diff --git a/packages/iios-messaging-ui/package.json b/packages/iios-messaging-ui/package.json
index b582f56..e785610 100644
--- a/packages/iios-messaging-ui/package.json
+++ b/packages/iios-messaging-ui/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@insignia/iios-messaging-ui",
-  "version": "0.1.4",
+  "version": "0.1.5",
   "type": "module",
   "main": "dist/index.js",
   "module": "dist/index.js",
diff --git a/packages/iios-messaging-ui/src/adapter.ts b/packages/iios-messaging-ui/src/adapter.ts
index 3ea31f5..3c72ace 100644
--- a/packages/iios-messaging-ui/src/adapter.ts
+++ b/packages/iios-messaging-ui/src/adapter.ts
@@ -80,4 +80,17 @@ export interface MessagingAdapter {
 
   /** Leave a channel by id. */
   leaveChannel?(threadId: string): Promise<void>;
+
+  // ── Group / channel administration (optional) ───────────────────
+  // Enable the settings panel for groups + channels. Absent methods hide their affordance;
+  // the server (OPA) still enforces who may actually add/remove/rename (admin-only).
+
+  /** Add a person to a group or private channel. */
+  addMember?(threadId: string, userId: string): Promise<void>;
+
+  /** Remove a person from a group or channel. */
+  removeMember?(threadId: string, userId: string): Promise<void>;
+
+  /** Rename a group or channel. */
+  renameConversation?(threadId: string, subject: string): Promise<void>;
 }
diff --git a/packages/iios-messaging-ui/src/adapters/mock.ts b/packages/iios-messaging-ui/src/adapters/mock.ts
index e75b370..b114d7c 100644
--- a/packages/iios-messaging-ui/src/adapters/mock.ts
+++ b/packages/iios-messaging-ui/src/adapters/mock.ts
@@ -163,6 +163,21 @@ export class MockAdapter implements MessagingAdapter {
     return MOCK_PEOPLE.map((p) => ({ ...p }));
   }
 
