diff --git a/server/src/auth/session.middleware.js b/server/src/auth/session.middleware.js
index 1171858..93ca03e 100644
--- a/server/src/auth/session.middleware.js
+++ b/server/src/auth/session.middleware.js
@@ -79,6 +79,44 @@ async function requireAuth(req, res, next) {
   }
 }
 
+// Best-effort AUTHENTICATION, as opposed to attachSession's best-effort decode.
+//
+// For a PUBLIC route whose content — not merely its presentation — depends on who
+// is asking. The Team activity feed is the first: `public` items go to everyone
+// and `members` items only to members and forum-granted users (TEAMS.md §4.3), so
+// an anonymous caller must be served, not rejected, and an authenticated one must
+// be identified properly.
+//
+// "Properly" is why this is not attachSession. That one decodes the token and
+// stops, which is right for reading back your own session but wrong here: a
+// banned account, a password change, or a logout would all keep working against
+// the private half of the feed until the JWT expired. This runs the same
+// database re-validation requireAuth does — status, cutoff, revocation — and on
+// any failure continues ANONYMOUSLY rather than 401ing. A caller whose session is
+// no longer good sees the public feed, which is exactly what they are entitled to.
+//
+// A database error also degrades to anonymous. On a public route the safe
+// direction is to serve less, and 500ing a page because a session lookup failed
+// would take the whole Team page down for callers who never sent a token.
+async function optionalAuth(req, res, next) {
+  const session = sessionService.validateSession(req)
+  if (!session) return next()
+  try {
+    const user = await users.getById(session.userId)
+    if (!user) return next()
+    if (user.status && user.status !== 'active') return next()
+    if (isBeforeCutoff(session, user.tokens_valid_after)) return next()
+    if (await sessionService.isSessionRevoked(session.sessionId)) return next()
+
+    req.user = user
+    req.session = session
+    req.authMethod = session.authMethod
+  } catch (err) {
+    log.warn('optionalAuth: continuing anonymously', { message: err.message })
+  }
+  return next()
+}
+
 // Gate middleware factory: allow only the listed roles. Assumes requireAuth ran
 // first so req.user is populated. Use for admin-only endpoints (users, site
 // mode, settings) so a lower-privilege editor cannot reach them.
@@ -91,6 +129,7 @@ function requireRole(...roles) {
 
 module.exports = {
   attachSession,
+  optionalAuth,
   requireAuth,
   requireRole,
 }
diff --git a/server/src/model/teams/teamProvider.js b/server/src/model/teams/teamProvider.js
index 945f983..b2253b7 100644
--- a/server/src/model/teams/teamProvider.js
+++ b/server/src/model/teams/teamProvider.js
@@ -163,10 +163,66 @@ function normaliseLeaders(answer) {
   return { ok: true, leaders }
 }
 
+/**
+ * `{ ok, members: [memberKey] }` — WHICH rows the module permits this viewer.
+ *
+ * Deliberately a set of keys rather than a set of rows. Core already holds the
+ * rows and knows their public shape; asking the module for rows back would let a
+ * module widen what is published — re-adding a `userId` or a `memberKey` that
+ * §3.2 says is never published — and core's field guarantee would then rest on
+ * every module's good behaviour rather than on core. So the module answers the
+ * question it actually owns (who may be seen at this rung) and core keeps the
+ * question it owns (what a member row looks like in public).
+ */
+function normaliseVisibleKeys(answer) {
+  if (!Array.isArray(answer.members)) return fail('projectRoster() answered ok with no members array')
+  const keys = []
+  for (const raw of answer.members) {
+    const key = str(raw)
+    if (!key) return fail('a projectRoster() entry is not a member key')
+    if (!keys.includes(key)) keys.push(key)
+  }
+  return { ok: true, members: keys }
+}
+
 const getTeams = () => call('getTeams', normaliseTeams)
 const getTeamMembers = (externalId) => call('getTeamMembers', normaliseMembers, externalId)
 const getTeamLeaders = (externalId) => call('getTeamLeaders', normaliseLeaders, externalId)
 
