listGuilds', async () => { throw new Error('table gone') })
+  const answer = await provider.getTeams()
+  assert.equal(answer.ok, false)
+  assert.match(answer.reason, /table gone/)
+})
+
+test('a guild absent from the board refuses rather than reporting an empty roster', async () => {
+  patch(db, 'findGuild', async () => [])
+  const members = await provider.getTeamMembers('99')
+  assert.equal(members.ok, false)
+  assert.match(members.reason, /not on the board/)
+
+  const leaders = await provider.getTeamLeaders('99')
+  assert.equal(leaders.ok, false)
+})
+
+test('a roster that has not arrived yet refuses — the board count is what tells us', async () => {
+  // Protocol 4's roster arrives on its own frames, separately from the
+  // guild.update that creates the board row, so there is a real window where a
+  // 155-member guild has no roster rows. Reporting that as an empty roster would
+  // depart every member.
+  patch(db, 'findGuild', async () => [guild({ members: 155 })])
+  patch(db, 'listGuildMembers', async () => [])
+
+  const answer = await provider.getTeamMembers('1')
+  assert.equal(answer.ok, false)
+  assert.match(answer.reason, /has not arrived yet/)
+  assert.match(answer.reason, /155/, 'the count is in the message, because it is the evidence')
+})
+
+test('a guild the board says is genuinely empty reports an empty roster', async () => {
+  // The other side of the same coin: when the board itself says zero, an empty
+  // roster is the truth and withholding it would freeze a disbanding guild's
+  // membership forever.
+  patch(db, 'findGuild', async () => [guild({ members: 0 })])
+  patch(db, 'listGuildMembers', async () => [])
+
+  const answer = await provider.getTeamMembers('1')
+  assert.equal(answer.ok, true)
+  assert.deepEqual(answer.members, [])
+})
+
+// ── The good answers ───────────────────────────────────────────────────────
+
+test('a guild becomes a Team keyed on its persistent ServUO id', async () => {
+  // The id survives a rename, which is what lets core apply its rename rule
+  // instead of seeing an unrelated new guild.
+  patch(db, 'listGuilds', async () => [guild()])
+  const answer = await provider.getTeams()
+
+  assert.equal(answer.ok, true)
+  assert.equal(answer.complete, true)
+  assert.deepEqual(answer.teams, [
+    { externalId: '1', name: 'The Silver Hand', abbr: 'TSH', meta: null },
+  ])
+})
+
+test('an alliance rides along as opaque meta', async () => {
+  patch(db, 'listGuilds', async () => [guild({ alliance: 'The Concord' })])
+  const { teams } = await provider.getTeams()
+  assert.deepEqual(teams[0].meta, { alliance: 'The Concord' })
+})
+
+test('the external id is a string, so core never compares a number to one', async () => {
+  patch(db, 'listGuilds', async () => [guild({ id: 42 })])
+  const { teams } = await provider.getTeams()
+  assert.equal(teams[0].externalId, '42')
+})
+
+test('a roster maps to the member shape core expects', async () => {
+  patch(db, 'findGuild', async () => [guild()])
+  patch(db, 'listGuildMembers', async () => [
+    member({ serial: '0x1', name: 'Aldric', is_online: 1 }),
+    member({ serial: '0x2', name: 'Bree', acct: null, is_online: 0 }),
+  ])
+
+  const { members } = await provider.getTeamMembers('1')
+  assert.equal(members.length, 2)
+  assert.equal(members[0].memberKey, '0x1')
+  assert.equal(members[0].displayName, 'Aldric')
+  assert.equal(members[0].online, true)
+  assert.equal(members[0].leader, true, 'matches the board’s leader_serial')
+  assert.equal(members[1].leader, false)
+  assert.equal(members[1].online, false)
+})
+
+test('rankLabel is null, honestly — the wire carries no guild rank', async () => {
+  // The roster member is the standard actor object (serial, name, player, acct?,
+  // webId?). Inventing a rank from the leader flag would be core displaying a
+  // label this module made up.
+  patch(db, 'findGuild', async () => [guild()])
+  patch(db, 'listGuildMembers', async () => [member()])
+  const { members } = await provider.getTeamMembers('1')
+  assert.equal(members[0].rankLabel, null)
+})
+
+test('a member with no account at all is fine and unlinked', async () => {
+  // §2.3 of the protocol spec: acct is genuinely optional — a PlayerMobile can
+  // have no Account, and the local test world contains such mobiles.
+  patch(db, 'findGuild', async () => [guild()])
+  patch(db, 'listGuildMembers', async () => [member({ acct: null, web_id: null, linked_user_id: null })])
+  const { members } = await provider.getTeamMembers('1')
+  assert.equal(members[0].userId, null)
+})
+
+test('userId comes from the roster’s web_id first, then the link table', async () => {
+  patch(db, 'findGuild', async () => [guild()])
+  patch(db, 'listGuildMembers', async () => [
+    member({ serial: '0xA', web_id: '7', linked_user_id: 99 }),   // roster wins
+    member({ serial: '0xB', web_id: null, linked_user_id: 12 }),  // fallback
+    member({ serial: '0xC', web_id: '0', linked_user_id: null }), // neither
+  ])
+  const { members } = await provider.getTeamMembers('1')
+  assert.equal(members[0].userId, 7, 'what the shard itself asserted at roster time')
+  assert.equal(members[1].userId, 12, 'the fallback for a row that predates the link')
+  assert.equal(members[2].userId, null)
+})
+
+test('web_id arrives as a string from the wire and is coerced', async () => {
+  patch(db, 'findGuild', async () => [guild()])
+  patch(db, 'listGuildMembers', async () => [member({ web_id: '42' })])
+  const { members } = await provider.getTeamMembers('1')
+  assert.equal(members[0].userId, 42)
+  assert.equal(typeof members[0].userId, 'number')
+})
+
+test('leadership is the board’s single leader — one, and honestly one', async () => {
+  // TEAMS.md §2.5 expects multiple leaders (GuildRank.Rank >= 4) and core
+  // supports them, but Protocol 4 does not put rank on the wire. Raising this to
+  // the full set is a protocol change, not something this file can fix.
+  patch(db, 'findGuild', async () => [guild({ leader_serial: '0x1' })])
+  assert.deepEqual((await provider.getTeamLeaders('1')).leaders, ['0x1'])
+})
+
+test('a guild with no leader on the board reports none rather than guessing', async () => {
+  patch(db, 'findGuild', async () => [guild({ leader_serial: null })])
+  const answer = await provider.getTeamLeaders('1')
+  assert.equal(answer.ok, true)
+  assert.deepEqual(answer.leaders, [])
+})
+
+test('an empty board is an authoritative empty list — the shard really has no guilds', async () => {
+  // Distinct from every refusal above: the socket is connected and the board is
+  // readable, so "no guilds" is a fact. Core still quarantines it before acting.
+  patch(db, 'listGuilds', async () => [])
+  const answer = await provider.getTeams()
+  assert.equal(answer.ok, true)
+  assert.deepEqual(answer.teams, [])
+})