diff --git a/apps/packages/ui/src/breadcrumb.tsx b/apps/packages/ui/src/breadcrumb.tsx
index 742e159850..4b1984f5be 100644
--- a/apps/packages/ui/src/breadcrumb.tsx
+++ b/apps/packages/ui/src/breadcrumb.tsx
@@ -4,6 +4,16 @@ import { Slot } from "radix-ui";
 import { cn } from "./lib/utils";
 import { IconChevronRight, IconDots } from "@tabler/icons-react";
 
+/**
+ * `aria-label` is an English default, not a fixed string: `{...props}` spreads
+ * AFTER it, so any consumer can pass a translated `aria-label` and win.
+ *
+ * Do NOT import an i18n runtime here. `@kandev/ui` must stay usable standalone
+ * and must not depend on the app's i18next instance, so localization happens at
+ * the call site — see docs/i18n.md ("How it's wired") and the app's three
+ * consumers (`page-topbar`, `task-top-bar-title`, `OfficeSimplePane`), which all
+ * pass `aria-label={t("common:breadcrumb")}`.
+ */
 function Breadcrumb({ className, ...props }: React.ComponentProps<"nav">) {
   return (
     <nav aria-label="breadcrumb" data-slot="breadcrumb" className={cn(className)} {...props} />
diff --git a/apps/web/components/config-chat/config-chat-copy.test.ts b/apps/web/components/config-chat/config-chat-copy.test.ts
new file mode 100644
index 0000000000..151347b43a
--- /dev/null
+++ b/apps/web/components/config-chat/config-chat-copy.test.ts
@@ -0,0 +1,118 @@
+import { describe, expect, it } from "vitest";
+import { t } from "@/lib/i18n";
+
+/**
+ * Byte-for-byte English for every string this migration externalized, as the
+ * Configuration Chat surfaces rendered them before it.
+ *
+ * An i18n migration must not change copy, and nothing else in the toolchain can
+ * tell you that it did: `i18n:check` proves a key resolves and that `en` and
+ * `pseudo` agree, lint proves nothing is hardcoded, and the pseudo-coverage
+ * oracle proves nothing is left in English. All four are green when a key
+ * resolves to a *different* sentence than the one it replaced — see
+ * docs/i18n.md, "An existing key is not automatically the right key".
+ *
+ * Two entries here are the ones that hazard actually applies to:
+ *
+ *   - `common:configurationChat` replaced `common:commandConfigurationChat`,
+ *     which held the byte-identical "Configuration Chat" for the command
+ *     palette. Folding them avoids a twin that could drift; this pins that the
+ *     fold did not move the palette's label.
+ *   - `common:cancel` is reused for the setup footer's Cancel button, which
+ *     rendered a bare literal "Cancel" before.
+ */
+const CONFIG_CHAT_COPY: Array<[key: string, english: string]> = [
+  // The feature name, rendered by the FAB, the panel header, the dialog
+  // heading and the command palette. One key, four surfaces.
+  ["common:configurationChat", "Configuration Chat"],
+  ["common:cancel", "Cancel"],
+  // The panel chrome.
+  ["configChat:openInQuickChat", "Open in Quick Chat"],
+  ["configChat:closePanel", "Close configuration chat"],
+  ["configChat:tagline", "Configure Kandev with natural language"],
+  // The setup surface, shared by the floating panel and the quick-chat dialog.
+  ["configChat:agentProfileHeading", "Configuration agent profile"],
+  [
+    "configChat:agentProfileHelp",
+    "Choose the agent with access to configuration tools. This becomes the workspace default.",
+  ],
+  ["configChat:tryAsking", "Try asking"],
+  ["configChat:promptHeading", "What would you like to configure?"],
+  ["configChat:promptPlaceholder", "Ask anything about your configuration..."],
+  ["configChat:startChat", "Start chat"],
+  ["configChat:startingChat", "Starting chat..."],
+  ["configChat:startChatAria", "Start configuration chat"],
+  [
+    "configChat:dialogDescription",
+    "Ask an agent to manage workflows, agent profiles, and MCP configuration.",
+  ],
+  [
+    "configChat:noAgentProfiles",
+    "No agent profiles are available. Create one in Agent settings first.",
+  ],
+  // Owned by `use-config-chat.ts`, which holds no JSX — lint reported the file
+  // as clean while both of these reached the user.
+  [
+    "configChat:profileUnavailable",
+    "The selected agent profile is not available yet. Try again shortly.",
+  ],
+  ["configChat:unknownError", "Unknown error"],
+];
+
+/**
+ * `SUGGESTION_PROMPTS` was a SCREAMING_CASE array, which
+ * `i18next/no-literal-string` skips entirely — four sentences the guard never
+ * reported. They are display copy the user then SENDS as a prompt, so they are
+ * translated; pinning them keeps that intentional.
+ */
+const SUGGESTION_COPY: Array<[key: string, english: string]> = [
+  ["configChat:suggestionAddReviewStep", "Add a 'Code Review' step to my workflow"],
+  ["configChat:suggestionCreateProfile", "Create a new agent profile with auto-approve enabled"],
+  ["configChat:suggestionShowWorkflow", "Show me the current workflow configuration"],
+  ["configChat:suggestionUpdateMcp", "Update the MCP servers for the default agent profile"],
+];
+
+/**
+ * `@kandev/ui` primitives must not import the app's i18n runtime, so their
+ * English defaults are overridden at the call site. These two are the labels
+ * the pseudo-coverage oracle reported on every migrated screen.
+ */
+const SHARED_CHROME_COPY: Array<[key: string, english: string]> = [
+  // `Breadcrumb`'s own `aria-label="breadcrumb"` default, lowercase as shadcn
+  // ships it. Overridden by page-topbar, task-top-bar-title and OfficeSimplePane.
+  ["common:breadcrumb", "breadcrumb"],
+  // sonner's `containerAriaLabel`, which defaults to "Notifications". Kept
+  // separate from `settings:notifications` (the settings PAGE name, per
+  // SEGMENT_LABEL_KEYS) on purpose: renaming that page must not rename the
+  // toast region a screen reader announces.
+  ["common:toastRegionLabel", "Notifications"],
+];
+
+describe("Configuration Chat English copy", () => {
+  it.each([...CONFIG_CHAT_COPY, ...SUGGESTION_COPY, ...SHARED_CHROME_COPY])(
+    "%s renders its pre-migration English",
+    (key, english) => {
+      expect(t(key)).toBe(english);
+    },
+  );
+
+  it("does not leave a twin of the feature name behind", () => {
+    // A missing key echoes itself, so this asserts the old palette-only key is
+    // really gone rather than quietly resolving to the same sentence.
+    expect(t("common:commandConfigurationChat")).toBe("commandConfigurationChat");
+  });
+
+  it("gives the toast region the same English as the settings page name, from its own key", () => {
+    // Note this asserts EQUALITY, and a failure is not necessarily a bug.
+    //
+    // The two are separate keys with different owners: `settings:notifications`
+    // is the settings PAGE name (per SEGMENT_LABEL_KEYS), while
+    // `common:toastRegionLabel` names the global toast region a screen reader
+    // announces. They happen to render the same word today.
+    //
+    // So a red here means only "they have diverged". Decide which one you meant
+    // to reword, change that one, and update this expectation — do NOT make the
+    // other follow, which is the coupling the two keys exist to prevent.
+    expect(t("common:toastRegionLabel")).toBe(t("settings:notifications"));
+  });
+});
diff --git a/apps/web/components/config-chat/config-chat-panel.tsx b/apps/web/components/config-chat/config-chat-panel.tsx
index 10b5738ffb..12ae2dac14 100644
--- a/apps/web/components/config-chat/config-chat-panel.tsx
+++ b/apps/web/components/config-chat/config-chat-panel.tsx
@@ -1,6 +1,7 @@
 "use client";
 