+/**
+ * Ask the module which roster rows this viewer may see (§3.3).
+ *
+ * The per-audience projection is the module's because the visibility framework
+ * and its rung configuration are module-owned (§10.5) — core does not know what a
+ * rung is. Core supplies the roster and a description of the viewer; the module
+ * returns the member keys it permits.
+ *
+ * **"No audience model" and "could not answer" are different, and the caller must
+ * be able to tell them apart** — so the refusal carries `projects`.
+ *
+ *   `projects: false` — no provider is registered, or the registered one does not
+ *     implement `projectRoster`. There is no rung system to consult and nothing
+ *     is being withheld; the roster is served at core's public shape. This is why
+ *     the member is OPTIONAL: bare core, and a module with no audience model of
+ *     its own, both render exactly the page core writes.
+ *
+ *   `projects: true` — the module HAS an audience model and core could not reach
+ *     it (refused, threw, timed out, answered malformed). Here the caller must
+ *     fail CLOSED, because "leave it alone" would mean publishing the very rows
+ *     the rungs exist to withhold. This is the one place in the Team subsystem
+ *     where unavailability is not staleness: everywhere else a refused call
+ *     leaves data alone, and doing that to a *visibility* question is a leak.
+ */
+async function projectRoster(externalId, members, viewer) {
+  const provider = registries.registeredTeamProvider()
+  if (!provider) return { ...fail('no team provider is registered'), projects: false }
+  if (typeof provider.projectRoster !== 'function') {
+    return { ...fail('provider does not project rosters'), projects: false }
+  }
+  const answer = await call('projectRoster', normaliseVisibleKeys, externalId, members, viewer)
+  return answer.ok ? answer : { ...answer, projects: true }
+}
+
 /** Which module is authoritative, or null. The reconciler keys sync state on it. */
 const providerModuleId = () => {
   const provider = registries.registeredTeamProvider()
@@ -177,6 +233,7 @@ module.exports = {
   getTeams,
   getTeamMembers,
   getTeamLeaders,
+  projectRoster,
   providerModuleId,
   CALL_TIMEOUT_MS,
 }
diff --git a/server/src/model/teams/teams.model.js b/server/src/model/teams/teams.model.js
index 7f09dae..c25eff2 100644
--- a/server/src/model/teams/teams.model.js
+++ b/server/src/model/teams/teams.model.js
@@ -156,6 +156,16 @@ async function listPublic({ limit = 50, offset = 0 } = {}) {
     teams: visible.slice(offset, offset + limit).map(publicTeam),
     total: visible.length,
     ...sync,
+    // What the `teams` nav feature flag resolves from (§3.5). True if a provider
+    // is registered OR any Team exists — the second half matters because Team
+    // rows outlive the module that filled them, and hiding the nav entry the
+    // moment a module is uninstalled would make every existing Team page
+    // unreachable from the site while still answering by URL.
+    //
+    // False only when there is nothing and no prospect of anything, which is
+    // exactly the bare-core case the flag exists for: a link to a permanently
+    // empty page is worse than no link.
+    enabled: Boolean(sync.configured) || visible.length > 0,
   }
 }
 
@@ -174,6 +184,19 @@ async function getPublic(slug) {
   const successor = row.succeeded_by ? await teamsDb.findById(row.succeeded_by) : null
   return {
     ...publicTeam(row),
+    // The three props the `team.overview` extension slot is declared with
+    // (§3.4). A module's slot component runs in the browser and has to know
+    // WHICH Team it is looking at, in its own vocabulary — `slug` is core's name
+    // for it and resolves nothing on the module's side.
+    //
+    // On this route only, deliberately: the index has no slot and would
+    // otherwise publish a module-internal identifier per row for nothing. None
+    // of the three names a person — they are a core row id, a game-side group
+    // id and a module name, and the identifiers §3.2 withholds (member keys,
+    // site account ids) are not among them.
+    id: row.id,
+    externalId: row.external_id,
+    moduleId: row.module_id,
     ...sync,
     successor: successor && !successor.hidden
       ? { slug: successor.slug, name: successor.display_name_override || successor.name }
@@ -181,14 +204,50 @@ async function getPublic(slug) {
   }
 }
 
