Add account auth with websocket login/register and sessions

client/index.html

@@ -9,12 +9,41 @@
     <main class="app">
       <h1>Chat Grid</h1>
       <div id="connectionStatus" role="status" aria-live="polite" aria-atomic="true"></div>
+      <section id="loginView" class="auth-panel">
+        <h2>Login</h2>
+        <div class="auth-row">
+          <label for="authUsername">Username</label>
+          <input id="authUsername" type="text" maxlength="32" autocomplete="username" />
+        </div>
+        <div class="auth-row">
+          <label for="authPassword">Password</label>
+          <input id="authPassword" type="password" maxlength="64" autocomplete="current-password" />
+        </div>
+        <button id="showRegisterButton" type="button">Create account</button>
+      </section>
+      <section id="registerView" class="auth-panel hidden">
+        <h2>Register</h2>
+        <div class="auth-row">
+          <label for="registerUsername">Username</label>
+          <input id="registerUsername" type="text" maxlength="32" autocomplete="username" />
+        </div>
+        <div class="auth-row">
+          <label for="registerPassword">Password</label>
+          <input id="registerPassword" type="password" maxlength="64" autocomplete="new-password" />
+        </div>
+        <div class="auth-row">
+          <label for="registerEmail">Email (optional)</label>
+          <input id="registerEmail" type="email" maxlength="320" autocomplete="email" />
+        </div>
+        <button id="showLoginButton" type="button">Back to login</button>
+      </section>
       <div id="nicknameContainer" class="nickname-row">
         <label for="preconnectNickname">Nickname</label>
         <input id="preconnectNickname" type="text" maxlength="32" autocomplete="nickname" />
       </div>
       <div class="controls" id="button-container">
         <button id="connectButton">Connect</button>
+        <button id="logoutButton">Log out</button>
         <button id="settingsButton">Settings</button>
         <button id="disconnectButton" class="hidden">Disconnect</button>
         <button id="focusGridButton" class="hidden" aria-controls="gameCanvas">Chat Grid</button>

client/public/version.js

@@ -1,5 +1,5 @@
 // Maintainer-controlled web client version.
 // Format: YYYY.MM.DD Rn (example: 2026.02.20 R2)
-window.CHGRID_WEB_VERSION = "2026.02.25 R242";
+window.CHGRID_WEB_VERSION = "2026.02.25 R243";
 // Optional display timezone for timestamps. Falls back to America/Detroit if unset/invalid.
 window.CHGRID_TIME_ZONE = "America/Detroit";

client/src/main.ts

@@ -90,12 +90,22 @@ declare global {
 type Dom = {
   connectionStatus: HTMLElement;
   appVersion: HTMLElement;
+  loginView: HTMLElement;
+  registerView: HTMLElement;
+  authUsername: HTMLInputElement;
+  authPassword: HTMLInputElement;
+  registerUsername: HTMLInputElement;
+  registerPassword: HTMLInputElement;
+  registerEmail: HTMLInputElement;
+  showRegisterButton: HTMLButtonElement;
+  showLoginButton: HTMLButtonElement;
   updatesSection: HTMLElement;
   updatesToggle: HTMLButtonElement;
   updatesPanel: HTMLDivElement;
   nicknameContainer: HTMLDivElement;
   preconnectNickname: HTMLInputElement;
   connectButton: HTMLButtonElement;
+  logoutButton: HTMLButtonElement;
   disconnectButton: HTMLButtonElement;
   focusGridButton: HTMLButtonElement;
   settingsButton: HTMLButtonElement;
@@ -113,12 +123,22 @@ type Dom = {
 const dom: Dom = {
   connectionStatus: requiredById('connectionStatus'),
   appVersion: requiredById('appVersion'),
+  loginView: requiredById('loginView'),
+  registerView: requiredById('registerView'),
+  authUsername: requiredById('authUsername'),
+  authPassword: requiredById('authPassword'),
+  registerUsername: requiredById('registerUsername'),
+  registerPassword: requiredById('registerPassword'),
+  registerEmail: requiredById('registerEmail'),
+  showRegisterButton: requiredById('showRegisterButton'),
+  showLoginButton: requiredById('showLoginButton'),
   updatesSection: requiredById('updatesSection'),
   updatesToggle: requiredById('updatesToggle'),
   updatesPanel: requiredById('updatesPanel'),
   nicknameContainer: requiredById('nicknameContainer'),
   preconnectNickname: requiredById('preconnectNickname'),
   connectButton: requiredById('connectButton'),
+  logoutButton: requiredById('logoutButton'),
   disconnectButton: requiredById('disconnectButton'),
   focusGridButton: requiredById('focusGridButton'),
   settingsButton: requiredById('settingsButton'),
@@ -203,6 +223,10 @@ let lastFocusedElement: Element | null = null;
 let lastAnnouncementText = '';
 let lastAnnouncementAt = 0;
 let outputMode = settings.loadOutputMode();
+let authMode: 'login' | 'register' = 'login';
+let authSessionToken = settings.loadAuthSessionToken();
+let authUsername = settings.loadAuthUsername();
+let pendingAuthRequest = false;
 const messageBuffer: string[] = [];
 let messageCursor = -1;
 const radioRuntime = new RadioStationRuntime(audio, getItemSpatialConfig);
@@ -482,14 +506,33 @@ function sanitizeName(value: string): string {
   return value.replace(/[\u0000-\u001F\u007F<>]/g, '').trim().slice(0, NICKNAME_MAX_LENGTH);
 }
 
+/** Normalizes auth username according to server policy. */
+function sanitizeAuthUsername(value: string): string {
+  return value
+    .trim()
+    .toLowerCase()
+    .replace(/[^a-z0-9_-]/g, '')
+    .slice(0, 32);
+}
+
 /** Enables/disables the connect button based on state and nickname validity. */
 function updateConnectAvailability(): void {
+  dom.logoutButton.disabled = !authSessionToken.trim() && !state.running;
   if (state.running) {
     dom.connectButton.disabled = true;
+    dom.loginView.classList.add('hidden');
+    dom.registerView.classList.add('hidden');
     return;
   }
-  const hasNickname = sanitizeName(dom.preconnectNickname.value).length > 0;
+  dom.loginView.classList.toggle('hidden', authMode !== 'login');
-  dom.connectButton.disabled = mediaSession.isConnecting() || !hasNickname;
+  dom.registerView.classList.toggle('hidden', authMode !== 'register');
+  const hasSessionToken = authSessionToken.trim().length > 0;
+  const hasLoginCredentials =
+    sanitizeAuthUsername(dom.authUsername.value).length >= 2 && dom.authPassword.value.trim().length >= 8;
+  const hasRegisterCredentials =
+    sanitizeAuthUsername(dom.registerUsername.value).length >= 2 && dom.registerPassword.value.trim().length >= 8;
+  const authReady = hasSessionToken || (authMode === 'login' ? hasLoginCredentials : hasRegisterCredentials);
+  dom.connectButton.disabled = mediaSession.isConnecting() || !authReady;
 }
 
 /** Restores persisted outbound effect levels from local storage. */
@@ -1294,6 +1337,112 @@ async function reconnectWithRetry(reason: 'heartbeat' | 'socketClose'): Promise<
   reconnectInFlight = false;
 }
 
