diff --git a/core/http/react-ui/e2e/group-chat.spec.js b/core/http/react-ui/e2e/group-chat.spec.js
new file mode 100644
index 000000000..57c3b76ea
--- /dev/null
+++ b/core/http/react-ui/e2e/group-chat.spec.js
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: MIT
+import { test, expect } from './coverage-fixtures.js'
+
+async function setup(page, models = ['alpha', 'beta']) {
+  await page.route('**/api/**', route => route.fulfill({ json: {} }))
+  await page.route('**/api/auth/status', route => route.fulfill({ json: { authEnabled: false } }))
+  await page.route('**/api/models/capabilities', route => route.fulfill({ json: { data: models.map(id => ({ id, capabilities: ['FLAG_CHAT'] })) } }))
+  await page.goto('/app/group-chat')
+}
+async function participants(page) {
+  await page.getByLabel('Model to add').selectOption('alpha')
+  await page.getByRole('button', { name: 'Add participant', exact: true }).click()
+  await page.getByLabel('Model to add').selectOption('beta')
+  await page.getByRole('button', { name: 'Add participant', exact: true }).click()
+}
+function sse(content = 'Reply', extra = '') {
+  return `data: ${JSON.stringify({ choices: [{ delta: { reasoning_content: 'private reasoning', content } }] })}\n\n${extra}data: [DONE]\n\n`
+}
+
+test('manual turns share attributed history and lock setup', async ({ page }) => {
+  const requests = []
+  await page.route('**/v1/chat/completions', async route => {
+    requests.push(route.request().postDataJSON())
+    await route.fulfill({ contentType: 'text/event-stream', body: sse(`Reply ${requests.length}`) })
+  })
+  await setup(page)
+  await participants(page)
+  await page.getByLabel('Name for alpha').fill('Planner')
+  await page.getByLabel('Objective').fill('Design a garden')
+  await page.getByLabel('Moderator message').fill('Use native plants')
+  await page.getByRole('button', { name: 'Add message', exact: true }).click()
+  await page.getByRole('button', { name: 'Give Planner a turn', exact: true }).click()
+  await expect(page.getByText('Reply 1', { exact: true })).toBeVisible()
+  await expect(page.getByLabel('Objective')).toBeDisabled()
+  await page.getByRole('button', { name: 'Give beta a turn', exact: true }).click()
+  await expect(page.getByText('Reply 2', { exact: true })).toBeVisible()
+  expect(requests.map(r => r.model)).toEqual(['alpha', 'beta'])
+  expect(requests[0].messages[0].content).toContain('Planner')
+  expect(JSON.stringify(requests[1].messages)).toContain('Planner (alpha)')
+  expect(JSON.stringify(requests[1].messages)).toContain('Reply 1')
+  expect(JSON.stringify(requests[1].messages)).not.toContain('private reasoning')
+  expect(requests[1].messages.at(-1).role).toBe('user')
+  expect(requests[1].messages.filter(m => m.role === 'assistant')).toEqual([])
+  await page.getByRole('button', { name: 'New conversation', exact: true }).click()
+  await expect(page.getByText('Reply 1', { exact: true })).toHaveCount(0)
+  await expect(page.getByLabel('Objective')).toBeEnabled()
+})
+
+test('bounded rounds run in order and reject invalid names', async ({ page }) => {
+  const requests = []
+  await page.route('**/v1/chat/completions', route => {
+    requests.push(route.request().postDataJSON().model)
+    return route.fulfill({ contentType: 'text/event-stream', body: sse() })
+  })
+  await setup(page)
+  await participants(page)
+  await page.getByLabel('Name for beta').fill('alpha')
+  await expect(page.getByRole('button', { name: 'Run one round', exact: true })).toBeDisabled()
+  await page.getByLabel('Name for beta').fill('  ')
+  await expect(page.getByRole('button', { name: 'Run one round', exact: true })).toBeDisabled()
+  await page.getByLabel('Name for beta').fill('beta')
+  await page.getByLabel('Number of rounds').fill('11')
+  await expect(page.getByRole('button', { name: 'Run rounds', exact: true })).toBeDisabled()
+  await page.getByLabel('Number of rounds').fill('2')
+  await page.getByRole('button', { name: 'Run rounds', exact: true }).click()
+  await expect(page.getByRole('button', { name: 'Run rounds', exact: true })).toBeEnabled()
+  expect(requests).toEqual(['alpha', 'beta', 'alpha', 'beta'])
+  await page.getByRole('button', { name: 'Run one round', exact: true }).click()
