diff --git a/.changeset/mosaic-to-localizable-error.md b/.changeset/mosaic-to-localizable-error.md
new file mode 100644
index 00000000000..a845151cc84
--- /dev/null
+++ b/.changeset/mosaic-to-localizable-error.md
@@ -0,0 +1,2 @@
+---
+---
diff --git a/.claude/skills/mosaic/references/controllers.md b/.claude/skills/mosaic/references/controllers.md
index c1481058f84..bc51468a921 100644
--- a/.claude/skills/mosaic/references/controllers.md
+++ b/.claude/skills/mosaic/references/controllers.md
@@ -28,6 +28,21 @@ complexity calls for:
 | Is a boolean or a controlled value, no async, nothing else depends on it | `useState`                  |
 | Has an async lifecycle, or two values that must change together          | A machine, same file        |
 | Has a coordinated async core plus some UI-only flags beside it           | Both — machine for the core |
+| Is one async action from a button, needing only pending and an error     | `usePendingAction`          |
+
+`usePendingAction(fn, { errorFallback })` covers any single async action a
+button starts: set a default, sign out a device, accept or decline a request. It
+ignores clicks while one is in flight, owns the error
+(see "Errors") and returns `{ run, isPending, errorMessage, reset }`. `run`
+resolves `true` on success, so the caller can close a dialog or move focus. It
+is not for:
+
+- a form → `useForm`
+- a confirm step → `Confirmation` / `Destructive`
+- an action whose result drives other state → a machine
+- per-row pending across a list, or holding pending through a redirect → the
+  connected and enterprise accounts controllers, until `usePendingAction` takes
+  a key
 
 `useUserProfileDeleteSectionController` earns a machine on three counts: the
 delete is async, a failure must land back on the previous step with a reason,
@@ -120,6 +135,36 @@ have a machine.
   }
   ```
 
+## Errors
+
+One path, so every error a user sees goes through the `errors.*` catalog:
+
+- **Owners map, nothing else does.** `toLocalizableError(cause)` from
+  `utils/errors.ts` is called only by the hooks that own a failure: `useForm`,
+  `useConfirmationController`, `useDestructiveController` and
+  `usePendingAction` (inline row actions). Use one of them instead of catching
+  in a feature.
+- **Owners hold an `ErrorDescription`.** It is either a `LocalizableError`
+  (Clerk gave a `code`) or an `UnlocalizableError` (`{ cause }`, the original
+  failure). `toLocalizableError` logs the second as
+  `[Clerk] Could not localize error`. Branch with `isLocalizableError` only
+  when a feature handles the two differently.
+- **Owners resolve copy at render; views get a string.** Owners return
+  `errorMessage` from `useErrorText()`: the
+  catalog entry for `code__paramName`, then `code`, then Clerk's message, then
+  the feature's `errorFallback`, then the generic error. Views never call
+  `useErrorText` on an error they did not create themselves.
+- Not there yet, each with a follow-up: `useForm` resolves when the save fails
+  and falls back to `form.error` instead of taking an `errorFallback`, and the
+  profile picture row resolves its controller's error in the view.
+- **`errorFallback` is the feature's copy for faults Clerk cannot describe**
+  (code bugs, non-Clerk errors). An `UnlocalizableError` renders the fallback,
+  never its cause's `.message`. A network failure has its own catalog entry,
+  `network_error`.
+- In tests, reject with `clerkApiError(code, message)` from
+  `src/__tests__/clerk-errors.ts` to assert catalog copy. Reject with a plain
+  `Error` (silence `console.error`) to assert the fallback.
+
 ## Testing
 
 The feature test covers the controller by default. Hold the
diff --git a/.claude/skills/mosaic/references/machines.md b/.claude/skills/mosaic/references/machines.md
index ea1db234cdb..00dafc70a09 100644
--- a/.claude/skills/mosaic/references/machines.md
+++ b/.claude/skills/mosaic/references/machines.md
@@ -42,14 +42,20 @@ deleting: {
     onDone: 'deleted',
     onError: {
       target: 'confirming',
-      actions: assign((_, event) => ({
-        errorMessage: event.error instanceof Error ? event.error.message : 'Something went wrong.',
-      })),
+      actions: assign((_, event) => ({ error: toLocalizableError(event.error) })),
     },
   }),
 }
 ```
 
+A machine whose surface shows no error yet still logs it, so a failure is never
+silent: `onError: { target: 'idle', actions: [assign(() => settled), (_, event) => console.error('[Clerk] User button action failed', event.error)] }`
+(`user-button.controller.tsx`).
+
+Context holds the `ErrorDescription`, never copy. The controller turns it into
+text at render with `errorText(error, errorFallback)`, so locale changes and
+overrides still apply (see `controllers.md` → "Errors").
+
 To wire it to Clerk data see `models.md`; to render its state see `views.md`; to
 test it see `testing.md`; to migrate a legacy component into this pattern see
 `migration.md`.
diff --git a/.claude/skills/mosaic/references/models.md b/.claude/skills/mosaic/references/models.md
index 44858716d3a..74ffaa77968 100644
--- a/.claude/skills/mosaic/references/models.md
+++ b/.claude/skills/mosaic/references/models.md
@@ -83,6 +83,11 @@ drops the fallback instead of holding the space open. Keep the two apart.
   `organizationId`), never a resource.
 - An async callback returns its promise — the controller drives pending state off
   it. Navigation callbacks stay fire-and-forget.
+- Never format an error. Let Clerk errors propagate untouched. For a failure
+  the model detects itself, throw
+  `new ClerkRuntimeError(message, { code })` and add the copy for `code` to
+  `src/localization/errors.messages.ts`. No `try`/`catch` that turns errors into
+  strings, no feature-level `toError` helpers.
 - No local UI state. What is open and what is in flight belong to the controller.
 - No React state machinery beyond the Clerk hooks themselves; the model is a
   derivation of what Clerk currently says.
diff --git a/.claude/skills/mosaic/references/views.md b/.claude/skills/mosaic/references/views.md
index 84253fd8355..8591cb6c450 100644
--- a/.claude/skills/mosaic/references/views.md
+++ b/.claude/skills/mosaic/references/views.md
@@ -45,14 +45,19 @@ Two shapes, chosen by whether the slice fetches its own data:
 ## Where the strings live
 
 Every string a view renders comes from the feature's `*.messages.ts`, shaped the
-way `@clerk/i18n` takes a base definition, so localizing is registering a
-namespace rather than hunting literals down first. A plural message is its forms;
-a parameterized one is its template. Import it as `m` and read through it:
+way `@clerk/i18n` takes a base definition. A plural message is its forms; a
+parameterized one is its template.
+
+Register the file as a namespace in `src/localization/registry.ts`, then read it
+with `useMessages` in the view or controller that renders it:
 
 ```tsx
-import { fill, plural, userButtonBase as m } from './user-button.messages';
+const m = useMessages('userButton');
 ```
 
+Never import a `*.messages.ts` directly. A direct import skips the customer's
+locale and overrides, so the copy can't be localized.
+
 ## Blocks
 
 A **block** is a view fragment that owns one piece of state nothing outside it can
diff --git a/packages/mosaic/src/__tests__/clerk-errors.ts b/packages/mosaic/src/__tests__/clerk-errors.ts
new file mode 100644
index 00000000000..f1b2082a704
--- /dev/null
+++ b/packages/mosaic/src/__tests__/clerk-errors.ts
@@ -0,0 +1,15 @@
+import { ClerkAPIResponseError } from '@clerk/shared/error';
+
+export function clerkApiError(code: string, longMessage: string, { paramName }: { paramName?: string } = {}) {
+  return new ClerkAPIResponseError(longMessage, {
+    data: [
+      {
+        code,
+        message: longMessage,
+        long_message: longMessage,
+        ...(paramName ? { meta: { param_name: paramName } } : {}),
+      },
+    ],
+    status: 422,
+  });
+}
diff --git a/packages/mosaic/src/blocks/confirmation/confirmation.controller.test.ts b/packages/mosaic/src/blocks/confirmation/confirmation.controller.test.ts
index 9480a74c191..849034f9a0d 100644
--- a/packages/mosaic/src/blocks/confirmation/confirmation.controller.test.ts
+++ b/packages/mosaic/src/blocks/confirmation/confirmation.controller.test.ts
@@ -1,9 +1,16 @@
 import { act, renderHook, waitFor } from '@testing-library/react';
-import { describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { createActor } from '../../machine/create-actor';
+import { SaveError } from '../../utils/errors';
 import { confirmationMachine, useConfirmationController } from './confirmation.controller';
 
+const blocked = new SaveError({ global: { code: 'action_blocked', message: 'Raw server sentence.' } });
+
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
 function start() {
   const actor = createActor(confirmationMachine).start();
   actor.send({ type: 'OPEN' });
@@ -43,24 +50,26 @@ describe('confirmationMachine', () => {
 
   it('lands back on confirming with the reason when the action fails', async () => {
     const actor = start();
-    actor.send({ type: 'CONFIRM', run: () => Promise.reject(new Error('Google is your only way to sign in.')) });
+    actor.send({ type: 'CONFIRM', run: () => Promise.reject(blocked) });
 
     await vi.waitFor(() => expect(actor.getSnapshot().value).toBe('confirming'));
-    expect(actor.getSnapshot().context.error).toBe('Google is your only way to sign in.');
+    expect(actor.getSnapshot().context.error).toEqual(blocked.formError.global);
   });
 
-  it('falls back to generic copy when the rejection is not an Error', async () => {
+  it('keeps the cause of an unexpected error, never its message', async () => {
+    vi.spyOn(console, 'error').mockImplementation(() => {});
+    const cause = new Error('Cannot read properties of undefined');
     const actor = start();
-    // eslint-disable-next-line @typescript-eslint/prefer-promise-reject-errors -- a non-Error rejection is the case under test
-    actor.send({ type: 'CONFIRM', run: () => Promise.reject('nope') });
+    actor.send({ type: 'CONFIRM', run: () => Promise.reject(cause) });
 
-    await vi.waitFor(() => expect(actor.getSnapshot().context.error).toBe('Something went wrong. Please try again.'));
+    await vi.waitFor(() => expect(actor.getSnapshot().value).toBe('confirming'));
+    expect(actor.getSnapshot().context.error).toEqual({ cause });
   });
 
   it('drops the error when cancelled, so the next open starts clean', async () => {
     const actor = start();
-    actor.send({ type: 'CONFIRM', run: () => Promise.reject(new Error('nope')) });
-    await vi.waitFor(() => expect(actor.getSnapshot().context.error).toBe('nope'));
+    actor.send({ type: 'CONFIRM', run: () => Promise.reject(blocked) });
+    await vi.waitFor(() => expect(actor.getSnapshot().context.error).toBeDefined());
 
     actor.send({ type: 'CANCEL' });
 
@@ -85,14 +94,24 @@ describe('useConfirmationController', () => {
     await waitFor(() => expect(result.current.isOpen).toBe(false));
   });
 
-  it('surfaces a failure as the error message and stays open', async () => {
+  it('surfaces a failure as the localized copy for its code and stays open', async () => {
     const { result } = renderHook(() => useConfirmationController());
     act(() => result.current.onOpenChange(true));
 
-    act(() => result.current.onConfirm(() => Promise.reject(new Error('nope'))));
+    act(() => result.current.onConfirm(() => Promise.reject(blocked)));
 
-    await waitFor(() => expect(result.current.errorMessage).toBe('nope'));
+    await waitFor(() => expect(result.current.errorMessage).toMatch(/contact support/));
     expect(result.current.isOpen).toBe(true);
     expect(result.current.isConfirming).toBe(false);
   });
+
+  it('surfaces the fallback it was given for an unexpected error', async () => {
+    vi.spyOn(console, 'error').mockImplementation(() => {});
+    const { result } = renderHook(() => useConfirmationController({ errorFallback: 'Unable to remove this member.' }));
+    act(() => result.current.onOpenChange(true));
+
+    act(() => result.current.onConfirm(() => Promise.reject(new Error('internal'))));
+
+    await waitFor(() => expect(result.current.errorMessage).toBe('Unable to remove this member.'));
+  });
 });
diff --git a/packages/mosaic/src/blocks/confirmation/confirmation.controller.ts b/packages/mosaic/src/blocks/confirmation/confirmation.controller.ts
index be5c6200f4c..053bb1a3f7d 100644
--- a/packages/mosaic/src/blocks/confirmation/confirmation.controller.ts
+++ b/packages/mosaic/src/blocks/confirmation/confirmation.controller.ts
@@ -1,9 +1,12 @@
+import type { ErrorDescription } from '../../localization';
+import { useErrorText } from '../../localization';
 import { setup } from '../../machine/setup';
 import { useMachine } from '../../machine/use-machine';
+import { toLocalizableError } from '../../utils/errors';
 
 export interface ConfirmationContext {
   run: () => Promise<void>;
-  error: string | undefined;
+  error: ErrorDescription | undefined;
 }
 
 export type ConfirmationEvent = { type: 'OPEN' } | { type: 'CONFIRM'; run: () => Promise<void> } | { type: 'CANCEL' };
@@ -14,10 +17,6 @@ function notSeated(): Promise<never> {
   return Promise.reject(new Error('confirmation run is not seated'));
 }
 
-function toMessage(cause: unknown): string {
-  return cause instanceof Error ? cause.message : 'Something went wrong. Please try again.';
-}
-
 export const confirmationMachine = createMachine({
   id: 'confirmation',
   initial: 'idle',
@@ -42,7 +41,7 @@ export const confirmationMachine = createMachine({
         onDone: { target: 'idle', actions: assign(() => ({ error: undefined })) },
         onError: {
           target: 'confirming',
-          actions: assign((_, event) => ({ error: toMessage(event.error) })),
+          actions: assign((_, event) => ({ error: toLocalizableError(event.error) })),
         },
       }),
     },
@@ -57,14 +56,23 @@ export interface ConfirmationController {
   errorMessage: string | undefined;
 }
 
-export function useConfirmationController(): ConfirmationController {
+export interface ConfirmationControllerOptions {
+  /** Copy shown when the action fails without an error Clerk can describe, such as a network or code fault (default: the generic error) */
+  errorFallback?: string;
+}
+
+export function useConfirmationController({
+  errorFallback,
+}: ConfirmationControllerOptions = {}): ConfirmationController {
   const [snapshot, send] = useMachine(confirmationMachine);
+  const errorText = useErrorText();
+  const { error } = snapshot.context;
 
   return {
     isOpen: snapshot.value === 'confirming' || snapshot.value === 'pending',
     onOpenChange: open => send({ type: open ? 'OPEN' : 'CANCEL' }),
     onConfirm: run => send({ type: 'CONFIRM', run }),
     isConfirming: snapshot.value === 'pending',
-    errorMessage: snapshot.context.error,
+    errorMessage: error ? errorText(error, errorFallback) : undefined,
   };
 }
diff --git a/packages/mosaic/src/blocks/confirmation/confirmation.test.tsx b/packages/mosaic/src/blocks/confirmation/confirmation.test.tsx
index e7f42bb6ce8..e75471cb252 100644
--- a/packages/mosaic/src/blocks/confirmation/confirmation.test.tsx
+++ b/packages/mosaic/src/blocks/confirmation/confirmation.test.tsx
@@ -1,8 +1,10 @@
 import { act, render, screen, waitFor } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
-import { describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 
+import { clerkApiError } from '../../__tests__/clerk-errors';
 import { Button } from '../../components/button';
+import type { MosaicLocalization } from '../../localization';
 import { MosaicProvider } from '../../mosaic-provider';
 import type { ConfirmationControlledProps, ConfirmationHandleProps } from './confirmation';
 import { Confirmation } from './confirmation';
@@ -101,11 +103,15 @@ interface Member {
 
 const preston: Member = { id: 'mem_1', name: 'Preston Booth' };
 
-function renderWithHandle(onConfirm: ConfirmationHandleProps<Member>['onConfirm'] = () => Promise.resolve()) {
+function renderWithHandle(
+  onConfirm: ConfirmationHandleProps<Member>['onConfirm'] = () => Promise.resolve(),
+  { errorFallback, localization }: { errorFallback?: string; localization?: MosaicLocalization } = {},
+) {
   const handle = Confirmation.createHandle<Member>();
   render(
-    <MosaicProvider>
+    <MosaicProvider localization={localization}>
       <Confirmation
+        errorFallback={errorFallback}
         handle={handle}
         title='Remove member'
         description={member => (
@@ -121,6 +127,10 @@ function renderWithHandle(onConfirm: ConfirmationHandleProps<Member>['onConfirm'
   return handle;
 }
 
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
 const removeButton = () => screen.getByRole('button', { name: 'Remove Preston Booth' });
 
 describe('Confirmation with a handle', () => {
@@ -175,7 +185,9 @@ describe('Confirmation with a handle', () => {
 
   it('keeps the dialog open and explains a failed attempt', async () => {
     const user = userEvent.setup();
-    const handle = renderWithHandle(() => Promise.reject(new Error('Preston Booth is the last admin.')));
+    const handle = renderWithHandle(() =>
+      Promise.reject(clerkApiError('organization_minimum_permissions_needed', 'Preston Booth is the last admin.')),
+    );
     act(() => {
       handle.open(preston);
     });
@@ -187,14 +199,56 @@ describe('Confirmation with a handle', () => {
     expect(removeButton()).not.toHaveAttribute('aria-busy', 'true');
   });
 