 import { memo, useCallback, useMemo, useState } from "react";
+import { useTranslation } from "react-i18next";
 import { useShallow } from "zustand/react/shallow";
 import { IconArrowsMaximize, IconSparkles, IconX } from "@tabler/icons-react";
 import { Button } from "@kandev/ui/button";
@@ -24,11 +25,12 @@ function useConfigChatPanelStore() {
 }
 
 function PanelHeader({ onExpand, onClose }: { onExpand: () => void; onClose: () => void }) {
+  const { t } = useTranslation();
   return (
     <header className="flex h-12 shrink-0 items-center justify-between border-b bg-muted/30 pl-3">
       <div className="flex min-w-0 items-center gap-2">
         <IconSparkles className="h-4 w-4 shrink-0 text-muted-foreground" />
-        <span className="truncate text-sm font-medium">Configuration Chat</span>
+        <span className="truncate text-sm font-medium">{t("common:configurationChat")}</span>
       </div>
       <div className="flex items-center">
         <Tooltip>
@@ -38,19 +40,19 @@ function PanelHeader({ onExpand, onClose }: { onExpand: () => void; onClose: ()
               variant="ghost"
               className="h-11 w-11 cursor-pointer rounded-none"
               onClick={onExpand}
-              aria-label="Open in Quick Chat"
+              aria-label={t("configChat:openInQuickChat")}
             >
               <IconArrowsMaximize className="h-4 w-4" />
             </Button>
           </TooltipTrigger>
-          <TooltipContent>Open in Quick Chat</TooltipContent>
+          <TooltipContent>{t("configChat:openInQuickChat")}</TooltipContent>
         </Tooltip>
         <Button
           size="icon"
           variant="ghost"
           className="h-11 w-11 cursor-pointer rounded-none"
           onClick={onClose}
-          aria-label="Close configuration chat"
+          aria-label={t("configChat:closePanel")}
         >
           <IconX className="h-4 w-4" />
         </Button>
@@ -133,6 +135,7 @@ export const ConfigChatPanel = memo(function ConfigChatPanel({
   setFloatingActionsHost,
 }: ConfigChatPanelProps) {
   const panel = useConfigChatPanelController(workspaceId);
+  const { t } = useTranslation();
 
   return (
     <Popover open={panel.isOpen} onOpenChange={panel.handleOpenChange}>
@@ -147,15 +150,15 @@ export const ConfigChatPanel = memo(function ConfigChatPanel({
                 "fixed bottom-[calc(1.5rem+var(--app-status-bar-height))] right-6 z-50 h-12 w-12 cursor-pointer rounded-full shadow-lg",
                 panel.isOpen && "pointer-events-none opacity-0",
               )}
-              aria-label="Configuration Chat"
+              aria-label={t("common:configurationChat")}
             >
               <IconSparkles className="h-6 w-6" />
             </Button>
           </PopoverTrigger>
         </TooltipTrigger>
         <TooltipContent side="left">
-          <p className="font-medium">Configuration Chat</p>
-          <p className="text-xs text-muted-foreground">Configure Kandev with natural language</p>
+          <p className="font-medium">{t("common:configurationChat")}</p>
+          <p className="text-xs text-muted-foreground">{t("configChat:tagline")}</p>
         </TooltipContent>
       </Tooltip>
       <PopoverContent
diff --git a/apps/web/components/config-chat/config-chat-setup.tsx b/apps/web/components/config-chat/config-chat-setup.tsx
index 45d13d811f..a353baadcb 100644
--- a/apps/web/components/config-chat/config-chat-setup.tsx
+++ b/apps/web/components/config-chat/config-chat-setup.tsx
@@ -1,6 +1,7 @@
 "use client";
 