-async function rosterPublic(slug) {
+/**
+ * A Team's roster, projected for the caller's audience rung (§3.3).
+ *
+ * The ROW filter is the module's: it owns the visibility framework and its
+ * configuration (§10.5), and core does not know what a rung is. The FIELD shape
+ * stays core's — every row that survives goes through `publicMember`, which
+ * withholds the member key and the user id whatever the module answers. So a
+ * module can narrow what is published and cannot widen it, and core's "neither is
+ * published" guarantee does not rest on every module's good behaviour.
+ *
+ * **A module that HAS a rung system and cannot answer withholds the roster.** That
+ * is the one Team call where a refusal is not staleness: leaving a visibility
+ * answer "alone" would publish the very rows the rungs exist to withhold. A
+ * deployment with no module, or one whose module does not project at all, is a
+ * different case entirely — nothing is being withheld there, so the roster is
+ * served whole at core's public shape (`projects: false`).
+ */
+async function rosterPublic(slug, viewer = null) {
   const row = await teamsDb.findBySlug(slug)
   if (!row || row.hidden) return null
   const [members, sync] = await Promise.all([
     access.rosterWithOverrides(row.id),
     syncStatus(),
   ])
-  return { members: members.map(publicMember), ...sync, rosterSyncedAt: row.roster_synced_at }
+
+  // The module gets the rows as it supplied them — this is its own data coming
+  // home — plus who is asking, which is all a rung decision needs.
+  const answer = await teamProvider.projectRoster(row.external_id, members, viewer)
+  let visible
+  if (answer.ok) visible = members.filter((m) => answer.members.includes(m.member_key))
+  else if (answer.projects) visible = [] // fail closed: it has rungs and we could not ask
+  else visible = members                 // nothing to fail closed ABOUT
+
+  return {
+    members: visible.map(publicMember),
+    ...sync,
+    rosterSyncedAt: row.roster_synced_at,
+    // Stated rather than implied. An empty roster has three quite different
+    // causes — a Team with no members, a rung that shows none, and a module that
+    // could not be asked — and a page that cannot tell them apart will report the
+    // last one as the first.
+    projected: answer.ok,
+    ...(answer.ok || !answer.projects ? {} : { projectionUnavailable: true }),
+  }
 }
 
 // ── Player ─────────────────────────────────────────────────────────────────
diff --git a/server/src/modules/registries.js b/server/src/modules/registries.js
index 7165f8e..e0fa24c 100644
--- a/server/src/modules/registries.js
+++ b/server/src/modules/registries.js
@@ -243,11 +243,22 @@ function checkLegShape(entry) {
   return { leg, label: label || leg, dispatch, classify }
 }
 
-// All three methods are REQUIRED, with no optional half. A provider that could
-// list Teams but not their members would leave core holding Teams it can never
+// Three methods are REQUIRED, with no optional half. A provider that could list
+// Teams but not their members would leave core holding Teams it can never
 // populate, and the reconciler has no sensible behaviour for that — it is not the
 // same as a call that fails, which is staleness and already handled (§2.4). A
 // module unable to answer one of the three answers `{ ok: false }` at call time.
+//
+// `projectRoster` is the fourth and is OPTIONAL (TEAMS.md §3.3): it expresses an
+// audience model, and a module with no rung system of its own has no opinion to
+// express. Omitting it means core serves rosters at its own public shape;
+// implementing it means core fails CLOSED when the call cannot be made, so this
+// is a member to add deliberately rather than by habit.
+//
+// The copy is explicit rather than a spread: this object is what core calls, so
+// anything not named here is not part of the contract and must not survive
+// registration. A method that silently rode along would look implemented from the
+// module's side and be invisible from core's.
 function checkTeamProviderShape(entry) {
   const provider = entry || {}
   const out = {}
@@ -257,6 +268,12 @@ function checkTeamProviderShape(entry) {
     }
     out[name] = provider[name]
   }
+  if (provider.projectRoster !== undefined) {
+    if (typeof provider.projectRoster !== 'function') {
+      throw new Error('registerTeamProvider: projectRoster must be a function if present')
+    }
+    out.projectRoster = provider.projectRoster
+  }
   return out
 }
 
