chore: v2.8.39 — no one can take a colleague's display name

A member kept renaming themselves to a colleague's display name, plus
"(you)", so the CPU/RAM card and every owner list showed two of that person.
A display name is now refused (409 ENAMETAKEN) when, with marks, case,
spaces, punctuation, bracketed parts and look-alike Cyrillic/Greek letters
ignored, it equals another account's display name or username — in
Settings → Account and on the Users page alike. Keeping the name one already
has stays allowed, so an older clash does not block an admin's other edits.

CLAUDE.md

@@ -1,6 +1,6 @@
 # Claude Code Working Guide
 
-_Last synced: v2.8.37 (2026-10-29) — the Artifacts page's installs list floats over the page, never clipped._ A change that makes any statement in this file, `AGENTS.md`, or a README wrong — a moved path, a new or changed extension point, a retired rule — updates that file in the same change-set and bumps this marker. **Bump = replace the version/date and a ≤ 1-line summary; never append a changelog here** — details belong in the commit message and `docs/`, because this whole file is loaded into every session.
+_Last synced: v2.8.39 (2026-10-29) — a display name may not read as another account's (ENAMETAKEN)._ A change that makes any statement in this file, `AGENTS.md`, or a README wrong — a moved path, a new or changed extension point, a retired rule — updates that file in the same change-set and bumps this marker. **Bump = replace the version/date and a ≤ 1-line summary; never append a changelog here** — details belong in the commit message and `docs/`, because this whole file is loaded into every session.
 
 ## Project mission
 - Maintain a reliable local-first dashboard for Claude Code session monitoring.

client/src/components/health/HostHealth.tsx

@@ -683,7 +683,12 @@ export function HostSections({ host, heap }: { host: HostState; heap?: HeapInfo
                     aria-expanded={isOpen}
                     className="flex w-full items-center gap-2 text-left disabled:cursor-default"
                   >
-                    <UserAvatar name={name} className="h-6 w-6 text-[10px]" />
+                    <UserAvatar
+                      name={name}
+                      userId={g.userId}
+                      avatarAt={g.avatarAt}
+                      className="h-6 w-6 text-[10px]"
+                    />
                     <span className="min-w-0 flex-1 truncate text-xs text-fg-secondary">
                       {name}
                     </span>

client/src/components/health/__tests__/HostHealth.test.tsx

@@ -69,6 +69,7 @@ const stats: HostStats = {
 const api = vi.hoisted(() => ({
   host: { stats: vi.fn(), history: vi.fn() },
   me: { avatarUrl: () => null },
+  users: { avatarUrl: () => null },
 }));
 vi.mock("../../../lib/api", async (importOriginal) => {
   const actual = await importOriginal<Record<string, unknown>>();

client/src/components/users/MemberPicker.tsx

@@ -13,6 +13,7 @@ import { useTranslation } from "react-i18next";
 import { Search } from "lucide-react";
 import type { AuthUser, ServerUserUsage } from "../../lib/api";
 import { Checkbox } from "../Checkbox";
+import { UserAvatar } from "./UserAvatar";
 
 export const ROLES: AuthUser["role"][] = ["admin", "developer", "analyst"];
 /** A role, every user, or the users in no pool group. */
@@ -168,7 +169,14 @@ export function MemberPicker({
               checked={chosen.has(u.id)}
               onChange={(on) => setMany([u.id], on)}
               label={
-                <span>
+                <span className="inline-flex items-center gap-1.5">
+                  <UserAvatar
+                    name={u.displayName || u.username}
+                    userId={u.id}
+                    avatarAt={u.avatarAt}
+                    letters={1}
+                    className="h-5 w-5 text-[10px]"
+                  />
                   {u.username}
                   {u.disabled && <span className="ml-1 text-fg-muted">({t("disabled")})</span>}
                   {note?.(u)}

client/src/components/users/PoolGroups.tsx

@@ -36,6 +36,7 @@ import { toast } from "../../lib/toast";
 import { ConfirmModal } from "../ConfirmModal";
 import { AiToolIcon } from "../AiToolIcon";
 import { MemberPicker } from "./MemberPicker";
+import { UserAvatar } from "./UserAvatar";
 