 import { useEffect, useRef, useState } from "react";
+import { useTranslation } from "react-i18next";
 import { IconLoader2, IconMessageCircle, IconSend2, IconSparkles } from "@tabler/icons-react";
 import { Button } from "@kandev/ui/button";
 import { Textarea } from "@kandev/ui/textarea";
@@ -8,11 +9,22 @@ import { useAppStore } from "@/components/state-provider";
 import type { QuickChatSessionKind } from "@/lib/state/slices/ui/types";
 import { ConfigurationChatToggle } from "@/components/quick-chat/configuration-chat-toggle";
 
-const SUGGESTION_PROMPTS = [
-  "Add a 'Code Review' step to my workflow",
-  "Create a new agent profile with auto-approve enabled",
-  "Show me the current workflow configuration",
-  "Update the MCP servers for the default agent profile",
+/**
+ * Catalog KEYS, not copy. Resolving these at module scope would freeze them at
+ * the boot locale (and hide them from the pseudo-locale, which only ever sees
+ * text that was never translated) — see docs/i18n.md. `Suggestions` resolves
+ * each one at render.
+ *
+ * These are display copy that the user then SENDS: picking one fills the
+ * composer, so the agent receives whatever locale the user is reading in. That
+ * is the intent — a French user should be able to send a French prompt — and
+ * none of these values is compared or persisted.
+ */
+const SUGGESTION_PROMPT_KEYS = [
+  "configChat:suggestionAddReviewStep",
+  "configChat:suggestionCreateProfile",
+  "configChat:suggestionShowWorkflow",
+  "configChat:suggestionUpdateMcp",
 ];
 
 type ConfigChatSetupBaseProps = {
@@ -31,15 +43,14 @@ type ConfigChatSetupProps = ConfigChatSetupBaseProps &
 
 function ProfileSelector({ onSelect }: { onSelect: (id: string) => void }) {
   const profiles = useAppStore((state) => state.agentProfiles.items ?? []);
+  const { t } = useTranslation();
   return (
     <section className="space-y-3" aria-labelledby="config-chat-agent-label">
       <div>
         <h3 id="config-chat-agent-label" className="text-sm font-medium">
-          Configuration agent profile
+          {t("configChat:agentProfileHeading")}
         </h3>
-        <p className="text-xs text-muted-foreground">
-          Choose the agent with access to configuration tools. This becomes the workspace default.
-        </p>
+        <p className="text-xs text-muted-foreground">{t("configChat:agentProfileHelp")}</p>
       </div>
       <div className="grid gap-2 sm:grid-cols-2">
         {profiles.map((profile) => (
@@ -66,20 +77,24 @@ function ProfileSelector({ onSelect }: { onSelect: (id: string) => void }) {
 }
 
 function Suggestions({ onSelect }: { onSelect: (prompt: string) => void }) {
+  const { t } = useTranslation();
   return (
     <section className="space-y-2" aria-labelledby="config-chat-suggestions-label">
       <h3 id="config-chat-suggestions-label" className="text-xs font-medium text-muted-foreground">
-        Try asking
+        {t("configChat:tryAsking")}
       </h3>
       <div className="grid gap-2 sm:grid-cols-2">
-        {SUGGESTION_PROMPTS.map((prompt) => (
+        {/* Keyed by the CATALOG KEY, not the resolved prompt: a React key should
+            be a stable identity, and keying on translated copy remounts every
+            button on a locale switch. */}
+        {SUGGESTION_PROMPT_KEYS.map((key) => (
           <button
-            key={prompt}
+            key={key}
             type="button"
-            onClick={() => onSelect(prompt)}
+            onClick={() => onSelect(t(key))}
             className="min-h-11 rounded-md border px-3 py-2 text-left text-xs text-muted-foreground transition-colors hover:border-primary/50 hover:bg-accent/50 hover:text-foreground"
           >
-            {prompt}
+            {t(key)}
           </button>
         ))}
       </div>
@@ -100,20 +115,21 @@ function ConfigChatFooter({
   startDisabled: boolean;
   isStarting: boolean;
 }) {
+  const { t } = useTranslation();
   return (
     <footer className="flex shrink-0 items-center justify-end gap-2 border-t bg-popover px-4 py-3 sm:px-8">
       <Button variant="outline" onClick={onCancel} disabled={disabled} className="cursor-pointer">
-        Cancel
+        {t("common:cancel")}
       </Button>
       <Button
         onClick={onStart}
         disabled={startDisabled}
         className="min-w-28 cursor-pointer"
-        aria-label="Start configuration chat"
+        aria-label={t("configChat:startChatAria")}
         data-dialog-default-action
       >
         {isStarting ? <IconLoader2 className="h-4 w-4 animate-spin" aria-hidden /> : null}
-        {isStarting ? "Starting chat..." : "Start chat"}
+        {isStarting ? t("configChat:startingChat") : t("configChat:startChat")}
       </Button>
     </footer>
   );
@@ -142,6 +158,7 @@ function ConfigPrompt({
   onChange,
   onSubmit,
 }: ConfigPromptProps) {
+  const { t } = useTranslation();
   return (
     <div
       className="shrink-0 border-t bg-popover px-4 py-4 sm:px-8"
@@ -152,7 +169,7 @@ function ConfigPrompt({
         aria-labelledby="config-chat-prompt-label"
       >
         <h3 id="config-chat-prompt-label" className="text-sm font-medium">
-          What would you like to configure?
+          {t("configChat:promptHeading")}
         </h3>
         <div className="flex items-end gap-2">
           <Textarea
@@ -171,7 +188,7 @@ function ConfigPrompt({
                 onSubmit();
               }
             }}
-            placeholder="Ask anything about your configuration..."
+            placeholder={t("configChat:promptPlaceholder")}
             disabled={disabled}
             className="min-h-20 max-h-32 resize-y"
           />
@@ -181,7 +198,7 @@ function ConfigPrompt({
               onClick={onSubmit}
               disabled={!canSubmit}
               className="h-11 w-11 shrink-0 cursor-pointer"
-              aria-label="Start configuration chat"
+              aria-label={t("configChat:startChatAria")}
             >
               {isStarting ? (
                 <IconLoader2 className="h-4 w-4 animate-spin" aria-hidden />
@@ -214,6 +231,7 @@ function ConfigGuidance({
   onSelectSuggestion: (prompt: string) => void;
   onKindChange?: (kind: QuickChatSessionKind) => void;
 }) {
+  const { t } = useTranslation();
   return (
     <div
       className="min-h-0 flex-1 overflow-y-auto px-4 py-6 sm:px-8 sm:py-8"
@@ -225,11 +243,9 @@ function ConfigGuidance({
             <header className="space-y-2">
               <div className="flex items-center gap-2">
                 <IconSparkles className="h-5 w-5 text-primary" aria-hidden />
-                <h2 className="text-lg font-semibold">Configuration Chat</h2>
+                <h2 className="text-lg font-semibold">{t("common:configurationChat")}</h2>
               </div>
-              <p className="text-sm text-muted-foreground">
-                Ask an agent to manage workflows, agent profiles, and MCP configuration.
-              </p>
+              <p className="text-sm text-muted-foreground">{t("configChat:dialogDescription")}</p>
             </header>
             {onKindChange && (
               <ConfigurationChatToggle
@@ -242,9 +258,7 @@ function ConfigGuidance({
         )}
 