+  async addMember(threadId: string, userId: string): Promise<void> {
+    const t = this.threads.get(threadId);
+    if (t && !t.participants.includes(userId)) t.participants = [...t.participants, userId];
+  }
+
+  async removeMember(threadId: string, userId: string): Promise<void> {
+    const t = this.threads.get(threadId);
+    if (t) t.participants = t.participants.filter((p) => p !== userId);
+  }
+
+  async renameConversation(threadId: string, subject: string): Promise<void> {
+    const t = this.threads.get(threadId);
+    if (t) t.subject = subject;
+  }
+
   async openThread(p: { participantIds: string[]; membership?: Membership; subject?: string }): Promise<{ threadId: string }> {
     // A DM to someone you already have reuses the existing 1:1 thread (dedupe, like the live door).
     if ((p.membership ?? (p.participantIds.length === 1 ? 'dm' : 'group')) === 'dm' && p.participantIds.length === 1) {
diff --git a/packages/iios-messaging-ui/src/components/conversation-settings.test.tsx b/packages/iios-messaging-ui/src/components/conversation-settings.test.tsx
new file mode 100644
index 0000000..3fa1c01
--- /dev/null
+++ b/packages/iios-messaging-ui/src/components/conversation-settings.test.tsx
@@ -0,0 +1,40 @@
+import { describe, it, expect } from 'vitest';
+import { render, screen, fireEvent, waitFor } from '@testing-library/react';
+import { MessagingProvider } from '../provider';
+import { MockAdapter } from '../adapters/mock';
+import { ConversationSettings } from './conversation-settings';
+
+function mount(adapter = new MockAdapter()) {
+  render(
+    <MessagingProvider adapter={adapter}>
+      <ConversationSettings threadId="th_mock_2" title="Storm crew" membership="group" onClose={() => {}} />
+    </MessagingProvider>,
+  );
+  return adapter;
+}
+
+describe('MockAdapter member management', () => {
+  it('adds and removes a member, and renames', async () => {
+    const a = new MockAdapter();
+    await a.addMember('th_mock_2', 'pp_sofia');
+    expect((await a.listMembers('th_mock_2')).some((m) => m.id === 'pp_sofia')).toBe(true);
+    await a.removeMember('th_mock_2', 'pp_sofia');
+    expect((await a.listMembers('th_mock_2')).some((m) => m.id === 'pp_sofia')).toBe(false);
+    await a.renameConversation('th_mock_2', 'Renamed');
+    expect((await a.listConversations()).find((c) => c.threadId === 'th_mock_2')?.title).toBe('Renamed');
+  });
+});
+
+describe('<ConversationSettings />', () => {
+  it('lists members and adds one from the directory', async () => {
+    const a = mount();
+    // A current member is shown.
+    await screen.findByText('Dan Whitaker');
+    // Add an addable person from the directory.
+    const sofia = await screen.findByText('Sofia Ramirez');
+    fireEvent.click(sofia);
+    await waitFor(async () => {
+      expect((await a.listMembers('th_mock_2')).some((m) => m.id === 'pp_sofia')).toBe(true);
+    });
+  });
+});
diff --git a/packages/iios-messaging-ui/src/components/conversation-settings.tsx b/packages/iios-messaging-ui/src/components/conversation-settings.tsx
new file mode 100644
index 0000000..2f627b7
--- /dev/null
+++ b/packages/iios-messaging-ui/src/components/conversation-settings.tsx
@@ -0,0 +1,145 @@
+import { useEffect, useMemo, useState } from 'react';
+import { useAdapter } from '../provider';
+import { ModalPortal } from './modal-portal';
+import type { Person } from '../types';
+
+/**
+ * Settings for a group or channel (public + private): rename, member list, add/remove people, and
+ * leave. Add/remove/rename appear only when the adapter implements them AND — for the server — OPA
+ * allows it (admin-only); the panel is optimistic and surfaces the error if the door refuses.
+ */
+export function ConversationSettings({
+  threadId,
+  title,
+  membership,
+  onClose,
+  onLeft,
+}: {
+  threadId: string;
+  title: string;
+  membership: 'group' | 'channel';
+  onClose: () => void;
+  onLeft?: () => void;
+}) {
+  const adapter = useAdapter();
+  const [members, setMembers] = useState<Person[]>([]);
+  const [directory, setDirectory] = useState<Person[]>([]);
+  const [name, setName] = useState(title);
+  const [q, setQ] = useState('');
+  const [busy, setBusy] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const [nonce, setNonce] = useState(0);
+
+  const canManage = typeof adapter.addMember === 'function' && typeof adapter.removeMember === 'function';
+  const canRename = typeof adapter.renameConversation === 'function';
+  const canLeave = membership === 'channel' && typeof adapter.leaveChannel === 'function';
+
+  useEffect(() => {
+    let alive = true;
+    void Promise.all([
+      adapter.listMembers ? adapter.listMembers(threadId) : Promise.resolve<Person[]>([]),
+      adapter.directory ? adapter.directory() : Promise.resolve<Person[]>([]),
