diff --git a/desktop/src/App.test.tsx b/desktop/src/App.test.tsx
index 65e54581..c6a61c57 100644
--- a/desktop/src/App.test.tsx
+++ b/desktop/src/App.test.tsx
@@ -30,6 +30,7 @@ import type {
 import { App } from "./App";
 import { __resetComposerBehaviorForTests } from "./app/composerBehavior";
 import { __resetEscapeLayersForTests } from "./app/escapeLayer";
+import { __setLocaleForTests } from "./app/i18n";
 import type {
   AnyRpcNotification,
   DesktopRuntime,
@@ -1505,6 +1506,7 @@ describe("desktop command center", () => {
     localStorage.clear();
     __resetComposerBehaviorForTests();
     __resetEscapeLayersForTests();
+    __setLocaleForTests("en");
   });
   afterEach(() => {
     cleanup();
diff --git a/desktop/src/app/i18n.ts b/desktop/src/app/i18n.ts
index fa9519b9..fbabf080 100644
--- a/desktop/src/app/i18n.ts
+++ b/desktop/src/app/i18n.ts
@@ -59,6 +59,29 @@ const ZH_CN: Record<string, string> = {
   "settings.composer.queue": "排队为下一个 Turn",
   "settings.composer.note":
     "仅在忙碌时生效;Cmd/Ctrl+Enter 执行另一种行为。空闲时 Enter 始终发送。本设置立即生效,仅保存在本机。",
+  // Updates card
+  "settings.updates.eyebrow": "签名发布通道",
+  "settings.updates.title": "应用更新",
+  "settings.updates.check": "检查更新",
+  "settings.updates.checking": "正在检查…",
+  "settings.updates.install": "安装",
+  "settings.updates.preparing": "准备中…",
+  "settings.updates.downloading": "下载中…",
+  "settings.updates.installing": "安装中…",
+  "settings.updates.upToDate": "当前已是最新版本。",
+  "settings.updates.available":
+    "DeepCode {{version}} 可用。安装前会验证软件包签名。",
+  "settings.updates.idle":
+    "仅在手动请求时检查更新。开发版本可能未配置发布通道。",
+  "settings.updates.checkingNote": "正在检查签名发布通道。",
+  // Diagnostics card
+  "settings.diagnostics.eyebrow": "故障排除",
+  "settings.diagnostics.title": "诊断",
+  "settings.diagnostics.export": "导出报告",
+  "settings.diagnostics.exporting": "导出中…",
+  "settings.diagnostics.runChecks": "运行检查",
+  "settings.diagnostics.savedTo": "已保存脱敏诊断报告至 {{path}}",
+  "settings.diagnostics.noProject": "未选择项目",
   // Sidebar
   "sidebar.threads": "会话",
   "sidebar.automations": "自动化",
@@ -67,12 +90,106 @@ const ZH_CN: Record<string, string> = {
   "sidebar.mcp": "MCP",
   "sidebar.settings": "设置",
   "sidebar.projects": "项目",
+  "sidebar.newThread": "新建会话",
+  "sidebar.searchSessions": "搜索会话",
+  "sidebar.openFolder": "打开本地文件夹",
+  "sidebar.openFolderHint": "CLI 中的会话将在此显示。",
+  "sidebar.noResults": "无匹配会话",
+  "sidebar.noResultsHint": "可按标题、项目或工作空间路径搜索。",
+  "sidebar.noSessions": "暂无会话",
+  "sidebar.showMore": "显示更多 {{count}} 个",
+  "sidebar.showLess": "收起",
+  "sidebar.previousSessions": "历史会话",
+  "sidebar.folderUnavailable": "原始文件夹不可用",
+  "sidebar.localAgent": "本地智能体",
+  "sidebar.agentReady": "本地智能体就绪",
+  "sidebar.sharedHistory": "共享会话历史",
   // Composer high-traffic strings
   "composer.hint.send": "↵ 发送",
   "composer.hint.steerQueue": "↵ 引导 · ⌘↵ 排队",
   "composer.hint.queueSteer": "↵ 排队 · ⌘↵ 引导",
   "composer.hint.newline": "⇧↵ 换行",
   "composer.queueNext": "排队下一个",
+  // Thread header
+  "thread.startThread": "开始本地编码会话",
+  "thread.folderUnavailable": "文件夹不可用",
+  "thread.noLocalFolder": "无本地文件夹",
+  "thread.previousSessions": "历史会话",
+  "thread.trustFolder": "信任文件夹",
+  "thread.trusted": "已信任",
+  "thread.trustedTooltip": "允许在此文件夹中执行",
+  "thread.folderUnavailableTooltip": "原始会话文件夹不再可用",
+  "thread.paper": "论文",
+  "thread.paperTooltip": "创建 Paper2Code 会话",
+  "thread.fork": "分叉",
+  "thread.forkTooltip": "分叉到独立工作树",
+  "thread.review": "审查",
+  "thread.closeReview": "关闭审查面板",
+  "thread.openReview": "打开审查面板",
+  // Approval card
+  "approval.label": "需要审批",
+  "approval.decision": "决定: {{status}}",
+  "approval.allowContinue": "允许 {{tool}} 继续?",
+  "approval.reviewOperation": "在智能体继续之前,请审查此操作。",
+  "approval.sensitiveOperation": "敏感操作",
+  "approval.reviewArguments": "查看参数",
+  "approval.allowOnce": "允许一次",
+  "approval.allowSession": "允许本次会话",
+  "approval.deny": "拒绝",
+  // Runtime notice
+  "runtime.offline": "本地应用服务器不可用。",
+  "runtime.restart": "重启服务",
+  // Goal rail
+  "goal.setGoal": "设定目标",
+  "goal.setGoalHint": "在普通 Turn 之间保持一个持久的目标",
+  "goal.sessionGoal": "会话目标",
+  "goal.turn": "Turn",
+  "goal.turns": "Turns",
+  "goal.tokens": "tokens",
+  "goal.continue": "继续",
+  "goal.editGoal": "编辑目标",
+  "goal.pause": "暂停",
+  "goal.pauseTooltip": "暂停自动继续;不会中断当前 Turn",
+  "goal.editReopen": "编辑并重新开启",
+  "goal.resume": "恢复",
+  "goal.edit": "编辑",
+  "goal.newGoal": "新建目标",
+  "goal.objectiveHint":
+    "目标编辑保持同一 Goal 身份,并到达活跃的 Turn。",
+  "goal.outcome": "目标结果",
+  "goal.tokenBudget": "Token 预算",
+  "goal.tokenBudgetOptional": "可选",
+  "goal.noLimit": "无限制",
+  "goal.skills": "技能",
+  "goal.cancel": "取消",
+  "goal.saveResume": "保存并恢复",
+  "goal.saveGoal": "保存目标",
+  "goal.startGoal": "开始目标",
+  "goal.clearGoal": "清除目标",
+  "goal.clearConfirm": "确定清除此会话目标?",
+  "goal.completionOutcome": "完成结果",
+  "goal.blockedOutcome": "阻塞结果",
+  "goal.relatedActivity": "相关活动",
+  "goal.noSkills": "未选择目标相关技能。",
+  "goal.activeTime": "{{duration}} 活跃时间",
+  "goal.noUsage": "尚无已完成的 Goal Turn 用量",
+  "goal.tokenBudgetLabel": "{{budget}} token 预算",
+  "goal.noTokenBudget": "无 token 预算",
+  "goal.decidingTurn": "决定 Turn",
+  "goal.goalDescription":
+    "目标 {{id}} 附属于此会话。普通后续对话引导工作方向,而不重写目标。",
+  "goal.closeEditor": "关闭目标编辑器",
+  "goal.describeOutcome": "描述 DeepCode 应达成的完整目标。",
+  // Inspector
+  "inspector.label": "检查器",
+  "inspector.views": "检查器视图",
+  "inspector.closeReview": "关闭审查面板",
+  "inspector.tab.changes": "变更",
+  "inspector.tab.files": "文件",
+  "inspector.tab.artifacts": "产物",
+  "inspector.tab.tests": "测试",
+  "inspector.tab.terminal": "终端",
+  "inspector.tab.details": "详情",
 };
 