+  it('shows the localized copy for the code a refusal carries', async () => {
+    const user = userEvent.setup();
+    const handle = renderWithHandle(() => Promise.reject(clerkApiError('action_blocked', 'Raw server sentence.')), {
+      localization: { overrides: { 'errors.action_blocked': 'Acción bloqueada.' } },
+    });
+    act(() => {
+      handle.open(preston);
+    });
+
+    await user.click(removeButton());
+
+    await waitFor(() => expect(screen.getByRole('alert')).toHaveTextContent('Acción bloqueada.'));
+  });
+
+  it('shows the fallback rather than what an unexpected error says', async () => {
+    vi.spyOn(console, 'error').mockImplementation(() => {});
+    const user = userEvent.setup();
+    const handle = renderWithHandle(() => Promise.reject(new TypeError('Cannot read properties of undefined')), {
+      errorFallback: 'Unable to remove this member.',
+    });
+    act(() => {
+      handle.open(preston);
+    });
+
+    await user.click(removeButton());
+
+    await waitFor(() => expect(screen.getByRole('alert')).toHaveTextContent('Unable to remove this member.'));
+  });
+
+  it('shows the generic error when no fallback is given', async () => {
+    vi.spyOn(console, 'error').mockImplementation(() => {});
+    const user = userEvent.setup();
+    const handle = renderWithHandle(() => Promise.reject(new Error('internal')));
+    act(() => {
+      handle.open(preston);
+    });
+
+    await user.click(removeButton());
+
+    await waitFor(() => expect(screen.getByRole('alert')).toHaveTextContent('Something went wrong. Please try again.'));
+  });
+
   it('starts the next open clean after a failure', async () => {
     const user = userEvent.setup();
-    const handle = renderWithHandle(() => Promise.reject(new Error('nope')));
+    const handle = renderWithHandle(() => Promise.reject(clerkApiError('action_blocked', 'nope')));
     act(() => {
       handle.open(preston);
     });
     await user.click(removeButton());
-    await waitFor(() => expect(screen.getByRole('alert')).toBeInTheDocument());
+    await waitFor(() => expect(screen.getByRole('alert')).not.toBeEmptyDOMElement());
 
     await user.click(screen.getByRole('button', { name: 'Cancel' }));
     await waitFor(() => expect(screen.queryByRole('alertdialog')).not.toBeInTheDocument());
diff --git a/packages/mosaic/src/blocks/confirmation/confirmation.tsx b/packages/mosaic/src/blocks/confirmation/confirmation.tsx
index bc7fece37e6..586fb6f9a0a 100644
--- a/packages/mosaic/src/blocks/confirmation/confirmation.tsx
+++ b/packages/mosaic/src/blocks/confirmation/confirmation.tsx
@@ -174,8 +174,10 @@ export interface ConfirmationHandleProps<Payload> {
   actionLabel: FromPayload<Payload, string>;
   /** Text of the cancel button (default: "Cancel") */
   cancelLabel?: string;
-  /** Runs the action for the payload. Resolve to close the dialog; reject with an `Error` to keep it open showing why */
+  /** Runs the action for the payload. Resolve to close the dialog; reject to keep it open showing why */
   onConfirm: (payload: Payload) => Promise<void> | void;
+  /** Copy shown when the action fails without an error Clerk can describe, such as a network or code fault (default: the generic error) */
+  errorFallback?: string;
 }
 
 function HandleConfirmation<Payload>({
@@ -187,8 +189,9 @@ function HandleConfirmation<Payload>({
   actionLabel,
   cancelLabel = 'Cancel',
   onConfirm,
+  errorFallback,
 }: ConfirmationHandleProps<Payload>) {
-  const controller = useConfirmationController();
+  const controller = useConfirmationController({ errorFallback });
 
   return (
     <Dialog.Root
diff --git a/packages/mosaic/src/blocks/destructive/destructive.controller.test.ts b/packages/mosaic/src/blocks/destructive/destructive.controller.test.ts
index f0a40cfb4ba..2360e9383cd 100644
--- a/packages/mosaic/src/blocks/destructive/destructive.controller.test.ts
+++ b/packages/mosaic/src/blocks/destructive/destructive.controller.test.ts
@@ -1,13 +1,18 @@
 import { ClerkAPIResponseError, ClerkRuntimeError } from '@clerk/shared/error';
 import { act, renderHook, waitFor } from '@testing-library/react';
-import { describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { deferred } from '../../__tests__/async';
 import type { ReverificationController } from '../../features/reverification';
+import { SaveError } from '../../utils/errors';
 import { useDestructiveController } from './destructive.controller';
 
 const idleReverification = { status: 'idle', visible: false, reset: vi.fn() } as ReverificationController;
 
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
 describe('useDestructiveController', () => {
   it('starts closed and opens from the opener or from onOpenChange', () => {
     const { result } = renderHook(() => useDestructiveController({ onDelete: () => Promise.resolve() }));
@@ -37,6 +42,21 @@ describe('useDestructiveController', () => {
     expect(result.current.isDeleting).toBe(true);
   });
 
+  it('shows the fallback, never the message, of an unexpected error', async () => {
+    vi.spyOn(console, 'error').mockImplementation(() => {});
+    const onDelete = () => Promise.reject(new Error('Cannot read properties of undefined'));
+    const { result } = renderHook(() =>
+      useDestructiveController({ onDelete, errorFallback: 'Unable to delete this account.' }),
+    );
+    act(() => result.current.onOpenChange(true));
+
+    await act(async () => {
+      await result.current.onDelete();
+    });
+
+    expect(result.current.errorMessage).toBe('Unable to delete this account.');
+  });
+
   it('stays open and pending until the action resolves, then closes', async () => {
     const pending = deferred<void>();
     const onDelete = vi.fn(() => pending.promise);
@@ -61,7 +81,7 @@ describe('useDestructiveController', () => {
   it('stays open with a message when the action rejects, and a retry can succeed', async () => {
     const onDelete = vi
       .fn<() => Promise<unknown>>()
-      .mockRejectedValueOnce(new Error('Your subscription is still active.'))
+      .mockRejectedValueOnce(new SaveError({ global: { code: 'action_blocked', message: 'Raw server sentence.' } }))
       .mockResolvedValueOnce(undefined);
     const { result } = renderHook(() => useDestructiveController({ onDelete }));
     act(() => result.current.onOpenChange(true));
@@ -71,7 +91,7 @@ describe('useDestructiveController', () => {
     });
     expect(result.current.open).toBe(true);
     expect(result.current.isDeleting).toBe(false);
-    expect(result.current.errorMessage).toBe('Something went wrong. Please try again.');
+    expect(result.current.errorMessage).toMatch(/contact support/);
 
     await act(async () => {
       await result.current.onDelete();
diff --git a/packages/mosaic/src/blocks/destructive/destructive.controller.ts b/packages/mosaic/src/blocks/destructive/destructive.controller.ts
index 7673772bd04..526639325fe 100644
--- a/packages/mosaic/src/blocks/destructive/destructive.controller.ts
+++ b/packages/mosaic/src/blocks/destructive/destructive.controller.ts
@@ -1,9 +1,10 @@
-import { isClerkAPIResponseError, isReverificationCancelledError } from '@clerk/shared/error';
+import { isReverificationCancelledError } from '@clerk/shared/error';
 import { useState } from 'react';
 
 import type { ReverificationController } from '../../features/reverification';
-import type { LocalizableError } from '../../localization';
-import { toLocalizableApiError, useErrorText } from '../../localization';
+import type { ErrorDescription } from '../../localization';
+import { useErrorText } from '../../localization';
+import { toLocalizableError } from '../../utils/errors';
 import type { DestructiveControlledProps } from './destructive';
 
 export type DestructiveController = Pick<
@@ -18,15 +19,18 @@ type DestructiveState =
   | { status: 'closed' }
   | { status: 'open-needs-confirmation' }
   | { status: 'open-pending' }
-  | { status: 'open-error'; errorMessage: string };
+  | { status: 'open-error'; error: ErrorDescription };
 
 /** Optional controller for use with Destructive block */
 export function useDestructiveController({
   onDelete,
   reverification,
+  errorFallback,
 }: {
   onDelete: () => Promise<unknown>;
   reverification?: ReverificationController;
+  /** Copy shown when the action fails without an error Clerk can describe, such as a network or code fault (default: the generic error) */
+  errorFallback?: string;
 }): DestructiveController {
   const [destructiveState, setDestructiveState] = useState<DestructiveState>({ status: 'closed' });
   const errorText = useErrorText();
@@ -44,7 +48,8 @@ export function useDestructiveController({
   return {
     open: status !== 'closed',
     isDeleting,
-    errorMessage: status === 'open-error' ? destructiveState.errorMessage : undefined,
+    errorMessage:
+      destructiveState.status === 'open-error' ? errorText(destructiveState.error, errorFallback) : undefined,
     reverification,
     step,
     openDestructiveDialog,
@@ -60,7 +65,7 @@ export function useDestructiveController({
             setDestructiveState({ status: 'closed' });
             return;
           }
-          setDestructiveState({ status: 'open-error', errorMessage: errorText(toLocalizableError(error)) });
+          setDestructiveState({ status: 'open-error', error: toLocalizableError(error) });
         }
       }
     },
@@ -79,8 +84,3 @@ export function useDestructiveController({
     },
   };
 }
-
-function toLocalizableError(error: unknown): LocalizableError {
-  const apiError = isClerkAPIResponseError(error) ? error.errors[0] : undefined;
-  return apiError ? toLocalizableApiError(apiError) : {};
-}
diff --git a/packages/mosaic/src/blocks/destructive/destructive.test.tsx b/packages/mosaic/src/blocks/destructive/destructive.test.tsx
index e8725625f74..d7f4b544d94 100644
--- a/packages/mosaic/src/blocks/destructive/destructive.test.tsx
+++ b/packages/mosaic/src/blocks/destructive/destructive.test.tsx
@@ -7,6 +7,7 @@ import { Button } from '../../components/button';
 import { Menu } from '../../components/menu';
 import type { ReverificationController } from '../../features/reverification';
 import { MosaicProvider } from '../../mosaic-provider';
+import { SaveError } from '../../utils/errors';
 import type { DestructiveControlledProps, DestructiveHandleProps } from './destructive';
 import { Destructive } from './destructive';
 
@@ -345,7 +346,9 @@ describe('Destructive with a handle', () => {
   it('shows a deletion failure, clears it on reopening, and allows retrying', async () => {
     const onDelete = vi
       .fn<DestructiveHandleProps<string>['onDelete']>()
-      .mockRejectedValueOnce(new Error('The account still has active projects.'))
+      .mockRejectedValueOnce(
+        new SaveError({ global: { code: 'account_has_projects', message: 'The account still has active projects.' } }),
+      )
       .mockResolvedValueOnce(undefined);
     const user = userEvent.setup();
     const handle = renderWithHandle(onDelete);
diff --git a/packages/mosaic/src/blocks/destructive/destructive.tsx b/packages/mosaic/src/blocks/destructive/destructive.tsx
index 4fd87db9da4..5e5dd15e8ae 100644
--- a/packages/mosaic/src/blocks/destructive/destructive.tsx
+++ b/packages/mosaic/src/blocks/destructive/destructive.tsx
@@ -214,6 +214,8 @@ export interface DestructiveHandleProps<Payload> {
   actionLabel: FromPayload<Payload, string>;
   cancelLabel?: string;
   onDelete: (payload: Payload) => Promise<void> | void;
+  /** Copy shown when the action fails without an error Clerk can describe, such as a network or code fault (default: the generic error) */
+  errorFallback?: string;
 }
 
 function HandleDestructive<Payload>({
@@ -226,8 +228,9 @@ function HandleDestructive<Payload>({
   actionLabel,
   cancelLabel,
   onDelete,
+  errorFallback,
 }: DestructiveHandleProps<Payload>) {
-  const controller = useConfirmationController();
+  const controller = useConfirmationController({ errorFallback });
 
   return (
     <Dialog.Root
diff --git a/packages/mosaic/src/components/dialog/dialog.tsx b/packages/mosaic/src/components/dialog/dialog.tsx
index 75d6f808d88..fd5353ff9a1 100644
--- a/packages/mosaic/src/components/dialog/dialog.tsx
+++ b/packages/mosaic/src/components/dialog/dialog.tsx
@@ -195,7 +195,7 @@ function useCloseButtonWarning(isAlert: boolean) {
       return;
     }
     console.warn(
-      '[clerk] <Dialog.CloseButton> is rendered inside an alert dialog. A corner X is a way out without answering; the cancel action in the surface is the way out.',
+      '[Clerk] <Dialog.CloseButton> is rendered inside an alert dialog. A corner X is a way out without answering; the cancel action in the surface is the way out.',
     );
   }, [isAlert]);
 }
@@ -309,7 +309,7 @@ function useNestedVariantWarning(isNestedInDialog: boolean, variant: DialogVaria
       return;
     }
     console.warn(
-      '[clerk] a variant="profile" Dialog opened inside another Dialog. A profile is a root-level surface that hosts what opens over it; open a card instead.',
+      '[Clerk] a variant="profile" Dialog opened inside another Dialog. A profile is a root-level surface that hosts what opens over it; open a card instead.',
     );
   }, [isNestedInDialog, variant]);
 }
@@ -326,7 +326,7 @@ function useCompactPlacementWarning(variant: DialogVariant, placement: DialogCom
       return;
     }
     console.warn(
-      `[clerk] <Dialog.Popup variant="profile" compactPlacement="${placement}"> — a profile fills the compact band and takes no placement. It was ignored.`,
+      `[Clerk] <Dialog.Popup variant="profile" compactPlacement="${placement}"> — a profile fills the compact band and takes no placement. It was ignored.`,
     );
   }, [variant, placement]);
 }
diff --git a/packages/mosaic/src/components/field/field.context.tsx b/packages/mosaic/src/components/field/field.context.tsx
index d1895463cea..7c64c431e1b 100644
--- a/packages/mosaic/src/components/field/field.context.tsx
+++ b/packages/mosaic/src/components/field/field.context.tsx
@@ -63,7 +63,7 @@ export function FieldProvider({ children, orientation, disabled, required, inval
       ) {
         warnedAboutMultipleControls.current = true;
         console.warn(
-          '[clerk] <Field.Root> supports a single form control. Use a separate <Field.Root> for each control or native <fieldset> semantics for grouped controls.',
+          '[Clerk] <Field.Root> supports a single form control. Use a separate <Field.Root> for each control or native <fieldset> semantics for grouped controls.',
         );
       }
 
diff --git a/packages/mosaic/src/components/field/field.test.tsx b/packages/mosaic/src/components/field/field.test.tsx
index d686061414d..07724fd91f5 100644
--- a/packages/mosaic/src/components/field/field.test.tsx
+++ b/packages/mosaic/src/components/field/field.test.tsx
@@ -347,7 +347,7 @@ describe('Mosaic Field', () => {
 
     expect(consoleWarn).toHaveBeenCalledTimes(1);
     expect(consoleWarn).toHaveBeenCalledWith(
-      '[clerk] <Field.Root> supports a single form control. Use a separate <Field.Root> for each control or native <fieldset> semantics for grouped controls.',
+      '[Clerk] <Field.Root> supports a single form control. Use a separate <Field.Root> for each control or native <fieldset> semantics for grouped controls.',
     );
     consoleWarn.mockRestore();
   });
@@ -747,7 +747,7 @@ describe('Mosaic Field', () => {
 
     render(<Field.Label render={<div />}>Email</Field.Label>);
 
-    expect(consoleWarn).toHaveBeenCalledWith('[clerk] <Field.Label> must render a native `<label>` element.');
+    expect(consoleWarn).toHaveBeenCalledWith('[Clerk] <Field.Label> must render a native `<label>` element.');
     consoleWarn.mockRestore();
   });
 });
diff --git a/packages/mosaic/src/components/field/field.tsx b/packages/mosaic/src/components/field/field.tsx
index c3dfac068e4..4a2f19ab232 100644
--- a/packages/mosaic/src/components/field/field.tsx
+++ b/packages/mosaic/src/components/field/field.tsx
@@ -25,7 +25,7 @@ import { styles } from './field.styles';
 function useNativeLabelWarning(label: HTMLElement | null) {
   React.useEffect(() => {
     if (process.env.NODE_ENV !== 'production' && label && label.tagName !== 'LABEL') {
-      console.warn('[clerk] <Field.Label> must render a native `<label>` element.');
+      console.warn('[Clerk] <Field.Label> must render a native `<label>` element.');
     }
   }, [label]);
 }
diff --git a/packages/mosaic/src/components/form/form.machine.ts b/packages/mosaic/src/components/form/form.machine.ts
index c90577f3d88..92ce1d89b9f 100644
--- a/packages/mosaic/src/components/form/form.machine.ts
+++ b/packages/mosaic/src/components/form/form.machine.ts
@@ -1,7 +1,7 @@
 import type { LocalizableError } from '../../localization';
 import { setup } from '../../machine/setup';
 import type { TransitionResult } from '../../machine/types';
-import { SaveError } from '../../utils/form-error';
+import { SaveError } from '../../utils/errors';
 import { keysOf, mapKeys } from '../../utils/object';
 import type { FieldFeedback, FormError, FormFieldErrors } from './form-submit-error';
 import { FormSubmitError } from './form-submit-error';
@@ -149,7 +149,7 @@ function savedFieldErrors<TValues extends object>(
 
 function toFormError<TValues extends object>(cause: unknown, context: FormContext<TValues>): FormError<TValues> {
   if (!(cause instanceof FormSubmitError) && !(cause instanceof SaveError)) {
-    console.error(cause);
+    console.error('[Clerk] Could not localize error', cause);
     return { message: context.fallbackMessage };
   }
   const error: FormError<TValues> =
diff --git a/packages/mosaic/src/components/form/use-form.test.ts b/packages/mosaic/src/components/form/use-form.test.ts
index f7b9ce8be8c..e96afb45a1d 100644
--- a/packages/mosaic/src/components/form/use-form.test.ts
+++ b/packages/mosaic/src/components/form/use-form.test.ts
@@ -2,7 +2,7 @@ import { act, renderHook } from '@testing-library/react';
 import { describe, expect, expectTypeOf, it, vi } from 'vitest';
 
 import { deferred, tick } from '../../__tests__/async';
-import { SaveError } from '../../utils/form-error';
+import { SaveError } from '../../utils/errors';
 import type { FieldFeedback } from './form-submit-error';
 import { FormSubmitError } from './form-submit-error';
 import { useForm } from './use-form';
@@ -146,7 +146,7 @@ describe('useForm', () => {
         await tick();
       });
       expect(result.current.error).toBe('Something went wrong. Please try again.');
-      expect(log).toHaveBeenCalledWith(cause);
+      expect(log).toHaveBeenCalledWith('[Clerk] Could not localize error', cause);
     }
     log.mockRestore();
   });
diff --git a/packages/mosaic/src/features/api-keys/api-keys-table.tsx b/packages/mosaic/src/features/api-keys/api-keys-table.tsx
index 8afc65bad00..158bf3da44a 100644
--- a/packages/mosaic/src/features/api-keys/api-keys-table.tsx
+++ b/packages/mosaic/src/features/api-keys/api-keys-table.tsx
@@ -95,6 +95,7 @@ function createErrorMessage(
       return m.nameTakenError;
     }
   }
+  // TODO: Move the token_quota_exceeded and token_creation_conflict copy into the errors catalog, let the model propagate Clerk errors, and give useForm an errorFallback so m.createError replaces the raw message.
   return error instanceof Error ? error.message : m.createError;
 }
 
diff --git a/packages/mosaic/src/features/api-keys/api-keys-table.view.tsx b/packages/mosaic/src/features/api-keys/api-keys-table.view.tsx
index ba16708c493..21aaed7861b 100644
--- a/packages/mosaic/src/features/api-keys/api-keys-table.view.tsx
+++ b/packages/mosaic/src/features/api-keys/api-keys-table.view.tsx
@@ -267,13 +267,8 @@ export function APIKeysTableView({
           confirmationValue={apiKey => apiKey.name}
           actionLabel={m.revoke}
           cancelLabel={m.cancel}
-          onDelete={async apiKey => {
-            try {
-              await removalFocus.remove(apiKey.id);
-            } catch (error) {
-              throw error instanceof Error ? error : new Error(m.revokeError);
-            }
-          }}
+          onDelete={apiKey => removalFocus.remove(apiKey.id)}
+          errorFallback={m.revokeError}
           finalFocus={removalFocus.finalFocus}
         />
       ) : null}
diff --git a/packages/mosaic/src/features/organization-profile/__tests__/invitations-table-tab.view.test.tsx b/packages/mosaic/src/features/organization-profile/__tests__/invitations-table-tab.view.test.tsx
index 380a03c75a6..75dca2a52fc 100644
--- a/packages/mosaic/src/features/organization-profile/__tests__/invitations-table-tab.view.test.tsx
+++ b/packages/mosaic/src/features/organization-profile/__tests__/invitations-table-tab.view.test.tsx
@@ -1,7 +1,7 @@
 import { act, render, screen, waitFor, within } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 import { useState } from 'react';
-import { describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { deferred } from '../../../__tests__/async';
 import { MosaicProvider } from '../../../mosaic-provider';
@@ -33,22 +33,30 @@ function renderView(overrides: Partial<InvitationsTableTabViewProps> = {}) {
 }
 
 describe('InvitationsTableTabView', () => {
-  it.each(['', '   '])('uses the localized revoke error when the rejection message is "%s"', async message => {
-    const user = userEvent.setup();
-    render(
-      <MosaicProvider
-        localization={{ overrides: { 'invitationsTableTab.revokeError': 'Could not revoke invitation.' } }}
-      >
-        <InvitationsTableTabView {...propsFor({ onRevoke: vi.fn().mockRejectedValue(new Error(message)) })} />
-      </MosaicProvider>,
-    );
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
 