+    ]).then(([m, d]) => {
+      if (alive) {
+        setMembers(m);
+        setDirectory(d);
+      }
+    });
+    return () => {
+      alive = false;
+    };
+  }, [adapter, threadId, nonce]);
+
+  const memberIds = useMemo(() => new Set(members.map((m) => m.id)), [members]);
+  const addable = directory.filter((p) => !memberIds.has(p.id) && p.name.toLowerCase().includes(q.trim().toLowerCase()));
+
+  async function run(fn: () => Promise<void>): Promise<void> {
+    setBusy(true);
+    setError(null);
+    try {
+      await fn();
+      setNonce((n) => n + 1);
+    } catch (e) {
+      setError(e instanceof Error ? e.message : String(e));
+    } finally {
+      setBusy(false);
+    }
+  }
+
+  return (
+    <ModalPortal>
+      <div className="miu-modal-overlay" onMouseDown={onClose}>
+        <div className="miu-modal" role="dialog" aria-modal="true" onMouseDown={(e) => e.stopPropagation()}>
+          <div className="miu-modal-head">
+            <span>{membership === 'channel' ? 'Channel' : 'Group'} settings</span>
+            <button type="button" className="miu-pane-close" onClick={onClose} aria-label="Close">✕</button>
+          </div>
+          <div className="miu-modal-body">
+            {canRename ? (
+              <div className="miu-field">
+                <span className="miu-field-lbl">Name</span>
+                <div className="miu-composer-row">
+                  <input className="miu-input" value={name} onChange={(e) => setName(e.target.value)} aria-label="Conversation name" />
+                  <button
+                    type="button"
+                    className="miu-send"
+                    disabled={busy || !name.trim() || name.trim() === title}
+                    onClick={() => void run(() => adapter.renameConversation!(threadId, name.trim()))}
+                  >
+                    Rename
+                  </button>
+                </div>
+              </div>
+            ) : null}
+
+            <div className="miu-field">
+              <span className="miu-field-lbl">Members · {members.length}</span>
+              <div className="miu-settings-list">
+                {members.map((m) => (
+                  <div key={m.id} className="miu-settings-member">
+                    <span className="miu-settings-name">{m.name}</span>
+                    <span className="miu-pill">{m.kind}</span>
+                    {canManage ? (
+                      <button type="button" className="miu-attach-x" title="Remove" disabled={busy} onClick={() => void run(() => adapter.removeMember!(threadId, m.id))}>
+                        ✕
+                      </button>
+                    ) : null}
+                  </div>
+                ))}
+              </div>
+            </div>
+
+            {canManage ? (
+              <div className="miu-field">
+                <span className="miu-field-lbl">Add people</span>
+                <input className="miu-input" value={q} onChange={(e) => setQ(e.target.value)} placeholder="Search people…" aria-label="Search people" />
+                <div className="miu-settings-list">
+                  {addable.length === 0 ? <div className="miu-empty">No one to add.</div> : null}
+                  {addable.slice(0, 25).map((p) => (
+                    <button key={p.id} type="button" className="miu-settings-member is-add" disabled={busy} onClick={() => void run(() => adapter.addMember!(threadId, p.id))}>
+                      <span className="miu-settings-name">{p.name}</span>
+                      <span className="miu-pill">{p.kind}</span>
+                      <span className="miu-settings-plus" aria-hidden="true">＋</span>
+                    </button>
+                  ))}
+                </div>
+              </div>
+            ) : null}
+
+            {error ? <div className="miu-empty miu-error">{error}</div> : null}
+          </div>
+          <div className="miu-modal-foot">
+            {canLeave ? (
+              <button type="button" className="miu-tab" disabled={busy} onClick={() => void run(async () => { await adapter.leaveChannel!(threadId); onLeft?.(); onClose(); })}>
+                Leave {membership}
+              </button>
+            ) : (
+              <span />
+            )}
+            <button type="button" className="miu-send" onClick={onClose}>Done</button>
+          </div>
+        </div>
+      </div>
+    </ModalPortal>
+  );
+}
diff --git a/packages/iios-messaging-ui/src/components/message-item.tsx b/packages/iios-messaging-ui/src/components/message-item.tsx
index 7cb7121..6b5e243 100644
--- a/packages/iios-messaging-ui/src/components/message-item.tsx
+++ b/packages/iios-messaging-ui/src/components/message-item.tsx
@@ -8,6 +8,20 @@ const REACTION_EMOJIS = ['👍', '❤️', '😂', '🎉', '👀'];
 