diff --git a/server/src/router/v1/public/teams.controller.js b/server/src/router/v1/public/teams.controller.js
index 701cc9b..e92da83 100644
--- a/server/src/router/v1/public/teams.controller.js
+++ b/server/src/router/v1/public/teams.controller.js
@@ -5,6 +5,7 @@
 // marked stale, because that is what the projection is for.
 
 const teams = require('../../../model/teams/teams.model')
+const teamActivity = require('../../../model/teams/teamActivity.model')
 
 const log = require('../../../utils/logger')('teams')
 
@@ -35,9 +36,18 @@ async function getTeam(req, res) {
   }
 }
 
+/**
+ * The roster, projected for whoever is asking (§3.3).
+ *
+ * The viewer is described to the module rather than handed over: it gets the
+ * caller's id and role, which is what a rung decision turns on, and not the user
+ * row — a module has `ctx.users.getById` if it needs more, and passing the whole
+ * record here would make every column of `users` part of this contract.
+ */
 async function getRoster(req, res) {
   try {
-    const roster = await teams.rosterPublic(req.params.slug)
+    const viewer = req.user ? { userId: req.user.id, role: req.user.role } : null
+    const roster = await teams.rosterPublic(req.params.slug, viewer)
     if (!roster) return res.status(404).json({ message: 'Team not found' })
     return res.json(roster)
   } catch (err) {
@@ -45,4 +55,28 @@ async function getRoster(req, res) {
   }
 }
 
-module.exports = { listTeams, getTeam, getRoster }
+/**
+ * A Team's activity feed (§4.3).
+ *
+ * The only handler in this tier that reads `req.user`, and it reads nothing else
+ * from the caller about what they may see: `limit` and `offset` are page
+ * controls, and the visibility filter is resolved from the session alone. A
+ * request parameter naming its own visibility is the bug the ENUM exists to
+ * prevent, so there is deliberately no way to ask for one.
+ *
+ * The cap is 100 rather than the index's 200 — every row carries a summary and an
+ * opaque payload, so a page of these is much larger than a page of Teams.
+ */
+async function getActivity(req, res) {
+  try {
+    const limit = Math.min(Math.max(Number.parseInt(req.query.limit, 10) || 50, 1), 100)
+    const offset = Math.max(Number.parseInt(req.query.offset, 10) || 0, 0)
+    const feed = await teamActivity.feedFor(req.params.slug, req.user ? req.user.id : null, { limit, offset })
+    if (!feed) return res.status(404).json({ message: 'Team not found' })
+    return res.json(feed)
+  } catch (err) {
+    return fail(res, err, 'activity')
+  }
+}
+
+module.exports = { listTeams, getTeam, getRoster, getActivity }
diff --git a/server/src/router/v1/public/teams.router.js b/server/src/router/v1/public/teams.router.js
index 3b17d25..71f12ef 100644
--- a/server/src/router/v1/public/teams.router.js
+++ b/server/src/router/v1/public/teams.router.js
@@ -12,6 +12,7 @@ const express = require('express')
 
 const ctrl = require('./teams.controller')
 const siteMode = require('../../../middleware/siteMode')
+const { optionalAuth } = require('../../../auth/session.middleware')
 
 const teamsRouter = express.Router()
 