 /** Pool tools with their labels, in display order. */
 export const POOL_TOOL_LABELS: { id: PoolTool; label: string }[] = [
@@ -363,12 +364,13 @@ export function PoolGroups({
         } ${isDragged(drag) ? "opacity-40" : ""}`}
         data-testid="pool-member"
       >
-        <span
-          className="flex h-4 w-4 items-center justify-center rounded-full bg-accent/15 text-[9px] font-semibold uppercase text-accent"
-          aria-hidden
-        >
-          {name.charAt(0)}
-        </span>
+        <UserAvatar
+          name={name}
+          userId={id}
+          avatarAt={u?.avatarAt}
+          letters={1}
+          className="h-4 w-4 text-[9px]"
+        />
         {name}
         {u && <span className="text-[10px] text-fg-muted">{t(`roles.${u.role}`)}</span>}
         {isAdmin && from && (

client/src/components/users/UserAvatar.tsx

@@ -4,7 +4,9 @@
  * (`GET /api/me/avatar`) or, with `userId`, another's (`GET
  * /api/users/:id/avatar`, staff only), versioned by `avatarAt`; without one —
  * or when the image fails to load — the first letters of its name. Used by the
- * sidebar's account row, its workspace owner groups and Settings → Account.
+ * sidebar's account row, its workspace owner groups, Settings → Account, the
+ * Users page and its editor, the pool board and member picker, and System
+ * Health's per-user CPU/RAM card.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 

client/src/components/users/UserEditDialog.tsx

@@ -33,6 +33,7 @@ import { copyText } from "../../lib/clipboard";
 import { isSubmitEnter } from "../../lib/keys";
 import { passwordProblems } from "../../lib/passwordRules";
 import { PasswordRules } from "./PasswordRules";
+import { UserAvatar } from "./UserAvatar";
 import { useDialog } from "../../hooks/useDialog";
 import { Switch } from "../Switch";
 import { Checkbox } from "../Checkbox";
@@ -243,12 +244,12 @@ export function UserEditDialog({
         className="flex max-h-[90vh] w-full max-w-2xl flex-col overflow-hidden rounded-xl border border-border bg-surface-1 shadow-xl"
       >
         <div className="flex items-start gap-3 border-b border-border px-5 py-4">
-          <span
-            aria-hidden
-            className="flex h-10 w-10 flex-shrink-0 items-center justify-center rounded-full bg-accent/15 text-sm font-semibold uppercase text-accent"
-          >
-            {shown.slice(0, 2)}
-          </span>
+          <UserAvatar
+            name={shown}
+            userId={user.id}
+            avatarAt={user.avatarAt}
+            className="h-10 w-10 text-sm"
+          />
           <div className="min-w-0 flex-1">
             <h2 id="user-edit-title" className="text-base font-semibold text-fg-primary">
               {t("edit.title", { name: user.displayName || user.username })}

client/src/components/users/__tests__/AccountPoolCard.test.tsx

@@ -33,7 +33,7 @@ const accountPool = vi.hoisted(() => ({
   updateGroup: vi.fn(),
   deleteGroup: vi.fn(),
 }));
-const users = vi.hoisted(() => ({ list: vi.fn() }));
+const users = vi.hoisted(() => ({ list: vi.fn(), avatarUrl: () => null }));
 const aiTools = vi.hoisted(() => ({
   list: vi.fn(),
   ompSharing: vi.fn(),

client/src/components/users/__tests__/UserEditDialog.test.tsx

@@ -13,7 +13,12 @@ import { render, screen, waitFor } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import type { ServerUserUsage } from "../../../lib/api";
 
-const users = vi.hoisted(() => ({ get: vi.fn(), update: vi.fn(), remove: vi.fn() }));
+const users = vi.hoisted(() => ({
+  get: vi.fn(),
+  update: vi.fn(),
+  remove: vi.fn(),
+  avatarUrl: () => null,
+}));
 const confirmDialog = vi.hoisted(() => vi.fn());
 vi.mock("../../../lib/confirm", () => ({ confirmDialog }));
 const lanes = vi.hoisted(() => ({ list: vi.fn() }));

client/src/components/users/__tests__/UserQuota.test.tsx

@@ -16,6 +16,7 @@ const users = vi.hoisted(() => ({
   setQuotaDefault: vi.fn(),
   update: vi.fn(),
   get: vi.fn(),
+  avatarUrl: () => null,
 }));
 const lanes = vi.hoisted(() => ({ list: vi.fn() }));
 vi.mock("../../../lib/api", async (importOriginal) => {

client/src/i18n/locales/en/users.json

@@ -79,6 +79,7 @@
     "EBADUSER": "Username: letters, digits, '.', '_' or '-' (up to 64).",
     "EBADPASSWORD": "Password cannot be empty.",
     "EBADEMAIL": "That email address does not look valid.",
+    "ENAMETAKEN": "Another account already uses that name. Pick one that is yours.",
     "EBADFIELD": "One of the values is not valid.",
     "ENOLANE": "That workspace no longer exists.",
     "ENOTOWNED": "That workspace is not this user's any more.",

client/src/i18n/locales/vi/users.json

@@ -79,6 +79,7 @@
     "EBADUSER": "Tên đăng nhập: chữ, số, '.', '_' hoặc '-' (tối đa 64 ký tự).",
     "EBADPASSWORD": "Mật khẩu không được để trống.",
     "EBADEMAIL": "Địa chỉ email không hợp lệ.",
+    "ENAMETAKEN": "Tên này đã có tài khoản khác dùng. Hãy chọn tên của chính bạn.",
     "EBADFIELD": "Có một giá trị không hợp lệ.",
     "ENOLANE": "Workspace đó không còn tồn tại.",
     "ENOTOWNED": "Workspace đó không còn thuộc người này.",