+  await expect(page.getByRole('button', { name: 'Run one round', exact: true })).toBeEnabled()
+  expect(requests).toEqual(['alpha', 'beta', 'alpha', 'beta', 'alpha', 'beta'])
+})
+
+test('stop cancels the run and prevents overlapping turns', async ({ page }) => {
+  let count = 0
+  let release
+  await page.route('**/v1/chat/completions', async route => {
+    count++
+    await new Promise(resolve => { release = resolve })
+    await route.fulfill({ contentType: 'text/event-stream', body: sse('late reply') }).catch(() => {})
+  })
+  await setup(page)
+  await participants(page)
+  await page.getByRole('button', { name: 'Run one round', exact: true }).click()
+  await expect(page.getByRole('button', { name: 'Give beta a turn', exact: true })).toBeDisabled()
+  await expect.poll(() => count).toBe(1)
+  await page.getByRole('button', { name: 'Stop', exact: true }).click()
+  release()
+  await expect(page.getByText('Incomplete', { exact: true })).toBeVisible()
+  await expect(page.getByRole('button', { name: 'Run one round', exact: true })).toBeEnabled()
+  expect(count).toBe(1)
+  await expect(page.getByText('late reply', { exact: true })).toHaveCount(0)
+})
+
+for (const [name, response, message] of [
+  ['HTTP failure', { status: 500, json: { error: { message: 'Backend failed' } } }, 'Backend failed'],
+  ['SSE failure', { contentType: 'text/event-stream', body: 'data: {"error":{"message":"Stream failed"}}\n\n' }, 'Stream failed'],
+  ['empty response', { contentType: 'text/event-stream', body: 'data: [DONE]\n\n' }, 'The model returned no text.'],
+]) {
+  test(`${name} stops remaining turns`, async ({ page }) => {
+    let count = 0
+    await page.route('**/v1/chat/completions', route => { count++; return route.fulfill(response) })
+    await setup(page)
+    await participants(page)
+    await page.getByRole('button', { name: 'Run one round', exact: true }).click()
+    await expect(page.getByRole('alert')).toContainText(message)
+    expect(count).toBe(1)
+  })
+}
+
+test('empty model discovery and chat permission', async ({ page }) => {
+  await setup(page, [])
+  await expect(page.getByText('No installed chat models available.', { exact: true })).toBeVisible()
+  await expect(page.getByRole('button', { name: 'Add participant', exact: true })).toBeDisabled()
+  await page.route('**/api/auth/status', route => route.fulfill({ json: { authEnabled: true, user: { role: 'user', permissions: {} } } }))
+  await page.reload()
+  await expect(page).toHaveURL(/\/app\/?$/)
+})
+
+async function stagedStream(page) {
+  await page.addInitScript(() => {
+    const original = window.fetch
+    window.groupRequests = []
+    window.groupAborted = false
+    window.fetch = async (input, options) => {
+      if (!String(input).endsWith('/v1/chat/completions')) return original(input, options)
+      window.groupRequests.push(JSON.parse(options.body))
+      return new Response(new ReadableStream({
+        start(controller) {
+          controller.enqueue(new TextEncoder().encode('data: {"choices":[{"delta":{"content":"unfinished text"}}]}\n\n'))
+          options.signal.addEventListener('abort', () => {
+            window.groupAborted = true
+            controller.error(new DOMException('Aborted', 'AbortError'))
+          })
+        },
+      }), { headers: { 'Content-Type': 'text/event-stream' } })
+    }
+  })
+}
+
+test('partial abort is excluded from later prompts and leaving cancels a stream', async ({ page }) => {
+  await stagedStream(page)
+  await setup(page)
+  await participants(page)
+  await page.getByRole('button', { name: 'Run one round', exact: true }).click()
+  await expect(page.getByText('unfinished text', { exact: true })).toBeVisible()
+  await page.getByRole('button', { name: 'Stop', exact: true }).click()
+  await expect(page.getByText('Incomplete', { exact: true })).toBeVisible()
+  await page.getByRole('button', { name: 'Give beta a turn', exact: true }).click()
+  const requests = await page.evaluate(() => window.groupRequests)
+  expect(requests).toHaveLength(2)
+  expect(JSON.stringify(requests[1])).not.toContain('unfinished text')
+  await page.evaluate(() => { window.groupAborted = false })
+  await page.getByRole('link', { name: 'Back to Chat', exact: true }).click()