+/** Switches pre-connect auth view between login and register modes. */
+function setAuthMode(mode: 'login' | 'register'): void {
+  authMode = mode;
+  dom.loginView.classList.toggle('hidden', mode !== 'login');
+  dom.registerView.classList.toggle('hidden', mode !== 'register');
+  updateConnectAvailability();
+}
+
+/** Builds outbound auth packet from local token or active auth form. */
+function buildAuthRequestPacket(): OutgoingMessage | null {
+  const token = authSessionToken.trim();
+  if (token) {
+    return { type: 'auth_resume', sessionToken: token };
+  }
+  if (authMode === 'register') {
+    const username = sanitizeAuthUsername(dom.registerUsername.value);
+    const password = dom.registerPassword.value;
+    const email = dom.registerEmail.value.trim();
+    if (!username || !password) return null;
+    return { type: 'auth_register', username, password, ...(email ? { email } : {}) };
+  }
+  const username = sanitizeAuthUsername(dom.authUsername.value);
+  const password = dom.authPassword.value;
+  if (!username || !password) return null;
+  return { type: 'auth_login', username, password };
+}
+
+/** Sends current auth request over signaling websocket after socket open. */
+function sendAuthRequest(): void {
+  const packet = buildAuthRequestPacket();
+  if (!packet) {
+    updateStatus('Enter username and password.');
+    audio.sfxUiCancel();
+    mediaSession.setConnecting(false);
+    updateConnectAvailability();
+    signaling.disconnect();
+    return;
+  }
+  pendingAuthRequest = true;
+  setConnectionStatus('Authenticating...');
+  signaling.send(packet);
+}
+
+/** Handles server auth-required prompts prior to world welcome. */
+function handleAuthRequired(message: string): void {
+  setConnectionStatus('Authentication required.');
+  updateStatus(message);
+}
+
+/** Applies auth result state and terminates failed auth attempts quickly. */
+async function handleAuthResult(message: Extract<IncomingMessage, { type: 'auth_result' }>): Promise<void> {
+  pendingAuthRequest = false;
+  if (!message.ok) {
+    dom.authPassword.value = '';
+    dom.registerPassword.value = '';
+    if (message.message.toLowerCase().includes('session')) {
+      authSessionToken = '';
+      settings.saveAuthSessionToken('');
+    }
+    updateStatus(message.message);
+    audio.sfxUiCancel();
+    mediaSession.setConnecting(false);
+    updateConnectAvailability();
+    signaling.disconnect();
+    setConnectionStatus('Authentication failed.');
+    return;
+  }
+
+  if (message.sessionToken) {
+    authSessionToken = message.sessionToken;
+    settings.saveAuthSessionToken(message.sessionToken);
+  }
+  if (message.username) {
+    authUsername = message.username;
+    settings.saveAuthUsername(message.username);
+    dom.authUsername.value = message.username;
+    dom.registerUsername.value = message.username;
+  }
+  if (message.nickname) {
+    const resolved = sanitizeName(message.nickname);
+    if (resolved) {
+      state.player.nickname = resolved;
+      dom.preconnectNickname.value = resolved;
+      settings.saveNickname(resolved);
+    }
+  }
+  dom.authPassword.value = '';
+  dom.registerPassword.value = '';
+  setConnectionStatus('Authenticated. Joining world...');
+}
+
+/** Clears stored auth session and returns UI to login mode. */
+function logOutAccount(): void {
+  authSessionToken = '';
+  authUsername = '';
+  settings.saveAuthSessionToken('');
+  settings.saveAuthUsername('');
+  if (state.running) {
+    signaling.send({ type: 'auth_logout' });
+    disconnect();
+  }
+  setAuthMode('login');
+  updateStatus('Logged out.');
+  updateConnectAvailability();
+}
+
 /** Builds dependencies shared by connect/disconnect flow helpers. */
 function getConnectionFlowDeps(): ConnectFlowDeps {
   return {
@@ -1322,6 +1471,7 @@ function getConnectionFlowDeps(): ConnectFlowDeps {
     mediaDescribeError: (error) => describeMediaError(error),
     mediaStopLocalMedia: () => stopLocalMedia(),
     signalingConnect: (handler) => signaling.connect(handler as (message: IncomingMessage) => Promise<void>),
+    signalingSendAuth: () => sendAuthRequest(),
     signalingDisconnect: () => signaling.disconnect(),
     onMessage: (message) => onSignalingMessage(message as IncomingMessage),
     persistPlayerPosition,
@@ -1423,6 +1573,8 @@ const onAppMessage = createOnMessageHandler({
   playIncomingItemUseSound: (url, x, y) => {
     void audio.playSpatialSample(url, { x, y }, { x: state.player.x, y: state.player.y }, 1);
   },
+  handleAuthRequired,
+  handleAuthResult,
 });
 
 /** Handles signaling packets with heartbeat/restart metadata before app-level dispatch. */
@@ -2429,20 +2581,51 @@ function setupUiHandlers(): void {
       persistPlayerPosition();
     },
   });
+  dom.showRegisterButton.addEventListener('click', () => {
+    setAuthMode('register');
+    dom.registerUsername.focus();
+  });
+  dom.showLoginButton.addEventListener('click', () => {
+    setAuthMode('login');
+    dom.authUsername.focus();
+  });
+  dom.logoutButton.addEventListener('click', () => {
+    logOutAccount();
+  });
+  dom.authUsername.addEventListener('input', () => {
+    dom.authUsername.value = sanitizeAuthUsername(dom.authUsername.value);
+    updateConnectAvailability();
+  });
+  dom.authPassword.addEventListener('input', () => {
+    updateConnectAvailability();
+  });
+  dom.registerUsername.addEventListener('input', () => {
+    dom.registerUsername.value = sanitizeAuthUsername(dom.registerUsername.value);
+    updateConnectAvailability();
+  });
+  dom.registerPassword.addEventListener('input', () => {
+    updateConnectAvailability();
+  });
+  dom.registerEmail.addEventListener('input', () => {
+    updateConnectAvailability();
+  });
 }
 
 setupInputHandlers();
 setupUiHandlers();
+dom.authUsername.value = sanitizeAuthUsername(authUsername);
+dom.registerUsername.value = sanitizeAuthUsername(authUsername);
 const storedNickname = sanitizeName(settings.loadNickname());
 dom.preconnectNickname.value = storedNickname;
 if (storedNickname) {
   state.player.nickname = storedNickname;
 }
+setAuthMode('login');
 updateConnectAvailability();
 updateDeviceSummary();
 updateStatus(
   isVersionReloadedSession()
     ? 'Client updated, please reconnect.'
-    : 'Welcome to the Chat Grid. Press the Settings button to configure your audio, then Connect to join the grid.',
+    : 'Welcome to the Chat Grid. Log in or register, configure audio if needed, then Connect to join the grid.',
 );
 setConnectionStatus(isVersionReloadedSession() ? 'Client updated, please reconnect.' : 'Not connected.');

client/src/network/messageHandlers.ts

@@ -73,6 +73,8 @@ type MessageHandlerDeps = {
   playLocateToneAt: (x: number, y: number) => void;
   resolveIncomingSoundUrl: (url: string) => string;
   playIncomingItemUseSound: (url: string, x: number, y: number) => void;
+  handleAuthRequired: (message: string) => void;
+  handleAuthResult: (message: Extract<IncomingMessage, { type: 'auth_result' }>) => Promise<void>;
 };
 