-    await user.click(screen.getByRole('button', { name: 'Manage ada@example.com' }));
-    await user.click(screen.getByRole('menuitem', { name: 'Revoke invitation' }));
-    await user.click(within(screen.getByRole('alertdialog')).getByRole('button', { name: 'Revoke invitation' }));
+  it.each(['', 'Cannot read properties of undefined'])(
+    'shows the localized revoke error, never the message "%s" of an unexpected error',
+    async message => {
+      vi.spyOn(console, 'error').mockImplementation(() => {});
+      const user = userEvent.setup();
+      render(
+        <MosaicProvider
+          localization={{ overrides: { 'invitationsTableTab.revokeError': 'Could not revoke invitation.' } }}
+        >
+          <InvitationsTableTabView {...propsFor({ onRevoke: vi.fn().mockRejectedValue(new Error(message)) })} />
+        </MosaicProvider>,
+      );
 
-    await waitFor(() => expect(screen.getByRole('alert')).toHaveTextContent('Could not revoke invitation.'));
-  });
+      await user.click(screen.getByRole('button', { name: 'Manage ada@example.com' }));
+      await user.click(screen.getByRole('menuitem', { name: 'Revoke invitation' }));
+      await user.click(within(screen.getByRole('alertdialog')).getByRole('button', { name: 'Revoke invitation' }));
+
+      await waitFor(() => expect(screen.getByRole('alert')).toHaveTextContent('Could not revoke invitation.'));
+    },
+  );
 
   it('distinguishes loading, an empty invitation list, and an empty search', () => {
     const { props, rerender } = renderView({ invitations: [], totalCount: 0, isLoading: true });
diff --git a/packages/mosaic/src/features/organization-profile/__tests__/members-table-tab.view.test.tsx b/packages/mosaic/src/features/organization-profile/__tests__/members-table-tab.view.test.tsx
index c1e433bd036..1147e0566e5 100644
--- a/packages/mosaic/src/features/organization-profile/__tests__/members-table-tab.view.test.tsx
+++ b/packages/mosaic/src/features/organization-profile/__tests__/members-table-tab.view.test.tsx
@@ -1,7 +1,7 @@
 import { act, render, screen, waitFor, within } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 import { useState } from 'react';
-import { describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { deferred } from '../../../__tests__/async';
 import { MosaicProvider } from '../../../mosaic-provider';
@@ -56,6 +56,28 @@ function renderView(overrides: Partial<MembersTableTabViewProps> = {}) {
 }
 
 describe('MembersTableTabView', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('shows the localized remove error, never the message of an unexpected error', async () => {
+    vi.spyOn(console, 'error').mockImplementation(() => {});
+    const user = userEvent.setup();
+    render(
+      <MosaicProvider localization={{ overrides: { 'membersTableTab.removeError': 'Could not remove member.' } }}>
+        <MembersTableTabView
+          {...propsFor({ onRemove: vi.fn().mockRejectedValue(new Error('Cannot read properties of undefined')) })}
+        />
+      </MosaicProvider>,
+    );
+
+    await user.click(screen.getByRole('button', { name: 'Manage Grace Hopper' }));
+    await user.click(screen.getByRole('menuitem', { name: 'Remove from organization' }));
+    await user.click(within(screen.getByRole('alertdialog')).getByRole('button', { name: 'Remove from organization' }));
+
+    expect(await screen.findByRole('alert')).toHaveTextContent('Could not remove member.');
+  });
+
   it('chooses loading, retained rows, and filtered empty results from the supplied state', () => {
     const { props, rerender } = renderView({ members: [], totalCount: 0, isLoading: true });
     expect(screen.getByRole('status')).toHaveTextContent('Loading members');
diff --git a/packages/mosaic/src/features/organization-profile/__tests__/requests-table-tab.view.test.tsx b/packages/mosaic/src/features/organization-profile/__tests__/requests-table-tab.view.test.tsx
index 6cce3f8fa86..64bcc01c62f 100644
--- a/packages/mosaic/src/features/organization-profile/__tests__/requests-table-tab.view.test.tsx
+++ b/packages/mosaic/src/features/organization-profile/__tests__/requests-table-tab.view.test.tsx
@@ -1,7 +1,7 @@
 import { act, render, screen, waitFor } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 import { useState } from 'react';
-import { describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { deferred } from '../../../__tests__/async';
 import { MosaicProvider } from '../../../mosaic-provider';
@@ -33,9 +33,14 @@ function renderView(overrides: Partial<RequestsTableTabViewProps> = {}) {
 }
 
 describe('RequestsTableTabView', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
   it.each(['Accept', 'Decline'] as const)(
     'holds the row while %s is pending and allows retry after failure',
     async action => {
+      vi.spyOn(console, 'error').mockImplementation(() => {});
       const user = userEvent.setup();
       const attempt = deferred<void>();
       const onDecision = vi
@@ -54,7 +59,7 @@ describe('RequestsTableTabView', () => {
       expect(onDecision).toHaveBeenCalledExactlyOnceWith('request-1');
       expect(onOtherDecision).not.toHaveBeenCalled();
 
-      await act(() => attempt.reject(new Error()));
+      await act(() => attempt.reject(new Error('Cannot read properties of undefined')));
       await waitFor(() =>
         expect(screen.getByRole('alert')).toHaveTextContent(
           action === 'Accept'
diff --git a/packages/mosaic/src/features/organization-profile/invitations-table-tab.view.tsx b/packages/mosaic/src/features/organization-profile/invitations-table-tab.view.tsx
index d867ce31c27..5842ea82516 100644
--- a/packages/mosaic/src/features/organization-profile/invitations-table-tab.view.tsx
+++ b/packages/mosaic/src/features/organization-profile/invitations-table-tab.view.tsx
@@ -244,13 +244,8 @@ export function InvitationsTableTabView({
           description={m.revokeDescription}
           actionLabel={m.revoke}
           cancelLabel={m.cancel}
-          onConfirm={async invitation => {
-            try {
-              await removalFocus.remove(invitation.id);
-            } catch (error) {
-              throw error instanceof Error && error.message.trim() ? error : new Error(m.revokeError);
-            }
-          }}
+          onConfirm={invitation => removalFocus.remove(invitation.id)}
+          errorFallback={m.revokeError}
           finalFocus={removalFocus.finalFocus}
         />
       ) : null}
diff --git a/packages/mosaic/src/features/organization-profile/members-table-tab.view.tsx b/packages/mosaic/src/features/organization-profile/members-table-tab.view.tsx
index a918b2431a9..7b37737444d 100644
--- a/packages/mosaic/src/features/organization-profile/members-table-tab.view.tsx
+++ b/packages/mosaic/src/features/organization-profile/members-table-tab.view.tsx
@@ -292,13 +292,8 @@ export function MembersTableTabView({
           description={m.removeDescription}
           actionLabel={m.remove}
           cancelLabel={m.cancel}
-          onConfirm={async member => {
-            try {
-              await removalFocus.remove(member.id);
-            } catch (error) {
-              throw error instanceof Error ? error : new Error(m.removeError);
-            }
-          }}
+          onConfirm={member => removalFocus.remove(member.id)}
+          errorFallback={m.removeError}
           finalFocus={removalFocus.finalFocus}
         />
       ) : null}
diff --git a/packages/mosaic/src/features/organization-profile/organization-profile-profile-section/organization-profile-edit-field.controller.ts b/packages/mosaic/src/features/organization-profile/organization-profile-profile-section/organization-profile-edit-field.controller.ts
index dca1ceb55b2..2b46bd3b049 100644
--- a/packages/mosaic/src/features/organization-profile/organization-profile-profile-section/organization-profile-edit-field.controller.ts
+++ b/packages/mosaic/src/features/organization-profile/organization-profile-profile-section/organization-profile-edit-field.controller.ts
@@ -29,6 +29,7 @@ function isSaveable(context: OrganizationProfileEditFieldContext): boolean {
   return context.value !== context.savedValue && context.value !== '';
 }
 
+// TODO: Move this dialog onto useForm so Clerk errors are localized by code and an unknown error never shows its message.
 function toFormError(cause: unknown): OrganizationProfileFormError {
   if (cause instanceof OrganizationProfileSaveError) {
     return { message: cause.message, field: cause.field };
diff --git a/packages/mosaic/src/features/organization-profile/requests-table-tab.view.tsx b/packages/mosaic/src/features/organization-profile/requests-table-tab.view.tsx
index 7a885b8cb99..3e8fdd167a1 100644
--- a/packages/mosaic/src/features/organization-profile/requests-table-tab.view.tsx
+++ b/packages/mosaic/src/features/organization-profile/requests-table-tab.view.tsx
@@ -12,6 +12,7 @@ import { Spinner } from '../../components/spinner';
 import { Table, type TableHeaderCellProps } from '../../components/table';
 import { VisuallyHidden } from '../../components/visually-hidden';
 import { useListRemovalFocus } from '../../hooks/use-list-removal-focus';
+import { type PendingAction, usePendingAction } from '../../hooks/use-pending-action';
 import { fill, useMessages } from '../../localization';
 import { useDataTable } from '../../primitives/hooks';
 import { mergeStyleProps, themeProps } from '../../props';
@@ -273,28 +274,17 @@ function RequestActions({
   const m = useMessages('requestsTableTab');
   const [acceptRef] = useState(() => registerAcceptTrigger(request.id));
   const [declineRef] = useState(() => registerDeclineTrigger(request.id));
-  const [runningAction, setRunningAction] = useState<OrganizationProfileRequest['pendingAction']>();
-  const [error, setError] = useState<string>();
-  const pendingAction = request.pendingAction ?? runningAction;
-  const runAction = async (action: 'accept' | 'decline', run: () => void | Promise<void>) => {
+  const accept = usePendingAction(() => onAccept?.(), { errorFallback: m.acceptError });
+  const decline = usePendingAction(() => onDecline?.(), { errorFallback: m.declineError });
+  const pendingAction =
+    request.pendingAction ?? (accept.isPending ? 'accept' : decline.isPending ? 'decline' : undefined);
+  const error = accept.errorMessage ?? decline.errorMessage;
+  const decide = (action: PendingAction<[]>, other: PendingAction<[]>) => {
     if (pendingAction) {
       return;
     }
-    setRunningAction(action);
-    setError(undefined);
-    try {
-      await run();
-    } catch (cause) {
-      setError(
-        cause instanceof Error && cause.message.trim()
-          ? cause.message
-          : action === 'accept'
-            ? m.acceptError
-            : m.declineError,
-      );
-    } finally {
-      setRunningAction(undefined);
-    }
+    other.reset();
+    void action.run();
   };
   return (
     <>
@@ -310,7 +300,7 @@ function RequestActions({
             variant='outline'
             color='neutral'
             aria-label={fill(m.declineRequest, { name: request.name ?? request.email })}
-            onClick={() => void runAction('decline', onDecline)}
+            onClick={() => decide(decline, accept)}
           >
             {m.decline}
           </SubmitButton>
@@ -324,7 +314,7 @@ function RequestActions({
             isPending={pendingAction === 'accept'}
             pendingLabel={m.accepting}
             aria-label={fill(m.acceptRequest, { name: request.name ?? request.email })}
-            onClick={() => void runAction('accept', onAccept)}
+            onClick={() => decide(accept, decline)}
           >
             {m.accept}
           </SubmitButton>
diff --git a/packages/mosaic/src/features/reverification/reverification.utils.ts b/packages/mosaic/src/features/reverification/reverification.utils.ts
index ac089479bec..3aca0d4b86a 100644
--- a/packages/mosaic/src/features/reverification/reverification.utils.ts
+++ b/packages/mosaic/src/features/reverification/reverification.utils.ts
@@ -8,6 +8,7 @@ import type {
   ReverificationStrategy,
 } from './reverification.types';
 
+// TODO: Return toLocalizableError(error) and render with errorText so Clerk errors are localized by code instead of shown raw.
 export function errorDetail(error: unknown): string | undefined {
   if (isClerkAPIResponseError(error)) {
     const first = error.errors[0];
diff --git a/packages/mosaic/src/features/user-button/__tests__/user-button.feature.test.tsx b/packages/mosaic/src/features/user-button/__tests__/user-button.feature.test.tsx
index 70c4d37400b..8d8909398a0 100644
--- a/packages/mosaic/src/features/user-button/__tests__/user-button.feature.test.tsx
+++ b/packages/mosaic/src/features/user-button/__tests__/user-button.feature.test.tsx
@@ -2,7 +2,7 @@ import { UNSAFE_PortalProvider as PortalProvider } from '@clerk/shared/react';
 import type { CustomPage, PhoneNumberJSON, UserJSON, Web3WalletJSON } from '@clerk/shared/types';
 import { act, screen, waitFor, within } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
-import { describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { type FakeFapiSeed, holdRequests, serveFapi } from '../../../__tests__/feature/fake-fapi';
 import {
@@ -20,6 +20,10 @@ import { renderWithClerk } from '../../../__tests__/feature/render';
 import type { UserButtonProps } from '../user-button';
 import { UserButton } from '../user-button';
 
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
 const acme = fapiOrganization({ id: 'org_1', name: 'Acme', members_count: 3 });
 const other = fapiOrganization({ id: 'org_9', name: 'Other' });
 const beta = fapiOrganization({ id: 'org_2', name: 'Beta' });
@@ -588,7 +592,8 @@ describe('UserButton', () => {
       await waitFor(() => expect(popup()).toBeNull());
     });
 
-    it('stays open and clears busy state when the switch fails', async () => {
+    it('stays open, clears busy state and logs the failure when the switch fails', async () => {
+      const log = vi.spyOn(console, 'error').mockImplementation(() => {});
       await renderUserButton();
       const user = await open();
       await screen.findByRole('button', { name: 'Other' });
@@ -597,11 +602,15 @@ describe('UserButton', () => {
       await user.click(screen.getByRole('button', { name: 'Other' }));
       expect(waiting()).toBe(true);
 
-      touch.fail();
+      touch.fail('session_touch_failed');
 
       await waitFor(() => expect(waiting()).toBe(false), { timeout: 2000 });
       expect(popup()).toBeInTheDocument();
       expect(signOut()).toBeEnabled();
+      expect(log).toHaveBeenCalledWith(
+        '[Clerk] User button action failed',
+        expect.objectContaining({ errors: [expect.objectContaining({ code: 'session_touch_failed' })] }),
+      );
     });
 
     it('still shows the action when reopened before it settles, and starts no second one', async () => {
diff --git a/packages/mosaic/src/features/user-button/user-button.controller.tsx b/packages/mosaic/src/features/user-button/user-button.controller.tsx
index 8a8a31e535a..1ed13abd0c7 100644
--- a/packages/mosaic/src/features/user-button/user-button.controller.tsx
+++ b/packages/mosaic/src/features/user-button/user-button.controller.tsx
@@ -84,7 +84,13 @@ const userButtonMachine = createMachine({
           { target: 'idle', actions: assign(() => settled) },
         ],
         // Leave `open` as the user left it. The error surface is a later change.
-        onError: { target: 'idle', actions: assign(() => settled) },
+        onError: {
+          target: 'idle',
+          actions: [
+            assign(() => settled),
+            (_, event) => console.error('[Clerk] User button action failed', event.error),
+          ],
+        },
       }),
     },
   },
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-account-section.model.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-account-section.model.test.tsx
index 5485c1364b7..9adba0054e8 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-account-section.model.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-account-section.model.test.tsx
@@ -3,8 +3,8 @@ import type * as SharedReact from '@clerk/shared/react';
 import { renderHook } from '@testing-library/react';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 
-import type { FormError } from '../../../utils/form-error';
-import { SaveError } from '../../../utils/form-error';
+import type { FormError } from '../../../utils/errors';
+import { SaveError } from '../../../utils/errors';
 import { useUserProfileAccountSectionModel } from '../user-profile-account-section/user-profile-account-section.model';
 
 interface FakeAttribute {
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-connected-accounts.feature.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-connected-accounts.feature.test.tsx
index 1da732402a0..424f6cf75b0 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-connected-accounts.feature.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-connected-accounts.feature.test.tsx
@@ -272,7 +272,7 @@ describe('connected accounts', () => {
     await renderWithClerk(<UserProfileConnectedAccountsSection />);
 
     await userEvent.setup().click(screen.getByRole('button', { name: 'Connect GitHub' }));
-    expect(await screen.findByText('OAuth flow did not receive a verification URL.')).toBeInTheDocument();
+    expect(await screen.findByText('The connection could not start. Please try again.')).toBeInTheDocument();
   });
 
   it('preserves modal state when connecting', async () => {
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-danger-section.integration.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-danger-section.integration.test.tsx
index f9ecc752971..fe64d963b70 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-danger-section.integration.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-danger-section.integration.test.tsx
@@ -4,6 +4,7 @@ import { render, screen, waitFor, within } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 
+import { clerkApiError } from '../../../__tests__/clerk-errors';
 import { MosaicProvider } from '../../../mosaic-provider';
 import { UserProfileDangerSection } from '../user-profile-danger-section/user-profile-danger-section';
 
@@ -119,7 +120,9 @@ describe('UserProfileDangerSection', () => {
   });
 
   it('keeps the dialog up with a message when the delete fails', async () => {
-    deleteUser = vi.fn(() => Promise.reject(new Error('Your subscription is still active.')));
+    deleteUser = vi.fn(() =>
+      Promise.reject(clerkApiError('subscription_active', 'Your subscription is still active.')),
+    );
     const user = userEvent.setup();
     renderSection();
     const dialog = await openDialog(user);
@@ -127,7 +130,7 @@ describe('UserProfileDangerSection', () => {
     await user.type(within(dialog).getByRole('textbox'), 'Delete account');
     await user.click(within(dialog).getByRole('button', { name: 'Delete account' }));
 