+  await expect.poll(() => page.evaluate(() => window.groupAborted)).toBe(true)
+  await page.getByRole('link', { name: 'Group chat', exact: true }).click()
+  await expect(page.getByText('unfinished text', { exact: true })).toHaveCount(0)
+})
+
+for (const [name, body] of [
+  ['truncated stream', 'data: {"choices":[{"delta":{"content":"partial"}}]}\n\n'],
+  ['malformed stream', 'data: not-json\n\n'],
+]) {
+  test(`${name} fails without scheduling the next participant`, async ({ page }) => {
+    let count = 0
+    await page.route('**/v1/chat/completions', route => { count++; return route.fulfill({ contentType: 'text/event-stream', body }) })
+    await setup(page)
+    await participants(page)
+    await page.getByRole('button', { name: 'Run one round', exact: true }).click()
+    await expect(page.getByRole('alert')).toBeVisible()
+    expect(count).toBe(1)
+  })
+}
diff --git a/core/http/react-ui/src/App.css b/core/http/react-ui/src/App.css
index f5ac4cd18..508494c47 100644
--- a/core/http/react-ui/src/App.css
+++ b/core/http/react-ui/src/App.css
@@ -13791,3 +13791,11 @@ button.lane:hover {
   touch-action: none;
   cursor: grab;
 }
+
+/* Group conversation: shared controls wrap on narrow screens. */
+.group-chat { max-width: 960px; margin: 0 auto; padding: var(--spacing-lg); }
+.group-chat .card { padding: var(--spacing-lg); }
+.group-chat-controls { display: flex; flex-wrap: wrap; align-items: end; gap: var(--spacing-md); }
+.group-chat-controls label { flex: 1 1 180px; }
+.group-chat textarea { width: 100%; resize: vertical; }
+.group-chat-content { white-space: pre-wrap; overflow-wrap: anywhere; }
diff --git a/core/http/react-ui/src/pages/Chat.jsx b/core/http/react-ui/src/pages/Chat.jsx
index d799efba0..7f7a379e5 100644
--- a/core/http/react-ui/src/pages/Chat.jsx
+++ b/core/http/react-ui/src/pages/Chat.jsx
@@ -1,5 +1,5 @@
 import { useState, useEffect, useRef, useCallback, useMemo } from 'react'
-import { useParams, useOutletContext, useNavigate, useLocation } from 'react-router-dom'
+import { Link, useParams, useOutletContext, useNavigate, useLocation } from 'react-router-dom'
 import { useTranslation } from 'react-i18next'
 import { fromState } from '../utils/editorNav'
 import { useChat } from '../hooks/useChat'
@@ -1020,6 +1020,7 @@ export default function Chat() {
             style={{ flex: '1 1 0', minWidth: 120 }}
           />
           <div className="chat-header-actions">
+            <Link className="btn btn-secondary" to="/app/group-chat">{t('group.title', 'Group chat')}</Link>
             {activeChat.model && isAdmin && (
               <button
                 type="button"
diff --git a/core/http/react-ui/src/pages/GroupChat.jsx b/core/http/react-ui/src/pages/GroupChat.jsx
new file mode 100644
index 000000000..3401c7590
--- /dev/null
+++ b/core/http/react-ui/src/pages/GroupChat.jsx
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: MIT
+import { useEffect, useRef, useState } from 'react'
+import { Link } from 'react-router-dom'
+import { useTranslation } from 'react-i18next'
+import { useModels } from '../hooks/useModels'
+import { CAP_CHAT } from '../utils/capabilities'
+import { streamChat } from '../utils/api'
+import { GroupRun, validParticipants } from '../utils/groupChat'
+
+export default function GroupChat() {
+  const { t } = useTranslation('chat')
+  const { models, loading, error: modelError } = useModels(CAP_CHAT)
+  const [model, setModel] = useState('')
+  const [participants, setParticipants] = useState([])
+  const [objective, setObjective] = useState('')
+  const [message, setMessage] = useState('')
+  const [transcript, setTranscript] = useState([])
+  const [rounds, setRounds] = useState('1')
+  const [locked, setLocked] = useState(false)
+  const [running, setRunning] = useState(false)
+  const [error, setError] = useState('')
+  const runner = useRef(null)
+  if (!runner.current) runner.current = new GroupRun(streamChat)
+  const mounted = useRef(true)
+  useEffect(() => {
+    mounted.current = true
+    return () => { mounted.current = false; runner.current.stop() }
+  }, [])
+  const selected = models.some(m => m.id === model) ? model : (models[0]?.id || '')
+  const valid = validParticipants(participants)