 function readLocale(): Locale {
diff --git a/desktop/src/components/RuntimeNotice.tsx b/desktop/src/components/RuntimeNotice.tsx
index 00befd16..d9578a19 100644
--- a/desktop/src/components/RuntimeNotice.tsx
+++ b/desktop/src/components/RuntimeNotice.tsx
@@ -1,4 +1,5 @@
 import { AlertTriangle, RotateCw, X } from "lucide-react";
+import { useTranslation } from "react-i18next";
 
 import type { BridgeError, SidecarStatus } from "../rpc/contracts";
 import styles from "./RuntimeNotice.module.css";
@@ -18,9 +19,10 @@ export function RuntimeNotice({
   onRestart,
   onDismissError,
 }: RuntimeNoticeProps) {
+  const { t } = useTranslation();
   if (!error && runtime.phase !== "crashed" && runtime.phase !== "stopped") return null;
   const serviceOffline = runtime.phase === "crashed" || runtime.phase === "stopped";
-  const message = error?.message ?? runtime.message ?? "The local App Server is unavailable.";
+  const message = error?.message ?? runtime.message ?? t("runtime.offline", "The local App Server is unavailable.");
   return (
     <div className={styles.notice} role="alert">
       <AlertTriangle size={18} aria-hidden="true" />
@@ -42,7 +44,7 @@ export function RuntimeNotice({
         {serviceOffline ? (
           <button type="button" onClick={onRestart} disabled={busy}>
             <RotateCw size={14} />
-            Restart service
+            {t("runtime.restart", "Restart service")}
           </button>
         ) : null}
       </div>
diff --git a/desktop/src/features/execution/ApprovalCard.tsx b/desktop/src/features/execution/ApprovalCard.tsx
index 5db21f6d..916dfc47 100644
--- a/desktop/src/features/execution/ApprovalCard.tsx
+++ b/desktop/src/features/execution/ApprovalCard.tsx
@@ -5,6 +5,7 @@ import {
   TerminalSquare,
   Wrench,
 } from "lucide-react";
+import { useTranslation } from "react-i18next";
 
 import type { Approval, ApprovalDecision } from "../../generated/app-server";
 import styles from "./ApprovalCard.module.css";
@@ -15,17 +16,17 @@ interface ApprovalCardProps {
   onRespond(approvalId: string, decision: ApprovalDecision): void;
 }
 
-function requestDetail(approval: Approval): string {
+function requestDetail(approval: Approval, t: (key: string, defaultValue: string, options?: Record<string, string>) => string): string {
   const tool = approval.request.toolName;
   const reason = approval.request.reason;
   if (typeof reason === "string" && reason) return reason;
-  if (typeof tool === "string" && tool) return `Allow ${tool} to continue?`;
-  return "Review this operation before the agent continues.";
+  if (typeof tool === "string" && tool) return t("approval.allowContinue", "Allow {{tool}} to continue?", { tool });
+  return t("approval.reviewOperation", "Review this operation before the agent continues.");
 }
 