 /**
@@ -81,6 +83,14 @@ type MessageHandlerDeps = {
 export function createOnMessageHandler(deps: MessageHandlerDeps): (message: IncomingMessage) => Promise<void> {
   return async function onMessage(message: IncomingMessage): Promise<void> {
     switch (message.type) {
+      case 'auth_required':
+        deps.handleAuthRequired(message.message);
+        break;
+
+      case 'auth_result':
+        await deps.handleAuthResult(message);
+        break;
+
       case 'welcome':
         if (message.worldConfig?.gridSize && Number.isInteger(message.worldConfig.gridSize) && message.worldConfig.gridSize > 0) {
           deps.setWorldGridSize(message.worldConfig.gridSize);

client/src/network/protocol.ts

@@ -48,6 +48,14 @@ export const welcomeMessageSchema = z.object({
       version: z.string().optional(),
     })
     .optional(),
+  auth: z
+    .object({
+      authenticated: z.boolean(),
+      userId: z.string().nullable().optional(),
+      username: z.string().nullable().optional(),
+      role: z.string().nullable().optional(),
+    })
+    .optional(),
   uiDefinitions: z
     .object({
       itemTypeOrder: z.array(z.string().min(1)),
@@ -85,6 +93,21 @@ export const welcomeMessageSchema = z.object({
     .optional(),
 });
 
+export const authRequiredSchema = z.object({
+  type: z.literal('auth_required'),
+  message: z.string(),
+});
+
+export const authResultSchema = z.object({
+  type: z.literal('auth_result'),
+  ok: z.boolean(),
+  message: z.string(),
+  sessionToken: z.string().optional(),
+  username: z.string().optional(),
+  role: z.string().optional(),
+  nickname: z.string().optional(),
+});
+
 export const signalMessageSchema = z.object({
   type: z.literal('signal'),
   senderId: z.string(),
@@ -203,6 +226,8 @@ export const itemPianoStatusSchema = z.object({
 });
 
 export const incomingMessageSchema = z.discriminatedUnion('type', [
+  authRequiredSchema,
+  authResultSchema,
   welcomeMessageSchema,
   signalMessageSchema,
   updatePositionSchema,
@@ -223,6 +248,10 @@ export const incomingMessageSchema = z.discriminatedUnion('type', [
 export type IncomingMessage = z.infer<typeof incomingMessageSchema>;
 
 export type OutgoingMessage =
+  | { type: 'auth_register'; username: string; password: string; email?: string }
+  | { type: 'auth_login'; username: string; password: string }
+  | { type: 'auth_resume'; sessionToken: string }
+  | { type: 'auth_logout' }
   | { type: 'signal'; targetId: string; sdp?: RTCSessionDescriptionInit; ice?: RTCIceCandidateInit }
   | { type: 'update_position'; x: number; y: number }
   | { type: 'teleport_complete'; x: number; y: number }

client/src/session/connectionFlow.ts

@@ -29,6 +29,7 @@ export type ConnectFlowDeps = {
   mediaDescribeError: (error: unknown) => string;
   mediaStopLocalMedia: () => void;
   signalingConnect: (onMessage: (message: unknown) => Promise<void>) => Promise<void>;
+  signalingSendAuth: () => void;
   signalingDisconnect: () => void;
   onMessage: (message: unknown) => Promise<void>;
   persistPlayerPosition: () => void;
@@ -46,14 +47,11 @@ export async function runConnectFlow(deps: ConnectFlowDeps): Promise<void> {
     return;
   }
   const nickname = deps.sanitizeName(deps.dom.preconnectNickname.value);
-  if (!nickname) {
+  deps.state.player.nickname = nickname || deps.state.player.nickname;
-    deps.updateStatus('Nickname is required.');
-    deps.updateConnectAvailability();
-    return;
-  }
-  deps.state.player.nickname = nickname;
   deps.dom.preconnectNickname.value = nickname;
-  deps.settingsSaveNickname(nickname);
+  if (nickname) {
+    deps.settingsSaveNickname(nickname);
+  }
   deps.mediaSetConnecting(true);
   deps.updateConnectAvailability();
 
@@ -85,6 +83,7 @@ export async function runConnectFlow(deps: ConnectFlowDeps): Promise<void> {
 
   try {
     await deps.signalingConnect(deps.onMessage);
+    deps.signalingSendAuth();
     window.setTimeout(() => {
       if (deps.state.running || !deps.mediaIsConnecting()) {
         return;

client/src/settings/settingsStore.ts

@@ -11,6 +11,8 @@ const MIC_INPUT_GAIN_STORAGE_KEY = 'chatGridMicInputGain';
 const MASTER_VOLUME_STORAGE_KEY = 'chatGridMasterVolume';
 const PEER_LISTEN_GAINS_STORAGE_KEY = 'chatGridPeerListenGains';
 const NICKNAME_STORAGE_KEY = 'spatialChatNickname';
+const AUTH_SESSION_TOKEN_STORAGE_KEY = 'chatGridAuthSessionToken';
+const AUTH_USERNAME_STORAGE_KEY = 'chatGridAuthUsername';
 
 type DevicePreference = {
   id: string;
@@ -113,6 +115,30 @@ export class SettingsStore {
     localStorage.setItem(NICKNAME_STORAGE_KEY, value);
   }
 
+  loadAuthSessionToken(): string {
+    return localStorage.getItem(AUTH_SESSION_TOKEN_STORAGE_KEY) || '';
+  }
+
+  saveAuthSessionToken(token: string): void {
+    if (token) {
+      localStorage.setItem(AUTH_SESSION_TOKEN_STORAGE_KEY, token);
+      return;
+    }
+    localStorage.removeItem(AUTH_SESSION_TOKEN_STORAGE_KEY);
+  }
+
+  loadAuthUsername(): string {
+    return localStorage.getItem(AUTH_USERNAME_STORAGE_KEY) || '';
+  }
+
+  saveAuthUsername(username: string): void {
+    if (username) {
+      localStorage.setItem(AUTH_USERNAME_STORAGE_KEY, username);
+      return;
+    }
+    localStorage.removeItem(AUTH_USERNAME_STORAGE_KEY);
+  }
+
   loadOutputMode(): 'mono' | 'stereo' {
     return localStorage.getItem(AUDIO_OUTPUT_MODE_STORAGE_KEY) === 'mono' ? 'mono' : 'stereo';
   }

client/src/styles.css

@@ -79,6 +79,44 @@ body {
   margin-bottom: 0.75rem;
 }
 
+.auth-panel {
+  width: min(460px, 95vw);
+  margin: 0 auto 0.75rem;
+  padding: 0.65rem;
+  border: 1px solid #334155;
+  border-radius: 0.6rem;
+  background: rgb(17 24 39 / 60%);
+}
+
+.auth-panel h2 {
+  margin: 0 0 0.5rem;
+  font-size: 1rem;
+  color: #cbd5e1;
+}
+
+.auth-row {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 0.5rem;
+  margin: 0.35rem 0;
+}
+
+.auth-row label {
+  color: #cbd5e1;
+  min-width: 135px;
+  text-align: right;
+}
+
+.auth-row input {
+  background: #111827;
+  color: #e5e7eb;
+  border: 1px solid #334155;
+  border-radius: 0.5rem;
+  padding: 0.4rem 0.6rem;
+  width: min(280px, 60vw);
+}
+
 .nickname-row {
   display: flex;
   justify-content: center;

deploy/README.md

@@ -37,6 +37,7 @@ Notes:
 This creates:
 - `/home/bestmidi/chgrid/server/.venv`
 - `/home/bestmidi/chgrid/server/config.toml` (if missing)
+- `/home/bestmidi/chgrid/server/.env` with `CHGRID_AUTH_SECRET` (if missing)
 