@@ -43,12 +44,34 @@ teamsRouter.get(
   '/:slug/members',
   // #swagger.tags = ['Public · Teams']
   // #swagger.summary = 'Get a Team roster'
-  // #swagger.description = 'In-game display names only. A member key is a game-internal identifier and a user id names a site account; neither is published. `linked` answers whether a character has an account behind it without saying which.'
+  // #swagger.description = 'In-game display names only. A member key is a game-internal identifier and a user id names a site account; neither is published, whatever the module’s projection answers. `linked` answers whether a character has an account behind it without saying which. WHICH rows appear is the module’s audience projection; sending a session is optional and may widen it.'
   // #swagger.parameters['slug'] = { in: 'path', required: true, schema: { type: 'string' }, description: 'The Team slug.' }
+  // #swagger.security = [{}, { "cookieAuth": [] }, { "bearerAuth": [] }]
   /* #swagger.responses[200] = { description: 'The roster, with sync freshness', content: { "application/json": { schema: { $ref: "#/components/schemas/PublicTeamRoster" } } } } */
   /* #swagger.responses[404] = { description: 'No such Team, or it is hidden', content: { "application/json": { schema: { $ref: "#/components/schemas/Error" } } } } */
   siteMode,
+  optionalAuth,
   ctrl.getRoster,
 )
 