-    expect(await screen.findByText('Something went wrong. Please try again.')).toBeInTheDocument();
+    expect(await screen.findByText('Your subscription is still active.')).toBeInTheDocument();
     expect(screen.getByRole('dialog')).toBeInTheDocument();
     expect(setActive).not.toHaveBeenCalled();
   });
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-device-actions.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-device-actions.test.tsx
index 4b9fb1a540b..5f5ea410364 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-device-actions.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-device-actions.test.tsx
@@ -2,8 +2,9 @@ import { createDeferredPromise } from '@clerk/shared/utils';
 import { act, render, screen, waitFor, within } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 import { useState } from 'react';
-import { describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 
+import { clerkApiError } from '../../../__tests__/clerk-errors';
 import { MosaicProvider } from '../../../mosaic-provider';
 import type { UserProfileDevice } from '../user-profile-active-devices.types';
 import { UserProfileActiveDevicesSectionView } from '../user-profile-active-devices-section.view';
@@ -44,6 +45,10 @@ async function openMenu(user: ReturnType<typeof userEvent.setup>, device: UserPr
   await user.click(screen.getByRole('button', { name: `Manage ${device.name}` }));
 }
 
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
 describe('active device details', () => {
   it('opens the details of the device the menu belongs to', async () => {
     const user = userEvent.setup();
@@ -99,14 +104,22 @@ describe('active device sign out', () => {
   });
 
   it('shows a failure in the confirmation and allows retrying', async () => {
+    vi.spyOn(console, 'error').mockImplementation(() => {});
     const user = userEvent.setup();
-    const onSignOutDevice = vi.fn().mockRejectedValueOnce(new Error('Unable to sign out')).mockResolvedValue(undefined);
+    const onSignOutDevice = vi
+      .fn()
+      .mockRejectedValueOnce(new Error('Cannot read properties of undefined'))
+      .mockResolvedValue(undefined);
     renderDevices(onSignOutDevice);
     await openMenu(user, mobile);
     await user.click(screen.getByRole('menuitem', { name: 'Sign out' }));
     await user.click(within(screen.getByRole('alertdialog')).getByRole('button', { name: 'Sign out' }));
 
-    await waitFor(() => expect(screen.getByRole('alert')).toHaveTextContent('Unable to sign out'));
+    await waitFor(() =>
+      expect(screen.getByRole('alert')).toHaveTextContent(
+        'Something went wrong signing this device out. Please try again.',
+      ),
+    );
 
     await user.click(within(screen.getByRole('alertdialog')).getByRole('button', { name: 'Sign out' }));
     await waitFor(() => expect(screen.queryByRole('alertdialog')).not.toBeInTheDocument());
@@ -157,7 +170,10 @@ describe('active device sign out', () => {
 
   it('keeps the details dialog open and explains a failed sign out', async () => {
     const user = userEvent.setup();
-    const onSignOutDevice = vi.fn().mockRejectedValueOnce(new Error('Unable to sign out')).mockResolvedValue(undefined);
+    const onSignOutDevice = vi
+      .fn()
+      .mockRejectedValueOnce(clerkApiError('session_not_found', 'Unable to sign out'))
+      .mockResolvedValue(undefined);
     renderDevices(onSignOutDevice);
     await openMenu(user, mobile);
     await user.click(screen.getByRole('menuitem', { name: 'View details' }));
@@ -213,16 +229,21 @@ describe('signing out of all other devices', () => {
   });
 
   it('holds the confirmation open and explains a failure', async () => {
+    vi.spyOn(console, 'error').mockImplementation(() => {});
     const user = userEvent.setup();
     const onSignOutAllOtherDevices = vi
       .fn()
-      .mockRejectedValueOnce(new Error('Unable to sign out of all devices'))
+      .mockRejectedValueOnce(new Error('Cannot read properties of undefined'))
       .mockResolvedValue(undefined);
     renderAll(onSignOutAllOtherDevices);
     await user.click(screen.getByRole('button', { name: 'Sign out of all devices' }));
     await user.click(within(confirmation()).getByRole('button', { name: 'Sign out' }));
 
-    expect(await screen.findByText('Unable to sign out of all devices')).toBeInTheDocument();
+    await waitFor(() =>
+      expect(screen.getByRole('alert')).toHaveTextContent(
+        'Something went wrong signing these devices out. Please try again.',
+      ),
+    );
     expect(confirmation()).toBeInTheDocument();
 
     await user.click(within(confirmation()).getByRole('button', { name: 'Sign out' }));
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-name.controller.test.ts b/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-name.controller.test.ts
index d746f5d7530..704c644a52a 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-name.controller.test.ts
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-name.controller.test.ts
@@ -1,7 +1,7 @@
 import { act, renderHook, waitFor } from '@testing-library/react';
 import { describe, expect, it, vi } from 'vitest';
 
-import { SaveError } from '../../../utils/form-error';
+import { SaveError } from '../../../utils/errors';
 import { useUserProfileEditNameController } from '../user-profile-account-section/user-profile-edit-name.controller';
 import type { UserProfileEditNameValue } from '../user-profile-account-section/user-profile-edit-name.dialog';
 
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-name.dialog.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-name.dialog.test.tsx
index c65ac8c800a..90a4f0bb31c 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-name.dialog.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-name.dialog.test.tsx
@@ -4,7 +4,7 @@ import { describe, expect, it, vi } from 'vitest';
 
 import { Button } from '../../../components/button';
 import { MosaicProvider } from '../../../mosaic-provider';
-import { SaveError } from '../../../utils/form-error';
+import { SaveError } from '../../../utils/errors';
 import { useUserProfileEditNameController } from '../user-profile-account-section/user-profile-edit-name.controller';
 import type {
   UserProfileEditNameDialogProps,
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-username.controller.test.ts b/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-username.controller.test.ts
index 4f5b7f27fd0..2c87dcd84ce 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-username.controller.test.ts
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-username.controller.test.ts
@@ -1,7 +1,7 @@
 import { act, renderHook, waitFor } from '@testing-library/react';
 import { describe, expect, it, vi } from 'vitest';
 
-import { SaveError } from '../../../utils/form-error';
+import { SaveError } from '../../../utils/errors';
 import { useUserProfileEditUsernameController } from '../user-profile-account-section/user-profile-edit-username.controller';
 
 function deferred() {
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-username.dialog.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-username.dialog.test.tsx
index 8cee1bbda25..cd3c1c2ff10 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-username.dialog.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-edit-username.dialog.test.tsx
@@ -5,7 +5,7 @@ import { describe, expect, it, vi } from 'vitest';
 import { Button } from '../../../components/button';
 import type { MosaicLocalization } from '../../../localization';
 import { MosaicProvider } from '../../../mosaic-provider';
-import { SaveError } from '../../../utils/form-error';
+import { SaveError } from '../../../utils/errors';
 import { useUserProfileEditUsernameController } from '../user-profile-account-section/user-profile-edit-username.controller';
 import type { UserProfileEditUsernameDialogProps } from '../user-profile-account-section/user-profile-edit-username.dialog';
 import { UserProfileEditUsernameDialog } from '../user-profile-account-section/user-profile-edit-username.dialog';
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-email-actions.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-email-actions.test.tsx
index 72090f2a4db..26d58ac7e24 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-email-actions.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-email-actions.test.tsx
@@ -4,6 +4,7 @@ import userEvent from '@testing-library/user-event';
 import { useState } from 'react';
 import { describe, expect, it, vi } from 'vitest';
 
+import { clerkApiError } from '../../../__tests__/clerk-errors';
 import { MosaicProvider } from '../../../mosaic-provider';
 import type { UserProfileAccountSectionViewProps } from '../user-profile-account-section/user-profile-account-section.view';
 import { UserProfileAccountSectionView } from '../user-profile-account-section/user-profile-account-section.view';
@@ -96,7 +97,7 @@ describe('email actions', () => {
     expect(within(dialog).getByRole('button', { name: 'Remove' })).toHaveAttribute('aria-busy', 'true');
 
     await act(async () => {
-      removal.reject(new Error('Unable to remove email.'));
+      removal.reject(clerkApiError('email_address_in_use', 'Unable to remove email.'));
       await removal.promise.catch(() => undefined);
     });
     expect(within(dialog).getByRole('alert')).toHaveTextContent('Unable to remove email.');
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-enterprise-accounts.feature.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-enterprise-accounts.feature.test.tsx
index 5785dc4f4ee..4cb3e4da970 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-enterprise-accounts.feature.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-enterprise-accounts.feature.test.tsx
@@ -26,7 +26,7 @@ async function renderSection(seed: FakeFapiSeed = signedIn()) {
 }
 
 describe('enterprise accounts', () => {
-  it('preserves the original cause when localizing a linking failure', async () => {
+  it('propagates a linking failure untouched', async () => {
     const feedback = vi.fn<(error: Error) => void>();
     function Connect() {
       const model = useUserProfileEnterpriseAccountsModel();
@@ -49,7 +49,7 @@ describe('enterprise accounts', () => {
     vi.spyOn(user, 'createExternalAccount').mockRejectedValue(cause);
     await userEvent.setup().click(await screen.findByRole('button', { name: 'Connect' }));
     await waitFor(() => expect(feedback).toHaveBeenCalledOnce());
-    expect(feedback.mock.calls[0]?.[0].cause).toBe(cause);
+    expect(feedback).toHaveBeenCalledWith(cause);
   });
 
   it('shows the fallback while Clerk loads', async () => {
@@ -338,7 +338,7 @@ describe('enterprise accounts', () => {
         localization={{
           locale: 'fr-FR',
           overrides: {
-            'userProfileEnterpriseAccountsSection.errors.missingVerificationUrl': 'La connexion ne peut pas démarrer.',
+            'errors.oauth_missing_verification_url': 'La connexion ne peut pas démarrer.',
           },
         }}
       >
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-mfa-section.view.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-mfa-section.view.test.tsx
index f6f04e0f0c9..2036628b25b 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-mfa-section.view.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-mfa-section.view.test.tsx
@@ -1,9 +1,10 @@
 import { act, render, screen, waitFor, within } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 import { useState } from 'react';
-import { describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { deferred } from '../../../__tests__/async';
+import { clerkApiError } from '../../../__tests__/clerk-errors';
 import { MosaicProvider } from '../../../mosaic-provider';
 import type { UserProfileMfaMethod, UserProfileMfaSectionViewProps } from '../user-profile-mfa-section.view';
 import { UserProfileMfaSectionView } from '../user-profile-mfa-section.view';
@@ -28,6 +29,10 @@ function renderView(overrides: Partial<UserProfileMfaSectionViewProps> = {}) {
   };
 }
 
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
 describe('MFA section', () => {
   it.each(['picker', 'custom', 'none'] as const)(
     'restores focus after removing methods with %s add control',
@@ -170,9 +175,17 @@ describe('MFA section', () => {
   });
 
   it.each([
-    { cause: new Error('Unable to update the default method.'), message: 'Unable to update the default method.' },
+    {
+      cause: clerkApiError('phone_number_not_verified', 'Unable to update the default method.'),
+      message: 'Unable to update the default method.',
+    },
+    {
+      cause: new Error('Cannot read properties of undefined'),
+      message: 'Unable to set this method as default. Please try again.',
+    },
     { cause: 'network failure', message: 'Unable to set this method as default. Please try again.' },
   ])('shows a default-change error and clears it on retry: $message', async ({ cause, message }) => {
+    vi.spyOn(console, 'error').mockImplementation(() => {});
     const user = userEvent.setup();
     const retry = deferred<void>();
     const onSetDefault = vi.fn().mockRejectedValueOnce(cause).mockReturnValueOnce(retry.promise);
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-passkeys-section.view.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-passkeys-section.view.test.tsx
index 560932c7fcd..00aeffb265c 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-passkeys-section.view.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-passkeys-section.view.test.tsx
@@ -1,18 +1,24 @@
 import { act, render, screen, waitFor, within } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 import { useState } from 'react';
-import { describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 
+import { clerkApiError } from '../../../__tests__/clerk-errors';
+import type { MosaicLocalization } from '../../../localization';
 import { MosaicProvider } from '../../../mosaic-provider';
 import type { UserProfilePasskey, UserProfilePasskeysSectionViewProps } from '../user-profile-passkeys-section.view';
 import { UserProfilePasskeysSectionView } from '../user-profile-passkeys-section.view';
 
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
 const passkeys: UserProfilePasskey[] = [
   { id: 'laptop', name: 'MacBook' },
   { id: 'phone', name: 'iPhone' },
 ];
 
-function renderView(overrides: Partial<UserProfilePasskeysSectionViewProps> = {}) {
+function renderView(overrides: Partial<UserProfilePasskeysSectionViewProps> = {}, localization?: MosaicLocalization) {
   const props: UserProfilePasskeysSectionViewProps = {
     passkeys,
     onAdd: vi.fn(),
@@ -21,7 +27,7 @@ function renderView(overrides: Partial<UserProfilePasskeysSectionViewProps> = {}
     ...overrides,
   };
   return render(
-    <MosaicProvider>
+    <MosaicProvider localization={localization}>
       <UserProfilePasskeysSectionView {...props} />
     </MosaicProvider>,
   );
@@ -91,7 +97,10 @@ describe('passkeys section', () => {
 
   it('renames through a prefilled form, preserves the draft after failure, and retries', async () => {
     const user = userEvent.setup();
-    const onRename = vi.fn().mockRejectedValueOnce(new Error('Try again')).mockResolvedValueOnce(undefined);
+    const onRename = vi
+      .fn()
+      .mockRejectedValueOnce(clerkApiError('passkey_rename_failed', 'Try again'))
+      .mockResolvedValueOnce(undefined);
     render(
       <MosaicProvider>
         <UserProfilePasskeysSectionView
@@ -119,6 +128,20 @@ describe('passkeys section', () => {
     await waitFor(() => expect(screen.queryByRole('dialog')).not.toBeInTheDocument());
   });
 
+  it('shows the rename fallback, never the message, when renaming fails unexpectedly', async () => {
+    vi.spyOn(console, 'error').mockImplementation(() => {});
+    const user = userEvent.setup();
+    renderView(
+      { onRename: vi.fn().mockRejectedValue(new Error('Cannot read properties of undefined')) },
+      { overrides: { 'userProfilePasskeys.saveError': 'Could not rename this passkey.' } },
+    );
+    await user.click(screen.getByRole('button', { name: 'Manage MacBook' }));
+    await user.click(screen.getByRole('menuitem', { name: 'Rename' }));
+    await user.type(screen.getByRole('textbox', { name: 'Passkey name' }), ' Pro');
+    await user.click(screen.getByRole('button', { name: 'Save' }));
+    expect(await screen.findByRole('alert')).toHaveTextContent('Could not rename this passkey.');
+  });
+
   it('keeps an empty section visible when Add is unavailable', () => {
     renderView({ passkeys: [], onAdd: undefined });
 
@@ -185,7 +208,10 @@ describe('passkeys section', () => {
 
   it('retries removal for the same passkey after a failure', async () => {
     const user = userEvent.setup();
-    const onRemove = vi.fn().mockRejectedValueOnce(new Error('Removal failed')).mockResolvedValueOnce(undefined);
+    const onRemove = vi
+      .fn()
+      .mockRejectedValueOnce(clerkApiError('passkey_not_found', 'Removal failed'))
+      .mockResolvedValueOnce(undefined);
     render(
       <MosaicProvider>
         <UserProfilePasskeysSectionView
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-phone-actions.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-phone-actions.test.tsx
index 3a8ab0b0e59..c0db771d9f3 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-phone-actions.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-phone-actions.test.tsx
@@ -3,6 +3,7 @@ import userEvent from '@testing-library/user-event';
 import { useState } from 'react';
 import { describe, expect, it, vi } from 'vitest';
 
+import { clerkApiError } from '../../../__tests__/clerk-errors';
 import { MosaicProvider } from '../../../mosaic-provider';
 import type { UserProfileAccountSectionViewProps } from '../user-profile-account-section/user-profile-account-section.view';
 import { UserProfileAccountSectionView } from '../user-profile-account-section/user-profile-account-section.view';
@@ -185,7 +186,7 @@ describe('phone actions', () => {
     const user = userEvent.setup();
     const onRemovePhone = vi
       .fn()
-      .mockRejectedValueOnce(new Error('Cannot remove this phone.'))
+      .mockRejectedValueOnce(clerkApiError('phone_number_in_use', 'Cannot remove this phone.'))
       .mockResolvedValue(undefined);
     renderPhone({ onRemovePhone });
     await user.click(screen.getByRole('button', { name: 'Manage +1 (801) 555-0100' }));
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-picture-row.view.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-picture-row.view.test.tsx
index ed4a42f090d..7c77b074811 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-picture-row.view.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-picture-row.view.test.tsx
@@ -3,7 +3,7 @@ import userEvent from '@testing-library/user-event';
 import { describe, expect, it, vi } from 'vitest';
 
 import { MosaicProvider } from '../../../mosaic-provider';
-import { SaveError } from '../../../utils/form-error';
+import { SaveError } from '../../../utils/errors';
 import type { UserProfilePictureRowViewProps } from '../user-profile-account-section/user-profile-picture-row.view';
 import { UserProfilePictureRowView } from '../user-profile-account-section/user-profile-picture-row.view';
 
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-picture.controller.test.ts b/packages/mosaic/src/features/user-profile/__tests__/user-profile-picture.controller.test.ts
index c5abf01570d..6850861809b 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-picture.controller.test.ts
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-picture.controller.test.ts
@@ -2,7 +2,7 @@ import { createDeferredPromise } from '@clerk/shared/utils';
 import { act, renderHook } from '@testing-library/react';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 
-import { SaveError } from '../../../utils/form-error';
+import { SaveError } from '../../../utils/errors';
 import type { UserProfilePictureControllerOptions } from '../user-profile-account-section/user-profile-picture.controller';
 import { useUserProfilePictureController } from '../user-profile-account-section/user-profile-picture.controller';
 
@@ -88,7 +88,7 @@ describe('useUserProfilePictureController', () => {
 
     await act(async () => result.current.onChange?.(file));
     expect(result.current.error).toEqual({ code: 'generic' });
-    expect(log).toHaveBeenCalledWith(failure);
+    expect(log).toHaveBeenCalledWith('[Clerk] Could not localize error', failure);
     log.mockRestore();
   });
 
diff --git a/packages/mosaic/src/features/user-profile/__tests__/user-profile-web3-actions.test.tsx b/packages/mosaic/src/features/user-profile/__tests__/user-profile-web3-actions.test.tsx
index e1b68f4007b..cbc866af4ee 100644
--- a/packages/mosaic/src/features/user-profile/__tests__/user-profile-web3-actions.test.tsx
+++ b/packages/mosaic/src/features/user-profile/__tests__/user-profile-web3-actions.test.tsx
@@ -4,6 +4,7 @@ import userEvent from '@testing-library/user-event';
 import { useState } from 'react';
 import { describe, expect, it, vi } from 'vitest';
 