 Edit `/home/bestmidi/chgrid/server/config.toml`:
 - `server.bind_ip = "127.0.0.1"`
@@ -45,6 +46,7 @@ Edit `/home/bestmidi/chgrid/server/config.toml`:
 - `tls.cert_file = ""`
 - `tls.key_file = ""`
 - `storage.state_file = "runtime/items.json"`
+- `auth.db_file = "runtime/chatgrid.db"`
 
 ## 4) Build and publish client
 

deploy/scripts/install_server.sh

@@ -49,5 +49,17 @@ fi
 
 mkdir -p runtime
 
+if [[ ! -f .env ]]; then
+  AUTH_SECRET="$(
+    python3 - <<'PY'
+import secrets
+print(secrets.token_urlsafe(64))
+PY
+  )"
+  printf "CHGRID_AUTH_SECRET=%s\n" "$AUTH_SECRET" > .env
+  chmod 600 .env
+  echo "created $SERVER_DIR/.env with CHGRID_AUTH_SECRET"
+fi
+
 echo "server install complete"
 echo "next: edit $SERVER_DIR/config.toml (TLS, bind_ip, port)"

deploy/systemd/chat-grid.service

@@ -8,6 +8,7 @@ User=bestmidi
 Group=bestmidi
 WorkingDirectory=/home/bestmidi/chgrid/server
 Environment=PATH=/home/bestmidi/chgrid/server/.venv/bin:/usr/bin:/bin
+EnvironmentFile=-/home/bestmidi/chgrid/server/.env
 ExecStartPre=/usr/bin/mkdir -p /home/bestmidi/chgrid/server/runtime
 ExecStart=/home/bestmidi/chgrid/server/.venv/bin/python main.py --config /home/bestmidi/chgrid/server/config.toml
 StandardOutput=append:/home/bestmidi/chgrid/server/runtime/server.log

docs/protocol-notes.md

@@ -10,6 +10,10 @@ This is a behavior guide for packet semantics beyond raw schemas.
 
 ## Client -> Server
 
+- `auth_register`: create account with username/password and optional email.
+- `auth_login`: authenticate with username/password.
+- `auth_resume`: resume prior session via stored session token.
+- `auth_logout`: revoke current session and disconnect.
 - `update_position`: client movement intent; server enforces world bounds and movement rate policy.
 - `teleport_complete`: client signals teleport landing; server rebroadcasts spatial landing cue.
 - `update_nickname`: nickname change request (server enforces uniqueness).
@@ -21,6 +25,8 @@ This is a behavior guide for packet semantics beyond raw schemas.
 
 ## Server -> Client
 
+- `auth_required`: authentication challenge after websocket connect.
+- `auth_result`: auth success/failure and session/account metadata.
 - `welcome`: initial snapshot with users/items plus server UI/world metadata.
 - `signal`: forwarded WebRTC offer/answer/ICE.
 - `update_position`, `update_nickname`, `user_left`: presence updates.
@@ -51,6 +57,11 @@ This is a behavior guide for packet semantics beyond raw schemas.
 
 ## Welcome Metadata
 
+- `welcome.auth`: authenticated account identity:
+  - `authenticated`
+  - `userId`
+  - `username`
+  - `role`
 - `welcome.worldConfig.gridSize`: server-authoritative grid size used by clients for bounds/drawing.
 - `welcome.worldConfig.movementTickMs`: server movement-rate window used for client movement pacing.
 - `welcome.worldConfig.movementMaxStepsPerTick`: max allowed grid steps per movement window.

docs/runtime-flow.md

@@ -3,10 +3,13 @@
 ## Connect Flow
 
 1. User clicks connect.
-2. Client validates nickname and sets up local media.
+2. Client validates auth form/session token and sets up local media.
 3. Client connects signaling websocket.
-4. Server sends `welcome` with users/items snapshot.
+4. Server sends `auth_required`.
-5. Client:
+5. Client sends `auth_login`, `auth_register`, or `auth_resume`.
+6. Server sends `auth_result`.
+7. Server sends `welcome` with users/items snapshot.
+8. Client:
    - applies `welcome.worldConfig.gridSize` for authoritative grid bounds/rendering
    - applies `welcome.worldConfig.movementTickMs` as movement pacing guidance
    - applies `welcome.worldConfig.movementMaxStepsPerTick` for movement-rate parity
@@ -38,6 +41,8 @@ Each frame:
 Core incoming message effects:
 
 - `signal`: WebRTC negotiation and ICE exchange.
+- `auth_required`: prompt client to authenticate before gameplay messages.
+- `auth_result`: auth success/failure with optional session token + account metadata.
 - `update_position`: update peer position; may play movement/teleport world sound.
 - `teleport_complete`: play peer teleport landing sound at final tile.
 - `update_nickname`: update peer display name.