+  const roundsValid = Number.isInteger(Number(rounds)) && Number(rounds) >= 1 && Number(rounds) <= 10
+
+  function addParticipant() {
+    if (locked || !selected || participants.length >= 6) return
+    let name = selected, suffix = 2
+    while (participants.some(p => p.name.trim().toLowerCase() === name.toLowerCase())) name = `${selected} ${suffix++}`
+    setParticipants([...participants, { name, model: selected }])
+  }
+  async function run(speaker, count = 1) {
+    if (runner.current.running || !valid) return
+    setLocked(true)
+    setRunning(true)
+    setError('')
+    try {
+      await runner.current.run({
+        participants: participants.map(p => ({ ...p, name: p.name.trim() })),
+        objective, transcript, speaker, rounds: count,
+        onUpdate: entries => { if (mounted.current) setTranscript(entries) },
+      })
+    } catch (err) {
+      if (mounted.current && err.name !== 'AbortError') setError(err.message)
+    } finally {
+      if (mounted.current) setRunning(false)
+    }
+  }
+  function addMessage(e) {
+    e.preventDefault()
+    if (!message.trim() || runner.current.running) return
+    setTranscript([...transcript, { name: t('group.moderator', 'Moderator'), content: message.trim(), status: 'complete' }])
+    setMessage('')
+  }
+  function reset() {
+    if (runner.current.running) return
+    setTranscript([])
+    setLocked(false)
+    setError('')
+    setMessage('')
+  }
+
+  return (
+    <div className="group-chat stack">
+      <header className="page-header">
+        <h1>{t('group.title', 'Group chat')}</h1>
+        <Link className="btn btn-secondary" to="/app/chat">{t('group.back', 'Back to Chat')}</Link>
+      </header>
+      <p className="text-note">{t('group.session', 'This text-only conversation stays in this page. Leaving or reloading clears its history. Models take turns sequentially.')}</p>
+      {(error || modelError) && <div role="alert" className="callout callout--warning">{error || modelError}</div>}
+      <section className="card stack" aria-label={t('group.setup', 'Conversation setup')}>
+        <h2>{t('group.participants', 'Participants')}</h2>
+        {loading && <p role="status">{t('group.loading', 'Loading chat models…')}</p>}
+        {!loading && models.length === 0 && <p>{t('group.emptyModels', 'No installed chat models available.')}</p>}
+        <div className="group-chat-controls">
+          <label className="stack">{t('group.model', 'Model to add')}
+            <select value={selected} onChange={e => setModel(e.target.value)} disabled={locked || loading || !selected}>
+              {!selected && <option value="">{t('group.select', 'Select a model')}</option>}
+              {models.map(m => <option key={m.id} value={m.id}>{m.id}</option>)}
+            </select>
+          </label>
+          <button className="btn btn-secondary" disabled={locked || !selected || participants.length >= 6} onClick={addParticipant}>{t('group.addParticipant', 'Add participant')}</button>
+        </div>
+        {participants.map((p, i) => <div className="group-chat-controls" key={i}>
+          <label className="stack">{t('group.name', 'Name for {{model}}', { model: p.model })}
+            <input value={p.name} disabled={locked} onChange={e => setParticipants(participants.map((item, index) => index === i ? { ...item, name: e.target.value } : item))} />
+          </label>
+          <span className="text-meta">{p.model}</span>
+          <button className="btn btn-secondary" disabled={locked} onClick={() => setParticipants(participants.filter((_, index) => index !== i))} aria-label={t('group.remove', 'Remove {{name}}', { name: p.name })}>{t('group.removeButton', 'Remove')}</button>
+          <button className="btn btn-primary" disabled={!valid || running} onClick={() => run(i)}>{t('group.turn', 'Give {{name}} a turn', { name: p.name })}</button>
+        </div>)}
+        {!valid && <p className="text-note">{t('group.validation', 'Add 2–6 participants with unique, nonempty names.')}</p>}
+        <label className="stack">{t('group.objective', 'Objective')}
+          <textarea rows={3} value={objective} onChange={e => setObjective(e.target.value)} disabled={locked} />
+        </label>