+import { clerkApiError } from '../../../__tests__/clerk-errors';
 import { MosaicProvider } from '../../../mosaic-provider';
 import { UserProfileWeb3WalletsSectionView } from '../user-profile-web3-wallets-section.view';
 
@@ -86,7 +87,7 @@ describe('Web3 wallet removal', () => {
     await user.click(remove);
     expect(onRemove).toHaveBeenCalledOnce();
     await act(async () => {
-      removal.reject(new Error('Unable to remove wallet'));
+      removal.reject(clerkApiError('web3_wallet_in_use', 'Unable to remove wallet'));
       await removal.promise.catch(() => undefined);
     });
     expect(within(dialog).getByRole('alert')).toHaveTextContent('Unable to remove wallet');
diff --git a/packages/mosaic/src/features/user-profile/user-profile-account-section/user-profile-account-section.model.ts b/packages/mosaic/src/features/user-profile/user-profile-account-section/user-profile-account-section.model.ts
index 9dd21959440..daf5fc22e3f 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-account-section/user-profile-account-section.model.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-account-section/user-profile-account-section.model.ts
@@ -4,7 +4,7 @@ import type { AttributeData, EnterpriseAccountResource, UserResource } from '@cl
 
 import { useMosaicEnvironment } from '../../../hooks/use-mosaic-environment';
 import type { MessageValues } from '../../../localization';
-import { save, SaveError, UNEXPECTED_ERROR } from '../../../utils/form-error';
+import { save, SaveError, UNEXPECTED_ERROR } from '../../../utils/errors';
 import type { UserProfileManagedBy } from '../user-profile-managed-by';
 import type {
   UserProfileEmail,
diff --git a/packages/mosaic/src/features/user-profile/user-profile-account-section/user-profile-picture.controller.ts b/packages/mosaic/src/features/user-profile/user-profile-account-section/user-profile-picture.controller.ts
index 765c08e981d..4d4f2b2226d 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-account-section/user-profile-picture.controller.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-account-section/user-profile-picture.controller.ts
@@ -2,7 +2,7 @@ import { useRef, useState } from 'react';
 
 import type { LocalizableError } from '../../../localization';
 import { FileUpload } from '../../../primitives/file-upload';
-import { toFormError } from '../../../utils/form-error';
+import { toFormError } from '../../../utils/errors';
 
 export interface UserProfilePictureControllerOptions {
   onChange?: (file: File) => Promise<void>;
diff --git a/packages/mosaic/src/features/user-profile/user-profile-active-devices-section.view.tsx b/packages/mosaic/src/features/user-profile/user-profile-active-devices-section.view.tsx
index ced3c9815ec..259e385cdf5 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-active-devices-section.view.tsx
+++ b/packages/mosaic/src/features/user-profile/user-profile-active-devices-section.view.tsx
@@ -1,8 +1,9 @@
 import * as stylex from '@stylexjs/stylex';
 import type { Ref } from 'react';
-import { useMemo, useRef, useState } from 'react';
+import { useMemo, useRef } from 'react';
 
 import { Confirmation } from '../../blocks/confirmation';
+import { useConfirmationController } from '../../blocks/confirmation/confirmation.controller';
 import type { ActionMenuAction } from '../../components/action-menu';
 import { ActionMenu } from '../../components/action-menu';
 import { Badge } from '../../components/badge';
@@ -47,32 +48,10 @@ export function UserProfileActiveDevicesSectionView({
   });
   const signOutDeviceAt = onSignOutDevice ? (device: UserProfileDevice) => removalFocus.remove(device.id) : undefined;
 
-  const [isSignOutAllOpen, setIsSignOutAllOpen] = useState(false);
-  const [isSigningOutAll, setIsSigningOutAll] = useState(false);
-  const [signOutAllError, setSignOutAllError] = useState<string>();
-  const signingOutAll = useRef(false);
+  const signOutAll = useConfirmationController({ errorFallback: m.signOutAllError });
   const signedOutAll = useRef(false);
   const signOutAllTrigger = useRef<HTMLButtonElement>(null);
 
-  const signOutAllOtherDevices = async () => {
-    if (!onSignOutAllOtherDevices || signingOutAll.current) {
-      return;
-    }
-    signingOutAll.current = true;
-    setIsSigningOutAll(true);
-    setSignOutAllError(undefined);
-    try {
-      await onSignOutAllOtherDevices();
-      signedOutAll.current = true;
-      setIsSignOutAllOpen(false);
-    } catch (error) {
-      setSignOutAllError(error instanceof Error ? error.message : m.signOutAllError);
-    } finally {
-      signingOutAll.current = false;
-      setIsSigningOutAll(false);
-    }
-  };
-
   // Confirming removes the other devices and the trigger with them — hence the dialog mounted
   // outside the card, and the current device as the place focus lands. Cancelling keeps the
   // trigger, so focus goes back to it.
@@ -95,7 +74,7 @@ export function UserProfileActiveDevicesSectionView({
                   color='neutral'
                   size='sm'
                   variant='outline'
-                  onClick={() => setIsSignOutAllOpen(true)}
+                  onClick={() => signOutAll.onOpenChange(true)}
                 >
                   {m.signOutAll}
                 </Button>
@@ -135,22 +114,22 @@ export function UserProfileActiveDevicesSectionView({
       </Section.Root>
       {onSignOutAllOtherDevices ? (
         <Confirmation
-          open={isSignOutAllOpen}
-          onOpenChange={open => {
-            setIsSignOutAllOpen(open);
-            if (!open) {
-              setSignOutAllError(undefined);
-            }
-          }}
+          open={signOutAll.isOpen}
+          onOpenChange={signOutAll.onOpenChange}
           color='primary'
           finalFocus={focusAfterSignOutAll}
           title={m.signOutAllDialog.title}
           description={plural(m.signOutAllDialog.description, otherDevices.length, locale)}
           actionLabel={m.signOutAllDialog.confirm}
           cancelLabel={m.signOutAllDialog.cancel}
-          onConfirm={() => void signOutAllOtherDevices()}
-          isConfirming={isSigningOutAll}
-          errorMessage={signOutAllError}
+          onConfirm={() =>
+            signOutAll.onConfirm(async () => {
+              await onSignOutAllOtherDevices();
+              signedOutAll.current = true;
+            })
+          }
+          isConfirming={signOutAll.isConfirming}
+          errorMessage={signOutAll.errorMessage}
         />
       ) : null}
       <UserProfileDeviceDetailsDialog
@@ -168,6 +147,7 @@ export function UserProfileActiveDevicesSectionView({
           cancelLabel={m.signOutDialog.cancel}
           finalFocus={removalFocus.finalFocus}
           onConfirm={device => signOutDeviceAt?.(device)}
+          errorFallback={m.detailsDialog.signOutError}
         />
       ) : null}
     </div>
diff --git a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-feedback.test.ts b/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-feedback.test.ts
deleted file mode 100644
index 3e709579a2f..00000000000
--- a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-feedback.test.ts
+++ /dev/null
@@ -1,75 +0,0 @@
-import { ClerkAPIResponseError } from '@clerk/shared/error';
-import { describe, expect, it } from 'vitest';
-
-import { resolveLocalization } from '../../../localization';
-import { connectedAccountFeedback } from './user-profile-connected-accounts-feedback';
-import { ConnectedAccountActionError } from './user-profile-connected-accounts-section.types';
-
-const errorText = ({ message }: { message?: string }) => message ?? 'Fallback';
-const messages = resolveLocalization({ locale: 'en' }).messages.userProfileConnectedAccounts;
-
-function apiError(data: ConstructorParameters<typeof ClerkAPIResponseError>[1]['data']) {
-  return new ClerkAPIResponseError('Invalid', { status: 422, data });
-}
-
-describe('connected account error messages', () => {
-  it('retains the internal action code and cause in localized feedback', () => {
-    const cause = new ConnectedAccountActionError('unavailable');
-    const feedback = connectedAccountFeedback(cause, messages, errorText);
-    expect(feedback).toBeInstanceOf(ConnectedAccountActionError);
-    expect(feedback.cause).toBe(cause);
-    expect(feedback).toMatchObject({ code: 'unavailable', cause, message: messages.errors.unavailable });
-  });
-
-  it('localizes errors raised by the model', () => {
-    expect(connectedAccountFeedback(new ConnectedAccountActionError('unavailable'), messages, errorText).message).toBe(
-      messages.errors.unavailable,
-    );
-    expect(
-      connectedAccountFeedback(new ConnectedAccountActionError('missing_verification_url'), messages, errorText)
-        .message,
-    ).toBe(messages.errors.missingVerificationUrl);
-  });
-
-  it('shows the first API error, preferring its long message', () => {
-    expect(
-      connectedAccountFeedback(
-        apiError([
-          { code: 'oauth_error', message: 'Short', long_message: 'GitHub is unavailable right now.' },
-          { code: 'other', message: 'Second' },
-        ]),
-        messages,
-        errorText,
-      ).message,
-    ).toBe('GitHub is unavailable right now.');
-    expect(
-      connectedAccountFeedback(apiError([{ code: 'oauth_error', message: 'Short' }]), messages, errorText).message,
-    ).toBe('Short');
-  });
-
-  it('passes the API code, parameter, and fallback copy to the canonical formatter', () => {
-    expect(
-      connectedAccountFeedback(
-        apiError([
-          { code: 'form_param_invalid', message: 'Short', long_message: 'Long', meta: { param_name: 'strategy' } },
-        ]),
-        messages,
-        ({ code, paramName, message }) => `${code}:${paramName}:${message}`,
-      ).message,
-    ).toBe('form_param_invalid:strategy:Long');
-  });
-
-  it('falls back to the generic message', () => {
-    expect(connectedAccountFeedback(apiError([]), messages, errorText).message).toBe(messages.errors.generic);
-    expect(connectedAccountFeedback(new Error('Popup closed'), messages, errorText).message).toBe(
-      messages.errors.generic,
-    );
-  });
-
-  it('preserves an empty API message and its cause', () => {
-    const cause = apiError([{ code: 'unknown', message: '', long_message: '' }]);
-    const feedback = connectedAccountFeedback(cause, messages, errorText);
-    expect(feedback.message).toBe('');
-    expect(feedback.cause).toBe(cause);
-  });
-});
diff --git a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-feedback.ts b/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-feedback.ts
deleted file mode 100644
index e4cef35f9af..00000000000
--- a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-feedback.ts
+++ /dev/null
@@ -1,27 +0,0 @@
-import { isClerkAPIResponseError } from '@clerk/shared/error';
-
-import type { LocalizableError, MosaicMessages } from '../../../localization';
-import { toLocalizableApiError } from '../../../localization';
-import { ConnectedAccountActionError } from './user-profile-connected-accounts-section.types';
-
-type Messages = MosaicMessages['userProfileConnectedAccounts'];
-
-export function connectedAccountFeedback(
-  error: unknown,
-  messages: Messages,
-  errorText: (error: LocalizableError) => string,
-): Error {
-  if (error instanceof ConnectedAccountActionError) {
-    const message =
-      error.code === 'missing_verification_url' ? messages.errors.missingVerificationUrl : messages.errors.unavailable;
-    return new ConnectedAccountActionError(error.code, message, { cause: error });
-  }
-  let message: string = messages.errors.generic;
-  if (isClerkAPIResponseError(error)) {
-    const first = error.errors[0];
-    if (first) {
-      message = errorText(toLocalizableApiError(first));
-    }
-  }
-  return new Error(message, { cause: error });
-}
diff --git a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.controller.ts b/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.controller.ts
index 588b29e4b4a..eca8f6e705a 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.controller.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.controller.ts
@@ -1,6 +1,8 @@
 import { useRef, useState } from 'react';
 
-import { useMessages } from '../../../localization';
+import type { ErrorDescription } from '../../../localization';
+import { useErrorText, useMessages } from '../../../localization';
+import { toLocalizableError } from '../../../utils/errors';
 import type {
   ConnectedAccountActionResult,
   UserProfileConnectedAccount,
@@ -31,8 +33,9 @@ export function useUserProfileConnectedAccountsController({
   onReconnect,
 }: UserProfileConnectedAccountsControllerOptions): UserProfileConnectedAccountsController {
   const messages = useMessages('userProfileConnectedAccounts');
+  const errorText = useErrorText();
   const [pendingId, setPendingId] = useState<string>();
-  const [errors, setErrors] = useState<Record<string, string>>({});
+  const [errors, setErrors] = useState<Record<string, ErrorDescription>>({});
   const connecting = useRef(false);
 
   const run = async (id: string, action: (id: string) => Promise<ConnectedAccountActionResult>) => {
@@ -48,20 +51,27 @@ export function useUserProfileConnectedAccountsController({
         await new Promise(resolve => setTimeout(resolve, OAUTH_REDIRECT_HOLD_MS));
       }
     } catch (error) {
-      setErrors(current => ({ ...current, [id]: error instanceof Error ? error.message : messages.errors.generic }));
+      setErrors(current => ({ ...current, [id]: toLocalizableError(error) }));
     } finally {
       connecting.current = false;
       setPendingId(undefined);
     }
   };
 
+  const errorFor = (id: string) => {
+    const error = errors[id];
+    return error ? errorText(error, messages.errors.generic) : undefined;
+  };
+
   return {
-    accounts: accounts.map(account =>
-      errors[account.id] ? { ...account, reconnectError: errors[account.id] } : account,
-    ),
-    availableProviders: availableProviders.map(provider =>
-      errors[provider.id] ? { ...provider, connectError: errors[provider.id] } : provider,
-    ),
+    accounts: accounts.map(account => {
+      const reconnectError = errorFor(account.id);
+      return reconnectError ? { ...account, reconnectError } : account;
+    }),
+    availableProviders: availableProviders.map(provider => {
+      const connectError = errorFor(provider.id);
+      return connectError ? { ...provider, connectError } : provider;
+    }),
     pendingId,
     onConnect: id => void run(id, onConnect),
     onReconnect: id => void run(id, onReconnect),
diff --git a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.messages.ts b/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.messages.ts
index c181f31860b..33e30c792ec 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.messages.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.messages.ts
@@ -16,7 +16,5 @@ export const userProfileConnectedAccountsMessages = {
   },
   errors: {
     generic: 'Something went wrong. Please try again.',
-    unavailable: 'This connected account is no longer available.',
-    missingVerificationUrl: 'OAuth flow did not receive a verification URL.',
   },
 } as const;
diff --git a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.model.ts b/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.model.ts
index 60970f8f377..dc88339dc31 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.model.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.model.ts
@@ -1,4 +1,5 @@
 import { iconImageUrl } from '@clerk/shared/constants';
+import { ClerkRuntimeError } from '@clerk/shared/error';
 import { appendModalState } from '@clerk/shared/internal/clerk-js/queryStateParams';
 import { OAUTH_PROVIDERS } from '@clerk/shared/oauth';
 import { useClerk, useUser } from '@clerk/shared/react';
@@ -18,15 +19,12 @@ import type {
 
 import { useMosaicEnvironment } from '../../../hooks/use-mosaic-environment';
 import { useMosaicRouter } from '../../../hooks/use-mosaic-router';
-import { useErrorText, useMessages } from '../../../localization';
-import { connectedAccountFeedback } from './user-profile-connected-accounts-feedback';
 import type {
   ConnectedAccountActionResult,
   ConnectedAccountProviderDisplay,
   UserProfileConnectedAccount,
   UserProfileConnectionProvider,
 } from './user-profile-connected-accounts-section.types';
-import { ConnectedAccountActionError } from './user-profile-connected-accounts-section.types';
 
 type AccountData = Pick<ExternalAccountResource, 'id' | 'provider' | 'approvedScopes' | 'username' | 'emailAddress'> & {
   verification:
@@ -245,8 +243,6 @@ export function useUserProfileConnectedAccountsModel({
   const { isLoaded, user } = useUser();
   const environment = useMosaicEnvironment();
   const router = useMosaicRouter();
-  const messages = useMessages('userProfileConnectedAccounts');
-  const errorText = useErrorText();
 
   if (!isLoaded || !environment) {
     return { status: 'loading' };
@@ -274,10 +270,13 @@ export function useUserProfileConnectedAccountsModel({
   const userId = user.id;
   const transport = clerk.__internal_oauthTransport;
 
+  const unavailable = () =>
+    new ClerkRuntimeError('This connected account is no longer available.', { code: 'connected_account_unavailable' });
+
   const requireCurrentUser = () => {
     const current = clerk.user;
     if (!current || current.id !== userId) {
-      throw new ConnectedAccountActionError('unavailable');
+      throw unavailable();
     }
     return current;
   };
@@ -289,7 +288,9 @@ export function useUserProfileConnectedAccountsModel({
   const completeVerification = async (response: ExternalAccountResource): Promise<ConnectedAccountActionResult> => {
     const url = response.verification?.externalVerificationRedirectURL;
     if (!url) {
-      throw new ConnectedAccountActionError('missing_verification_url');
+      throw new ClerkRuntimeError('OAuth flow did not receive a verification URL.', {
+        code: 'oauth_missing_verification_url',
+      });
     }
 
     requireCurrentUser();
@@ -305,65 +306,54 @@ export function useUserProfileConnectedAccountsModel({
     return 'redirecting';
   };
 
-  async function runAction<T>(action: () => Promise<T>): Promise<T> {
-    try {
-      return await action();
-    } catch (error) {
-      throw connectedAccountFeedback(error, messages, errorText);
-    }
-  }
-
   return {
     ...projection,
     userId,
-    connect: strategyId =>
-      runAction(async () => {
-        const provider = providers.find(candidate => candidate.enabled && candidate.strategy === strategyId);
-        if (!provider) {
-          throw new ConnectedAccountActionError('unavailable');
-        }
-        const redirectUrl = await getRedirectUrl();
-        const current = requireCurrentUser();
-        const response = await current.createExternalAccount({
-          strategy: provider.strategy,
-          redirectUrl: withModalState(redirectUrl, provider.provider),
-          additionalScopes: additionalOAuthScopes ? additionalOAuthScopes[provider.provider] : [],
-        });
-        return completeVerification(response);
-      }),
-    reconnect: accountId =>
-      runAction(async () => {
-        const redirectUrl = await getRedirectUrl();
-        const current = requireCurrentUser();
-        const account = current.externalAccounts.find(candidate => candidate.id === accountId);
-        if (!account) {
-          throw new ConnectedAccountActionError('unavailable');
-        }
-        const { plan: recovery } = recoveryFor(account, additionalOAuthScopes, providers);
-        if (!recovery) {
-          throw new ConnectedAccountActionError('unavailable');
-        }
+    connect: async strategyId => {
+      const provider = providers.find(candidate => candidate.enabled && candidate.strategy === strategyId);
+      if (!provider) {
+        throw unavailable();
+      }
+      const redirectUrl = await getRedirectUrl();
+      const current = requireCurrentUser();
+      const response = await current.createExternalAccount({
+        strategy: provider.strategy,
+        redirectUrl: withModalState(redirectUrl, provider.provider),
+        additionalScopes: additionalOAuthScopes ? additionalOAuthScopes[provider.provider] : [],
+      });
+      return completeVerification(response);
+    },
+    reconnect: async accountId => {
+      const redirectUrl = await getRedirectUrl();
+      const current = requireCurrentUser();
+      const account = current.externalAccounts.find(candidate => candidate.id === accountId);
+      if (!account) {
+        throw unavailable();
+      }
+      const { plan: recovery } = recoveryFor(account, additionalOAuthScopes, providers);
+      if (!recovery) {
+        throw unavailable();
+      }
 