server/app/auth_service.py

@@ -0,0 +1,397 @@
+"""Account and session persistence service for websocket authentication."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+import base64
+import hashlib
+import hmac
+import os
+from pathlib import Path
+import re
+import secrets
+import sqlite3
+import time
+import uuid
+
+
+SESSION_TTL_MS = 14 * 24 * 60 * 60 * 1000
+SALT_BYTES = 16
+PBKDF2_ITERATIONS = 310_000
+PBKDF2_DKLEN = 32
+USERNAME_PATTERN = re.compile(r"^[a-z0-9_-]+$")
+
+
+@dataclass(frozen=True)
+class AuthUser:
+    """Authenticated account identity details."""
+
+    id: str
+    username: str
+    role: str
+    status: str
+    email: str | None
+    last_nickname: str | None
+
+
+@dataclass(frozen=True)
+class AuthSession:
+    """Session validation result with user identity."""
+
+    session_id: str
+    token: str
+    user: AuthUser
+
+
+class AuthError(ValueError):
+    """Raised when authentication input or policy checks fail."""
+
+
+class AuthService:
+    """Manages account registration, login, and rolling session validation."""
+
+    def __init__(
+        self,
+        db_path: Path,
+        token_hash_secret: str,
+        password_min_length: int,
+        password_max_length: int,
+        username_min_length: int,
+        username_max_length: int,
+    ):
+        """Initialize auth database connection and schema."""
+
+        self.db_path = db_path
+        self.db_path.parent.mkdir(parents=True, exist_ok=True)
+        self.password_min_length = max(1, int(password_min_length))
+        self.password_max_length = max(self.password_min_length, int(password_max_length))
+        self.username_min_length = max(1, int(username_min_length))
+        self.username_max_length = max(self.username_min_length, int(username_max_length))
+        secret = token_hash_secret.strip()
+        if not secret:
+            raise AuthError("CHGRID_AUTH_SECRET is required when auth is enabled.")
+        self._token_secret = secret.encode("utf-8")
+        self._conn = sqlite3.connect(self.db_path, check_same_thread=False)
+        self._conn.row_factory = sqlite3.Row
+        self._ensure_schema()
+
+    def close(self) -> None:
+        """Close the underlying SQLite connection."""
+
+        self._conn.close()
+
+    def bootstrap_admin(self, username: str, password: str, email: str | None = None) -> AuthUser:
+        """Create the first admin account, or fail if one already exists."""
+
+        existing = self._conn.execute("SELECT 1 FROM users WHERE role = 'admin' LIMIT 1").fetchone()
+        if existing is not None:
+            raise AuthError("An admin account already exists.")
+        created = self.register(username, password, email=email, role="admin")
+        return created.user
+
+    def register(
+        self,
+        username: str,
+        password: str,
+        *,
+        email: str | None = None,
+        role: str = "user",
+    ) -> AuthSession:
+        """Register an account and issue a session token."""
+
+        normalized_username = self._normalize_username(username)
+        self._validate_username(normalized_username)
+        self._validate_password(password)
+        normalized_email = self._normalize_email(email)
+        if role not in {"user", "admin"}:
+            raise AuthError("role must be user or admin.")
+        now_ms = self.now_ms()
+        user_id = str(uuid.uuid4())
+        password_hash = self._hash_password(password)
+        try:
+            self._conn.execute(
+                """
+                INSERT INTO users (
+                    id, username, password_hash, email, role, status, last_nickname, created_at_ms, updated_at_ms, last_login_at_ms
+                ) VALUES (?, ?, ?, ?, ?, 'active', NULL, ?, ?, ?)
+                """,
+                (user_id, normalized_username, password_hash, normalized_email, role, now_ms, now_ms, now_ms),
+            )
+            self._conn.commit()
+        except sqlite3.IntegrityError as exc:
+            message = str(exc).lower()
+            if "users.username" in message:
+                raise AuthError("Username is already taken.") from exc
+            if "users.email" in message:
+                raise AuthError("Email is already in use.") from exc
+            raise
+        user = self._get_user_by_username(normalized_username)
+        if user is None:
+            raise AuthError("Failed to load newly created user.")
+        return self._create_session(user)
+
+    def login(self, username: str, password: str) -> AuthSession:
+        """Authenticate credentials and issue a fresh session."""
+
+        normalized_username = self._normalize_username(username)
+        user_row = self._conn.execute(
+            """
+            SELECT id, username, password_hash, email, role, status, last_nickname
+            FROM users
+            WHERE username = ?
+            """,
+            (normalized_username,),
+        ).fetchone()
+        if user_row is None:
+            raise AuthError("Invalid username or password.")
+        if user_row["status"] != "active":
+            raise AuthError("Account is disabled.")
+        if not self._verify_password(password, user_row["password_hash"]):
+            raise AuthError("Invalid username or password.")
+        user = self._row_to_user(user_row)
+        self._conn.execute(
+            "UPDATE users SET last_login_at_ms = ?, updated_at_ms = ? WHERE id = ?",
+            (self.now_ms(), self.now_ms(), user.id),
+        )
+        self._conn.commit()
+        return self._create_session(user)
+
+    def resume(self, token: str) -> AuthSession:
+        """Validate a session token and apply rolling expiry."""
+
+        cleaned = token.strip()
+        if not cleaned:
+            raise AuthError("Missing session token.")
+        token_hash = self._hash_token(cleaned)
+        row = self._conn.execute(
+            """
+            SELECT s.id AS session_id, s.user_id, s.expires_at_ms, s.revoked_at_ms,
+                   u.username, u.role, u.status, u.email, u.last_nickname
+            FROM sessions s
+            JOIN users u ON u.id = s.user_id
+            WHERE s.token_hash = ?
+            """,
+            (token_hash,),
+        ).fetchone()
+        if row is None:
+            raise AuthError("Invalid session.")
+        if row["revoked_at_ms"] is not None:
+            raise AuthError("Session has been revoked.")
+        now_ms = self.now_ms()
+        if int(row["expires_at_ms"]) <= now_ms:
+            self._conn.execute("UPDATE sessions SET revoked_at_ms = ? WHERE id = ?", (now_ms, row["session_id"]))
+            self._conn.commit()
+            raise AuthError("Session has expired.")
+        if row["status"] != "active":
+            raise AuthError("Account is disabled.")
+        new_expiry = now_ms + SESSION_TTL_MS
+        self._conn.execute(
+            "UPDATE sessions SET last_seen_at_ms = ?, expires_at_ms = ? WHERE id = ?",
+            (now_ms, new_expiry, row["session_id"]),
+        )
+        self._conn.commit()
+        user = AuthUser(
+            id=row["user_id"],
+            username=row["username"],
+            role=row["role"],
+            status=row["status"],
+            email=row["email"],
+            last_nickname=row["last_nickname"],
+        )
+        return AuthSession(session_id=row["session_id"], token=cleaned, user=user)
+
+    def revoke(self, token: str) -> None:
+        """Revoke a session token if it exists."""
+