client/src/lib/api.ts

@@ -684,6 +684,8 @@ export interface HostUsageGroup {
   username?: string;
   /** The user's display name, null when none is set (absent from an older server). */
   displayName?: string | null;
+  /** When the user's avatar was last set (null = none; absent from an older server). */
+  avatarAt?: string | null;
   /** % of the whole machine's CPU (100 = every core busy) over the sample. */
   cpu: number;
   /** Resident memory, bytes (shared pages count in every process). */

client/src/pages/__tests__/__snapshots__/screens.snapshot.test.tsx.snap

@@ -7316,7 +7316,7 @@ exports[`screen snapshots > Settings — about 1`] = `
                 <span
                   class="text-status-warning/90"
                 >
-                  UI build v2.8.37 (rebuild client to match)
+                  UI build v2.8.39 (rebuild client to match)
                 </span>
               </p>
             </div>

docs/API.md

@@ -89,9 +89,9 @@ A dashboard shared by several people runs in **server mode** ([SERVER-MODE.md](S
 | `POST /api/auth/login` `{username, password}` | `{user}` + the cookie; `401 EBADLOGIN`, `429 ETOOMANY`, `404 ENOTSERVER` in local mode |
 | `POST /api/auth/logout` | `{ok: true}`, cookie cleared |
 