         {!hasProfiles && (
-          <p className="text-sm text-muted-foreground">
-            No agent profiles are available. Create one in Agent settings first.
-          </p>
+          <p className="text-sm text-muted-foreground">{t("configChat:noAgentProfiles")}</p>
         )}
 
         {hasProfiles && needsProfileSelection && <ProfileSelector onSelect={onSelectProfile} />}
diff --git a/apps/web/components/config-chat/use-config-chat.ts b/apps/web/components/config-chat/use-config-chat.ts
index 37dc4cdf76..e97ffa8383 100644
--- a/apps/web/components/config-chat/use-config-chat.ts
+++ b/apps/web/components/config-chat/use-config-chat.ts
@@ -3,6 +3,7 @@
 import { useCallback, useRef, useState } from "react";
 import { useShallow } from "zustand/react/shallow";
 import { useAppStore, useAppStoreApi } from "@/components/state-provider";
+import { t } from "@/lib/i18n";
 import { updateWorkspaceAction } from "@/app/actions/workspaces";
 import { startConfigChat } from "@/lib/api/domains/workspace-api";
 import { getQuickChatSetupSessionId } from "@/lib/state/slices/ui/quick-chat-session";
@@ -105,6 +106,12 @@ function registerStartedSession({
   // The config-chat endpoint has no title field, so name the tab from the
   // opening prompt and save it to the task — otherwise the label would live
   // only in this browser and be lost on the next resync.
+  //
+  // "Config Chat" is deliberately NOT translated: `persistQuickChatRename`
+  // writes it to the task title, so translating it would store a
+  // locale-dependent value that then renders unchanged after a locale switch,
+  // on surfaces this directory does not own. Same call as the built-in layout
+  // profile names and the seeded workflow step names.
   const derivedName = prompt.slice(0, 40) || "Config Chat";
   store.renameQuickChatSession(response.session_id, derivedName);
   void persistQuickChatRename(response.session_id, response.task_id, derivedName).catch(
@@ -161,7 +168,7 @@ export function useConfigChat(workspaceId: string) {
         .getState()
         .agentProfiles.items.find((item) => item.id === agentProfileId);
       if (!profile) {
-        setError("The selected agent profile is not available yet. Try again shortly.");
+        setError(t("configChat:profileUnavailable"));
         return undefined;
       }
       if (activeWorkspaceStarts.has(workspaceId)) return undefined;
@@ -202,7 +209,10 @@ export function useConfigChat(workspaceId: string) {
         return response.session_id;
       } catch (err) {
         if (latestRequestId.current !== requestId) return undefined;
-        setError(err instanceof Error ? err.message : "Unknown error");
+        // `err.message` is an API/network diagnostic and stays English by
+        // design (docs/i18n.md, "the interpolated-value limit"); the FALLBACK
+        // for a payload-less throw is our copy and is translated.
+        setError(err instanceof Error ? err.message : t("configChat:unknownError"));
         return undefined;
       } finally {
         if (activeWorkspaceStarts.get(workspaceId) === workspaceStart) {
diff --git a/apps/web/components/global-commands.tsx b/apps/web/components/global-commands.tsx
index 00ee83f0cb..fa0303e380 100644
--- a/apps/web/components/global-commands.tsx
+++ b/apps/web/components/global-commands.tsx
@@ -171,7 +171,7 @@ export function GlobalCommands() {
   const configChatCommand: CommandItem = useMemo(
     () => ({
       id: "config-chat",
-      label: t("common:commandConfigurationChat"),
+      label: t("common:configurationChat"),
       group: t(GROUP_ACTIONS),
       icon: <IconSparkles className="size-3.5" />,
       keywords: searchKeywords(t, "common:commandConfigChatKeywords"),
diff --git a/apps/web/components/page-topbar.tsx b/apps/web/components/page-topbar.tsx
index f64f6189ae..27dae58231 100644
--- a/apps/web/components/page-topbar.tsx
+++ b/apps/web/components/page-topbar.tsx
@@ -1,6 +1,7 @@
 import Link from "@/components/routing/app-link";
 import { forwardRef } from "react";
 import type { ReactNode } from "react";
+import { useTranslation } from "react-i18next";
 import { IconArrowLeft, IconHome } from "@tabler/icons-react";
 import {
   Breadcrumb,
@@ -92,6 +93,7 @@ function TopbarBreadcrumb({
   icon?: ReactNode;
   showPhoneHome: boolean;
 }) {
+  const { t } = useTranslation();
   // The Home prefix is redundant on desktop, where the AppSidebar always shows
   // a Home nav item. Only render the back link when a page sets a non-root
   // backHref (e.g. a true ancestor route within a section).
@@ -101,7 +103,7 @@ function TopbarBreadcrumb({
   // users with no way back. Keep the home crumb phone-only.
   const showHomeCrumb = !showBackLink && showPhoneHome;
   return (
-    <Breadcrumb className="relative z-10 min-w-0">
+    <Breadcrumb className="relative z-10 min-w-0" aria-label={t("common:breadcrumb")}>
       <BreadcrumbList className="flex-nowrap text-sm">
         {showBackLink && (
           <>
diff --git a/apps/web/components/task/simple/OfficeSimplePane.tsx b/apps/web/components/task/simple/OfficeSimplePane.tsx
index 0d7904cd6f..e1f62c2d44 100644
--- a/apps/web/components/task/simple/OfficeSimplePane.tsx
+++ b/apps/web/components/task/simple/OfficeSimplePane.tsx
@@ -1,6 +1,7 @@
 "use client";
 