 const isImage = (mime: string): boolean => mime.startsWith('image/');
 
+/** Slack-style message time: today shows the clock, then "Yesterday", weekday, else a date. */
+function messageTime(iso: string): string {
+  const d = new Date(iso);
+  if (Number.isNaN(+d)) return '';
+  const now = new Date();
+  const time = d.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' });
+  if (d.toDateString() === now.toDateString()) return time;
+  const yesterday = new Date(now);
+  yesterday.setDate(now.getDate() - 1);
+  if (d.toDateString() === yesterday.toDateString()) return `Yesterday ${time}`;
+  if (now.getTime() - d.getTime() < 7 * 86400000) return `${d.toLocaleDateString([], { weekday: 'short' })} ${time}`;
+  return `${d.toLocaleDateString([], { month: 'short', day: 'numeric' })} ${time}`;
+}
+
 function AttachmentView({ att }: { att: Attachment }) {
   if (isImage(att.mime)) {
     return (
@@ -54,6 +68,9 @@ export function MessageItem({
           {m.text ? highlightMentions(m.text, memberNames) : null}
           {m.attachment ? <AttachmentView att={m.attachment} /> : null}
         </div>
+        <time className="miu-msg-time" dateTime={m.at} title={Number.isNaN(+new Date(m.at)) ? '' : new Date(m.at).toLocaleString()}>
+          {messageTime(m.at)}
+        </time>
         <div className="miu-msg-actions">
           {canReact ? (
             <div className="miu-react-wrap">
diff --git a/packages/iios-messaging-ui/src/components/messenger.tsx b/packages/iios-messaging-ui/src/components/messenger.tsx
index 2b7e54e..e28c2b7 100644
--- a/packages/iios-messaging-ui/src/components/messenger.tsx
+++ b/packages/iios-messaging-ui/src/components/messenger.tsx
@@ -34,6 +34,7 @@ export function Messenger() {
 
   const channels = useMemo(() => conversations.filter((c) => c.membership === 'channel'), [conversations]);
   const dms = useMemo(() => conversations.filter((c) => c.membership !== 'channel'), [conversations]);
+  const selectedConversation = useMemo(() => conversations.find((c) => c.threadId === selected) ?? null, [conversations, selected]);
 
   function pick(threadId: string): void {
     setBrowsing(false);
@@ -104,7 +105,16 @@ export function Messenger() {
             }}
           />
         ) : (
-          <Thread threadId={selected} activeRootId={activeRoot} onOpenThread={setActiveRoot} />
+          <Thread
+            threadId={selected}
+            conversation={selectedConversation}
+            activeRootId={activeRoot}
+            onOpenThread={setActiveRoot}
+            onLeft={() => {
+              refetch();
+              setSelected(null);
+            }}
+          />
         )}
       </section>
 
diff --git a/packages/iios-messaging-ui/src/components/thread.tsx b/packages/iios-messaging-ui/src/components/thread.tsx
index 0f21efa..8526365 100644
--- a/packages/iios-messaging-ui/src/components/thread.tsx
+++ b/packages/iios-messaging-ui/src/components/thread.tsx
@@ -1,8 +1,10 @@
-import { useMemo } from 'react';
+import { useMemo, useState } from 'react';
 import { useMessages } from '../hooks/use-messages';
 import { useMembers } from '../hooks/use-members';
 import { Composer } from './composer';
 import { MessageItem } from './message-item';
+import { ConversationSettings } from './conversation-settings';
+import type { Conversation } from '../types';
 