-function requestTool(approval: Approval): string {
+function requestTool(approval: Approval, t: (key: string, defaultValue: string) => string): string {
   const tool = approval.request.toolName;
-  return typeof tool === "string" && tool.trim() ? tool : "Sensitive operation";
+  return typeof tool === "string" && tool.trim() ? tool : t("approval.sensitiveOperation", "Sensitive operation");
 }
 
 function requestArguments(approval: Approval): string | null {
@@ -61,27 +62,28 @@ function CategoryIcon({ category }: { category: Approval["category"] }) {
 }
 
 export function ApprovalCard({ approval, busy, onRespond }: ApprovalCardProps) {
+  const { t } = useTranslation();
   if (approval.status !== "pending") {
     return (
       <p className={styles.resolution}>
-        Decision: {approval.status.replaceAll("_", " ")}
+        {t("approval.decision", "Decision: {{status}}", { status: approval.status.replaceAll("_", " ") })}
       </p>
     );
   }
   const argumentsPreview = requestArguments(approval);
   return (
-    <div className={styles.card} aria-label="Approval required">
+    <div className={styles.card} aria-label={t("approval.label", "Approval required")}>
       <div className={styles.operation}>
         <CategoryIcon category={approval.category} />
         <span>
-          <strong>{requestTool(approval)}</strong>
+          <strong>{requestTool(approval, t)}</strong>
           <small>{approval.category.replaceAll("_", " ")}</small>
         </span>
       </div>
-      <p>{requestDetail(approval)}</p>
+      <p>{requestDetail(approval, t)}</p>
       {argumentsPreview ? (
         <details className={styles.arguments}>
-          <summary>Review arguments</summary>
+          <summary>{t("approval.reviewArguments", "Review arguments")}</summary>
           <pre>{argumentsPreview}</pre>
         </details>
       ) : null}
@@ -91,14 +93,14 @@ export function ApprovalCard({ approval, busy, onRespond }: ApprovalCardProps) {
           onClick={() => onRespond(approval.id, "approved_once")}
           disabled={busy}
         >
-          Allow once
+          {t("approval.allowOnce", "Allow once")}
         </button>
         <button
           type="button"
           onClick={() => onRespond(approval.id, "approved_session")}
           disabled={busy}
         >
-          Allow for Session
+          {t("approval.allowSession", "Allow for Session")}
         </button>
         <button
           className={styles.danger}
@@ -106,7 +108,7 @@ export function ApprovalCard({ approval, busy, onRespond }: ApprovalCardProps) {
           onClick={() => onRespond(approval.id, "denied")}
           disabled={busy}
         >
-          Deny
+          {t("approval.deny", "Deny")}
         </button>
       </div>
     </div>
diff --git a/desktop/src/features/goal/GoalRail.tsx b/desktop/src/features/goal/GoalRail.tsx
index 6d9fee43..69f60d48 100644
--- a/desktop/src/features/goal/GoalRail.tsx
+++ b/desktop/src/features/goal/GoalRail.tsx
@@ -10,6 +10,7 @@ import {
   X,
 } from "lucide-react";
 import { useMemo, useState } from "react";
+import { useTranslation } from "react-i18next";
 