+// The one route in this tier that reads the caller's identity. `optionalAuth`
+// serves anonymous callers rather than rejecting them, and identifies an
+// authenticated one properly enough that a banned or logged-out account drops
+// back to the public half of the feed at once (TEAMS.md §4.3).
+teamsRouter.get(
+  '/:slug/activity',
+  // #swagger.tags = ['Public · Teams']
+  // #swagger.summary = 'A Team’s activity feed, filtered to what the caller may see'
+  // #swagger.description = 'Items are `public` or `members`. Anyone who can see the Team gets the public ones; members and forum-granted users also get the members-only ones, and the response says which via `scope` so a client can render "some items are hidden" rather than presenting a filtered feed as the whole one. Sending a session is optional.'
+  // #swagger.parameters['slug'] = { in: 'path', required: true, schema: { type: 'string' }, description: 'The Team slug.' }
+  // #swagger.parameters['limit'] = { in: 'query', required: false, schema: { type: 'integer' }, description: 'Page size, max 100 (default 50).' }
+  // #swagger.parameters['offset'] = { in: 'query', required: false, schema: { type: 'integer' }, description: 'Rows to skip (default 0).' }
+  // #swagger.security = [{}, { "cookieAuth": [] }, { "bearerAuth": [] }]
+  /* #swagger.responses[200] = { description: 'One page of the feed', content: { "application/json": { schema: { $ref: "#/components/schemas/PublicTeamActivity" } } } } */
+  /* #swagger.responses[404] = { description: 'No such Team, or it is hidden from this caller', content: { "application/json": { schema: { $ref: "#/components/schemas/Error" } } } } */
+  siteMode,
+  optionalAuth,
+  ctrl.getActivity,
+)
+
 module.exports = teamsRouter
diff --git a/server/swagger/swagger.js b/server/swagger/swagger.js
index 03ebf40..47731ee 100644
--- a/server/swagger/swagger.js
+++ b/server/swagger/swagger.js
@@ -979,6 +979,12 @@ const doc = {
         properties: {
           teams: { type: 'array', items: { $ref: '#/components/schemas/PublicTeam' } },
           total: { type: 'integer', example: 12 },
+          enabled: {
+            type: 'boolean',
+            description:
+              'Whether this deployment has Teams at all — a provider is registered, or Teams exist from one that since went away. The `teams` nav feature flag resolves from this; false means bare core, where a Teams link would lead to a permanently empty page.',
+            example: true,
+          },
         },
       },
       PublicTeamMember: {
@@ -999,6 +1005,41 @@ const doc = {
         properties: {
           members: { type: 'array', items: { $ref: '#/components/schemas/PublicTeamMember' } },
           rosterSyncedAt: { type: 'string', format: 'date-time', nullable: true },
+          projected: {
+            type: 'boolean',
+            description:
+              'Whether the module applied its own audience projection to this roster. False means the module declined or does not project, and the roster was served at core’s public shape — never the full one.',
+            example: true,
+          },
+        },
+      },
+      PublicTeamActivityItem: {
+        type: 'object',
+        description:
+          '`summary` is already-rendered text supplied by whoever pushed the item; core never composes one. `kind` and `payload` are opaque to core — only the module’s `team.overview` slot renders anything richer than the text.',
+        properties: {
+          id: { type: 'integer', example: 4821 },
+          source: { type: 'string', description: '`core` or a module id.', example: 'uo' },
+          kind: { type: 'string', example: 'uo.champion.completed' },
+          summary: { type: 'string', example: 'Completed Champion Neira' },
+          visibility: { type: 'string', enum: ['public', 'members'] },
+          occurredAt: { type: 'string', format: 'date-time' },
+          payload: { type: 'object', nullable: true, additionalProperties: true },
+        },
+      },
+      PublicTeamActivity: {
+        type: 'object',
+        properties: {
+          items: { type: 'array', items: { $ref: '#/components/schemas/PublicTeamActivityItem' } },
+          total: { type: 'integer', description: 'Matching rows for THIS caller’s visibility, so paging is honest.', example: 137 },
+          limit: { type: 'integer', example: 50 },
+          offset: { type: 'integer', example: 0 },
+          scope: {
+            type: 'string',
+            enum: ['public', 'members'],
+            description:
+              'Which visibilities this caller received. `public` means members-only items were withheld — render that fact rather than presenting a filtered feed as the whole one.',
+          },
         },
       },
       PlayerTeamList: {
diff --git a/server/test/teamProvider.test.js b/server/test/teamProvider.test.js
index 75bdd5b..f160d6b 100644
--- a/server/test/teamProvider.test.js
+++ b/server/test/teamProvider.test.js
@@ -287,3 +287,90 @@ test('a hung call does not hold the process open until its deadline', async () =