 import { useEffect, useState, useCallback, useRef } from "react";
+import { useTranslation } from "react-i18next";
 import Link from "@/components/routing/app-link";
 import {
   IconCopy,
@@ -98,8 +99,9 @@ function commentsReadOnly(task: Task, sessions: TaskSession[]): boolean {
 }
 
 function TaskBreadcrumb({ task }: { task: Task }) {
+  const { t } = useTranslation();
   return (
-    <Breadcrumb>
+    <Breadcrumb aria-label={t("common:breadcrumb")}>
       <BreadcrumbList className="text-sm">
         <BreadcrumbItem>
           <BreadcrumbLink asChild>
diff --git a/apps/web/components/task/task-top-bar-title.tsx b/apps/web/components/task/task-top-bar-title.tsx
index 6cf7b9db1a..aac00ce4fd 100644
--- a/apps/web/components/task/task-top-bar-title.tsx
+++ b/apps/web/components/task/task-top-bar-title.tsx
@@ -1,6 +1,7 @@
 "use client";
 
 import { useCallback, useEffect, useRef, useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Breadcrumb, BreadcrumbItem, BreadcrumbList, BreadcrumbPage } from "@kandev/ui/breadcrumb";
 import { Tooltip, TooltipContent, TooltipTrigger } from "@kandev/ui/tooltip";
 import { Input } from "@kandev/ui/input";
@@ -15,6 +16,7 @@ type TaskTopBarTitleProps = {
 
 export function TaskTopBarTitle({ taskId, taskTitle, isArchived }: TaskTopBarTitleProps) {
   const { renameTaskById } = useTaskActions();
+  const { t } = useTranslation();
   const [isEditing, setIsEditing] = useState(false);
   const [draft, setDraft] = useState("");
   const titleRef = useRef<HTMLSpanElement>(null);
@@ -92,7 +94,7 @@ export function TaskTopBarTitle({ taskId, taskTitle, isArchived }: TaskTopBarTit
   }
 