 import type {
   Goal,
@@ -58,6 +59,7 @@ export function GoalRail({
   const [objective, setObjective] = useState("");
   const [tokenBudget, setTokenBudget] = useState("");
   const [skillIds, setSkillIds] = useState<string[]>([]);
+  const { t } = useTranslation();
   const selectableSkills = useMemo(
     () => skills.filter((skill) => skill.selectable && skill.enabled),
     [skills],
@@ -110,8 +112,8 @@ export function GoalRail({
         disabled={!enabled || busy}
       >
         <Target size={14} />
-        <span>Set a Goal</span>
-        <small>Keep a durable outcome across ordinary Turns</small>
+        <span>{t("goal.setGoal", "Set a Goal")}</span>
+        <small>{t("goal.setGoalHint", "Keep a durable outcome across ordinary Turns")}</small>
       </button>
     );
   }
@@ -120,7 +122,7 @@ export function GoalRail({
     <section
       className={styles.rail}
       data-status={presentation?.status ?? "draft"}
-      aria-label="Session Goal"
+      aria-label={t("goal.sessionGoal", "Session Goal")}
     >
       {goal ? (
         <>
@@ -139,11 +141,11 @@ export function GoalRail({
                 <span>{presentation?.label}</span>
                 <i>·</i>
                 {presentation?.linkedTurnCount ?? 0}{" "}
-                {presentation?.linkedTurnCount === 1 ? "Turn" : "Turns"}
+                {presentation?.linkedTurnCount === 1 ? t("goal.turn", "Turn") : t("goal.turns", "Turns")}
                 {goal.tokensUsed > 0 ? (
                   <>
                     <i>·</i>
-                    {compactNumber(goal.tokensUsed)} tokens
+                    {compactNumber(goal.tokensUsed)} {t("goal.tokens", "tokens")}
                   </>
                 ) : null}
               </small>
@@ -169,7 +171,7 @@ export function GoalRail({
                     disabled={!enabled || busy}
                   >
                     <Play size={12} />
-                    Continue
+                    {t("goal.continue", "Continue")}
                   </button>
                 ) : null}
                 <button
@@ -177,16 +179,16 @@ export function GoalRail({
                   onClick={() => openEditor()}
                   disabled={!enabled || busy}
                 >
-                  Edit Goal
+                  {t("goal.editGoal", "Edit Goal")}
                 </button>
                 <button
                   type="button"
                   onClick={() => void onPause()}
                   disabled={busy}
-                  title="Pause automatic continuation; the current Turn is not interrupted"
+                  title={t("goal.pauseTooltip", "Pause automatic continuation; the current Turn is not interrupted")}
                 >
                   <Pause size={12} />
-                  Pause
+                  {t("goal.pause", "Pause")}
                 </button>
               </>
             ) : goal.status === "complete" ? (
@@ -195,7 +197,7 @@ export function GoalRail({
                 onClick={() => openEditor(true)}
                 disabled={!enabled || busy}
               >
-                Edit & reopen
+                {t("goal.editReopen", "Edit & reopen")}
               </button>
             ) : (
               <>
@@ -205,14 +207,14 @@ export function GoalRail({
                   disabled={!enabled || busy}
                 >
                   <Play size={12} />
-                  Resume
+                  {t("goal.resume", "Resume")}
                 </button>
                 <button
                   type="button"
                   onClick={() => openEditor(goal.status === "complete")}
                   disabled={!enabled || busy}
                 >
-                  Edit
+                  {t("goal.edit", "Edit")}
                 </button>
               </>
             )}
@@ -220,25 +222,23 @@ export function GoalRail({
           {expanded ? (
             <div className={styles.details}>
               <p>
-                Goal <code>{shortId(goal.id)}</code> stays attached to this
-                Session. Normal follow-ups steer the work without rewriting the
-                objective.
+                {t("goal.goalDescription", "Goal {{id}} stays attached to this Session. Normal follow-ups steer the work without rewriting the objective.", { id: shortId(goal.id) })}
               </p>
               <p>
                 {goal.timeUsedSeconds > 0
-                  ? `${formatDuration(goal.timeUsedSeconds)} active time`
-                  : "No completed Goal Turn usage yet"}
+                  ? t("goal.activeTime", "{{duration}} active time", { duration: formatDuration(goal.timeUsedSeconds) })
+                  : t("goal.noUsage", "No completed Goal Turn usage yet")}
                 {goal.tokenBudget
-                  ? ` · ${compactNumber(goal.tokenBudget)} token budget`
-                  : " · no token budget"}
+                  ? ` · ${t("goal.tokenBudgetLabel", "{{budget}} token budget", { budget: compactNumber(goal.tokenBudget) })}`
+                  : ` · ${t("goal.noTokenBudget", "no token budget")}`}
               </p>
               {outcome ? (
-                <section className={styles.outcome} aria-label="Goal outcome">
+                <section className={styles.outcome} aria-label={t("goal.outcome", "Goal outcome")}>
                   <header>
                     <strong>
                       {outcome.status === "complete"
-                        ? "Completion outcome"
-                        : "Blocked outcome"}
+                        ? t("goal.completionOutcome", "Completion outcome")
+                        : t("goal.blockedOutcome", "Blocked outcome")}
                     </strong>
                     <small>
                       {outcome.source}
@@ -249,12 +249,12 @@ export function GoalRail({
                   <p>{outcome.reason}</p>
                   {outcome.decidedByTurnId ? (
                     <small>
-                      Deciding Turn <code>{shortId(outcome.decidedByTurnId)}</code>
+                      {t("goal.decidingTurn", "Deciding Turn")} <code>{shortId(outcome.decidedByTurnId)}</code>
                     </small>
                   ) : null}
                   {outcome.evidenceRefs.length ? (
                     <div className={styles.evidence}>
-                      <span>Related activity</span>
+                      <span>{t("goal.relatedActivity", "Related activity")}</span>
                       {outcome.evidenceRefs.map((evidence) => (
                         <button
                           type="button"
@@ -283,20 +283,20 @@ export function GoalRail({
                   })}
                 </ul>
               ) : (
-                <p>No Goal-specific Skills selected.</p>
+                <p>{t("goal.noSkills", "No Goal-specific Skills selected.")}</p>
               )}
               <button
                 className={styles.clearButton}
                 type="button"
                 onClick={() => {
-                  if (window.confirm("Clear this Session Goal?")) {
+                  if (window.confirm(t("goal.clearConfirm", "Clear this Session Goal?"))) {
                     void onClear();
                   }
                 }}
                 disabled={busy}
               >
                 <Trash2 size={12} />
-                Clear Goal
+                {t("goal.clearGoal", "Clear Goal")}
               </button>
             </div>
           ) : null}
@@ -313,46 +313,45 @@ export function GoalRail({
         >
           <header>
             <div>
-              <strong>{goal ? "Edit Goal" : "New Goal"}</strong>
+              <strong>{goal ? t("goal.editGoal", "Edit Goal") : t("goal.newGoal", "New Goal")}</strong>
               <span>
-                Objective edits keep the same Goal identity and reach the active
-                Turn.
+                {t("goal.objectiveHint", "Objective edits keep the same Goal identity and reach the active Turn.")}
               </span>
             </div>
             <button
               type="button"
               onClick={() => setEditorOpen(false)}
-              aria-label="Close Goal editor"
+              aria-label={t("goal.closeEditor", "Close Goal editor")}
             >
               <X size={14} />
             </button>
           </header>
           <label>
-            <span>Outcome</span>
+            <span>{t("goal.outcome", "Outcome")}</span>
             <textarea
               value={objective}
               onChange={(event) => setObjective(event.target.value)}
-              placeholder="Describe the complete outcome DeepCode should achieve."
+              placeholder={t("goal.describeOutcome", "Describe the complete outcome DeepCode should achieve.")}
               rows={4}
               autoFocus
             />
           </label>
           <label>
-            <span>Token budget <small>optional</small></span>
+            <span>{t("goal.tokenBudget", "Token budget")} <small>{t("goal.tokenBudgetOptional", "optional")}</small></span>
             <input
               type="number"
               min={1}
               step={1}
               value={tokenBudget}
               onChange={(event) => setTokenBudget(event.target.value)}
-              placeholder="No limit"
+              placeholder={t("goal.noLimit", "No limit")}
             />
           </label>
           {selectableSkills.length ? (
             <fieldset>
               <legend>
                 <Sparkles size={12} />
-                Skills
+                {t("goal.skills", "Skills")}
                 <small>
                   {skillIds.length}/{MAX_GOAL_SKILLS}
                 </small>
@@ -386,7 +385,7 @@ export function GoalRail({
           ) : null}
           <footer>
             <button type="button" onClick={() => setEditorOpen(false)}>
-              Cancel
+              {t("goal.cancel", "Cancel")}
             </button>
             <button
               className={styles.primary}
@@ -394,7 +393,7 @@ export function GoalRail({
               disabled={!enabled || busy || !objective.trim()}
             >
               <Target size={12} />
-              {goal ? (resumeAfterSave ? "Save & resume" : "Save Goal") : "Start Goal"}
+              {goal ? (resumeAfterSave ? t("goal.saveResume", "Save & resume") : t("goal.saveGoal", "Save Goal")) : t("goal.startGoal", "Start Goal")}
             </button>
           </footer>
         </form>
diff --git a/desktop/src/features/inspector/Inspector.tsx b/desktop/src/features/inspector/Inspector.tsx
index 257f5dd0..b4438d57 100644
--- a/desktop/src/features/inspector/Inspector.tsx
+++ b/desktop/src/features/inspector/Inspector.tsx
@@ -1,5 +1,6 @@
 import { useEffect, useMemo } from "react";
 import { X } from "lucide-react";
+import { useTranslation } from "react-i18next";
 