 test('the budget is the documented ten seconds', () => {
   assert.equal(teamProvider.CALL_TIMEOUT_MS, 10_000)
 })
+
+// ── projectRoster: the optional fourth member (§3.3) ───────────────────────
+//
+// The one Team call where a refusal must NOT be treated as staleness. Every test
+// below exists because the obvious implementation — reuse `call()` and serve the
+// roster when it fails — silently publishes the rows the rungs exist to withhold.
+
+const rows = [{ member_key: '0x1' }, { member_key: '0x2' }]
+
+test('projectRoster is optional: a provider without it registers fine', () => {
+  const api = registries.stage('uo')
+  assert.doesNotThrow(() => api.registerTeamProvider(ok()))
+})
+
+test('a non-function projectRoster is rejected at registration, not at call time', () => {
+  const api = registries.stage('uo')
+  assert.throws(
+    () => api.registerTeamProvider({ ...ok(), projectRoster: 'yes please' }),
+    /projectRoster must be a function/,
+  )
+})
+
+test('an unregistered method cannot ride along into the provider core calls', () => {
+  register('uo', { ...ok(), somethingElse: async () => 'hi' })
+  assert.equal(registries.registeredTeamProvider().somethingElse, undefined)
+})
+
+test('no provider at all is projects:false — nothing is being withheld', async () => {
+  const answer = await teamProvider.projectRoster('g1', rows, null)
+  assert.equal(answer.ok, false)
+  assert.equal(answer.projects, false)
+})
+
+test('a provider that does not project is projects:false, not a failure to fear', async () => {
+  register('uo', ok())
+  const answer = await teamProvider.projectRoster('g1', rows, null)
+  assert.equal(answer.ok, false)
+  assert.equal(answer.projects, false)
+})
+
+test('a provider that HAS projectRoster and refuses is projects:true — the caller must fail closed', async () => {
+  register('uo', { ...ok(), projectRoster: async () => ({ ok: false, reason: 'atlas not loaded' }) })
+  const answer = await teamProvider.projectRoster('g1', rows, null)
+  assert.equal(answer.ok, false)
+  assert.equal(answer.projects, true)
+  assert.equal(answer.reason, 'atlas not loaded')
+})
+
+test('a projectRoster that throws is projects:true as well — a bug is not permission', async () => {
+  register('uo', { ...ok(), projectRoster: async () => { throw new Error('boom') } })
+  const answer = await teamProvider.projectRoster('g1', rows, null)
+  assert.equal(answer.projects, true)
+})
+
+test('the module receives the rows and the viewer, and answers with member keys', async () => {
+  let seen
+  register('uo', {
+    ...ok(),
+    projectRoster: async (externalId, members, viewer) => {
+      seen = { externalId, members, viewer }
+      return { ok: true, members: ['0x2'] }
+    },
+  })
+  const answer = await teamProvider.projectRoster('g1', rows, { userId: 7, role: 'player' })
+  assert.deepEqual(seen.members, rows)
+  assert.deepEqual(seen.viewer, { userId: 7, role: 'player' })
+  assert.equal(seen.externalId, 'g1')
+  assert.deepEqual(answer.members, ['0x2'])
+})
+
+test('a malformed key list is a refusal, so the caller fails closed rather than serving garbage', async () => {
+  for (const bad of [{ ok: true }, { ok: true, members: ['ok', ''] }, { ok: true, members: 'all' }]) {
+    // eslint-disable-next-line no-await-in-loop
+    register('uo', { ...ok(), projectRoster: async () => bad })
+    // eslint-disable-next-line no-await-in-loop
+    const answer = await teamProvider.projectRoster('g1', rows, null)
+    assert.equal(answer.ok, false, JSON.stringify(bad))
+    assert.equal(answer.projects, true)
+    registries._reset()
+  }
+})
+
+test('duplicate keys are collapsed', async () => {
+  register('uo', { ...ok(), projectRoster: async () => ({ ok: true, members: ['0x1', '0x1', '0x2'] }) })
+  const answer = await teamProvider.projectRoster('g1', rows, null)
+  assert.deepEqual(answer.members, ['0x1', '0x2'])
+})
diff --git a/server/test/teamRoster.test.js b/server/test/teamRoster.test.js
new file mode 100644
index 0000000..a0b45ba
--- /dev/null
+++ b/server/test/teamRoster.test.js
@@ -0,0 +1,122 @@
+// The roster read and its audience projection (docs/website/TEAMS.md §3.2, §3.3).
+//
+// Two questions meet here and the file exists to keep them apart:
+//
+//   WHICH ROWS  is the module's — it owns the visibility framework and its rung
+//               configuration, and core does not know what a rung is.
+//   WHAT A ROW  is core's — the member key and the user id are never published,
+//   LOOKS LIKE  whatever the module answers.
+//
+// The dangerous simplification is to let the module return rows instead of keys:
+// core's field guarantee would then rest on every module's good behaviour rather
+// than on core, and one module re-adding a `userId` would publish site accounts
+// against in-game characters on a public page.
+const { test, beforeEach, afterEach } = require('node:test')
+const assert = require('node:assert/strict')
+
+const teamsDb = require('../src/model/teams/teams.db')