+        cleaned = token.strip()
+        if not cleaned:
+            return
+        token_hash = self._hash_token(cleaned)
+        self._conn.execute(
+            "UPDATE sessions SET revoked_at_ms = ? WHERE token_hash = ? AND revoked_at_ms IS NULL",
+            (self.now_ms(), token_hash),
+        )
+        self._conn.commit()
+
+    def set_last_nickname(self, user_id: str, nickname: str) -> None:
+        """Persist the most recent nickname for one user."""
+
+        cleaned = nickname.strip()
+        if not cleaned:
+            return
+        self._conn.execute(
+            "UPDATE users SET last_nickname = ?, updated_at_ms = ? WHERE id = ?",
+            (cleaned, self.now_ms(), user_id),
+        )
+        self._conn.commit()
+
+    @staticmethod
+    def now_ms() -> int:
+        """Return unix epoch timestamp in milliseconds."""
+
+        return int(time.time() * 1000)
+
+    def _ensure_schema(self) -> None:
+        """Create required auth tables and indexes when missing."""
+
+        self._conn.execute("PRAGMA foreign_keys = ON")
+        self._conn.execute(
+            """
+            CREATE TABLE IF NOT EXISTS users (
+                id TEXT PRIMARY KEY,
+                username TEXT NOT NULL UNIQUE,
+                password_hash TEXT NOT NULL,
+                email TEXT UNIQUE,
+                role TEXT NOT NULL CHECK(role IN ('user', 'admin')) DEFAULT 'user',
+                status TEXT NOT NULL CHECK(status IN ('active', 'disabled')) DEFAULT 'active',
+                last_nickname TEXT,
+                created_at_ms INTEGER NOT NULL,
+                updated_at_ms INTEGER NOT NULL,
+                last_login_at_ms INTEGER
+            )
+            """
+        )
+        self._conn.execute(
+            """
+            CREATE TABLE IF NOT EXISTS sessions (
+                id TEXT PRIMARY KEY,
+                user_id TEXT NOT NULL,
+                token_hash TEXT NOT NULL UNIQUE,
+                created_at_ms INTEGER NOT NULL,
+                last_seen_at_ms INTEGER NOT NULL,
+                expires_at_ms INTEGER NOT NULL,
+                revoked_at_ms INTEGER,
+                ip TEXT,
+                user_agent TEXT,
+                FOREIGN KEY(user_id) REFERENCES users(id) ON DELETE CASCADE
+            )
+            """
+        )
+        self._conn.execute("CREATE UNIQUE INDEX IF NOT EXISTS idx_users_username ON users(username)")
+        self._conn.execute(
+            "CREATE UNIQUE INDEX IF NOT EXISTS idx_users_email ON users(email) WHERE email IS NOT NULL"
+        )
+        self._conn.execute("CREATE INDEX IF NOT EXISTS idx_sessions_user_id ON sessions(user_id)")
+        self._conn.execute("CREATE INDEX IF NOT EXISTS idx_sessions_expires ON sessions(expires_at_ms)")
+        self._conn.execute("CREATE INDEX IF NOT EXISTS idx_sessions_token_hash ON sessions(token_hash)")
+        self._conn.commit()
+
+    def _create_session(self, user: AuthUser) -> AuthSession:
+        """Issue and persist a new session token for a user."""
+
+        token = secrets.token_urlsafe(48)
+        token_hash = self._hash_token(token)
+        now_ms = self.now_ms()
+        expires_at_ms = now_ms + SESSION_TTL_MS
+        session_id = str(uuid.uuid4())
+        self._conn.execute(
+            """
+            INSERT INTO sessions (id, user_id, token_hash, created_at_ms, last_seen_at_ms, expires_at_ms, revoked_at_ms, ip, user_agent)
+            VALUES (?, ?, ?, ?, ?, ?, NULL, NULL, NULL)
+            """,
+            (session_id, user.id, token_hash, now_ms, now_ms, expires_at_ms),
+        )
+        self._conn.commit()
+        return AuthSession(session_id=session_id, token=token, user=user)
+
+    def _get_user_by_username(self, username: str) -> AuthUser | None:
+        """Fetch one user by normalized username."""
+
+        row = self._conn.execute(
+            "SELECT id, username, role, status, email, last_nickname FROM users WHERE username = ?",
+            (username,),
+        ).fetchone()
+        if row is None:
+            return None
+        return self._row_to_user(row)
+
+    @staticmethod
+    def _row_to_user(row: sqlite3.Row) -> AuthUser:
+        """Convert a DB row into AuthUser."""
+
+        return AuthUser(
+            id=row["id"],
+            username=row["username"],
+            role=row["role"],
+            status=row["status"],
+            email=row["email"],
+            last_nickname=row["last_nickname"],
+        )
+
+    @staticmethod
+    def _normalize_username(username: str) -> str:
+        """Normalize username into canonical stored form."""
+
+        return username.strip().lower()
+
+    @staticmethod
+    def _normalize_email(email: str | None) -> str | None:
+        """Normalize optional email and collapse blanks to None."""
+
+        if email is None:
+            return None
+        cleaned = email.strip().lower()
+        return cleaned or None
+
+    def _validate_username(self, username: str) -> None:
+        """Validate username against length and character policy."""
+
+        if not (self.username_min_length <= len(username) <= self.username_max_length):
+            raise AuthError(
+                f"Username must be between {self.username_min_length} and {self.username_max_length} characters."
+            )
+        if USERNAME_PATTERN.fullmatch(username) is None:
+            raise AuthError("Username may include lowercase letters, numbers, underscores, and dashes only.")
+
+    def _validate_password(self, password: str) -> None:
+        """Validate password length policy."""
+
+        if not (self.password_min_length <= len(password) <= self.password_max_length):
+            raise AuthError(
+                f"Password must be between {self.password_min_length} and {self.password_max_length} characters."
+            )
+
+    @staticmethod
+    def _hash_password(password: str) -> str:
+        """Hash a password with PBKDF2-HMAC-SHA256 and random salt."""
+
+        salt = os.urandom(SALT_BYTES)
+        digest = hashlib.pbkdf2_hmac(
+            "sha256",
+            password.encode("utf-8"),
+            salt,
+            PBKDF2_ITERATIONS,
+            dklen=PBKDF2_DKLEN,
+        )
+        salt_b64 = base64.b64encode(salt).decode("ascii")
+        digest_b64 = base64.b64encode(digest).decode("ascii")
+        return f"pbkdf2_sha256${PBKDF2_ITERATIONS}${salt_b64}${digest_b64}"
+
+    @staticmethod
+    def _verify_password(password: str, stored: str) -> bool:
+        """Verify plaintext password against stored PBKDF2 hash."""
+
+        try:
+            algo, iterations_raw, salt_b64, digest_b64 = stored.split("$", 3)
+        except ValueError:
+            return False
+        if algo != "pbkdf2_sha256":
+            return False
+        try:
+            salt = base64.b64decode(salt_b64.encode("ascii"))
+            expected = base64.b64decode(digest_b64.encode("ascii"))
+            computed = hashlib.pbkdf2_hmac(
+                "sha256",
+                password.encode("utf-8"),
+                salt,
+                int(iterations_raw),
+                dklen=len(expected),
+            )
+        except (ValueError, TypeError):
+            return False
+        return hmac.compare_digest(computed, expected)
+
+    def _hash_token(self, token: str) -> str:
+        """Hash a session token with server secret before persistence."""
+
+        return hmac.new(self._token_secret, token.encode("utf-8"), hashlib.sha256).hexdigest()