-In server mode a **developer** sees only rows of the workspaces they own (`lanes.owner_id`): every list, count, chart and cost answer is limited to them, and a request naming another user's session, agent, workspace or run (in the path, query or body) answers `404 ENOTFOUND`. Admin and analyst see everything; `GET /api/users` lists every account (`displayName`, `email`, `createdAt`, `logins`, `lastLoginAt` — the last login ever, kept after it ends —, `mustChangePassword` included) with its workspaces, sessions and `today` (since the viewer's local midnight — `?tz_offset=` is the browser's `getTimezoneOffset()`, UTC without it) / 7 / 30-day `{cost, tokens}`, `GET /api/users/storage[?refresh=1]` each user's home size (`{storage: {<id>: {bytes, files, partial, measuredAt} | null}, measuring}` — measured in the background, see [SERVER-MODE.md](SERVER-MODE.md)), `GET /api/users/tmux` each member's own tmux server under one Linux user per account (`{available, installed, matched, users: [{id, username, running, stuck?, version, pid, startedAt, sessions, busy, outdated}]}`; an admin's `POST /api/users/:id/tmux-restart` and `POST /api/users/tmux-restart-idle` restart them with `currentPassword`, audited, `409 ETMUXSTUCK` for a server that will not stop), `GET /api/host` the machine and each user's live share of it (`{at, hostname, os, uptime, cpu: {model, cores, load}, memory: {total, available, used, swapTotal, swapUsed}, disks: [{device, mount, type, kind: "HDD"|"SSD"|null, total, used, free}], homesMount, gpus: [{name, utilization, memoryUsed, memoryTotal}], usage: {cpu, sampleMs, groups: [{key, kind: "user"|"host"|"system", userId?, username?, cpu, memory, memoryPercent, processes, top: [{pid, name, cpu, memory}]}]} | null, bootTime, network: [{name, rx, tx}], diskIo: [{name, read, write}], temperatures: [{chip, label, celsius}], pressure: {cpu, memory, io: {some10, some60, full10} | null} | null (Linux PSI, `/proc/pressure/*`: % of the last 10 / 60 s tasks stalled on it), topProcesses: [{pid, name, cpu, memory, group}], process: {pid, node, uptime, rss, heapUsed}}`, `cpu` also carrying `physicalCores` and `perCore` (busy % per thread), rates in bytes/s over the sample — read-only, cached 3 s, `usage` null and the lists empty off Linux), `GET /api/host/history?range=1h|6h|24h` the CPU/memory history every server on Linux keeps in memory since it started (both read by the Dashboard's System Health tab and open to every signed-in user — `/host` is not staff-only) (`{range, intervalMs, running, startedAt, points: [{at, cpu, memory, memoryUsed, swapUsed, load1, users: {<id>: {cpu, memory}}}]}`, one point per 30 s, averaged to ≤ 360), `GET /api/users/:id/details[?tz_offset=]` one account in full for the Administration page's user detail (`{user (with logins, lastLoginAt), sessions: {total, active, firstAt, lastAt}, usage: {today, last7d, last30d, daily: [{date, cost, tokens}] (30 local days, oldest first), byTool, byModel: [{key, cost, tokens, sessions}]}, workspaces: [{id, title, cwd, tool, kind, branch, status, createdAt, sessions, lastActiveAt, livePanes}], panes: [{id, laneId, laneTitle, laneCwd, tool, model, account, proxy, sessionId, startedAt, status}], recentSessions (15, with cost/tokens), pool: {claude|codex|cursor: {pin, group, accounts: [{name, kind, email, expired, allowed, pinned, quota, quotaPercent, full, livePanes, spend5h, spend7d, userSpend5h, userSpend7d, userTokens5h, userTokens7d, userRuns7d, userLivePanes, userLastAt}]}}, audit}` — `user*` fields are only the runs on that user's workspaces; never a token; `404 ENOUSER`), and `GET /api/users/audit[?limit=]` the staff reads of developers' sessions and admins' account changes (kept `AGENTHUB_AUDIT_DAYS` days, default 180, `0` = forever) (`reader`/`owner` are usernames, `reader_display`/`owner_display` their display names or null) (all `403 EADMIN` for a developer). `GET /api/users` also carries each account's [spend quota](SERVER-MODE.md#spend-quotas) — `quotaSetting` (`{mode: "default"|"unlimited"|"custom", limit_usd?, period?, tz_offset?}`) and `quota` (the one binding them now with `spend`, `pct`, `exceeded`, `resetsAt`, or null) — and the top-level `quotaDefault`; an admin sets the default with `PUT /api/users/quota-default` `{quota: {limit_usd, period, tz_offset} | null, currentPassword}` and a user's own with `PATCH /api/users/:id` `{quota}` (`400 EBADQUOTA`). A workspace owner over their quota gets `429 EQUOTA` from `POST /api/run` and `POST /api/lanes/:id/start`. See [SERVER-MODE.md](SERVER-MODE.md#what-each-user-sees).
+In server mode a **developer** sees only rows of the workspaces they own (`lanes.owner_id`): every list, count, chart and cost answer is limited to them, and a request naming another user's session, agent, workspace or run (in the path, query or body) answers `404 ENOTFOUND`. Admin and analyst see everything; `GET /api/users` lists every account (`displayName`, `email`, `createdAt`, `logins`, `lastLoginAt` — the last login ever, kept after it ends —, `mustChangePassword` included) with its workspaces, sessions and `today` (since the viewer's local midnight — `?tz_offset=` is the browser's `getTimezoneOffset()`, UTC without it) / 7 / 30-day `{cost, tokens}`, `GET /api/users/storage[?refresh=1]` each user's home size (`{storage: {<id>: {bytes, files, partial, measuredAt} | null}, measuring}` — measured in the background, see [SERVER-MODE.md](SERVER-MODE.md)), `GET /api/users/tmux` each member's own tmux server under one Linux user per account (`{available, installed, matched, users: [{id, username, running, stuck?, version, pid, startedAt, sessions, busy, outdated}]}`; an admin's `POST /api/users/:id/tmux-restart` and `POST /api/users/tmux-restart-idle` restart them with `currentPassword`, audited, `409 ETMUXSTUCK` for a server that will not stop), `GET /api/host` the machine and each user's live share of it (`{at, hostname, os, uptime, cpu: {model, cores, load}, memory: {total, available, used, swapTotal, swapUsed}, disks: [{device, mount, type, kind: "HDD"|"SSD"|null, total, used, free}], homesMount, gpus: [{name, utilization, memoryUsed, memoryTotal}], usage: {cpu, sampleMs, groups: [{key, kind: "user"|"host"|"system", userId?, username?, displayName?, avatarAt?, cpu, memory, memoryPercent, processes, top: [{pid, name, cpu, memory}]}]} | null, bootTime, network: [{name, rx, tx}], diskIo: [{name, read, write}], temperatures: [{chip, label, celsius}], pressure: {cpu, memory, io: {some10, some60, full10} | null} | null (Linux PSI, `/proc/pressure/*`: % of the last 10 / 60 s tasks stalled on it), topProcesses: [{pid, name, cpu, memory, group}], process: {pid, node, uptime, rss, heapUsed}}`, `cpu` also carrying `physicalCores` and `perCore` (busy % per thread), rates in bytes/s over the sample — read-only, cached 3 s, `usage` null and the lists empty off Linux), `GET /api/host/history?range=1h|6h|24h` the CPU/memory history every server on Linux keeps in memory since it started (both read by the Dashboard's System Health tab and open to every signed-in user — `/host` is not staff-only) (`{range, intervalMs, running, startedAt, points: [{at, cpu, memory, memoryUsed, swapUsed, load1, users: {<id>: {cpu, memory}}}]}`, one point per 30 s, averaged to ≤ 360), `GET /api/users/:id/details[?tz_offset=]` one account in full for the Administration page's user detail (`{user (with logins, lastLoginAt), sessions: {total, active, firstAt, lastAt}, usage: {today, last7d, last30d, daily: [{date, cost, tokens}] (30 local days, oldest first), byTool, byModel: [{key, cost, tokens, sessions}]}, workspaces: [{id, title, cwd, tool, kind, branch, status, createdAt, sessions, lastActiveAt, livePanes}], panes: [{id, laneId, laneTitle, laneCwd, tool, model, account, proxy, sessionId, startedAt, status}], recentSessions (15, with cost/tokens), pool: {claude|codex|cursor: {pin, group, accounts: [{name, kind, email, expired, allowed, pinned, quota, quotaPercent, full, livePanes, spend5h, spend7d, userSpend5h, userSpend7d, userTokens5h, userTokens7d, userRuns7d, userLivePanes, userLastAt}]}}, audit}` — `user*` fields are only the runs on that user's workspaces; never a token; `404 ENOUSER`), and `GET /api/users/audit[?limit=]` the staff reads of developers' sessions and admins' account changes (kept `AGENTHUB_AUDIT_DAYS` days, default 180, `0` = forever) (`reader`/`owner` are usernames, `reader_display`/`owner_display` their display names or null) (all `403 EADMIN` for a developer). `GET /api/users` also carries each account's [spend quota](SERVER-MODE.md#spend-quotas) — `quotaSetting` (`{mode: "default"|"unlimited"|"custom", limit_usd?, period?, tz_offset?}`) and `quota` (the one binding them now with `spend`, `pct`, `exceeded`, `resetsAt`, or null) — and the top-level `quotaDefault`; an admin sets the default with `PUT /api/users/quota-default` `{quota: {limit_usd, period, tz_offset} | null, currentPassword}` and a user's own with `PATCH /api/users/:id` `{quota}` (`400 EBADQUOTA`). A workspace owner over their quota gets `429 EQUOTA` from `POST /api/run` and `POST /api/lanes/:id/start`. See [SERVER-MODE.md](SERVER-MODE.md#what-each-user-sees).
 