+        {locked && <p className="text-note">{t('group.locked', 'Setup is locked. Start a new conversation to change participants or the objective.')}</p>}
+      </section>
+      <div className="group-chat-controls">
+        <button className="btn btn-primary" disabled={!valid || running} onClick={() => run(undefined, 1)}>{t('group.oneRound', 'Run one round')}</button>
+        <label className="stack">{t('group.rounds', 'Number of rounds')}
+          <input type="number" min="1" max="10" step="1" value={rounds} onChange={e => setRounds(e.target.value)} disabled={running} />
+        </label>
+        <button className="btn btn-primary" disabled={!valid || running || !roundsValid} onClick={() => run(undefined, Number(rounds))}>{t('group.runRounds', 'Run rounds')}</button>
+        {running && <button className="btn btn-danger" onClick={() => runner.current.stop()}>{t('group.stop', 'Stop')}</button>}
+        <button className="btn btn-secondary" disabled={running} onClick={reset}>{t('group.new', 'New conversation')}</button>
+      </div>
+      <p className="text-note">{t('group.order', 'Rounds follow participant order. Each run is limited to 1–10 rounds. Stop ends the active request and cancels remaining turns.')}</p>
+      <section className="stack" aria-label={t('group.transcript', 'Shared transcript')} aria-busy={running}>
+        <h2>{t('group.transcript', 'Shared transcript')}</h2>
+        {transcript.length === 0 && <p className="text-note">{t('group.empty', 'Add a moderator message or give a participant the first turn.')}</p>}
+        {transcript.map((entry, i) => <article className="card stack" key={i}>
+          <strong>{entry.name}{entry.model && <span className="text-meta"> ({entry.model})</span>}</strong>
+          <div className="group-chat-content">{entry.content}</div>
+          {entry.status === 'streaming' && <span role="status">{t('group.generating', 'Generating…')}</span>}
+          {entry.status === 'incomplete' && <><span>{t('group.incomplete', 'Incomplete')}</span><span className="text-note">{t('group.excluded', 'Excluded from future model context.')}</span></>}
+        </article>)}
+      </section>
+      <form className="stack" onSubmit={addMessage}>
+        <label className="stack">{t('group.message', 'Moderator message')}
+          <textarea rows={3} value={message} onChange={e => setMessage(e.target.value)} disabled={running} />
+        </label>
+        <button className="btn btn-primary" type="submit" disabled={running || !message.trim()}>{t('group.addMessage', 'Add message')}</button>
+      </form>
+    </div>
+  )
+}
diff --git a/core/http/react-ui/src/router.jsx b/core/http/react-ui/src/router.jsx
index 136e0ddf6..b895963aa 100644
--- a/core/http/react-ui/src/router.jsx
+++ b/core/http/react-ui/src/router.jsx
@@ -77,6 +77,7 @@ export function preloadRoute(path) {
 }
 
 const Home = page('', () => import('./pages/Home'))
+const GroupChat = page(null, () => import('./pages/GroupChat'))
 const Chat = page('chat', () => import('./pages/Chat'))
 const Models = page('models', () => import('./pages/Models'))
 const ManageRedirect = page('manage', () => import('./pages/ManageRedirect'))
@@ -153,6 +154,7 @@ function Feature({ feature, children }) {
 const appChildren = [
   { index: true, element: <Home /> },
   { path: 'chat', element: <Chat /> },
+  { path: 'group-chat', element: <Feature feature="chat"><GroupChat /></Feature> },
   { path: 'chat/:model', element: <Chat /> },
   { path: 'image', element: <ImageGen /> },
   { path: 'image/:model', element: <ImageGen /> },
diff --git a/core/http/react-ui/src/utils/groupChat.js b/core/http/react-ui/src/utils/groupChat.js
new file mode 100644
index 000000000..59f2278f3
--- /dev/null
+++ b/core/http/react-ui/src/utils/groupChat.js
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: MIT
+export function validParticipants(participants) {
+  const names = participants.map(p => p.name.trim().toLowerCase())
+  return participants.length >= 2 && participants.length <= 6 &&
+    participants.every(p => p.model && p.name.trim()) && new Set(names).size === names.length
+}
+
+export function buildMessages(objective, participant, transcript) {
+  // A shared transcript is quoted user context, never this model's assistant history.