 import type {
   Artifact,
@@ -59,6 +60,7 @@ export function Inspector({
   onDirtyChange,
   onClose,
 }: InspectorProps) {
+  const { t } = useTranslation();
   const workbench = useCodeWorkbench(runtime, thread);
   const selected = items.find((item) => item.id === selectedItemId) ?? null;
   const dirty = Boolean(
@@ -110,9 +112,18 @@ export function Inspector({
     return null;
   };
 
+  const TAB_LABELS: Record<string, string> = {
+    changes: t("inspector.tab.changes", "changes"),
+    files: t("inspector.tab.files", "files"),
+    artifacts: t("inspector.tab.artifacts", "artifacts"),
+    tests: t("inspector.tab.tests", "tests"),
+    terminal: t("inspector.tab.terminal", "terminal"),
+    details: t("inspector.tab.details", "details"),
+  };
+
   return (
-    <aside className={styles.inspector} aria-label="Inspector">
-      <div className={styles.tabs} role="tablist" aria-label="Inspector views">
+    <aside className={styles.inspector} aria-label={t("inspector.label", "Inspector")}>
+      <div className={styles.tabs} role="tablist" aria-label={t("inspector.views", "Inspector views")}>
         {tabs.map((candidate) => (
           <button
             key={candidate}
@@ -121,7 +132,7 @@ export function Inspector({
             aria-selected={tab === candidate}
             onClick={() => onTabChange(candidate)}
           >
-            {candidate}
+            {TAB_LABELS[candidate] ?? candidate}
             {badge(candidate) ? ` ${badge(candidate)}` : ""}
           </button>
         ))}
@@ -130,7 +141,7 @@ export function Inspector({
         className={styles.close}
         type="button"
         onClick={onClose}
-        aria-label="Close review panel"
+        aria-label={t("inspector.closeReview", "Close review panel")}
       >
         <X size={16} />
       </button>
diff --git a/desktop/src/features/navigation/DesktopSidebar.tsx b/desktop/src/features/navigation/DesktopSidebar.tsx
index c87370e2..7ba74e1f 100644
--- a/desktop/src/features/navigation/DesktopSidebar.tsx
+++ b/desktop/src/features/navigation/DesktopSidebar.tsx
@@ -142,8 +142,8 @@ export function DesktopSidebar({
       regularGroups.push({
         key: "recovered-history",
         project: null,
-        displayName: "Previous sessions",
-        description: "Original folders unavailable",
+        displayName: t("sidebar.previousSessions", "Previous sessions"),
+        description: t("sidebar.folderUnavailable", "Original folders unavailable"),
         threads: recoveredThreads,
         active: recoveredThreads.some(
           (thread) => thread.projectId === selectedProjectId,
@@ -151,7 +151,7 @@ export function DesktopSidebar({
       });
     }
     return regularGroups;
-  }, [normalizedQuery, projects, selectedProjectId, threads]);
+  }, [normalizedQuery, projects, selectedProjectId, t, threads]);
   const activeGroupKey =
     projectGroups.find((group) => group.active)?.key ?? null;
   const disclosure = useProjectDisclosure(activeGroupKey);
@@ -192,7 +192,7 @@ export function DesktopSidebar({
         </span>
         <span className={styles.brandCopy}>
           <strong>DeepCode</strong>
-          <small>Local agent</small>
+          <small>{t("sidebar.localAgent", "Local agent")}</small>
         </span>
       </div>
 