-An admin changes accounts with `POST /api/users` (`{username, password, role}` → `201 {user}`; the password may be any non-empty starting one and the account gets `mustChangePassword: true`), `GET /api/users/:id` (`{user, workspaces: [{id, title, cwd}]}`, the account with `logins` and `lastLoginAt`, for the Edit form; admin or analyst), `GET /api/users/:id/avatar` (that account's picture for the sidebar's owner groups — admin or analyst, `nosniff` + `sandbox` CSP, `404 ENOAVATAR`; a workspace in `GET /api/lanes` carries `owner_avatar_at` to version its URL), `PATCH /api/users/:id` (any of `{displayName?, email?, role?, disabled?, password?, addWorkspaces?: [laneId], removeWorkspaces?: [laneId], signOut?: true}` — every field validated before any is written; `removeWorkspaces` leaves the workspace with no owner and answers `409 ENOTOWNED` for one the user does not own; an admin's own `password`/`signOut` keeps the login it came from; a password for SOMEONE ELSE may be anything non-empty and sets their `mustChangePassword`, the admin's OWN must pass every rule below, `400 EWEAKPASSWORD` with `rules`), `POST /api/users/:id/password` (`{password}`; that user's logins end; the same two bars) `POST /api/users/:id/workspaces` (`{laneId}`; the workspace's owner becomes that user) and `DELETE /api/users/:id` (delete for good: the user's logins, panes, workspaces' records, prefs and — under S3 — their Linux account and whole home, removed FIRST so a refusal (`502 EPROVISION`) leaves every row; `409 ESELF` for yourself, `409 ELASTADMIN` for the last admin; session history and the audit log stay). No path — this API or the `agenthub users` CLI — may demote, disable or delete the last enabled admin (`409 ELASTADMIN`). Every one carries `currentPassword`, the admin's own password: `403 EREAUTH` when it is wrong or missing, `429 ETOOMANY` after 10 wrong tries in 15 minutes. `409 ESELF` for an admin's own role or disable, `409 EEXISTS` for a taken name, `400 EBADUSER`/`EBADPASSWORD`/`EBADROLE`/`EBADEMAIL`/`EBADFIELD`, `404 ENOUSER`/`ENOLANE`; a developer or analyst gets `403 EADMIN`, and local mode `403 ELOCALMODE`. No answer carries a password hash; each change is written to the audit log.
+An admin changes accounts with `POST /api/users` (`{username, password, role}` → `201 {user}`; the password may be any non-empty starting one and the account gets `mustChangePassword: true`), `GET /api/users/:id` (`{user, workspaces: [{id, title, cwd}]}`, the account with `logins` and `lastLoginAt`, for the Edit form; admin or analyst), `GET /api/users/:id/avatar` (that account's picture for the sidebar's owner groups — admin or analyst, `nosniff` + `sandbox` CSP, `404 ENOAVATAR`; a workspace in `GET /api/lanes` carries `owner_avatar_at` to version its URL), `PATCH /api/users/:id` (any of `{displayName?, email?, role?, disabled?, password?, addWorkspaces?: [laneId], removeWorkspaces?: [laneId], signOut?: true}` — every field validated before any is written; `removeWorkspaces` leaves the workspace with no owner and answers `409 ENOTOWNED` for one the user does not own; an admin's own `password`/`signOut` keeps the login it came from; a password for SOMEONE ELSE may be anything non-empty and sets their `mustChangePassword`, the admin's OWN must pass every rule below, `400 EWEAKPASSWORD` with `rules`), `POST /api/users/:id/password` (`{password}`; that user's logins end; the same two bars) `POST /api/users/:id/workspaces` (`{laneId}`; the workspace's owner becomes that user) and `DELETE /api/users/:id` (delete for good: the user's logins, panes, workspaces' records, prefs and — under S3 — their Linux account and whole home, removed FIRST so a refusal (`502 EPROVISION`) leaves every row; `409 ESELF` for yourself, `409 ELASTADMIN` for the last admin; session history and the audit log stay). No path — this API or the `agenthub users` CLI — may demote, disable or delete the last enabled admin (`409 ELASTADMIN`). Every one carries `currentPassword`, the admin's own password: `403 EREAUTH` when it is wrong or missing, `429 ETOOMANY` after 10 wrong tries in 15 minutes. `409 ESELF` for an admin's own role or disable, `409 EEXISTS` for a taken name, `409 ENAMETAKEN` for a `displayName` that reads as another account's (the same rule as `PATCH /api/me/account`), `400 EBADUSER`/`EBADPASSWORD`/`EBADROLE`/`EBADEMAIL`/`EBADFIELD`, `404 ENOUSER`/`ENOLANE`; a developer or analyst gets `403 EADMIN`, and local mode `403 ELOCALMODE`. No answer carries a password hash; each change is written to the audit log.
 