+  const history = transcript.filter(e => e.status === 'complete').map(e =>
+    `${e.name}${e.model ? ` (${e.model})` : ''}:\n${e.content}`
+  ).join('\n\n')
+  return [
+    { role: 'system', content: `You are ${participant.name} (${participant.model}) in a moderated group conversation. Speak only for yourself. Other speakers' contributions are context.\n\nModerator objective:\n${objective || 'Discuss the shared conversation.'}` },
+    { role: 'user', content: `${history || 'No contributions yet.'}\n\nIt is now ${participant.name}'s turn. Contribute to the discussion.` },
+  ]
+}
+
+export async function readCompletion(stream, signal, onContent = () => {}) {
+  signal.throwIfAborted()
+  if (!stream) throw new Error('The model returned no stream.')
+  const reader = stream.getReader()
+  const decoder = new TextDecoder()
+  let buffer = '', content = '', done = false
+  const abort = () => { void reader.cancel().catch(() => {}) }
+  signal.addEventListener('abort', abort, { once: true })
+  try {
+    while (!done) {
+      signal.throwIfAborted()
+      const chunk = await reader.read()
+      signal.throwIfAborted()
+      buffer += chunk.done ? decoder.decode() : decoder.decode(chunk.value, { stream: true })
+      // Normalize after buffering so a CRLF split across chunks remains intact.
+      let match
+      while ((match = /\r?\n\r?\n/.exec(buffer))) {
+        const frame = buffer.slice(0, match.index)
+        buffer = buffer.slice(match.index + match[0].length)
+        const data = frame.split(/\r?\n/).filter(l => l.startsWith('data:')).map(l => l.slice(5).trimStart()).join('\n')
+        if (!data) continue
+        if (data === '[DONE]') { done = true; break }
+        let payload
+        try { payload = JSON.parse(data) } catch { throw new Error('Malformed model stream.') }
+        if (payload.error) throw new Error(payload.error.message || String(payload.error))
+        const choice = payload.choices?.[0]
+        if (choice?.finish_reason && !['stop', 'length'].includes(choice.finish_reason)) throw new Error(`The model stopped: ${choice.finish_reason}`)
+        if (typeof choice?.delta?.content === 'string') {
+          content += choice.delta.content
+          onContent(content)
+        }
+        if (choice?.finish_reason === 'length') throw new Error('The model reached its output limit. The response is incomplete.')
+      }
+      if (chunk.done && !done) throw new Error('The model stream ended before completion.')
+    }
+    if (!content.trim()) throw new Error('The model returned no text.')
+    return content
+  } finally {
+    signal.removeEventListener('abort', abort)
+    void reader.cancel().catch(() => {})
+    reader.releaseLock()
+  }
+}
+
+export class GroupRun {
+  constructor(provider) { this.provider = provider; this.controller = null }
+  get running() { return this.controller !== null }
+  stop() { this.controller?.abort() }
+
+  async run({ participants, rounds = 1, speaker, objective = '', transcript, onUpdate = () => {} }) {
+    if (this.running) throw new Error('A run is already active.')
+    if (!validParticipants(participants)) throw new Error('Choose 2–6 participants with unique, nonempty names.')
+    if (!Number.isInteger(rounds) || rounds < 1 || rounds > 10) throw new Error('Choose 1–10 rounds.')
+    if (speaker !== undefined && (!Number.isInteger(speaker) || !participants[speaker])) throw new Error('Unknown participant.')
+    const controller = new AbortController()
+    this.controller = controller
+    const { signal } = controller
+    let entries = transcript.map(e => ({ ...e }))
+    const order = speaker === undefined ? Array.from({ length: rounds }, () => participants).flat() : [participants[speaker]]
+    const publish = () => onUpdate(entries.map(e => ({ ...e })))
+    try {
+      for (const participant of order) {
+        signal.throwIfAborted()
+        const messages = buildMessages(objective, participant, entries)
+        const entry = { ...participant, content: '', status: 'streaming' }
+        entries.push(entry)
+        publish()
+        try {
+          const stream = await this.provider({ model: participant.model, messages, stream: true }, signal)
+          signal.throwIfAborted()
+          entry.content = await readCompletion(stream, signal, content => { entry.content = content; publish() })
+          signal.throwIfAborted()
+          entry.status = 'complete'
+          publish()
+        } catch (error) {
+          entry.status = 'incomplete'
+          publish()
+          throw error
+        }
+      }
+      return entries
+    } finally {