   return (
-    <Breadcrumb className="min-w-0 max-w-full">
+    <Breadcrumb className="min-w-0 max-w-full" aria-label={t("common:breadcrumb")}>
       <BreadcrumbList className="min-w-0 max-w-full flex-nowrap text-sm">
         <BreadcrumbItem className="min-w-0 max-w-full">
           <Tooltip>
diff --git a/apps/web/eslint.i18n.options.mjs b/apps/web/eslint.i18n.options.mjs
index 00f3318b6e..3296beb402 100644
--- a/apps/web/eslint.i18n.options.mjs
+++ b/apps/web/eslint.i18n.options.mjs
@@ -1091,4 +1091,41 @@ export const i18nGuardFiles = [
   "components/settings/utility-sections.tsx",
   "components/settings/voice-mode-settings.tsx",
   "lib/settings/external-mcp-tools.ts",
+  // Configuration Chat. `ConfigChatProvider` mounts the FAB on EVERY /settings
+  // route, so its `aria-label="Configuration Chat"` was the last text finding
+  // the pseudo-coverage oracle reported across the whole migrated surface.
+  //
+  // `use-config-chat.ts` holds no JSX, so `mode: "jsx-only"` never inspects it;
+  // the entry records that it was read by eye. The count from
+  // `pnpm run lint:i18n` reported it as 0 while it owned two strings that reach
+  // the user — the `setError` for a missing agent profile, and the fallback for
+  // a throw with no `message`. It imports the module-level `t` rather than the
+  // hook so each resolves when `startSession` runs, keeping `t` out of the
+  // callback's dependency array.
+  //
+  // `SUGGESTION_PROMPT_KEYS` in `config-chat-setup.tsx` was `SUGGESTION_PROMPTS`,
+  // four sentences the guard skipped entirely because the identifier is
+  // SCREAMING_CASE. They now travel as catalog keys and resolve at render.
+  //
+  // Copy lives in a new `configChat` namespace, except the feature NAME
+  // ("Configuration Chat"), which the command palette also renders and which is
+  // therefore `common:configurationChat` — `common:commandConfigurationChat`
+  // held the byte-identical string and was folded into it rather than left as a
+  // twin free to drift.
+  //
+  // Deliberately left in English: the `"Config Chat"` session-name fallback in
+  // `use-config-chat.ts`. `persistQuickChatRename` writes it to the task title,
+  // so translating it would persist a locale-dependent value — the same call as
+  // the built-in layout profile names and the seeded workflow step names.
+  //
+  // NOT listed, and not migrated here:
+  //   - `components/settings/config-chat-agent-section.tsx`, the Configuration
+  //     Chat card on Settings → Utility Agents. #2218 migrates it with the page
+  //     that owns it, into `settings:configChatAgent*`.
+  //   - `components/quick-chat/**`. `quick-chat-modal.tsx` renders
+  //     `ConfigChatSetup` in its `presentation="dialog"` form and calls
+  //     `useConfigChat`, so it inherits everything migrated here, but its own
+  //     chrome — and `configuration-chat-toggle.tsx`, which `ConfigChatSetup`
+  //     renders — is still English and belongs to the quick-chat migration.
+  "components/config-chat/*.{ts,tsx}",
 ];
diff --git a/apps/web/src/app-shell.tsx b/apps/web/src/app-shell.tsx
index 672798d064..a4b4a2485d 100644
--- a/apps/web/src/app-shell.tsx
+++ b/apps/web/src/app-shell.tsx
@@ -1,3 +1,5 @@
+import { useTranslation } from "react-i18next";
+
 import { AppSidebar } from "@/components/app-sidebar/app-sidebar";
 import { AppStatusSurfaceProvider } from "@/components/app-status-bar/app-status-surface-provider";
 import { CommandPanel } from "@/components/command-panel";
@@ -24,6 +26,26 @@ type AppShellProps = {
   children: React.ReactNode;
 };
 