@@ -205,13 +205,13 @@ export function DesktopSidebar({
             disabled={busy || !canCreateThread}
           >
             <Plus size={16} strokeWidth={1.9} />
-            New thread
+            {t("sidebar.newThread", "New thread")}
             <kbd>⌘N</kbd>
           </button>
 
           <label className={styles.search}>
             <Search size={16} strokeWidth={1.8} aria-hidden="true" />
-            <span className={styles.srOnly}>Search Sessions</span>
+            <span className={styles.srOnly}>{t("sidebar.searchSessions", "Search Sessions")}</span>
             <input
               ref={searchRef}
               value={query}
@@ -222,7 +222,7 @@ export function DesktopSidebar({
                   event.currentTarget.blur();
                 }
               }}
-              placeholder="Search Sessions"
+              placeholder={t("sidebar.searchSessions", "Search Sessions")}
               spellCheck={false}
             />
             <kbd>⌘K</kbd>
@@ -299,15 +299,15 @@ export function DesktopSidebar({
           <button className={styles.emptyProject} type="button" onClick={onOpenProject}>
             <FolderOpen size={18} />
             <span>
-              <strong>Open a local folder</strong>
-              <small>Your CLI Sessions will appear here.</small>
+              <strong>{t("sidebar.openFolder", "Open a local folder")}</strong>
+              <small>{t("sidebar.openFolderHint", "Your CLI Sessions will appear here.")}</small>
             </span>
           </button>
         ) : normalizedQuery && projectGroups.length === 0 ? (
           <div className={styles.noResults}>
             <Search size={16} />
-            <strong>No matching Sessions</strong>
-            <small>Search by title, project, or workspace path.</small>
+            <strong>{t("sidebar.noResults", "No matching Sessions")}</strong>
+            <small>{t("sidebar.noResultsHint", "Search by title, project, or workspace path.")}</small>
           </div>
         ) : (
           projectGroups.map((group) => {
@@ -381,8 +381,8 @@ export function DesktopSidebar({
       <footer className={styles.footer}>
         <Sparkles size={14} aria-hidden="true" />
         <span>
-          <strong>{runtime.phase === "ready" ? "Local agent ready" : runtime.phase}</strong>
-          <small>Shared Session history</small>
+          <strong>{runtime.phase === "ready" ? t("sidebar.agentReady", "Local agent ready") : runtime.phase}</strong>
+          <small>{t("sidebar.sharedHistory", "Shared Session history")}</small>
         </span>
         <span className={styles.runtimeDot} data-phase={runtime.phase} aria-hidden="true" />
       </footer>
@@ -418,6 +418,7 @@ function ProjectSessions({
   onDeleteThread,
 }: ProjectSessionsProps) {
   const [showAll, setShowAll] = useState(false);
+  const { t } = useTranslation();
 
   if (!expanded) return null;
 
@@ -441,7 +442,7 @@ function ProjectSessions({
   return (
     <div className={styles.threadList} id={id}>
       {threads.length === 0 ? (
-        <p className={styles.noSessions}>No Sessions</p>
+        <p className={styles.noSessions}>{t("sidebar.noSessions", "No Sessions")}</p>
       ) : (
         visibleThreads.map((thread) => (
           <SessionRow
@@ -462,7 +463,7 @@ function ProjectSessions({
           className={styles.showMore}
           onClick={() => setShowAll((current) => !current)}
         >
-          {showAll ? "Show less" : `Show ${hiddenCount} more`}
+          {showAll ? t("sidebar.showLess", "Show less") : t("sidebar.showMore", "Show {{count}} more", { count: hiddenCount })}
         </button>
       ) : null}
     </div>
diff --git a/desktop/src/features/settings/sections/DiagnosticsCard.tsx b/desktop/src/features/settings/sections/DiagnosticsCard.tsx
index 82ec93b9..fdef7af8 100644
--- a/desktop/src/features/settings/sections/DiagnosticsCard.tsx
+++ b/desktop/src/features/settings/sections/DiagnosticsCard.tsx
@@ -2,6 +2,7 @@
 