-        const response =
-          recovery.kind === 'reauthorize'
-            ? await account.reauthorize({
-                additionalScopes: recovery.additionalScopes,
-                redirectUrl: withModalState(redirectUrl),
-              })
-            : await current.createExternalAccount({
-                strategy: recovery.strategy,
-                redirectUrl: withModalState(redirectUrl),
-                additionalScopes: recovery.additionalScopes,
-              });
-        return completeVerification(response);
-      }),
-    remove: accountId =>
-      runAction(async () => {
-        const account = requireCurrentUser().externalAccounts.find(candidate => candidate.id === accountId);
-        if (!account) {
-          throw new ConnectedAccountActionError('unavailable');
-        }
-        await account.destroy();
-      }),
+      const response =
+        recovery.kind === 'reauthorize'
+          ? await account.reauthorize({
+              additionalScopes: recovery.additionalScopes,
+              redirectUrl: withModalState(redirectUrl),
+            })
+          : await current.createExternalAccount({
+              strategy: recovery.strategy,
+              redirectUrl: withModalState(redirectUrl),
+              additionalScopes: recovery.additionalScopes,
+            });
+      return completeVerification(response);
+    },
+    remove: async accountId => {
+      const account = requireCurrentUser().externalAccounts.find(candidate => candidate.id === accountId);
+      if (!account) {
+        throw unavailable();
+      }
+      await account.destroy();
+    },
   };
 }
diff --git a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.types.ts b/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.types.ts
index 276150261f0..adcd5ffc3d5 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.types.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-connected-accounts-section/user-profile-connected-accounts-section.types.ts
@@ -28,14 +28,3 @@ export interface UserProfileConnectedAccountsSectionViewProps {
   onReconnect?: (id: string) => void;
   onRemove?: (id: string) => void | Promise<void>;
 }
-
-export class ConnectedAccountActionError extends Error {
-  constructor(
-    readonly code: 'unavailable' | 'missing_verification_url',
-    message: string = code,
-    options?: ErrorOptions,
-  ) {
-    super(message, options);
-    this.name = 'ConnectedAccountActionError';
-  }
-}
diff --git a/packages/mosaic/src/features/user-profile/user-profile-device-details.dialog.tsx b/packages/mosaic/src/features/user-profile/user-profile-device-details.dialog.tsx
index 8d050f0939b..df90ead4fa5 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-device-details.dialog.tsx
+++ b/packages/mosaic/src/features/user-profile/user-profile-device-details.dialog.tsx
@@ -1,10 +1,9 @@
-import { useRef, useState } from 'react';
-
 import { Button, SubmitButton } from '../../components/button';
 import { Card } from '../../components/card';
 import { DataList } from '../../components/data-list';
 import type { DialogFocusTarget, DialogHandle } from '../../components/dialog';
 import { Dialog } from '../../components/dialog';
+import { usePendingAction } from '../../hooks/use-pending-action';
 import { fill, useMessages } from '../../localization';
 import type { UserProfileDevice } from './user-profile-active-devices.types';
 
@@ -45,27 +44,13 @@ function DeviceDetailsCard({
   onSignOut: UserProfileDeviceDetailsDialogProps['onSignOut'];
 }) {
   const m = useMessages('userProfileActiveDevices');
-  const [isSigningOut, setIsSigningOut] = useState(false);
-  const [errorMessage, setErrorMessage] = useState<string>();
-  const signingOut = useRef(false);
-
-  const signOut = async () => {
-    if (!onSignOut || signingOut.current) {
-      return;
-    }
-    signingOut.current = true;
-    setIsSigningOut(true);
-    setErrorMessage(undefined);
-    try {
-      await onSignOut(device);
+  const signOut = usePendingAction(
+    async () => {
+      await onSignOut?.(device);
       handle.close();
-    } catch (error) {
-      setErrorMessage(error instanceof Error ? error.message : m.detailsDialog.signOutError);
-    } finally {
-      signingOut.current = false;
-      setIsSigningOut(false);
-    }
-  };
+    },
+    { errorFallback: m.detailsDialog.signOutError },
+  );
 
   const fields: { label: string; value: string | undefined }[] = [
     { label: m.detailsDialog.model, value: device.model },
@@ -91,7 +76,7 @@ function DeviceDetailsCard({
         role='alert'
         color='negative'
       >
-        {errorMessage}
+        {signOut.errorMessage}
       </Card.Banner>
       {details.length > 0 ? (
         <Card.Content>
@@ -110,8 +95,8 @@ function DeviceDetailsCard({
           <SubmitButton
             type='button'
             fullWidth
-            isPending={isSigningOut}
-            onClick={() => void signOut()}
+            isPending={signOut.isPending}
+            onClick={() => void signOut.run()}
           >
             {m.detailsDialog.signOut}
           </SubmitButton>
diff --git a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-feedback.test.ts b/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-feedback.test.ts
deleted file mode 100644
index adf4d171c62..00000000000
--- a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-feedback.test.ts
+++ /dev/null
@@ -1,49 +0,0 @@
-import { ClerkAPIResponseError } from '@clerk/shared/error';
-import { describe, expect, it } from 'vitest';
-
-import { resolveLocalization } from '../../../localization';
-import { enterpriseAccountErrorMessage } from './user-profile-enterprise-accounts-feedback';
-
-const messages = resolveLocalization({ locale: 'en' }).messages.userProfileEnterpriseAccountsSection;
-const errorText = ({ message }: { message?: string }) => message || messages.errors.generic;
-
-function apiError(data: ConstructorParameters<typeof ClerkAPIResponseError>[1]['data']) {
-  return new ClerkAPIResponseError('Invalid', { status: 422, data });
-}
-
-describe('enterprise account error messages', () => {
-  it('shows the first API error, preferring its long message', () => {
-    expect(
-      enterpriseAccountErrorMessage(
-        apiError([
-          { code: 'oauth_error', message: 'Short', long_message: 'The identity provider is unavailable.' },
-          { code: 'other', message: 'Second' },
-        ]),
-        errorText,
-        messages.errors.generic,
-      ),
-    ).toBe('The identity provider is unavailable.');
-    expect(
-      enterpriseAccountErrorMessage(
-        apiError([{ code: 'oauth_error', message: 'Short' }]),
-        errorText,
-        messages.errors.generic,
-      ),
-    ).toBe('Short');
-  });
-
-  it('falls back to the generic message', () => {
-    expect(enterpriseAccountErrorMessage(apiError([]), errorText, messages.errors.generic)).toBe(
-      messages.errors.generic,
-    );
-    expect(enterpriseAccountErrorMessage(new TypeError('Failed to fetch'), errorText, messages.errors.generic)).toBe(
-      messages.errors.generic,
-    );
-  });
-
-  it('uses the section fallback for empty API messages', () => {
-    expect(
-      enterpriseAccountErrorMessage(apiError([{ code: 'unknown', message: '', long_message: '' }]), errorText, 'Retry'),
-    ).toBe('Retry');
-  });
-});
diff --git a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-feedback.ts b/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-feedback.ts
deleted file mode 100644
index 64a39361910..00000000000
--- a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-feedback.ts
+++ /dev/null
@@ -1,16 +0,0 @@
-import { isClerkAPIResponseError } from '@clerk/shared/error';
-
-import type { LocalizableError } from '../../../localization';
-import { toLocalizableApiError } from '../../../localization';
-
-export function enterpriseAccountErrorMessage(
-  error: unknown,
-  errorText: (error: LocalizableError) => string,
-  fallback: string,
-): string {
-  if (isClerkAPIResponseError(error)) {
-    const first = error.errors[0];
-    return first ? errorText(toLocalizableApiError(first, fallback)) : fallback;
-  }
-  return fallback;
-}
diff --git a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.controller.ts b/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.controller.ts
index b53c19e4a3f..06eabb11de5 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.controller.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.controller.ts
@@ -1,5 +1,8 @@
 import { useRef, useState } from 'react';
 
+import type { ErrorDescription } from '../../../localization';
+import { useErrorText } from '../../../localization';
+import { toLocalizableError } from '../../../utils/errors';
 import type {
   EnterpriseAccountActionResult,
   UserProfileEnterpriseAccount,
@@ -10,7 +13,7 @@ export interface UserProfileEnterpriseAccountsControllerOptions {
   accounts: UserProfileEnterpriseAccount[];
   connections: UserProfileEnterpriseConnection[];
   onConnect: (connectionId: string) => Promise<EnterpriseAccountActionResult>;
-  errorMessage: string;
+  errorFallback: string;
 }
 
 export interface UserProfileEnterpriseAccountsController {
@@ -24,10 +27,11 @@ export function useUserProfileEnterpriseAccountsController({
   accounts,
   connections,
   onConnect,
-  errorMessage,
+  errorFallback,
 }: UserProfileEnterpriseAccountsControllerOptions): UserProfileEnterpriseAccountsController {
   const [pendingId, setPendingId] = useState<string>();
-  const [connectErrors, setConnectErrors] = useState<Record<string, string>>({});
+  const errorText = useErrorText();
+  const [connectErrors, setConnectErrors] = useState<Record<string, ErrorDescription>>({});
   const connecting = useRef(false);
 
   const run = async (id: string) => {
@@ -43,7 +47,7 @@ export function useUserProfileEnterpriseAccountsController({
         await new Promise(resolve => setTimeout(resolve, 2000));
       }
     } catch (error) {
-      setConnectErrors(current => ({ ...current, [id]: error instanceof Error ? error.message : errorMessage }));
+      setConnectErrors(current => ({ ...current, [id]: toLocalizableError(error) }));
     } finally {
       connecting.current = false;
       setPendingId(undefined);
@@ -52,9 +56,10 @@ export function useUserProfileEnterpriseAccountsController({
 
   return {
     accounts,
-    connections: connections.map(connection =>
-      connectErrors[connection.id] ? { ...connection, connectError: connectErrors[connection.id] } : connection,
-    ),
+    connections: connections.map(connection => {
+      const error = connectErrors[connection.id];
+      return error ? { ...connection, connectError: errorText(error, errorFallback) } : connection;
+    }),
     pendingId,
     onConnect: id => void run(id),
   };
diff --git a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.messages.ts b/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.messages.ts
index 23125b9a5c0..0fbf1d5ee31 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.messages.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.messages.ts
@@ -5,7 +5,5 @@ export const userProfileEnterpriseAccountsMessages = {
   requiresAction: 'Requires action',
   errors: {
     generic: 'Something went wrong. Please try again.',
-    unavailable: 'This enterprise connection is no longer available.',
-    missingVerificationUrl: 'The connection could not start. Please try again.',
   },
 } as const;
diff --git a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.model.ts b/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.model.ts
index dfb1ef1dcad..00dd76a2054 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.model.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.model.ts
@@ -1,11 +1,10 @@
+import { ClerkRuntimeError } from '@clerk/shared/error';
 import { appendModalState } from '@clerk/shared/internal/clerk-js/queryStateParams';
 import { __internal_useUserEnterpriseConnections, useClerk, useUser } from '@clerk/shared/react';
 import type { EnterpriseAccountResource, EnterpriseConnectionResource } from '@clerk/shared/types';
 
 import { useMosaicEnvironment } from '../../../hooks/use-mosaic-environment';
 import { useMosaicRouter } from '../../../hooks/use-mosaic-router';
-import { useErrorText, useMessages } from '../../../localization';
-import { enterpriseAccountErrorMessage } from './user-profile-enterprise-accounts-feedback';
 import type {
   EnterpriseAccountActionResult,
   UserProfileEnterpriseAccount,
@@ -77,8 +76,6 @@ export function useUserProfileEnterpriseAccountsModel({
 }: { mode?: 'modal' | 'mounted' } = {}): UserProfileEnterpriseAccountsModel {
   const clerk = useClerk();
   const router = useMosaicRouter();
-  const m = useMessages('userProfileEnterpriseAccountsSection');
-  const errorText = useErrorText();
   const { isLoaded, user } = useUser();
   const environment = useMosaicEnvironment();
   const { data: connections = [] } = __internal_useUserEnterpriseConnections({
@@ -105,10 +102,15 @@ export function useUserProfileEnterpriseAccountsModel({
 
   const userId = user.id;
 
+  const unavailable = () =>
+    new ClerkRuntimeError('This enterprise connection is no longer available.', {
+      code: 'enterprise_connection_unavailable',
+    });
+
   const currentUser = () => {
     const current = clerk.user;
     if (!current || current.id !== userId) {
-      throw new Error(m.errors.unavailable);
+      throw unavailable();
     }
     return current;
   };
@@ -119,19 +121,17 @@ export function useUserProfileEnterpriseAccountsModel({
     connect: async connectionId => {
       const current = currentUser();
       if (!projection.connections.some(connection => connection.id === connectionId)) {
-        throw new Error(m.errors.unavailable);
+        throw unavailable();
       }
       const url = window.location.href;
       const redirectUrl = mode === 'modal' ? appendModalState({ url, componentName: 'UserProfile' }) : url;
-      const account = await current
-        .createExternalAccount({ enterpriseConnectionId: connectionId, redirectUrl })
-        .catch(error => {
-          throw new Error(enterpriseAccountErrorMessage(error, errorText, m.errors.generic), { cause: error });
-        });
+      const account = await current.createExternalAccount({ enterpriseConnectionId: connectionId, redirectUrl });
       currentUser();
       const redirect = account.verification?.externalVerificationRedirectURL;
       if (!redirect) {
-        throw new Error(m.errors.missingVerificationUrl);
+        throw new ClerkRuntimeError('OAuth flow did not receive a verification URL.', {
+          code: 'oauth_missing_verification_url',
+        });
       }
       router.windowNavigate(redirect);
       return 'redirecting';
diff --git a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.tsx b/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.tsx
index 15411130eaf..153c981c49f 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.tsx
+++ b/packages/mosaic/src/features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.tsx
@@ -33,7 +33,7 @@ function EnterpriseAccounts({ model }: { model: Extract<UserProfileEnterpriseAcc
     accounts: model.accounts,
     connections: model.connections,
     onConnect: model.connect,
-    errorMessage: m.errors.generic,
+    errorFallback: m.errors.generic,
   });
 
   return <UserProfileEnterpriseAccountsSectionView {...controller} />;
diff --git a/packages/mosaic/src/features/user-profile/user-profile-mfa-section.view.tsx b/packages/mosaic/src/features/user-profile/user-profile-mfa-section.view.tsx
index c0f7c275357..aa8c23b2a66 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-mfa-section.view.tsx
+++ b/packages/mosaic/src/features/user-profile/user-profile-mfa-section.view.tsx
@@ -3,6 +3,7 @@ import { type ReactNode, type Ref, useMemo, useRef, useState } from 'react';
 import { Confirmation } from '../../blocks/confirmation';
 import { Section } from '../../components/section';
 import { useListRemovalFocus } from '../../hooks/use-list-removal-focus';
+import { usePendingAction } from '../../hooks/use-pending-action';
 import { fill, type MosaicMessages, useMessages } from '../../localization';
 import { UserProfileAddMfaDialog } from './user-profile-add-mfa.dialog';
 import { UserProfileAddMfaView } from './user-profile-add-mfa.view';
@@ -51,32 +52,10 @@ export function UserProfileMfaSectionView({
   });
   const removeMethod = useMemo(() => Confirmation.createHandle<UserProfileMfaMethod>(), []);
   const [pickerOpen, setPickerOpen] = useState(false);
-  const [isSettingDefault, setIsSettingDefault] = useState(false);
-  const [defaultError, setDefaultError] = useState<string>();
-  const settingDefault = useRef(false);
-
-  const setDefault = async (id: string) => {
+  const setDefault = usePendingAction((id: string) => onSetDefault?.(id), { errorFallback: m.setDefaultError });
+  const canSetDefault = (id: string) => {
     const method = methods.find(method => method.id === id);
-    if (
-      !onSetDefault ||
-      method?.type !== 'sms' ||
-      !method.canSetDefault ||
-      method.isDefault ||
-      settingDefault.current
-    ) {
-      return;
-    }
-    settingDefault.current = true;
-    setIsSettingDefault(true);
-    setDefaultError(undefined);
-    try {
-      await onSetDefault(id);
-    } catch (error) {
-      setDefaultError(error instanceof Error ? error.message : m.setDefaultError);
-    } finally {
-      settingDefault.current = false;
-      setIsSettingDefault(false);
-    }
+    return method?.type === 'sms' && method.canSetDefault && !method.isDefault;
   };
 
   return (
@@ -112,12 +91,20 @@ export function UserProfileMfaSectionView({
             method={method}
             triggerRef={removalFocus.registerTrigger(method.id)}
             onRemove={onRemove ? () => removeMethod.open(method) : undefined}
-            onSetDefault={onSetDefault && !isSettingDefault ? id => void setDefault(id) : undefined}
+            onSetDefault={
+              onSetDefault && !setDefault.isPending
+                ? id => {
+                    if (canSetDefault(id)) {
+                      void setDefault.run(id);
+                    }
+                  }
+                : undefined
+            }
             onRegenerateBackupCodes={onRegenerateBackupCodes}
           />
         ))}
       </UserProfileSecurityList>
-      <Section.Error>{defaultError}</Section.Error>
+      <Section.Error>{setDefault.errorMessage}</Section.Error>
       {onRemove ? (
         <Confirmation
           handle={removeMethod}
diff --git a/packages/mosaic/src/features/user-profile/user-profile-passkey-row.view.tsx b/packages/mosaic/src/features/user-profile/user-profile-passkey-row.view.tsx
index b8343d0c3c9..0c75e25b59c 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-passkey-row.view.tsx
+++ b/packages/mosaic/src/features/user-profile/user-profile-passkey-row.view.tsx
@@ -6,8 +6,7 @@ import { ActionMenu } from '../../components/action-menu';
 import { Dialog } from '../../components/dialog';
 import { Icon, IconFrame } from '../../components/icon';
 import { Section } from '../../components/section';
-import { fill } from '../../localization/messages';
-import { userProfilePasskeysMessages as m } from './user-profile-passkeys-section.messages';
+import { fill, useMessages } from '../../localization';
 import { styles } from './user-profile-passkeys-section.styles';
 import type { UserProfilePasskey } from './user-profile-passkeys-section.view';
 import { useUserProfileRenamePasskeyController } from './user-profile-rename-passkey.controller';
@@ -24,6 +23,7 @@ export function UserProfilePasskeyRowView({
   onRename?: (id: string, name: string) => void | Promise<void>;
   onRemove?: () => void;
 }) {
+  const m = useMessages('userProfilePasskeys');
   const renameDialog = useMemo(() => Dialog.createHandle(), []);
   const controller = useUserProfileRenamePasskeyController({ id: passkey.id, name: passkey.name, onRename });
   const description =
diff --git a/packages/mosaic/src/features/user-profile/user-profile-passkeys-section.view.tsx b/packages/mosaic/src/features/user-profile/user-profile-passkeys-section.view.tsx
index 38de095b398..1c38afb1857 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-passkeys-section.view.tsx
+++ b/packages/mosaic/src/features/user-profile/user-profile-passkeys-section.view.tsx
@@ -6,9 +6,8 @@ import { Field } from '../../components/field';
 import { Icon } from '../../components/icon';
 import { Section } from '../../components/section';
 import { useListRemovalFocus } from '../../hooks/use-list-removal-focus';
-import { fill } from '../../localization/messages';
+import { fill, useMessages } from '../../localization';
 import { UserProfilePasskeyRowView } from './user-profile-passkey-row.view';
-import { userProfilePasskeysMessages as m } from './user-profile-passkeys-section.messages';
 import { styles } from './user-profile-passkeys-section.styles';
 