+/**
+ * sonner names its toast region `Notifications alt+T` by default — copy a
+ * screen-reader user hears on every screen, and the last un-migrated
+ * `aria-label` the pseudo-coverage oracle reported.
+ *
+ * Deliberately its own component rather than a `t()` call in `AppShell`:
+ * `<I18nProvider>` is mounted BY `AppShell`, so `AppShell`'s own render runs
+ * outside the provider and would not re-render on a locale switch.
+ */
+function AppToaster() {
+  const { t } = useTranslation();
+  return (
+    <SonnerToaster
+      richColors
+      position="top-right"
+      containerAriaLabel={t("common:toastRegionLabel")}
+    />
+  );
+}
+
 export function AppShell({ children }: AppShellProps) {
   return (
     <I18nProvider>
@@ -31,7 +53,7 @@ export function AppShell({ children }: AppShellProps) {
         <DiffWorkerPoolProvider>
           <TooltipProvider>
             <ToastProvider>
-              <SonnerToaster richColors position="top-right" />
+              <AppToaster />
               <SessionFailureToastBridge />
               <TaskDeletedToastBridge />
               <UpdateAvailableToastBridge />
diff --git a/apps/web/src/locales/en/common.json b/apps/web/src/locales/en/common.json
index 659c522d9e..f712a8a031 100644
--- a/apps/web/src/locales/en/common.json
+++ b/apps/web/src/locales/en/common.json
@@ -7,8 +7,8 @@
   "changelog": "Changelog",
   "commandAgentsSettings": "Agents Settings",
   "commandAgentsSettingsKeywords": "agents, agent settings, agent profiles, installed agents, claude",
+  "breadcrumb": "breadcrumb",
   "commandConfigChatKeywords": "config chat, config mode, configure kandev, workflow configuration, mcp configuration",
-  "commandConfigurationChat": "Configuration Chat",
   "commandExecutorsSettings": "Executors Settings",
   "commandExecutorsSettingsKeywords": "executors, executor profiles, execution environment, environment variables, runtime, compute",
   "commandGoToAllTasks": "Go to All Tasks",
@@ -34,6 +34,7 @@
   "commandThemeKeywords": "theme, color theme, appearance",
   "commandWorkspaceSettings": "Workspace Settings",
   "commandWorkspaceSettingsKeywords": "workspace, workspaces",
+  "configurationChat": "Configuration Chat",
   "contextCompactionCountHelp": "Kandev infers this count from observed context usage drops. Missing samples or provider resets can make it approximate.",
   "contextCompactions": "Compactions",
   "createAWorkspaceToConfigureThisIntegration": "Create a workspace to configure this integration.",
@@ -77,6 +78,7 @@
   "taskUnavailable": "Task unavailable",
   "taskUnavailableDescription": "We could not load this task. It may have been deleted or you may not have access.",
   "title": "Title",
+  "toastRegionLabel": "Notifications",
   "unsavedChanges": "Unsaved changes",
   "workspace": "Workspace",
   "workspaces": "Workspaces",
diff --git a/apps/web/src/locales/en/configChat.json b/apps/web/src/locales/en/configChat.json
new file mode 100644
index 0000000000..040951eebc
--- /dev/null
+++ b/apps/web/src/locales/en/configChat.json
@@ -0,0 +1,21 @@
+{
+  "agentProfileHeading": "Configuration agent profile",
+  "agentProfileHelp": "Choose the agent with access to configuration tools. This becomes the workspace default.",
+  "closePanel": "Close configuration chat",
+  "dialogDescription": "Ask an agent to manage workflows, agent profiles, and MCP configuration.",
+  "noAgentProfiles": "No agent profiles are available. Create one in Agent settings first.",
+  "openInQuickChat": "Open in Quick Chat",
+  "profileUnavailable": "The selected agent profile is not available yet. Try again shortly.",
+  "promptHeading": "What would you like to configure?",
+  "promptPlaceholder": "Ask anything about your configuration...",
+  "startChat": "Start chat",
+  "startChatAria": "Start configuration chat",
+  "startingChat": "Starting chat...",
+  "suggestionAddReviewStep": "Add a 'Code Review' step to my workflow",
+  "suggestionCreateProfile": "Create a new agent profile with auto-approve enabled",
+  "suggestionShowWorkflow": "Show me the current workflow configuration",
+  "suggestionUpdateMcp": "Update the MCP servers for the default agent profile",
+  "tagline": "Configure Kandev with natural language",
+  "tryAsking": "Try asking",
+  "unknownError": "Unknown error"
+}
diff --git a/apps/web/src/locales/pseudo/common.json b/apps/web/src/locales/pseudo/common.json
index 594f304abd..8919c4f5a2 100644
--- a/apps/web/src/locales/pseudo/common.json
+++ b/apps/web/src/locales/pseudo/common.json
@@ -7,8 +7,8 @@
   "changelog": "Ćĥàńĝēĺōĝ",
   "commandAgentsSettings": "Àĝēńţś Śēţţĩńĝś",
   "commandAgentsSettingsKeywords": "àĝēńţś, àĝēńţ śēţţĩńĝś, àĝēńţ ƥŕōƒĩĺēś, ĩńśţàĺĺēď àĝēńţś, ćĺàũďē",
+  "breadcrumb": "ƀŕēàďćŕũḿƀ",
   "commandConfigChatKeywords": "ćōńƒĩĝ ćĥàţ, ćōńƒĩĝ ḿōďē, ćōńƒĩĝũŕē ķàńďēv, ŵōŕķƒĺōŵ ćōńƒĩĝũŕàţĩōń, ḿćƥ ćōńƒĩĝũŕàţĩōń",
-  "commandConfigurationChat": "Ćōńƒĩĝũŕàţĩōń Ćĥàţ",
   "commandExecutorsSettings": "Ēxēćũţōŕś Śēţţĩńĝś",
   "commandExecutorsSettingsKeywords": "ēxēćũţōŕś, ēxēćũţōŕ ƥŕōƒĩĺēś, ēxēćũţĩōń ēńvĩŕōńḿēńţ, ēńvĩŕōńḿēńţ vàŕĩàƀĺēś, ŕũńţĩḿē, ćōḿƥũţē",
   "commandGoToAllTasks": "Ĝō ţō Àĺĺ Ţàśķś",
@@ -34,6 +34,7 @@