+      this.controller = null
+    }
+  }
+}
diff --git a/core/http/react-ui/tests/group-chat.test.mjs b/core/http/react-ui/tests/group-chat.test.mjs
new file mode 100644
index 000000000..552763ffd
--- /dev/null
+++ b/core/http/react-ui/tests/group-chat.test.mjs
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: MIT
+import test from 'node:test'
+import assert from 'node:assert/strict'
+import { buildMessages, readCompletion, GroupRun, validParticipants } from '../src/utils/groupChat.js'
+const participants = [{ name: 'Planner', model: 'alpha' }, { name: 'Critic', model: 'beta' }]
+const event = data => `data: ${JSON.stringify(data)}\n\n`
+const reply = text => event({ choices: [{ delta: { content: text, reasoning_content: 'secret' } }] })
+const stream = (...chunks) => new ReadableStream({ start(c) { chunks.forEach(s => c.enqueue(new TextEncoder().encode(s))); c.close() } })
+const complete = () => stream(reply('hello'), 'data: [DONE]\n\n')
+test('projects all completed contributions as attributed context with a user turn', () => {
+  const messages = buildMessages('Plan a garden', participants[1], [
+    { name: 'Moderator', content: 'Native plants', status: 'complete' },
+    { ...participants[0], content: 'Use oak', reasoning: 'secret', status: 'complete' },
+    { ...participants[1], content: 'unfinished', status: 'incomplete' },
+  ])
+  assert.equal(messages[0].role, 'system')
+  assert.match(messages[0].content, /Critic/)
+  assert.match(messages[0].content, /Plan a garden/)
+  assert.equal(messages.at(-1).role, 'user')
+  assert.match(messages.at(-1).content, /Planner \(alpha\)/)
+  assert.match(messages.at(-1).content, /Use oak/)
+  assert.doesNotMatch(JSON.stringify(messages), /secret|unfinished/)
+  assert.equal(messages.some(m => m.role === 'assistant'), false)
+})
+test('validates participant bounds and unique trimmed names', () => {
+  assert.equal(validParticipants(participants), true)
+  for (const p of [[], participants.slice(0, 1), [...participants, { name: ' planner ', model: 'a' }], [{ name: ' ', model: 'a' }, participants[1]], Array(7).fill(participants[0])]) assert.equal(validParticipants(p), false)
+})
+test('decodes fragmented SSE, ignores reasoning and accepts CRLF', async () => {
+  let text = ''
+  const s = reply('héllo').replaceAll('\n', '\r\n') + 'data: [DONE]\r\n\r\n'
+  assert.equal(await readCompletion(stream(...[...s]), new AbortController().signal, value => { text = value }), 'héllo')
+  assert.equal(text, 'héllo')
+})
+for (const [name, chunks, pattern] of [
+  ['SSE error', [event({ error: { message: 'Stream failed' } })], /Stream failed/],
+  ['malformed', ['data: not-json\n\n'], /Malformed/],
+  ['truncated', [reply('partial')], /ended/],
+  ['empty', ['data: [DONE]\n\n'], /no text/],
+  ['length limit', [event({ choices: [{ delta: { content: 'partial' }, finish_reason: 'length' }] }), 'data: [DONE]\n\n'], /limit/],
+]) test(name, async () => assert.rejects(readCompletion(stream(...chunks), new AbortController().signal), pattern))
+test('runs ordered rounds with attributed prior turns', async () => {
+  const requests = []
+  const runner = new GroupRun(async body => { requests.push(body); return complete() })
+  const history = await runner.run({ participants, rounds: 2, objective: 'Discuss', transcript: [] })
+  assert.deepEqual(requests.map(r => r.model), ['alpha', 'beta', 'alpha', 'beta'])
+  assert.equal(history.length, 4)
+  assert.match(requests[1].messages[1].content, /Planner \(alpha\)/)
+  assert.equal(history.every(e => e.status === 'complete'), true)
+})
+test('bounds rounds and stops on provider HTTP failure', async () => {
+  let calls = 0
+  const runner = new GroupRun(async () => { calls++; throw Error('HTTP 500') })
+  for (const rounds of [0, 11, 1.5, NaN]) await assert.rejects(runner.run({ participants, rounds, transcript: [] }), /rounds/)
+  await assert.rejects(runner.run({ participants, rounds: 2, transcript: [] }), /HTTP 500/)
+  assert.equal(calls, 1)
+})
+for (const partial of [false, true]) test(`abort ${partial ? 'after partial' : 'before content'} prevents future turns and overlap`, async () => {
+  let calls = 0, started
+  const ready = new Promise(resolve => { started = resolve })
+  let latest
+  const runner = new GroupRun(async () => {
+    calls++
+    return new ReadableStream({ start(c) { if (partial) c.enqueue(new TextEncoder().encode(reply('partial'))); started() } })
+  })
+  const run = runner.run({ participants, rounds: 2, transcript: [], onUpdate: entries => { latest = entries } })
+  await ready
+  await assert.rejects(runner.run({ participants, rounds: 1, transcript: [] }), /already/)