 `GET /api/accounts[?force=1]` lists the Claude account pool ([SERVER-MODE.md](SERVER-MODE.md#claude-account-pool)): `{accounts: [{name, addedAt, expiresAt, expired, livePanes, spend5h, spend7d, tokens5h, tokens7d, quota: {fiveHour, sevenDay, checkedAt, error} | null, quotaPercent, full}], codex: [{name, kind: "apikey"|"chatgpt", addedAt, livePanes, spend5h, spend7d, tokens5h, tokens7d, quota: {windows: [{label, usedPercent, resetsAt}], asOf} | null, quotaPercent, full}], pins: {claude: [{userId, username, account, pinnedAt}], codex: […]}, blockPercent}` — `pins` are the users an admin pinned to one account (empty in local mode, keyed by tool: `claude`, `codex`, `cursor`); `codex` is the [Codex account pool](SERVER-MODE.md#codex-account-pool); `cursor: [{name, kind: "apikey", addedAt, livePanes, …}]` is the [Cursor account pool](SERVER-MODE.md#cursor-account-pool) (API keys; `quota` null, spend 0); `groups: [{id, name, createdAt, users: [{userId, username}], accounts: {claude: [names], codex: […], cursor: […]}}]` are the [pool groups](SERVER-MODE.md#account-pool-groups) (empty in local mode). `spend*`/`tokens*` = the sessions the account's runs held, over the hours they held them (a Codex session counts whole once its run started in the window). It never includes a key or a token. `force=1` re-reads every quota first. Run rows (`/api/run/history`) carry `account`, the pool account their pane ran on (`null` = the machine's own login).
 