 import { Download, RefreshCw } from "lucide-react";
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 
 import type { Project } from "../../../generated/app-server";
 import type { DesktopRuntime } from "../../../rpc/contracts";
@@ -15,6 +16,7 @@ export function DiagnosticsCard({
   runtime: DesktopRuntime;
   project: Project | null;
 }) {
+  const { t } = useTranslation();
   const diagnostics = useDiagnostics(runtime, project?.id ?? null);
   const [exporting, setExporting] = useState(false);
   const [exportPath, setExportPath] = useState<string | null>(null);
@@ -39,8 +41,8 @@ export function DiagnosticsCard({
     <section className={styles.section}>
       <header className={styles.sectionHeader}>
         <div>
-          <p className={styles.eyebrow}>Troubleshooting</p>
-          <h2>Diagnostics</h2>
+          <p className={styles.eyebrow}>{t("settings.diagnostics.eyebrow", "Troubleshooting")}</p>
+          <h2>{t("settings.diagnostics.title", "Diagnostics")}</h2>
         </div>
         <div className={styles.headerActions}>
           <button
@@ -50,7 +52,7 @@ export function DiagnosticsCard({
             onClick={() => void exportDiagnostics()}
           >
             <Download size={14} />
-            {exporting ? "Exporting…" : "Export report"}
+            {exporting ? t("settings.diagnostics.exporting", "Exporting…") : t("settings.diagnostics.export", "Export report")}
           </button>
           <button
             className={styles.secondaryButton}
@@ -59,7 +61,7 @@ export function DiagnosticsCard({
             onClick={() => void diagnostics.refresh()}
           >
             <RefreshCw size={14} />
-            Run checks
+            {t("settings.diagnostics.runChecks", "Run checks")}
           </button>
         </div>
       </header>
@@ -68,7 +70,7 @@ export function DiagnosticsCard({
       ) : null}
       {exportError ? <p className={styles.errorBanner}>{exportError}</p> : null}
       {exportPath ? (
-        <p className={styles.note}>Sanitized diagnostics saved to {exportPath}</p>
+        <p className={styles.note}>{t("settings.diagnostics.savedTo", "Sanitized diagnostics saved to {{path}}", { path: exportPath })}</p>
       ) : null}
       {diagnostics.diagnostics ? (
         <>
@@ -106,10 +108,10 @@ export function DiagnosticsCard({
               value={String(diagnostics.diagnostics.automationCount)}
             />
             <Diagnostic
-              label="Project config"
+              label={t("settings.diagnostics.noProject", "Project config")}
               value={
                 diagnostics.diagnostics.projectConfigPath ??
-                "No project selected"
+                t("settings.diagnostics.noProject", "No project selected")
               }
             />
           </dl>
diff --git a/desktop/src/features/settings/sections/UpdatesCard.tsx b/desktop/src/features/settings/sections/UpdatesCard.tsx
index e1419f6d..0aad2db6 100644
--- a/desktop/src/features/settings/sections/UpdatesCard.tsx
+++ b/desktop/src/features/settings/sections/UpdatesCard.tsx
@@ -2,6 +2,7 @@
 
 import { Download, Rocket } from "lucide-react";
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 
 import type {
   DesktopRuntime,
@@ -13,6 +14,7 @@ import styles from "../../management/ManagementWorkspace.module.css";
 type UpdateState = "idle" | "checking" | "current" | "available" | "installing";
 
 export function UpdatesCard({ runtime }: { runtime: DesktopRuntime }) {
+  const { t } = useTranslation();
   const [updateInfo, setUpdateInfo] = useState<DesktopUpdateInfo | null>(null);
   const [updateState, setUpdateState] = useState<UpdateState>("idle");
   const [updateProgress, setUpdateProgress] =
@@ -50,8 +52,8 @@ export function UpdatesCard({ runtime }: { runtime: DesktopRuntime }) {
     <section className={styles.section}>
       <header className={styles.sectionHeader}>
         <div>
-          <p className={styles.eyebrow}>Signed release channel</p>
-          <h2>Application updates</h2>
+          <p className={styles.eyebrow}>{t("settings.updates.eyebrow", "Signed release channel")}</p>
+          <h2>{t("settings.updates.title", "Application updates")}</h2>
         </div>
         <div className={styles.headerActions}>
           {updateInfo ? (
@@ -63,8 +65,8 @@ export function UpdatesCard({ runtime }: { runtime: DesktopRuntime }) {
             >
               <Download size={14} />
               {updateState === "installing"
-                ? updateProgressLabel(updateProgress)
-                : `Install ${updateInfo.version}`}
+                ? updateProgressLabel(updateProgress, t)
+                : `${t("settings.updates.install", "Install")} ${updateInfo.version}`}
             </button>
           ) : null}
           <button
@@ -74,41 +76,45 @@ export function UpdatesCard({ runtime }: { runtime: DesktopRuntime }) {
             onClick={() => void checkForUpdate()}
           >
             <Rocket size={14} />
-            {updateState === "checking" ? "Checking…" : "Check for updates"}
+            {updateState === "checking" ? t("settings.updates.checking", "Checking…") : t("settings.updates.check", "Check for updates")}
           </button>
         </div>
       </header>
       {updateError ? <p className={styles.errorBanner}>{updateError}</p> : null}
       <p className={styles.note}>
-        {updateStatusMessage(updateState, updateInfo, updateProgress)}
+        {updateStatusMessage(updateState, updateInfo, updateProgress, t)}
       </p>
       {updateInfo?.body ? <p>{updateInfo.body}</p> : null}
     </section>
   );
 }
 
-function updateProgressLabel(progress: DesktopUpdateProgress | null): string {
-  if (!progress || progress.phase === "started") return "Preparing…";
-  if (progress.phase === "finished") return "Installing…";
-  if (!progress.totalBytes) return "Downloading…";
+function updateProgressLabel(
+  progress: DesktopUpdateProgress | null,
+  t: (key: string, defaultValue: string) => string,
+): string {
+  if (!progress || progress.phase === "started") return t("settings.updates.preparing", "Preparing…");
+  if (progress.phase === "finished") return t("settings.updates.installing", "Installing…");
+  if (!progress.totalBytes) return t("settings.updates.downloading", "Downloading…");
   const percentage = Math.min(
     100,
     Math.round((progress.downloadedBytes / progress.totalBytes) * 100),
   );
-  return `Downloading ${percentage}%`;
+  return `${t("settings.updates.downloading", "Downloading…").replace("…", "")} ${percentage}%`;
 }
 