server/app/client.py

@@ -13,6 +13,11 @@ class ClientConnection:
 
     websocket: ServerConnection
     id: str
+    authenticated: bool = False
+    user_id: str | None = None
+    username: str | None = None
+    role: str = "user"
+    session_token: str | None = None
     nickname: str = "user..."
     x: int = 20
     y: int = 20

server/app/config.py

@@ -49,6 +49,16 @@ class WorldConfigSection(BaseModel):
     grid_size: int = Field(default=41, ge=1)
 
 
+class AuthConfigSection(BaseModel):
+    """Authentication persistence and validation settings."""
+
+    db_file: str = "runtime/chatgrid.db"
+    password_min_length: int = Field(default=8, ge=1)
+    password_max_length: int = Field(default=32, ge=1)
+    username_min_length: int = Field(default=2, ge=1)
+    username_max_length: int = Field(default=32, ge=1)
+
+
 class AppConfig(BaseModel):
     """Top-level application configuration document."""
 
@@ -58,6 +68,7 @@ class AppConfig(BaseModel):
     logging: LoggingConfigSection = LoggingConfigSection()
     storage: StorageConfigSection = StorageConfigSection()
     world: WorldConfigSection = WorldConfigSection()
+    auth: AuthConfigSection = AuthConfigSection()
 
 
 def load_config(path: Path | None) -> AppConfig:

server/app/item_service.py

@@ -45,7 +45,7 @@ class ItemService:
             title=item_def.default_title,
             x=client.x,
             y=client.y,
-            createdBy=client.id,
+            createdBy=client.username or client.nickname or client.id,
             createdAt=now,
             updatedAt=now,
             version=1,

server/app/models.py

@@ -41,6 +41,28 @@ class ChatMessagePacket(BasePacket):
     message: str = Field(min_length=1, max_length=500)
 
 
+class AuthRegisterPacket(BasePacket):
+    type: Literal["auth_register"]
+    username: str = Field(min_length=1, max_length=128)
+    password: str = Field(min_length=1, max_length=256)
+    email: str | None = Field(default=None, max_length=320)
+
+
+class AuthLoginPacket(BasePacket):
+    type: Literal["auth_login"]
+    username: str = Field(min_length=1, max_length=128)
+    password: str = Field(min_length=1, max_length=256)
+
+
+class AuthResumePacket(BasePacket):
+    type: Literal["auth_resume"]
+    sessionToken: str = Field(min_length=1, max_length=512)
+
+
+class AuthLogoutPacket(BasePacket):
+    type: Literal["auth_logout"]
+
+
 class PingPacket(BasePacket):
     type: Literal["ping"]
     clientSentAt: int
@@ -100,6 +122,10 @@ ClientPacket = (
     | TeleportCompletePacket
     | UpdateNicknamePacket
     | ChatMessagePacket
+    | AuthRegisterPacket
+    | AuthLoginPacket
+    | AuthResumePacket
+    | AuthLogoutPacket
     | PingPacket
     | ItemAddPacket
     | ItemPickupPacket
@@ -128,6 +154,22 @@ class WelcomePacket(BasePacket):
     worldConfig: dict | None = None
     uiDefinitions: dict | None = None
     serverInfo: dict | None = None
+    auth: dict | None = None
+
+
+class AuthRequiredPacket(BasePacket):
+    type: Literal["auth_required"]
+    message: str
+
+
+class AuthResultPacket(BasePacket):
+    type: Literal["auth_result"]
+    ok: bool
+    message: str
+    sessionToken: str | None = None
+    username: str | None = None
+    role: str | None = None
+    nickname: str | None = None
 
 
 class UserLeftPacket(BasePacket):

server/app/server.py

@@ -5,6 +5,7 @@ from __future__ import annotations
 import argparse
 import asyncio
 from datetime import datetime
+from getpass import getpass
 from importlib.metadata import PackageNotFoundError, version as package_version
 import json
 import logging
@@ -21,6 +22,7 @@ from zoneinfo import ZoneInfo
 from pydantic import ValidationError, TypeAdapter
 from websockets.asyncio.server import ServerConnection, serve
 
+from .auth_service import AuthError, AuthService
 from .client import ClientConnection
 from .config import load_config
 from .item_catalog import (
@@ -39,6 +41,12 @@ from .item_catalog import (
 from .item_type_handlers import get_item_type_handler
 from .item_service import ItemService
 from .models import (
+    AuthLoginPacket,
+    AuthLogoutPacket,
+    AuthRegisterPacket,
+    AuthRequiredPacket,
+    AuthResultPacket,
+    AuthResumePacket,
     BroadcastChatMessagePacket,
     BroadcastNicknamePacket,
     BroadcastPositionPacket,
@@ -91,6 +99,12 @@ class SignalingServer:
         port: int,
         ssl_cert: str | None,
         ssl_key: str | None,
+        auth_db_path: Path | None = None,
+        auth_token_hash_secret: str = "dev-secret",
+        password_min_length: int = 8,
+        password_max_length: int = 32,
+        username_min_length: int = 2,
+        username_max_length: int = 32,
         max_message_size: int = 2_000_000,
         state_file: Path | None = None,
         grid_size: int = 41,
@@ -104,6 +118,15 @@ class SignalingServer:
         self.max_message_size = max_message_size
         self._ssl_context = self._build_ssl_context(ssl_cert, ssl_key)
         self.clients: dict[ServerConnection, ClientConnection] = {}
+        resolved_auth_db_path = auth_db_path or Path.cwd() / "runtime" / f"chatgrid_auth_{uuid.uuid4().hex}.db"
+        self.auth_service = AuthService(
+            db_path=resolved_auth_db_path,
+            token_hash_secret=auth_token_hash_secret,
+            password_min_length=password_min_length,
+            password_max_length=password_max_length,
+            username_min_length=username_min_length,
+            username_max_length=username_max_length,
+        )
         self.item_service = ItemService(state_file=state_file)
         self.item_last_use_ms: dict[str, int] = {}
         self.active_piano_keys_by_client: dict[str, set[str]] = {}
@@ -714,22 +737,19 @@ class SignalingServer:
                 await asyncio.Future()
         finally:
             self._flush_state_save()
+            self.auth_service.close()
 
     async def _handle_client(self, websocket: ServerConnection) -> None:
         """Handle one websocket client's connect/message/disconnect lifecycle."""
 
         client = ClientConnection(websocket=websocket, id=str(uuid.uuid4()))
-        client.x = random.randrange(self.grid_size)
+        LOGGER.info("websocket opened id=%s", client.id)
-        client.y = random.randrange(self.grid_size)
-        now_ms = self.item_service.now_ms()
-        client.last_position_update_ms = now_ms
-        client.movement_window_index = self._movement_window_index(now_ms)
-        client.movement_window_steps_used = 0
-        self.clients[websocket] = client
-        LOGGER.info("client connected id=%s total=%d", client.id, len(self.clients))
 
         try:
-            await self._send_welcome(client)
+            await self._send(
+                websocket,
+                AuthRequiredPacket(type="auth_required", message="Authentication required."),
+            )
             async for raw_message in websocket:
                 await self._handle_message(client, raw_message)
         finally:
@@ -780,9 +800,101 @@ class SignalingServer:
             },
             uiDefinitions=self._build_ui_definitions(),
             serverInfo={"instanceId": self.instance_id, "version": self.server_version},
+            auth={
+                "authenticated": client.authenticated,
+                "userId": client.user_id,
+                "username": client.username,
+                "role": client.role if client.authenticated else None,
+            },
         )
         await self._send(client.websocket, packet)
 
+    async def _activate_authenticated_client(self, client: ClientConnection) -> None:
+        """Move an authenticated websocket client into the active world roster."""
+
+        if client.websocket in self.clients:
+            return
+        client.x = random.randrange(self.grid_size)
+        client.y = random.randrange(self.grid_size)
+        now_ms = self.item_service.now_ms()
+        client.last_position_update_ms = now_ms
+        client.movement_window_index = self._movement_window_index(now_ms)
+        client.movement_window_steps_used = 0
+        self.clients[client.websocket] = client
+        LOGGER.info(
+            "client authenticated id=%s user_id=%s username=%s total=%d",
+            client.id,
+            client.user_id,
+            client.username,
+            len(self.clients),
+        )
+        await self._send_welcome(client)
+        await self._broadcast(
+            BroadcastChatMessagePacket(
+                type="chat_message",
+                message=f"{client.nickname} has logged in.",
+                system=True,
+            ),
+            exclude=client.websocket,
+        )
+
+    async def _handle_auth_packet(self, client: ClientConnection, packet: ClientPacket) -> bool:
+        """Handle pre-auth packets; returns True when packet was an auth command."""
+
+        if client.authenticated and isinstance(packet, (AuthLoginPacket, AuthRegisterPacket, AuthResumePacket)):
+            await self._send(
+                client.websocket,
+                AuthResultPacket(type="auth_result", ok=False, message="Already authenticated."),
+            )
+            return True
+
+        try:
+            if isinstance(packet, AuthRegisterPacket):
+                session = self.auth_service.register(packet.username, packet.password, email=packet.email)
+            elif isinstance(packet, AuthLoginPacket):
+                session = self.auth_service.login(packet.username, packet.password)
+            elif isinstance(packet, AuthResumePacket):
+                session = self.auth_service.resume(packet.sessionToken)
+            elif isinstance(packet, AuthLogoutPacket):
+                if client.session_token:
+                    self.auth_service.revoke(client.session_token)
+                    client.session_token = None
+                await self._send(
+                    client.websocket,
+                    AuthResultPacket(type="auth_result", ok=True, message="Logged out."),
+                )
+                await client.websocket.close()
+                return True
+            else:
+                return False
+        except AuthError as exc:
+            await self._send(
+                client.websocket,
+                AuthResultPacket(type="auth_result", ok=False, message=str(exc)),
+            )
+            return True
+
+        client.authenticated = True
+        client.user_id = session.user.id
+        client.username = session.user.username
+        client.role = session.user.role
+        client.session_token = session.token
+        client.nickname = session.user.last_nickname or client.nickname
+        await self._send(
+            client.websocket,
+            AuthResultPacket(
+                type="auth_result",
+                ok=True,
+                message="Authenticated.",
+                sessionToken=session.token,
+                username=session.user.username,
+                role=session.user.role,
+                nickname=client.nickname,
+            ),
+        )
+        await self._activate_authenticated_client(client)
+        return True
+
     def _build_ui_definitions(self) -> dict:
         """Build server-owned UI definitions for item/menu rendering."""
 