+  await new Promise(resolve => setImmediate(resolve))
+  runner.stop()
+  await assert.rejects(run, { name: 'AbortError' })
+  assert.equal(calls, 1)
+  assert.equal(latest[0].status, 'incomplete')
+  assert.equal(latest[0].content, partial ? 'partial' : '')
+  assert.doesNotMatch(JSON.stringify(buildMessages('', participants[1], latest)), /partial/)
+  assert.equal(runner.running, false)
+})
+test('manual grant runs only the selected participant', async () => {
+  const runner = new GroupRun(async body => { assert.equal(body.model, 'beta'); return complete() })
+  const history = await runner.run({ participants, speaker: 1, transcript: [] })
+  assert.equal(history.length, 1)
+  assert.equal(history[0].name, 'Critic')
+})
+test('stream failures mark partial output incomplete and stop the round', async () => {
+  let count = 0, latest
+  const runner = new GroupRun(async () => { count++; return stream(reply('partial')) })
+  await assert.rejects(runner.run({ participants, rounds: 2, transcript: [], onUpdate: entries => { latest = entries } }), /ended/)
+  assert.equal(count, 1)
+  assert.equal(latest[0].status, 'incomplete')
+  assert.equal(latest[0].content, 'partial')
+})
+test('already-aborted reader emits no content', async () => {
+  const controller = new AbortController()
+  controller.abort()
+  await assert.rejects(readCompletion(complete(), controller.signal, () => assert.fail('stale content')), { name: 'AbortError' })
+})
diff --git a/docs/content/features/group-chat.md b/docs/content/features/group-chat.md
new file mode 100644
index 000000000..2617a537a
--- /dev/null
+++ b/docs/content/features/group-chat.md
@@ -0,0 +1,56 @@
++++
+title = "Group chat"
+weight = 23
+toc = true
+description = "Moderate a shared conversation between installed chat models"
+categories = ["Features"]
++++
+
+Group chat lets you moderate a text conversation between 2–6 participants.
+Each participant uses an installed chat model and has a unique display name.
+You can use the same model for multiple participants.
+
+## Start a conversation
+
+1. Open **Chat** in the web UI and select **Group chat**. The page is also available at `/app/group-chat`.
+2. Select a model under **Model to add**, then select **Add participant**.
+3. Add at least two participants. Give each participant a unique, nonempty name.
+4. Enter an **Objective**, such as “Compare three ways to reduce our application's startup time.”
+5. Optionally enter a **Moderator message** and select **Add message**.
+
+Participants and the objective remain editable until the first model turn.
+After that turn starts, select **New conversation** to unlock setup and clear the transcript.
+The page uses the existing chat permission and chat completions API.
+
+## Control turns
+
+Select **Give [name] a turn** to request one response from that participant.
+Select **Run one round** to give every participant one turn, in the displayed order.
+To repeat that order, set **Number of rounds** to 1–10 and select **Run rounds**.
+You can add moderator messages between runs.
+
+Each request includes the objective, the participant's identity, and all completed contributions with their speakers' names.
+Other participants' responses appear as shared context, not as the current model's previous assistant responses.
+Private reasoning is neither displayed nor included in later requests.
+
+The page sends one request at a time. It does not generate responses concurrently.
+Sequential requests avoid simultaneous generation, but do not unload models or guarantee that only one model remains in memory.
+Configure model loading and memory limits on your LocalAI server as needed.
+
+## Stop or recover from an error
+
+Select **Stop** to cancel the active request and all remaining turns in the run.
+A server error, malformed or truncated stream, empty response, or output limit also stops the run.
+Partial responses remain visible as **Incomplete** and are excluded from future requests.
+You can resume with another turn or start a new conversation.
+
+## Limits and history
+
+{{% notice note %}}
+History exists only while this page is open. Leaving the page or reloading clears it and cancels any active request.
+Group chat does not save conversations or support attachments, tool calls, or automatic speaker selection.
+{{% /notice %}}
+
+Each request includes the full completed transcript. Long conversations can exceed a model's context window.
+Start a new conversation when the discussion becomes too long for your selected models.
+Select **Back to Chat** to return to normal chat.