 function updateStatusMessage(
   state: UpdateState,
   update: DesktopUpdateInfo | null,
   progress: DesktopUpdateProgress | null,
+  t: (key: string, defaultValue: string, options?: Record<string, string>) => string,
 ): string {
   if (state === "checking")
-    return "Checking the configured signed release channel.";
-  if (state === "current") return "This installation is up to date.";
+    return t("settings.updates.checkingNote", "Checking the configured signed release channel.");
+  if (state === "current") return t("settings.updates.upToDate", "This installation is up to date.");
   if (state === "available" && update) {
-    return `DeepCode ${update.version} is available. The package signature is verified before installation.`;
+    return t("settings.updates.available", "DeepCode {{version}} is available. The package signature is verified before installation.", { version: update.version });
   }
-  if (state === "installing") return updateProgressLabel(progress);
-  return "Updates are checked only when requested. Development builds may not configure a release channel.";
+  if (state === "installing") return updateProgressLabel(progress, t);
+  return t("settings.updates.idle", "Updates are checked only when requested. Development builds may not configure a release channel.");
 }
diff --git a/desktop/src/features/thread/ThreadHeader.tsx b/desktop/src/features/thread/ThreadHeader.tsx
index eb69c7a5..994ff377 100644
--- a/desktop/src/features/thread/ThreadHeader.tsx
+++ b/desktop/src/features/thread/ThreadHeader.tsx
@@ -8,6 +8,7 @@ import {
   ShieldCheck,
   ShieldAlert,
 } from "lucide-react";
+import { useTranslation } from "react-i18next";
 
 import { isRecoveredHistoryProject } from "../../app/projectPresentation";
 import type { Project, Thread } from "../../generated/app-server";
@@ -27,10 +28,10 @@ interface ThreadHeaderProps {
   onToggleInspector(): void;
 }
 
-function workspaceLabel(thread: Thread | null, project: Project | null): string {
-  if (isRecoveredHistoryProject(project)) return "Folder unavailable";
+function workspaceLabel(thread: Thread | null, project: Project | null, t: (key: string, defaultValue: string) => string): string {
+  if (isRecoveredHistoryProject(project)) return t("thread.folderUnavailable", "Folder unavailable");
   const path = thread?.workspacePath ?? project?.canonicalPath;
-  if (!path) return "No local folder";
+  if (!path) return t("thread.noLocalFolder", "No local folder");
   const parts = path.split("/").filter(Boolean);
   return parts.at(-1) ?? path;
 }
@@ -47,12 +48,13 @@ export function ThreadHeader({
   onCreatePaperThread,
   onToggleInspector,
 }: ThreadHeaderProps) {
+  const { t } = useTranslation();
   const recoveredHistory = isRecoveredHistoryProject(project);
-  const title = thread?.title ?? "Start a local coding thread";
+  const title = thread?.title ?? t("thread.startThread", "Start a local coding thread");
   const root = recoveredHistory
-    ? "Previous sessions"
+    ? t("thread.previousSessions", "Previous sessions")
     : (project?.displayName ?? "DeepCode");
-  const workspace = thread ? workspaceLabel(thread, project) : null;
+  const workspace = thread ? workspaceLabel(thread, project, t) : null;
   return (
     <header className={styles.header}>
       <div className={styles.identity}>
@@ -85,10 +87,10 @@ export function ThreadHeader({
         {recoveredHistory ? (
           <span
             className={styles.unavailableState}
-            title="The original Session folder is no longer available"
+            title={t("thread.folderUnavailableTooltip", "The original Session folder is no longer available")}
           >
             <FolderX size={14} />
-            Folder unavailable
+            {t("thread.folderUnavailable", "Folder unavailable")}
           </span>
         ) : project?.trustState === "untrusted" ? (
           <button
@@ -98,12 +100,12 @@ export function ThreadHeader({
             disabled={busy}
           >
             <ShieldAlert size={16} />
-            Trust folder
+            {t("thread.trustFolder", "Trust folder")}
           </button>
         ) : project ? (
-          <span className={styles.trustState} title="Execution is allowed in this folder">
+          <span className={styles.trustState} title={t("thread.trustedTooltip", "Execution is allowed in this folder")}>
             <ShieldCheck size={14} />
-            Trusted
+            {t("thread.trusted", "Trusted")}
           </span>
         ) : null}
 
@@ -114,20 +116,20 @@ export function ThreadHeader({
                 type="button"
                 onClick={onCreatePaperThread}
                 disabled={busy || hasActiveWork}
-                title="Create a Paper2Code thread"
+                title={t("thread.paperTooltip", "Create a Paper2Code thread")}
               >
                 <ScrollText size={16} />
-                Paper
+                {t("thread.paper", "Paper")}
               </button>
             ) : null}
             <button
               type="button"
               onClick={onForkThread}
               disabled={busy || hasActiveWork}
-              title="Fork into an isolated worktree"
+              title={t("thread.forkTooltip", "Fork into an isolated worktree")}
             >
               <GitFork size={16} />
-              Fork
+              {t("thread.fork", "Fork")}
             </button>
           </>
         ) : null}
@@ -139,10 +141,10 @@ export function ThreadHeader({
             data-active={inspectorOpen}
             onClick={onToggleInspector}
             aria-pressed={inspectorOpen}
-            title={inspectorOpen ? "Close review panel" : "Open review panel"}
+            title={inspectorOpen ? t("thread.closeReview", "Close review panel") : t("thread.openReview", "Open review panel")}
           >
             <Files size={16} />
-            Review
+            {t("thread.review", "Review")}
             {inspectorOpen ? <PanelRightClose size={14} /> : <PanelRight size={14} />}
           </button>
         ) : null}