 /**
  * The main conversation view: top-level messages + composer. Replies (messages with a
@@ -11,16 +13,24 @@ import { MessageItem } from './message-item';
  */
 export function Thread({
   threadId,
+  conversation,
   activeRootId,
   onOpenThread,
+  onLeft,
 }: {
   threadId: string | null;
+  conversation?: Conversation | null;
   activeRootId?: string | null;
   onOpenThread?: (rootId: string) => void;
+  onLeft?: () => void;
 }) {
   const { messages, loading, error, send, react, upload, typingUserIds, seenIds, sendTyping, canReact, canUpload } = useMessages(threadId);
   const members = useMembers(threadId);
   const memberNames = useMemo(() => members.map((m) => m.name), [members]);
+  const [settingsOpen, setSettingsOpen] = useState(false);
+
+  const membership = conversation?.membership;
+  const manageable = membership === 'group' || membership === 'channel';
 
   const topLevel = useMemo(() => messages.filter((m) => !m.parentInteractionId), [messages]);
   const replyCount = useMemo(() => {
@@ -35,6 +45,19 @@ export function Thread({
 
   return (
     <div className={`miu-thread${activeRootId ? ' has-pane' : ''}`}>
+      {conversation ? (
+        <div className="miu-thread-head">
+          <span className="miu-thread-title">
+            {membership === 'channel' ? '# ' : ''}
+            {conversation.title || 'Conversation'}
+          </span>
+          {manageable ? (
+            <button type="button" className="miu-thread-settings" title="Settings" aria-label="Conversation settings" onClick={() => setSettingsOpen(true)}>
+              ⚙
+            </button>
+          ) : null}
+        </div>
+      ) : null}
       <div className="miu-messages">
         {loading && messages.length === 0 ? <div className="miu-empty">Loading…</div> : null}
         {error ? <div className="miu-empty miu-error">{error}</div> : null}
@@ -56,6 +79,16 @@ export function Thread({
       </div>
 
       <Composer members={members} canUpload={canUpload} upload={upload} onSend={send} onTyping={sendTyping} />
+
+      {settingsOpen && manageable && conversation ? (
+        <ConversationSettings
+          threadId={conversation.threadId}
+          title={conversation.title || ''}
+          membership={membership as 'group' | 'channel'}
+          onClose={() => setSettingsOpen(false)}
+          {...(onLeft ? { onLeft } : {})}
+        />
+      ) : null}
     </div>
   );
 }
diff --git a/packages/iios-messaging-ui/src/styles.css b/packages/iios-messaging-ui/src/styles.css
index 207b3e2..fc6a0bc 100644
--- a/packages/iios-messaging-ui/src/styles.css
+++ b/packages/iios-messaging-ui/src/styles.css
@@ -162,6 +162,80 @@
   gap: 2px;
   flex-shrink: 0;
 }
+.miu-msg-time {
+  font-size: 11px;
+  color: var(--miu-muted);
+  flex-shrink: 0;
+  white-space: nowrap;
+}
+
+/* thread header + group/channel settings */
+.miu-thread-head {
+  flex: 0 0 auto;
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 8px;
+  padding: 10px 14px;
+  border-bottom: 1px solid var(--miu-border);
+}
+.miu-thread-title {
+  font-weight: 700;
+  font-size: 14px;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+.miu-thread-settings {
+  flex-shrink: 0;
+  border: none;
+  background: none;
+  color: var(--miu-muted);
+  cursor: pointer;
+  font-size: 16px;
+  line-height: 1;
+  padding: 4px;
+  border-radius: 8px;
+}
+.miu-thread-settings:hover {
+  background: var(--miu-panel-2);
+  color: var(--miu-text);
+}
+.miu-settings-list {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+  max-height: 240px;
+  overflow-y: auto;
+}
+.miu-settings-member {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 7px 10px;
+  border: 1px solid var(--miu-border);
+  border-radius: 10px;
+  background: var(--miu-panel);
+  color: var(--miu-text);
+  font-size: 13px;
+  text-align: left;
+}
+.miu-settings-member.is-add {
+  cursor: pointer;
+}
+.miu-settings-member.is-add:hover {
+  border-color: var(--miu-accent);
+}
+.miu-settings-name {
+  flex: 1 1 auto;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+.miu-settings-plus {
+  color: var(--miu-accent);
+  font-weight: 700;
+}
 .miu-thread-link {
   align-self: flex-start;
   margin-top: 3px;