@@ -840,6 +952,22 @@ class SignalingServer:
             PACKET_LOGGER.warning("invalid packet from id=%s: %s", client.id, exc)
             return
 
+        # Compatibility path for local tests injecting pre-authenticated clients
+        # directly into server.clients without running websocket auth handshake.
+        if not client.authenticated and client.websocket in self.clients:
+            client.authenticated = True
+            client.user_id = client.user_id or client.id
+            client.username = client.username or client.nickname
+
+        if await self._handle_auth_packet(client, packet):
+            return
+        if not client.authenticated:
+            await self._send(
+                client.websocket,
+                AuthResultPacket(type="auth_result", ok=False, message="Authenticate before sending gameplay actions."),
+            )
+            return
+
         if isinstance(packet, UpdatePositionPacket):
             if not self._is_in_bounds(packet.x, packet.y):
                 PACKET_LOGGER.warning(
@@ -975,6 +1103,8 @@ class SignalingServer:
                 )
                 return
             client.nickname = requested_nickname
+            if client.user_id:
+                self.auth_service.set_last_nickname(client.user_id, client.nickname)
             if old_nickname == "user...":
                 LOGGER.info("user login id=%s nickname=%s", client.id, client.nickname)
             else:
@@ -1471,6 +1601,7 @@ def run() -> None:
     parser.add_argument("--ssl-cert", default=None)
     parser.add_argument("--ssl-key", default=None)
     parser.add_argument("--allow-insecure-ws", action="store_true", default=None)
+    parser.add_argument("--bootstrap-admin", action="store_true", default=False)
     args = parser.parse_args()
 
     config_path = Path(args.config) if args.config else None
@@ -1499,15 +1630,51 @@ def run() -> None:
             "TLS is required when insecure ws is disabled. Set tls.cert_file/tls.key_file in config.toml."
         )
 
+    auth_secret = os.getenv("CHGRID_AUTH_SECRET", "").strip()
+    if not auth_secret:
+        raise SystemExit("CHGRID_AUTH_SECRET is required.")
+    auth_db_value = config.auth.db_file.strip()
+    if not auth_db_value:
+        raise SystemExit("auth.db_file must not be empty.")
+    auth_base_dir = config_path.parent if config_path is not None else Path.cwd()
+    auth_db_path = Path(auth_db_value)
+    if not auth_db_path.is_absolute():
+        auth_db_path = auth_base_dir / auth_db_path
+    auth_db_path.parent.mkdir(parents=True, exist_ok=True)
+
     logging.basicConfig(
         level=getattr(logging, config.logging.level.upper(), logging.INFO),
         format="%(asctime)s %(levelname)s %(name)s %(message)s",
     )
+    if args.bootstrap_admin:
+        auth_service = AuthService(
+            db_path=auth_db_path,
+            token_hash_secret=auth_secret,
+            password_min_length=config.auth.password_min_length,
+            password_max_length=config.auth.password_max_length,
+            username_min_length=config.auth.username_min_length,
+            username_max_length=config.auth.username_max_length,
+        )
+        try:
+            username = input("Admin username: ").strip()
+            password = getpass("Admin password: ")
+            email = input("Admin email (optional): ").strip() or None
+            created = auth_service.bootstrap_admin(username, password, email=email)
+            print(f"Admin created: {created.username}")
+        finally:
+            auth_service.close()
+        return
     server = SignalingServer(
         host,
         port,
         ssl_cert,
         ssl_key,
+        auth_db_path=auth_db_path,
+        auth_token_hash_secret=auth_secret,
+        password_min_length=config.auth.password_min_length,
+        password_max_length=config.auth.password_max_length,
+        username_min_length=config.auth.username_min_length,
+        username_max_length=config.auth.username_max_length,
         max_message_size=config.network.max_message_bytes,
         state_file=state_file,
         grid_size=config.world.grid_size,

server/config.example.toml

@@ -29,3 +29,13 @@ state_save_max_delay_ms = 1000
 [world]
 # Grid width/height in cells. Valid coordinates are 0..grid_size-1.
 grid_size = 41
+
+[auth]
+# SQLite file for account/session data. Relative paths resolve from this config file directory.
+db_file = "runtime/chatgrid.db"
+# Password length policy.
+password_min_length = 8
+password_max_length = 32
+# Username length policy.
+username_min_length = 2
+username_max_length = 32

server/tests/test_auth_service.py

@@ -0,0 +1,52 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from app.auth_service import AuthError, AuthService
+
+
+def make_auth_service(tmp_path: Path) -> AuthService:
+    return AuthService(
+        db_path=tmp_path / "chatgrid.db",
+        token_hash_secret="test-secret",
+        password_min_length=8,
+        password_max_length=32,
+        username_min_length=2,
+        username_max_length=32,
+    )
+
+
+def test_register_and_resume_session(tmp_path: Path) -> None:
+    service = make_auth_service(tmp_path)
+    try:
+        session = service.register("User_One", "password99", email="a@example.com")
+        assert session.user.username == "user_one"
+        resumed = service.resume(session.token)
+        assert resumed.user.id == session.user.id
+        assert resumed.user.role == "user"
+    finally:
+        service.close()
+
+
+def test_login_rejects_invalid_password(tmp_path: Path) -> None:
+    service = make_auth_service(tmp_path)
+    try:
+        service.register("alpha", "password99")
+        with pytest.raises(AuthError):
+            service.login("alpha", "wrong-pass")
+    finally:
+        service.close()
+
+
+def test_bootstrap_admin_once(tmp_path: Path) -> None:
+    service = make_auth_service(tmp_path)
+    try:
+        admin = service.bootstrap_admin("root-admin", "password99", email=None)
+        assert admin.role == "admin"
+        with pytest.raises(AuthError):
+            service.bootstrap_admin("another-admin", "password99")
+    finally:
+        service.close()
+