@@ -110,7 +110,7 @@ An admin (server mode) adds an account with `POST /api/accounts` `{tool: "claude
 | `PUT /api/me/pool-accounts` `{tool, account: "<name>" \| null}` | the account's new sessions of `tool` run on `account` (`null` = automatic): `{tool, choice, switched}` — `switched` as for an admin's pin (a Claude login goes into the home at once). Below an admin's pin (`409 ELOCKED`), only an account the group allows (`404 ENOACCOUNT`), `400 EBADTOOL`; login cookie only, audited |
 | `POST /api/me/onboarded` | the first-run setup is done or skipped (kept from the first call) |
 | `GET /api/me/account` | Settings → Account. Server mode: `{mode: "server", user: {id, username, role, disabled, displayName, email, avatarAt, createdAt}, workspaces, sessions, logins, lastLoginAt}`; local mode `{mode: "local"}` |
-| `PATCH /api/me/account` `{displayName?, email?}` | the account's own profile (`""`/`null` clears), the same shape back; `400 EBADFIELD` (display name over 100 characters or with control characters) / `EBADEMAIL` |
+| `PATCH /api/me/account` `{displayName?, email?}` | the account's own profile (`""`/`null` clears), the same shape back; `400 EBADFIELD` (display name over 100 characters or with control characters) / `EBADEMAIL`; `409 ENAMETAKEN` for a display name that reads as another account's display name or username (marks, case, punctuation, bracketed parts like "(you)" and look-alike letters ignored; keeping the name you have is always allowed) |
 | `POST /api/me/password` `{currentPassword, newPassword}` | `{ok: true}`; every other login of the account ends, this one stays, and `mustChangePassword` clears. The new password must pass every rule — at least 8 characters, a lower-case and an upper-case letter, a digit, a symbol, not containing the username — and differ from the current one: `400 EWEAKPASSWORD` with `error.rules` (`length`, `lower`, `upper`, `digit`, `symbol`, `username`, `reused`). `403 EREAUTH` wrong current password (`429 ETOOMANY` after 10), `400 EBADPASSWORD` |
 | `POST /api/me/sign-out-others` | `{ended}` — every login of the account but this one ends |
 | `GET /api/me/avatar` | server mode: the account's own picture (`nosniff`, `sandbox` CSP; the client adds `?v=<avatarAt>`), `404 ENOAVATAR` when it has none |

docs/SERVER-MODE.md

@@ -372,7 +372,13 @@ Wherever the dashboard names a person — the sidebar's sign-out tooltip, the
 workspace list's owner groups, the Users page and its audit log, the Edit user
 form — it shows their display name when one is set, else the username (the
 Users page keeps `@username` beside a display name). Logging in, the CLI and
-the Linux account always use the username.
+the Linux account always use the username. No one can pose as a colleague: a
+display name that reads as another account's display name or username — marks,
+case, spaces, punctuation, a bracketed part like "(you)" and look-alike letters
+from other alphabets ignored — is refused (`409 ENAMETAKEN`), whether the user
+sets it in Settings → Account or an admin does on the Users page. A name an
+account already has is kept on an unrelated save; rename an old clash from the
+Users page.
 
 Under S3 an admin's folder browser opens on their own home too; ticking
 **Server folder** opens the host account's home (`/home/<host>`), where a

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "agenthub",
-  "version": "2.8.37",
+  "version": "2.8.39",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "agenthub",
-      "version": "2.8.37",
+      "version": "2.8.39",
       "hasInstallScript": true,
       "license": "UNLICENSED",
       "dependencies": {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "agenthub",
-  "version": "2.8.37",
+  "version": "2.8.39",
   "bin": {
     "agenthub": "bin/agenthub.js"
   },

server/__tests__/server-mode-user-edit.test.js

@@ -222,6 +222,26 @@ describe("Settings → Account (/api/me)", () => {
     assert.equal(bad.body.error.code, "EBADEMAIL");
   });
 
+  it("refuses a display name that reads as another account's (ENAMETAKEN)", async () => {
+    assert.equal(auth.nameKey("Nguyễn Ngọc Trí Vĩ (you)"), auth.nameKey("nguyen.ngoc-tri VI"));
+    assert.equal(auth.nameKey("Đào"), "dao");
+    // Cyrillic о and а in place of Latin letters.
+    assert.equal(auth.nameKey("Mіа Trоn"), auth.nameKey("Mia Tron"));
+    const leo = await login("leo", "member-pass-2");
+    // mia's display name is "Mia Tran"; boss has none, only a username.
+    for (const name of ["MIA TRẦN (you)", "Mia\u200b Tran", "mia", "Bóss"]) {
+      const r = await call("PATCH", "/api/me/account", { cookie: leo, body: { displayName: name } });
+      assert.equal(r.status, 409, name);
+      assert.equal(r.body.error.code, "ENAMETAKEN");
+    }
+    assert.equal(auth.findUser("leo").display_name, "Leo N");
+    // Keeping one's own name, or a name of one's own, still works.
+    for (const name of ["Leo N", "Leo Nguyen"]) {
+      const r = await call("PATCH", "/api/me/account", { cookie: leo, body: { displayName: name } });
+      assert.equal(r.status, 200, name);
+    }
+  });
+
   it("changes its own password only with the old one, keeping this login", async () => {
     const leo = await login("leo", "member-pass-2");
     const other = await login("leo", "member-pass-2");

server/lib/auth.js

@@ -20,7 +20,8 @@
  *   admin on the Users page (`server/routes/users.js`), where every change
  *   needs the admin's own password again (`confirmPassword`, throttled).
  *   An account also carries an optional display name and email
- *   (`validateProfile`), which its owner edits in Settings → Account without
+ *   (`validateProfile`; no two accounts may read as one name — `assertNameFree`,
+ *   ENAMETAKEN), which its owner edits in Settings → Account without
  *   that step-up; changing their OWN password there needs the old one and
  *   keeps the login it was changed from (`setPassword`'s `keepToken`).
  * - Two password bars: an admin may GIVE any non-empty password (a create or a
@@ -247,6 +248,47 @@ function validateProfile(body) {
   return out;
 }
 