   "commandThemeKeywords": "ţĥēḿē, ćōĺōŕ ţĥēḿē, àƥƥēàŕàńćē",
   "commandWorkspaceSettings": "Ŵōŕķśƥàćē Śēţţĩńĝś",
   "commandWorkspaceSettingsKeywords": "ŵōŕķśƥàćē, ŵōŕķśƥàćēś",
+  "configurationChat": "Ćōńƒĩĝũŕàţĩōń Ćĥàţ",
   "contextCompactionCountHelp": "Ķàńďēv ĩńƒēŕś ţĥĩś ćōũńţ ƒŕōḿ ōƀśēŕvēď ćōńţēxţ ũśàĝē ďŕōƥś. Ḿĩśśĩńĝ śàḿƥĺēś ōŕ ƥŕōvĩďēŕ ŕēśēţś ćàń ḿàķē ĩţ àƥƥŕōxĩḿàţē.",
   "contextCompactions": "Ćōḿƥàćţĩōńś",
   "createAWorkspaceToConfigureThisIntegration": "Ćŕēàţē à ŵōŕķśƥàćē ţō ćōńƒĩĝũŕē ţĥĩś ĩńţēĝŕàţĩōń.",
@@ -77,6 +78,7 @@
   "taskUnavailable": "Ţàśķ ũńàvàĩĺàƀĺē",
   "taskUnavailableDescription": "Ŵē ćōũĺď ńōţ ĺōàď ţĥĩś ţàśķ. Ĩţ ḿàŷ ĥàvē ƀēēń ďēĺēţēď ōŕ ŷōũ ḿàŷ ńōţ ĥàvē àććēśś.",
   "title": "Ţĩţĺē",
+  "toastRegionLabel": "Ńōţĩƒĩćàţĩōńś",
   "unsavedChanges": "Ũńśàvēď ćĥàńĝēś",
   "workspace": "Ŵōŕķśƥàćē",
   "workspaces": "Ŵōŕķśƥàćēś",
diff --git a/apps/web/src/locales/pseudo/configChat.json b/apps/web/src/locales/pseudo/configChat.json
new file mode 100644
index 0000000000..62b30d87ab
--- /dev/null
+++ b/apps/web/src/locales/pseudo/configChat.json
@@ -0,0 +1,21 @@
+{
+  "agentProfileHeading": "Ćōńƒĩĝũŕàţĩōń àĝēńţ ƥŕōƒĩĺē",
+  "agentProfileHelp": "Ćĥōōśē ţĥē àĝēńţ ŵĩţĥ àććēśś ţō ćōńƒĩĝũŕàţĩōń ţōōĺś. Ţĥĩś ƀēćōḿēś ţĥē ŵōŕķśƥàćē ďēƒàũĺţ.",
+  "closePanel": "Ćĺōśē ćōńƒĩĝũŕàţĩōń ćĥàţ",
+  "dialogDescription": "Àśķ àń àĝēńţ ţō ḿàńàĝē ŵōŕķƒĺōŵś, àĝēńţ ƥŕōƒĩĺēś, àńď ḾĆƤ ćōńƒĩĝũŕàţĩōń.",
+  "noAgentProfiles": "Ńō àĝēńţ ƥŕōƒĩĺēś àŕē àvàĩĺàƀĺē. Ćŕēàţē ōńē ĩń Àĝēńţ śēţţĩńĝś ƒĩŕśţ.",
+  "openInQuickChat": "Ōƥēń ĩń Qũĩćķ Ćĥàţ",
+  "profileUnavailable": "Ţĥē śēĺēćţēď àĝēńţ ƥŕōƒĩĺē ĩś ńōţ àvàĩĺàƀĺē ŷēţ. Ţŕŷ àĝàĩń śĥōŕţĺŷ.",
+  "promptHeading": "Ŵĥàţ ŵōũĺď ŷōũ ĺĩķē ţō ćōńƒĩĝũŕē?",
+  "promptPlaceholder": "Àśķ àńŷţĥĩńĝ àƀōũţ ŷōũŕ ćōńƒĩĝũŕàţĩōń...",
+  "startChat": "Śţàŕţ ćĥàţ",
+  "startChatAria": "Śţàŕţ ćōńƒĩĝũŕàţĩōń ćĥàţ",
+  "startingChat": "Śţàŕţĩńĝ ćĥàţ...",
+  "suggestionAddReviewStep": "Àďď à 'Ćōďē Ŕēvĩēŵ' śţēƥ ţō ḿŷ ŵōŕķƒĺōŵ",
+  "suggestionCreateProfile": "Ćŕēàţē à ńēŵ àĝēńţ ƥŕōƒĩĺē ŵĩţĥ àũţō-àƥƥŕōvē ēńàƀĺēď",
+  "suggestionShowWorkflow": "Śĥōŵ ḿē ţĥē ćũŕŕēńţ ŵōŕķƒĺōŵ ćōńƒĩĝũŕàţĩōń",
+  "suggestionUpdateMcp": "Ũƥďàţē ţĥē ḾĆƤ śēŕvēŕś ƒōŕ ţĥē ďēƒàũĺţ àĝēńţ ƥŕōƒĩĺē",
+  "tagline": "Ćōńƒĩĝũŕē Ķàńďēv ŵĩţĥ ńàţũŕàĺ ĺàńĝũàĝē",
+  "tryAsking": "Ţŕŷ àśķĩńĝ",
+  "unknownError": "Ũńķńōŵń ēŕŕōŕ"
+}
diff --git a/docs/i18n.md b/docs/i18n.md
index 6fbe643a8c..d648418c1a 100644
--- a/docs/i18n.md
+++ b/docs/i18n.md
@@ -349,9 +349,34 @@ completeness check: anything still rendering plain English under it was missed.
 - **Locale source of truth**: the `kandev_locale` cookie. The Go shell
   (`apps/backend/internal/webapp/shell.go`) reads it to set `<html lang>` and
   seed the boot payload, so first paint matches with no flash.
-- **Shared UI**: `@kandev/ui` primitives still carry their own hardcoded
-  accessibility labels ("Close", "Toggle Sidebar"). Localizing them needs a
-  strings-provider seam in the package; not done yet.
+- **Shared UI**: `@kandev/ui` primitives carry their own hardcoded accessibility
+  labels ("Close", "Toggle Sidebar", "Loading", "Go to next page"). The package
+  must not import the app's i18n runtime — it has to stay usable standalone — so
+  these are localized at the **call site**, not in the package. Check the shape
+  before inventing a seam, because the two halves differ:
+  - **A label in an ATTRIBUTE needs nothing.** Every one of them sits on an
+    element that spreads `{...props}` *after* it, so the overridable string prop
+    the spec asks for already exists and the English literal is only its default.
+    `Breadcrumb`'s `aria-label="breadcrumb"` was this shape: the fix was
+    `aria-label={t("common:breadcrumb")}` at its three consumers (`page-topbar`,
+    `task-top-bar-title`, `OfficeSimplePane`) plus a comment in the package
+    recording the contract. A `label?: string` prop would have duplicated a prop
+    React already gives you. Same shape, still un-overridden: `SidebarRail`'s
+    `aria-label`/`title`, `Spinner`'s `aria-label="Loading"`, and `Pagination`'s
+    three.
+  - **A label that is a TEXT CHILD does need a seam**, because a consumer cannot
+    reach it through `{...props}`: the `<span className="sr-only">` in
+    `DialogContent`, `SidebarTrigger` and `BreadcrumbEllipsis` ("Close", "Toggle
+    Sidebar", "More"), and `PaginationPrevious`/`PaginationNext`'s visible
+    "Previous"/"Next". Each wants an optional label prop defaulting to today's
+    text. Open — the dialog "Close" is the one a pseudo walk keeps surfacing,
+    because every integration settings page renders it.
+
+  A third-party primitive is the same call: sonner names its toast region
+  `Notifications alt+T` and accepts `containerAriaLabel`, which `AppToaster` in
+  `src/app-shell.tsx` passes. That has to be its own component — `<I18nProvider>`
+  is mounted *by* `AppShell`, so a `t()` call in `AppShell`'s own render sits
+  outside the provider and would not re-render on a locale switch.
 - **Tests**: `vitest.setup.ts` calls `initI18nForTests()`. react-i18next falls
   back to the default instance when no provider is present, so no render wrapper
   is needed and every test's render tree is unchanged.