 export interface UserProfilePasskey {
@@ -33,6 +32,7 @@ export function UserProfilePasskeysSectionView({
   onRename,
   onRemove,
 }: UserProfilePasskeysSectionViewProps) {
+  const m = useMessages('userProfilePasskeys');
   const addButton = useRef<HTMLButtonElement>(null);
   const section = useRef<HTMLDivElement>(null);
   const removalFocus = useListRemovalFocus({
diff --git a/packages/mosaic/src/features/user-profile/user-profile-password-section/user-profile-password-errors.ts b/packages/mosaic/src/features/user-profile/user-profile-password-section/user-profile-password-errors.ts
index c6383bd61ec..ac33d87fb78 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-password-section/user-profile-password-errors.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-password-section/user-profile-password-errors.ts
@@ -3,8 +3,9 @@ import type { ClerkAPIError, PasswordSettingsData } from '@clerk/shared/types';
 import { snakeToCamel } from '@clerk/shared/underscore';
 
 import { FormSubmitError } from '../../../components/form';
-import type { LocalizableError, MosaicMessages } from '../../../localization';
+import type { ErrorDescription, MosaicMessages } from '../../../localization';
 import { toLocalizableApiError } from '../../../localization';
+import { toLocalizableError } from '../../../utils/errors';
 import { passwordComplexityMessage, passwordStrengthMessage } from './user-profile-password-feedback';
 import type { UserProfileEditPasswordValues } from './user-profile-password-section.types';
 
@@ -32,7 +33,7 @@ function passwordError(
   settings: Settings,
   messages: Messages,
   locale: string,
-  errorText: (error: LocalizableError) => string,
+  errorText: (error: ErrorDescription) => string,
 ) {
   const first = errors[0];
   if (!first) {
@@ -52,16 +53,17 @@ function passwordError(
   );
 }
 
+// TODO: Move onto save() and drop toLocalizableApiError.
 export function passwordFormError(
   error: unknown,
   requiresCurrentPassword: boolean,
   settings: Settings,
   messages: Messages,
   locale: string,
-  errorText: (error: LocalizableError) => string,
+  errorText: (error: ErrorDescription) => string,
 ): FormSubmitError<UserProfileEditPasswordValues> {
   if (typeof error !== 'object' || error === null || !isClerkAPIResponseError(error)) {
-    return new FormSubmitError({ message: errorText({ message: error instanceof Error ? error.message : undefined }) });
+    return new FormSubmitError({ message: errorText(toLocalizableError(error)) });
   }
   const fields: { currentPassword?: string; newPassword?: string } = {};
   const passwordErrors: ClerkAPIError[] = [];
diff --git a/packages/mosaic/src/features/user-profile/user-profile-password-section/user-profile-password-feedback.test.ts b/packages/mosaic/src/features/user-profile/user-profile-password-section/user-profile-password-feedback.test.ts
index a111719c53e..8247ea627a4 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-password-section/user-profile-password-feedback.test.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-password-section/user-profile-password-feedback.test.ts
@@ -2,7 +2,7 @@ import { ClerkAPIResponseError } from '@clerk/shared/error';
 import type { PasswordStrength } from '@clerk/shared/types';
 import { renderHook } from '@testing-library/react';
 import { createElement, type ReactNode } from 'react';
-import { describe, expect, it } from 'vitest';
+import { describe, expect, it, vi } from 'vitest';
 
 import { FormSubmitError } from '../../../components/form';
 import { MosaicLocalizationProvider, resolveLocalization, useErrorText } from '../../../localization';
@@ -197,13 +197,15 @@ describe('password error feedback', () => {
     ).toBe('Your password is not strong enough.');
   });
 
-  it('returns form errors for unexpected failures', () => {
+  it('returns the generic form error for unexpected failures, never their message', () => {
+    const log = vi.spyOn(console, 'error').mockImplementation(() => {});
     expect(
       passwordFormError(new Error('Connection interrupted'), true, settings, messages, localization.locale, resolver()),
-    ).toMatchObject({ banner: 'Connection interrupted' });
+    ).toMatchObject({ banner: 'Something went wrong. Please try again.' });
     expect(passwordFormError(undefined, true, settings, messages, localization.locale, resolver())).toBeInstanceOf(
       FormSubmitError,
     );
+    log.mockRestore();
   });
 });
 
diff --git a/packages/mosaic/src/features/user-profile/user-profile-rename-passkey.controller.ts b/packages/mosaic/src/features/user-profile/user-profile-rename-passkey.controller.ts
index 5aa10686cc9..773e2ff4c17 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-rename-passkey.controller.ts
+++ b/packages/mosaic/src/features/user-profile/user-profile-rename-passkey.controller.ts
@@ -1,13 +1,15 @@
+import type { ErrorDescription } from '../../localization';
+import { useErrorText, useMessages } from '../../localization';
 import { setup } from '../../machine/setup';
 import { useMachine } from '../../machine/use-machine';
-import { userProfilePasskeysMessages as m } from './user-profile-passkeys-section.messages';
+import { toLocalizableError } from '../../utils/errors';
 
 interface UserProfileRenamePasskeyContext {
   passkeyId: string;
   savedName: string;
   name: string;
   onRename: ((id: string, name: string) => void | Promise<void>) | undefined;
-  error: string | undefined;
+  error: ErrorDescription | undefined;
 }
 
 type UserProfileRenamePasskeyEvent =
@@ -53,7 +55,7 @@ const userProfileRenamePasskeyMachine = createMachine({
         onDone: { target: 'idle' },
         onError: {
           target: 'editing',
-          actions: assign((_, event) => ({ error: event.error instanceof Error ? event.error.message : m.saveError })),
+          actions: assign((_, event) => ({ error: toLocalizableError(event.error) })),
         },
       }),
     },
@@ -82,6 +84,8 @@ export function useUserProfileRenamePasskeyController({
   name,
   onRename,
 }: UserProfileRenamePasskeyControllerOptions): UserProfileRenamePasskeyController {
+  const m = useMessages('userProfilePasskeys');
+  const errorText = useErrorText();
   const [snapshot, send] = useMachine(userProfileRenamePasskeyMachine, {
     context: { passkeyId: id, savedName: name, onRename },
   });
@@ -94,6 +98,6 @@ export function useUserProfileRenamePasskeyController({
     onSubmit: () => send({ type: 'SAVE' }),
     canSave: isSaveable(snapshot.context),
     isSaving: snapshot.value === 'saving',
-    error: snapshot.context.error,
+    error: snapshot.context.error ? errorText(snapshot.context.error, m.saveError) : undefined,
   };
 }
diff --git a/packages/mosaic/src/features/user-profile/user-profile-rename-passkey.dialog.tsx b/packages/mosaic/src/features/user-profile/user-profile-rename-passkey.dialog.tsx
index 25cef6658d9..bb3451ddc7d 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-rename-passkey.dialog.tsx
+++ b/packages/mosaic/src/features/user-profile/user-profile-rename-passkey.dialog.tsx
@@ -6,7 +6,7 @@ import type { DialogHandle } from '../../components/dialog';
 import { Dialog } from '../../components/dialog';
 import { Field } from '../../components/field';
 import { Input } from '../../components/input';
-import { userProfilePasskeysMessages as m } from './user-profile-passkeys-section.messages';
+import { useMessages } from '../../localization';
 
 export interface UserProfileRenamePasskeyDialogProps {
   handle: DialogHandle;
@@ -31,6 +31,7 @@ export function UserProfileRenamePasskeyDialog({
   error,
   onSubmit,
 }: UserProfileRenamePasskeyDialogProps) {
+  const m = useMessages('userProfilePasskeys');
   const formId = useId();
   const inputRef = useRef<HTMLInputElement>(null);
   return (
diff --git a/packages/mosaic/src/hooks/__tests__/use-pending-action.test.tsx b/packages/mosaic/src/hooks/__tests__/use-pending-action.test.tsx
new file mode 100644
index 00000000000..ce7c3c45ccf
--- /dev/null
+++ b/packages/mosaic/src/hooks/__tests__/use-pending-action.test.tsx
@@ -0,0 +1,104 @@
+import { act, renderHook } from '@testing-library/react';
+import type { ReactNode } from 'react';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { deferred } from '../../__tests__/async';
+import { clerkApiError } from '../../__tests__/clerk-errors';
+import { MosaicProvider } from '../../mosaic-provider';
+import { usePendingAction } from '../use-pending-action';
+
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
+function blocked() {
+  return clerkApiError('action_blocked', 'Raw server sentence.');
+}
+
+describe('usePendingAction', () => {
+  it('reports success and leaves no error', async () => {
+    const { result } = renderHook(() => usePendingAction(() => Promise.resolve()));
+
+    let succeeded: boolean | undefined;
+    await act(async () => {
+      succeeded = await result.current.run();
+    });
+
+    expect(succeeded).toBe(true);
+    expect(result.current.errorMessage).toBeUndefined();
+  });
+
+  it('is pending while the action runs and ignores a second run until it settles', async () => {
+    const pending = deferred<void>();
+    const action = vi.fn(() => pending.promise);
+    const { result } = renderHook(() => usePendingAction(action));
+
+    act(() => {
+      void result.current.run();
+      void result.current.run();
+    });
+
+    expect(result.current.isPending).toBe(true);
+    expect(action).toHaveBeenCalledOnce();
+    await act(async () => {
+      pending.resolve();
+      await pending.promise;
+    });
+    expect(result.current.isPending).toBe(false);
+  });
+
+  it('passes its arguments to the action', async () => {
+    const action = vi.fn((_id: string) => Promise.resolve());
+    const { result } = renderHook(() => usePendingAction(action));
+
+    await act(() => result.current.run('phone_1'));
+
+    expect(action).toHaveBeenCalledWith('phone_1');
+  });
+
+  it('reports failure with the localized copy for the code Clerk refused with', async () => {
+    const wrapper = ({ children }: { children: ReactNode }) => (
+      <MosaicProvider localization={{ overrides: { 'errors.action_blocked': 'Acción bloqueada.' } }}>
+        {children}
+      </MosaicProvider>
+    );
+    const { result } = renderHook(() => usePendingAction(() => Promise.reject(blocked())), { wrapper });
+
+    let succeeded: boolean | undefined;
+    await act(async () => {
+      succeeded = await result.current.run();
+    });
+
+    expect(succeeded).toBe(false);
+    expect(result.current.errorMessage).toBe('Acción bloqueada.');
+    expect(result.current.isPending).toBe(false);
+  });
+
+  it('shows the fallback, never the message, of an unexpected error', async () => {
+    vi.spyOn(console, 'error').mockImplementation(() => {});
+    const { result } = renderHook(() =>
+      usePendingAction(() => Promise.reject(new Error('Cannot read properties of undefined')), {
+        errorFallback: 'Unable to sign out.',
+      }),
+    );
+
+    await act(() => result.current.run());
+
+    expect(result.current.errorMessage).toBe('Unable to sign out.');
+  });
+
+  it('clears the last error when run again and when reset', async () => {
+    const action = vi.fn<() => Promise<void>>().mockRejectedValueOnce(blocked()).mockResolvedValueOnce(undefined);
+    const { result } = renderHook(() => usePendingAction(action));
+    await act(() => result.current.run());
+    expect(result.current.errorMessage).toBeDefined();
+
+    await act(() => result.current.run());
+    expect(result.current.errorMessage).toBeUndefined();
+
+    action.mockRejectedValueOnce(blocked());
+    await act(() => result.current.run());
+    act(() => result.current.reset());
+    expect(result.current.errorMessage).toBeUndefined();
+  });
+});
diff --git a/packages/mosaic/src/hooks/use-accessible-description-warning.ts b/packages/mosaic/src/hooks/use-accessible-description-warning.ts
index cee19c99846..836a4e7bc3c 100644
--- a/packages/mosaic/src/hooks/use-accessible-description-warning.ts
+++ b/packages/mosaic/src/hooks/use-accessible-description-warning.ts
@@ -42,7 +42,7 @@ export function useAccessibleDescriptionWarning(
         return;
       }
       console.warn(
-        `[clerk] <${component}.Popup> renders an alert dialog with no description. Render a \`<${descriptionPart ?? `${component}.Description`}>\` inside it — it is announced with the title, and is what says which decision is being asked for.`,
+        `[Clerk] <${component}.Popup> renders an alert dialog with no description. Render a \`<${descriptionPart ?? `${component}.Description`}>\` inside it — it is announced with the title, and is what says which decision is being asked for.`,
       );
     }, 0);
 
diff --git a/packages/mosaic/src/hooks/use-accessible-name-warning.ts b/packages/mosaic/src/hooks/use-accessible-name-warning.ts
index 5bcbb4c0bc4..a33914cafd2 100644
--- a/packages/mosaic/src/hooks/use-accessible-name-warning.ts
+++ b/packages/mosaic/src/hooks/use-accessible-name-warning.ts
@@ -42,7 +42,7 @@ export function useAccessibleNameWarning(node: HTMLElement | null, component: st
         return;
       }
       console.warn(
-        `[clerk] <${component}.Popup> renders a dialog with no accessible name. Pass \`aria-label\`, or render a \`<${titlePart ?? `${component}.Title`}>\` inside it.`,
+        `[Clerk] <${component}.Popup> renders a dialog with no accessible name. Pass \`aria-label\`, or render a \`<${titlePart ?? `${component}.Title`}>\` inside it.`,
       );
     }, 0);
 
diff --git a/packages/mosaic/src/hooks/use-pending-action.ts b/packages/mosaic/src/hooks/use-pending-action.ts
new file mode 100644
index 00000000000..17ee4c44f0b
--- /dev/null
+++ b/packages/mosaic/src/hooks/use-pending-action.ts
@@ -0,0 +1,57 @@
+import { useRef, useState } from 'react';
+
+import type { ErrorDescription } from '../localization';
+import { useErrorText } from '../localization';
+import { toLocalizableError } from '../utils/errors';
+
+export interface PendingActionOptions {
+  /** Copy shown when the action fails without an error Clerk can describe, such as a network or code fault (default: the generic error) */
+  errorFallback?: string;
+}
+
+export interface PendingAction<TArgs extends unknown[]> {
+  run: (...args: TArgs) => Promise<boolean>;
+  isPending: boolean;
+  errorMessage: string | undefined;
+  reset: () => void;
+}
+
+/**
+ * Runs an inline action, such as a row button, and tracks whether it is pending and why it failed.
+ * `run` resolves `true` on success and `false` on failure, and ignores calls while one is in flight.
+ */
+export function usePendingAction<TArgs extends unknown[]>(
+  action: (...args: TArgs) => Promise<unknown> | void,
+  { errorFallback }: PendingActionOptions = {},
+): PendingAction<TArgs> {
+  const errorText = useErrorText();
+  const [isPending, setIsPending] = useState(false);
+  const [error, setError] = useState<ErrorDescription>();
+  const running = useRef(false);
+
+  const run = async (...args: TArgs) => {
+    if (running.current) {
+      return false;
+    }
+    running.current = true;
+    setIsPending(true);
+    setError(undefined);
+    try {
+      await action(...args);
+      return true;
+    } catch (cause) {
+      setError(toLocalizableError(cause));
+      return false;
+    } finally {
+      running.current = false;
+      setIsPending(false);
+    }
+  };
+
+  return {
+    run,
+    isPending,
+    errorMessage: error ? errorText(error, errorFallback) : undefined,
+    reset: () => setError(undefined),
+  };
+}
diff --git a/packages/mosaic/src/localization/errors.messages.ts b/packages/mosaic/src/localization/errors.messages.ts
index 3f9acc7e9cf..a6f21c93e2f 100644
--- a/packages/mosaic/src/localization/errors.messages.ts
+++ b/packages/mosaic/src/localization/errors.messages.ts
@@ -1,9 +1,12 @@
+// TODO: Seed this catalog from the unstable__errors entries in @clerk/localizations so existing copy and translations carry over.
 export const errorMessages: { readonly generic: string } & Readonly<Record<string, string>> = {
   generic: 'Something went wrong. Please try again.',
   action_blocked: "This action couldn't be completed. Please try again later or contact support if this persists.",
   avatar_file_count_exceeded: 'Only one file can be uploaded at a time.',
   avatar_file_size_exceeded: 'File size exceeds the maximum limit of 10MB. Please choose a smaller file.',
   avatar_file_type_invalid: 'File type not supported. Please upload a JPG, PNG, GIF, or WEBP image.',
+  connected_account_unavailable: 'This connected account is no longer available.',
+  enterprise_connection_unavailable: 'This enterprise connection is no longer available.',
   form_new_password_matches_current: 'New password cannot be the same as the current password.',
   form_password_incorrect: 'Your current password is incorrect.',
   form_password_length_too_short: 'Your password is too short. It must be at least 8 characters long.',
@@ -17,4 +20,6 @@ export const errorMessages: { readonly generic: string } & Readonly<Record<strin
   form_password_validation_failed: 'Incorrect Password',
   form_username_invalid_length: 'Your username must be between {min_length} and {max_length} characters long.',
   form_username_needs_non_number_char: 'Your username must contain at least one non-numeric character.',
+  network_error: 'Unable to reach the server. Check your connection and try again.',
+  oauth_missing_verification_url: 'The connection could not start. Please try again.',
 };
diff --git a/packages/mosaic/src/localization/errors.test.tsx b/packages/mosaic/src/localization/errors.test.tsx
index 9d0d601bc08..a44c687a964 100644
--- a/packages/mosaic/src/localization/errors.test.tsx
+++ b/packages/mosaic/src/localization/errors.test.tsx
@@ -57,9 +57,24 @@ describe('useErrorText', () => {
   });
 
   it('falls back to the generic message when there is nothing else', () => {
-    expect(errorText({ 'errors.generic': 'Algo salió mal.' })({})).toBe('Algo salió mal.');
+    expect(errorText({ 'errors.generic': 'Algo salió mal.' })({ cause: new Error('boom') })).toBe('Algo salió mal.');
     expect(errorText()({ code: 'toString' })).toBe('Something went wrong. Please try again.');
   });
+
+  it('uses the fallback it is given ahead of the generic message', () => {
+    expect(errorText()({ cause: new Error('boom') }, 'Unable to sign out.')).toBe('Unable to sign out.');
+  });
+
+  it('prefers the copy for the code and the message Clerk sent over the fallback', () => {
+    const text = errorText({ 'errors.form_identifier_exists': 'Ya existe.' });
+    expect(text({ code: 'form_identifier_exists', message: 'Taken' }, 'Unable to save.')).toBe('Ya existe.');
+    expect(text({ code: 'unknown', message: 'Taken' }, 'Unable to save.')).toBe('Taken');
+  });
+
+  it('never shows an empty message', () => {
+    expect(errorText()({ code: 'unknown', message: '' }, 'Unable to save.')).toBe('Unable to save.');
+    expect(errorText()({ code: 'unknown', message: '' })).toBe('Something went wrong. Please try again.');
+  });
 });
 
 describe('Clerk API error localization', () => {
@@ -90,10 +105,8 @@ describe('Clerk API error localization', () => {
     expect(text(toLocalizableApiError(firstError([{ code: 'unknown', message: 'Short' }])))).toBe('Short');
   });
 