+// Latin look-alikes from other scripts, so "Vĩ" in Cyrillic still collides.
+const CONFUSABLE = {
+  а: "a", в: "b", е: "e", к: "k", м: "m", н: "h", о: "o", р: "p", с: "c", т: "t",
+  у: "y", х: "x", і: "i", ј: "j", ԁ: "d", ѕ: "s", ӏ: "l", α: "a", β: "b", ε: "e",
+  η: "n", ι: "i", κ: "k", ν: "v", ο: "o", ρ: "p", τ: "t", υ: "u", χ: "x", "ı": "i",
+};
+
+/**
+ * The name two accounts may not share: no marks (Vĩ = Vi), đ = d, any case,
+ * look-alike letters folded, and only letters and digits outside brackets —
+ * so "Nguyễn Ngọc Trí Vĩ (you)" and "nguyen.ngoc-tri vi" are both one name.
+ */
+function nameKey(s) {
+  return String(s || "")
+    .normalize("NFKD")
+    .replace(/\p{M}/gu, "")
+    .toLowerCase()
+    .replace(/\([^)]*\)|\[[^\]]*\]/g, "")
+    .replace(/[đð]/g, "d")
+    .replace(/./gu, (c) => CONFUSABLE[c] ?? c)
+    .replace(/[^\p{L}\p{N}]/gu, "");
+}
+
+/**
+ * Refuse (ENAMETAKEN) a display name that reads as another account's display
+ * name or username, so no one can pose as a colleague. Keeping the name one
+ * already has is always allowed — a clash from before this rule is no reason
+ * to block an admin's unrelated edit.
+ */
+function assertNameFree(userId, fields) {
+  if (!("display_name" in fields) || !fields.display_name) return;
+  const key = nameKey(fields.display_name);
+  if (!key) return;
+  const own = sql("SELECT display_name FROM users WHERE id = ?").get(userId);
+  if (own && own.display_name === fields.display_name) return;
+  const rows = sql("SELECT id, username, display_name FROM users WHERE id != ?").all(userId);
+  if (rows.some((u) => nameKey(u.username) === key || nameKey(u.display_name) === key)) {
+    throw err("ENAMETAKEN", "displayName: another account already uses that name");
+  }
+}
+
 /** Write `validateProfile`'s result for one account. */
 function setProfile(userId, fields) {
   for (const [col, value] of Object.entries(fields)) {
@@ -812,6 +854,8 @@ module.exports = {
   unassignWorkspace,
   ownedWorkspaces,
   validateProfile,
+  nameKey,
+  assertNameFree,
   setProfile,
   validatePassword,
   validateOwnPassword,

server/lib/host-stats.js

@@ -555,12 +555,13 @@ async function usage(t0, t1, p0, p1, mem) {
 
 const round = (n) => Math.round(n * 10) / 10;
 
-/** A user's group fields: id, username and display name (every viewer reads them). */
+/** A user's group fields: id, username, display name and avatar version (every viewer reads them). */
 const userExtra = (u) => ({
   kind: "user",
   userId: u.id,
   username: u.username,
   displayName: u.displayName ?? null,
+  avatarAt: u.avatarAt ?? null,
 });
 
 async function collect() {

server/routes/me.js

@@ -197,6 +197,7 @@ const { recordAccountChange } = require("../lib/audit");
 const ACCOUNT_STATUS = {
   EBADFIELD: 400,
   EBADEMAIL: 400,
+  ENAMETAKEN: 409,
   EBADPASSWORD: 400,
   EWEAKPASSWORD: 400,
   EBADIMAGE: 400,
@@ -262,6 +263,7 @@ router.patch(
   sameOriginGuard,
   accountWrite(async (_req, user, body) => {
     const fields = auth.validateProfile({ displayName: body.displayName, email: body.email });
+    auth.assertNameFree(user.id, fields);
     auth.setProfile(user.id, fields);
     return { out: accountView(user.id), action: "own profile" };
   })

server/routes/users.js

@@ -171,6 +171,7 @@ router.get("/tmux", (_req, res) => {
 const STATUS = {
   EBADUSER: 400,
   EBADEMAIL: 400,
+  ENAMETAKEN: 409,
   ENOTOWNED: 409,
   EBADPASSWORD: 400,
   EWEAKPASSWORD: 400,
@@ -562,6 +563,7 @@ router.patch(
 
     // 1. Validate everything — nothing is written until all of it passes.
     const profile = auth.validateProfile(body);
+    auth.assertNameFree(u.id, profile);
     const roleChange = body.role !== undefined && body.role !== u.role;
     if (roleChange) {
       if (self) throw ESELF("you cannot change your own role");