+const access = require('../src/model/teams/teamAccess.model')
+const teamProvider = require('../src/model/teams/teamProvider')
+const teamSync = require('../src/model/teams/teamSync.model')
+const teams = require('../src/model/teams/teams.model')
+
+const saved = new Map()
+
+function patch(mod, name, fn) {
+  if (!saved.has(mod)) saved.set(mod, new Map())
+  if (!saved.get(mod).has(name)) saved.get(mod).set(name, mod[name])
+  mod[name] = fn
+}
+
+function restore() {
+  for (const [mod, names] of saved) for (const [name, fn] of names) mod[name] = fn
+  saved.clear()
+}
+
+const ROWS = [
+  { member_key: '0x1', display_name: 'Aldric', user_id: 7, is_leader: 1, rank_label: 'Leader', online: 1 },
+  { member_key: '0x2', display_name: 'Brenna', user_id: null, is_leader: 0, rank_label: null, online: 0 },
+  { member_key: '0x3', display_name: 'Cadfael', user_id: 9, is_leader: 0, rank_label: null, online: 0 },
+]
+
+beforeEach(() => {
+  patch(teamsDb, 'findBySlug', async (slug) =>
+    (slug === 'the-guild'
+      ? { id: 1, external_id: 'g1', slug, hidden: 0, status: 'active', roster_synced_at: null }
+      : undefined))
+  patch(access, 'rosterWithOverrides', async () => ROWS.map((r) => ({ ...r })))
+  // syncStatus() reads sync state and the poll interval; neither is what this
+  // file is about, and both would otherwise reach the pool.
+  patch(teamProvider, 'providerModuleId', () => null)
+  patch(teamSync, 'intervalSeconds', async () => 900)
+})
+afterEach(restore)
+
+test('with no module projecting, the whole roster is served at core\'s public shape', async () => {
+  patch(teamProvider, 'projectRoster', async () => ({ ok: false, projects: false, reason: 'no provider' }))
+  const roster = await teams.rosterPublic('the-guild', null)
+  assert.equal(roster.members.length, 3)
+  assert.equal(roster.projected, false)
+  assert.equal(roster.projectionUnavailable, undefined, 'nothing was withheld, so nothing to report')
+})
+
+test('the module chooses which rows a viewer sees', async () => {
+  patch(teamProvider, 'projectRoster', async () => ({ ok: true, members: ['0x2'] }))
+  const roster = await teams.rosterPublic('the-guild', null)
+  assert.deepEqual(roster.members.map((m) => m.displayName), ['Brenna'])
+  assert.equal(roster.projected, true)
+})
+
+test('a module that projects but cannot answer withholds the roster — it does not serve it', async () => {
+  // The whole point. "Leave it alone" is right for a roster SYNC and wrong for a
+  // visibility question: it would publish exactly what the rungs withhold.
+  patch(teamProvider, 'projectRoster', async () => ({ ok: false, projects: true, reason: 'sidecar down' }))
+  const roster = await teams.rosterPublic('the-guild', null)
+  assert.deepEqual(roster.members, [])
+  assert.equal(roster.projected, false)
+  assert.equal(roster.projectionUnavailable, true, 'an empty roster must be distinguishable from a silent one')
+})
+
+test('the module cannot widen the published fields, only narrow the rows', async () => {
+  // A module answering with keys it was given still yields core's shape. There is
+  // no answer it can give that puts a member key or a user id on a public page.
+  patch(teamProvider, 'projectRoster', async () => ({ ok: true, members: ['0x1', '0x2', '0x3'] }))
+  const roster = await teams.rosterPublic('the-guild', null)
+  for (const member of roster.members) {
+    assert.deepEqual(
+      Object.keys(member).sort(),
+      ['displayName', 'isLeader', 'linked', 'online', 'rankLabel'],
+      'the public member shape is core\'s and is closed',
+    )
+  }
+  assert.deepEqual(roster.members.map((m) => m.linked), [true, false, true])
+})
+
+test('a key the module invents matches nothing rather than adding a row', async () => {
+  patch(teamProvider, 'projectRoster', async () => ({ ok: true, members: ['0x1', '0xNOPE'] }))
+  const roster = await teams.rosterPublic('the-guild', null)
+  assert.equal(roster.members.length, 1)
+})
+
+test('the viewer is described to the module, not handed over', async () => {
+  let seen
+  patch(teamProvider, 'projectRoster', async (externalId, members, viewer) => {
+    seen = viewer
+    return { ok: true, members: members.map((m) => m.member_key) }
+  })
+  await teams.rosterPublic('the-guild', { userId: 7, role: 'player' })
+  assert.deepEqual(seen, { userId: 7, role: 'player' })
+})
+
+test('an unknown slug is not found, and the module is never consulted about it', async () => {
+  let called = false
+  patch(teamProvider, 'projectRoster', async () => { called = true; return { ok: true, members: [] } })
+  assert.equal(await teams.rosterPublic('no-such-team', null), null)
+  assert.equal(called, false)
+})
+
+test('a hidden team\'s roster does not answer publicly at all', async () => {
+  patch(teamsDb, 'findBySlug', async () => ({ id: 1, external_id: 'g1', slug: 'x', hidden: 1, status: 'active' }))
+  patch(teamProvider, 'projectRoster', async () => ({ ok: true, members: ['0x1'] }))
+  assert.equal(await teams.rosterPublic('x', null), null)
+})