-  it('preserves an empty message unless the feature provides a fallback', () => {
+  it('uses the feature fallback for an empty message', () => {
     const error = firstError([{ code: 'unknown', message: '', long_message: '' }]);
-    const text = errorText();
-    expect(text(toLocalizableApiError(error))).toBe('');
-    expect(text(toLocalizableApiError(error, 'Retry'))).toBe('Retry');
+    expect(errorText()(toLocalizableApiError(error, 'Retry'))).toBe('Retry');
   });
 });
diff --git a/packages/mosaic/src/localization/errors.ts b/packages/mosaic/src/localization/errors.ts
index d45afbfd554..170e6509bdd 100644
--- a/packages/mosaic/src/localization/errors.ts
+++ b/packages/mosaic/src/localization/errors.ts
@@ -5,13 +5,25 @@ import type { MessageValues } from './messages';
 import { fill } from './messages';
 
 export interface LocalizableError {
-  code?: string;
+  code: string;
   paramName?: string;
   message?: string;
   /** Values for the `{placeholder}`s in whichever message the code resolves to. */
   params?: MessageValues;
 }
 
+/** A failure Clerk cannot describe, such as a code fault. Rendering it shows the fallback; `cause` is the original. */
+export interface UnlocalizableError {
+  cause: unknown;
+}
+
+/** What an owner holds about a failure, whether or not Clerk could describe it. */
+export type ErrorDescription = LocalizableError | UnlocalizableError;
+
+export function isLocalizableError(error: ErrorDescription): error is LocalizableError {
+  return !('cause' in error);
+}
+
 export function toLocalizableApiError(error: ClerkAPIError, fallback?: string): LocalizableError {
   const message = error.longMessage || error.message;
   return {
@@ -21,12 +33,22 @@ export function toLocalizableApiError(error: ClerkAPIError, fallback?: string):
   };
 }
 
-export function useErrorText(): (error: LocalizableError) => string {
+/**
+ * Turns an error into copy: the catalog entry for its code on that field, then for its code, then the
+ * message Clerk sent, then `fallback`, then the generic error.
+ */
+export function useErrorText(): (error: ErrorDescription, fallback?: string) => string {
   const messages = useMessages('errors');
   const lookup = (key: string | undefined) => (key && Object.hasOwn(messages, key) ? messages[key] : undefined);
-  return ({ code, paramName, message, params }) => {
+  return (error, fallback) => {
+    if (!isLocalizableError(error)) {
+      return fallback || messages.generic;
+    }
+    const { code, paramName, message, params } = error;
     const template =
-      lookup(code && paramName ? `${code}__${paramName}` : undefined) ?? lookup(code) ?? message ?? messages.generic;
+      lookup(paramName ? `${code}__${paramName}` : undefined) ??
+      lookup(code) ??
+      (message || fallback || messages.generic);
     return params ? fill(template, params) : template;
   };
 }
diff --git a/packages/mosaic/src/localization/index.ts b/packages/mosaic/src/localization/index.ts
index 6fb16605066..349e55081d4 100644
--- a/packages/mosaic/src/localization/index.ts
+++ b/packages/mosaic/src/localization/index.ts
@@ -1,7 +1,7 @@
 export type { MosaicCatalog, MosaicLocalization } from './catalog';
 export { MosaicLocalizationProvider, resolveLocalization, useLocale, useMessages } from './context';
-export type { LocalizableError } from './errors';
-export { toLocalizableApiError, useErrorText } from './errors';
+export type { ErrorDescription, LocalizableError, UnlocalizableError } from './errors';
+export { isLocalizableError, toLocalizableApiError, useErrorText } from './errors';
 export type { MosaicMessages } from './registry';
 export { mosaicMessages } from './registry';
 export type { MessageComponents, MessageValues, PluralForms, RichOptions } from './messages';
diff --git a/packages/mosaic/src/localization/registry.ts b/packages/mosaic/src/localization/registry.ts
index 9064579842f..2a40f6b2d6c 100644
--- a/packages/mosaic/src/localization/registry.ts
+++ b/packages/mosaic/src/localization/registry.ts
@@ -24,6 +24,7 @@ import { userProfileConnectedAccountsMessages } from '../features/user-profile/u
 import { userProfileDangerSectionMessages } from '../features/user-profile/user-profile-danger-section/user-profile-danger-section.messages';
 import { userProfileEnterpriseAccountsMessages } from '../features/user-profile/user-profile-enterprise-accounts-section/user-profile-enterprise-accounts-section.messages';
 import { userProfileMfaMessages } from '../features/user-profile/user-profile-mfa-section.messages';
+import { userProfilePasskeysMessages } from '../features/user-profile/user-profile-passkeys-section.messages';
 import { userProfilePasswordSectionMessages } from '../features/user-profile/user-profile-password-section/user-profile-password-section.messages';
 import { userProfileWeb3WalletsMessages } from '../features/user-profile/user-profile-web3-wallets.messages';
 import { errorMessages } from './errors.messages';
@@ -56,6 +57,7 @@ export const mosaicMessages = {
   userProfileDangerSection: userProfileDangerSectionMessages,
   userProfileEnterpriseAccountsSection: userProfileEnterpriseAccountsMessages,
   userProfileMfa: userProfileMfaMessages,
+  userProfilePasskeys: userProfilePasskeysMessages,
   userProfilePasswordSection: userProfilePasswordSectionMessages,
   userProfileWeb3Wallets: userProfileWeb3WalletsMessages,
 };
diff --git a/packages/mosaic/src/utils/errors.test.tsx b/packages/mosaic/src/utils/errors.test.tsx
new file mode 100644
index 00000000000..e1175b97ee0
--- /dev/null
+++ b/packages/mosaic/src/utils/errors.test.tsx
@@ -0,0 +1,82 @@
+import { ClerkAPIResponseError, ClerkRuntimeError } from '@clerk/shared/error';
+import { renderHook } from '@testing-library/react';
+import type { ReactNode } from 'react';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { isLocalizableError, MosaicLocalizationProvider, resolveLocalization, useErrorText } from '../localization';
+import { SaveError, toLocalizableError } from './errors';
+
+function errorText() {
+  const wrapper = ({ children }: { children: ReactNode }) => (
+    <MosaicLocalizationProvider value={resolveLocalization({})}>{children}</MosaicLocalizationProvider>
+  );
+  return renderHook(() => useErrorText(), { wrapper }).result.current;
+}
+
+function silenceConsole() {
+  return vi.spyOn(console, 'error').mockImplementation(() => {});
+}
+
+describe('toLocalizableError', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('reads the global error a save left, code and all', () => {
+    const cause = new SaveError({ global: { code: 'action_blocked', message: 'Raw server sentence.' } });
+    expect(toLocalizableError(cause)).toEqual({ code: 'action_blocked', message: 'Raw server sentence.' });
+  });
+
+  it('falls back to the first field error when a save named only fields', () => {
+    const cause = new SaveError({ fields: { name: { code: 'form_param_nil', paramName: 'name' } } });
+    expect(toLocalizableError(cause)).toEqual({ code: 'form_param_nil', paramName: 'name' });
+  });
+
+  it('keeps the cause of a save that carried nothing', () => {
+    silenceConsole();
+    const cause = new SaveError({});
+    expect(toLocalizableError(cause)).toEqual({ cause });
+  });
+
+  it('maps a Clerk API error by its code, field and message', () => {
+    const cause = new ClerkAPIResponseError('Forbidden', {
+      status: 403,
+      data: [{ code: 'not_allowed_access', message: 'Short', long_message: 'Long', meta: { param_name: 'role' } }],
+    });
+    expect(toLocalizableError(cause)).toEqual({ code: 'not_allowed_access', paramName: 'role', message: 'Long' });
+  });
+
+  it('maps a Clerk runtime error by its code', () => {
+    const cause = new ClerkRuntimeError('Something broke.', { code: 'cannot_render_user_missing' });
+    expect(toLocalizableError(cause)).toEqual({ code: 'cannot_render_user_missing' });
+  });
+
+  it('localizes a network failure instead of falling back', () => {
+    const error = toLocalizableError(new ClerkRuntimeError('Failed to fetch', { code: 'network_error' }));
+    expect(errorText()(error, 'Unable to save.')).toBe(
+      'Unable to reach the server. Check your connection and try again.',
+    );
+  });
+
+  it('keeps the cause of an error Clerk cannot describe and never shows its message', () => {
+    const log = silenceConsole();
+    const cause = new Error('Cannot read properties of undefined');
+    const error = toLocalizableError(cause);
+    expect(error).toEqual({ cause });
+    expect(isLocalizableError(error)).toBe(false);
+    expect(errorText()(error, 'Unable to save.')).toBe('Unable to save.');
+    expect(log).toHaveBeenCalledWith('[Clerk] Could not localize error', cause);
+  });
+
+  it('keeps the cause of something that is not an error at all', () => {
+    silenceConsole();
+    expect(toLocalizableError('nope')).toEqual({ cause: 'nope' });
+    expect(toLocalizableError(undefined)).toEqual({ cause: undefined });
+  });
+
+  it('keeps the cause of a Clerk API error that carries no errors', () => {
+    silenceConsole();
+    const cause = new ClerkAPIResponseError('Server error', { status: 500, data: [] });
+    expect(toLocalizableError(cause)).toEqual({ cause });
+  });
+});
diff --git a/packages/mosaic/src/utils/form-error.ts b/packages/mosaic/src/utils/errors.ts
similarity index 59%
rename from packages/mosaic/src/utils/form-error.ts
rename to packages/mosaic/src/utils/errors.ts
index 45dd494ae4d..20fb5650616 100644
--- a/packages/mosaic/src/utils/form-error.ts
+++ b/packages/mosaic/src/utils/errors.ts
@@ -1,7 +1,7 @@
 import { isClerkAPIResponseError, isClerkRuntimeError } from '@clerk/shared/error';
 import { snakeToCamel } from '@clerk/shared/underscore';
 
-import type { LocalizableError, MessageValues } from '../localization';
+import type { ErrorDescription, LocalizableError, MessageValues } from '../localization';
 
 export interface FormError<TField extends string = string> {
   global?: LocalizableError;
@@ -21,40 +21,53 @@ export class SaveError<TField extends string = string> extends Error {
   }
 }
 
-function toClerkFormError<TField extends string>(
-  cause: unknown,
-  fields: readonly TField[],
-  params: MessageValues | undefined,
-): FormError<TField> | undefined {
+/** Reads every error a Clerk failure carries, or `undefined` when the cause is not from Clerk. */
+function toClerkErrors(cause: unknown, params?: MessageValues): LocalizableError[] | undefined {
+  if (!(cause instanceof Error)) {
+    return undefined;
+  }
   if (isClerkRuntimeError(cause)) {
-    return {
-      global: {
+    return [
+      {
         code: cause.code,
         ...(cause.longMessage ? { message: cause.longMessage } : {}),
         ...(params ? { params } : {}),
       },
-    };
+    ];
   }
   if (!isClerkAPIResponseError(cause)) {
     return undefined;
   }
-  const error: FormError<TField> = {};
-  for (const apiError of cause.errors) {
-    const paramName = apiError.meta?.paramName;
-    const localizable: LocalizableError = {
-      code: apiError.code,
+  return cause.errors.map(error => {
+    const paramName = error.meta?.paramName;
+    return {
+      code: error.code,
       ...(paramName ? { paramName } : {}),
-      message: apiError.longMessage || apiError.message,
+      message: error.longMessage || error.message,
       ...(params ? { params } : {}),
     };
-    const field = fields.find(f => paramName && snakeToCamel(paramName) === f);
+  });
+}
+
+function toClerkFormError<TField extends string>(
+  cause: unknown,
+  fields: readonly TField[],
+  params: MessageValues | undefined,
+): FormError<TField> | undefined {
+  const errors = toClerkErrors(cause, params);
+  if (!errors) {
+    return undefined;
+  }
+  const formError: FormError<TField> = {};
+  for (const error of errors) {
+    const field = fields.find(f => error.paramName && snakeToCamel(error.paramName) === f);
     if (field) {
-      error.fields = { ...error.fields, [field]: error.fields?.[field] ?? localizable };
+      formError.fields = { ...formError.fields, [field]: formError.fields?.[field] ?? error };
     } else {
-      error.global ??= localizable;
+      formError.global ??= error;
     }
   }
-  return error;
+  return formError;
 }
 
 /**
@@ -79,11 +92,27 @@ export async function save<TField extends string = never>(
   }
 }
 
+/**
+ * Reads what to tell the user about a failed action. A Clerk error keeps its code so the catalog can
+ * localize it; anything else keeps its cause, is logged, and renders as the caller's fallback.
+ */
+export function toLocalizableError(cause: unknown): ErrorDescription {
+  const error =
+    cause instanceof SaveError
+      ? (cause.formError.global ?? Object.values(cause.formError.fields ?? {}).find(field => field !== undefined))
+      : toClerkErrors(cause)?.[0];
+  if (error) {
+    return error;
+  }
+  console.error('[Clerk] Could not localize error', cause);
+  return { cause };
+}
+
 /** Reads what a rejected save left for the view. An unrecognized rejection is the generic error. */
 export function toFormError<TField extends string = string>(cause: unknown): FormError<TField> {
   if (cause instanceof SaveError) {
     return cause.formError;
   }
-  console.error(cause);
+  console.error('[Clerk] Could not localize error', cause);
   return { global: UNEXPECTED_ERROR };
 }
diff --git a/packages/swingset/src/stories/fixtures/user-profile-edit-name.ts b/packages/swingset/src/stories/fixtures/user-profile-edit-name.ts
index 083b7436224..9c0068093a6 100644
--- a/packages/swingset/src/stories/fixtures/user-profile-edit-name.ts
+++ b/packages/swingset/src/stories/fixtures/user-profile-edit-name.ts
@@ -1,6 +1,6 @@
 import type { UserProfileEditNameValue } from '@clerk/mosaic/features/user-profile/user-profile-account-section/user-profile-edit-name.dialog';
-import type { FormError } from '@clerk/mosaic/utils/form-error';
-import { SaveError } from '@clerk/mosaic/utils/form-error';
+import type { FormError } from '@clerk/mosaic/utils/errors';
+import { SaveError } from '@clerk/mosaic/utils/errors';
 import { useState } from 'react';
 
 import { useChaosFixture } from '@/components/ChaosProvider';
diff --git a/packages/swingset/src/stories/fixtures/user-profile-edit-username.ts b/packages/swingset/src/stories/fixtures/user-profile-edit-username.ts
index 67a08f99aea..5e1dc6115b3 100644
--- a/packages/swingset/src/stories/fixtures/user-profile-edit-username.ts
+++ b/packages/swingset/src/stories/fixtures/user-profile-edit-username.ts
@@ -1,5 +1,5 @@
-import type { FormError } from '@clerk/mosaic/utils/form-error';
-import { SaveError } from '@clerk/mosaic/utils/form-error';
+import type { FormError } from '@clerk/mosaic/utils/errors';
+import { SaveError } from '@clerk/mosaic/utils/errors';
 import { useState } from 'react';
 
 import { useChaosFixture } from '@/components/ChaosProvider';
diff --git a/packages/swingset/src/stories/user-profile-account-section.stories.tsx b/packages/swingset/src/stories/user-profile-account-section.stories.tsx
index 54a81a99f38..407cae0a6f8 100644
--- a/packages/swingset/src/stories/user-profile-account-section.stories.tsx
+++ b/packages/swingset/src/stories/user-profile-account-section.stories.tsx
@@ -7,7 +7,7 @@ import { UserProfileAccountSectionView } from '@clerk/mosaic/features/user-profi
 import type { UserProfileAddPhoneDialogProps } from '@clerk/mosaic/features/user-profile/user-profile-account-section/user-profile-add-phone.dialog';
 import { UserProfileVerifyEmailLinkDialog } from '@clerk/mosaic/features/user-profile/user-profile-account-section/user-profile-verify-email-link.dialog';
 import { UserProfileVerifyEmailSsoDialog } from '@clerk/mosaic/features/user-profile/user-profile-account-section/user-profile-verify-email-sso.dialog';
-import type { FormError } from '@clerk/mosaic/utils/form-error';
+import type { FormError } from '@clerk/mosaic/utils/errors';
 import { useState } from 'react';
 
 import type { StoryMeta } from '@/lib/types';
@@ -224,8 +224,10 @@ export function EditNameFails() {
     <AccountSection
       allowMultipleAccounts={false}
       failWith={{
-        global: { message: 'Your name could not be updated.' },
-        fields: { lastName: { message: 'Last name must be 64 characters or fewer.' } },
+        global: { code: 'internal_clerk_error', message: 'Your name could not be updated.' },
+        fields: {
+          lastName: { code: 'form_param_max_length_exceeded', message: 'Last name must be 64 characters or fewer.' },
+        },
       }}
     />
   );
@@ -236,8 +238,8 @@ export function EditUsernameFails() {
     <AccountSection
       allowMultipleAccounts={false}
       usernameFailWith={{
-        global: { message: 'Your username could not be updated.' },
-        fields: { username: { message: 'That username is already taken.' } },
+        global: { code: 'internal_clerk_error', message: 'Your username could not be updated.' },
+        fields: { username: { code: 'form_identifier_exists', message: 'That username is already taken.' } },
       }}
     />
   );