diff --git a/backend/__tests__/unit/routes/hostedMcpConnect.callback.test.js b/backend/__tests__/unit/routes/hostedMcpConnect.callback.test.js
index 181dfd92cd..b30c6a91e1 100644
--- a/backend/__tests__/unit/routes/hostedMcpConnect.callback.test.js
+++ b/backend/__tests__/unit/routes/hostedMcpConnect.callback.test.js
@@ -450,6 +450,79 @@ describe('hosted-mcp connect: callback', () => {
     }
   });
 
+  // TASK-344: a refused grant is never stored, so when the vendor revoke can't
+  // be confirmed the grant is still live at the vendor and only the person can
+  // remove it there. The redirect names the entry's own page; it says nothing
+  // when the revoke went through (the arm above pins that exact shape).
+  it('a refused overbroad grant whose vendor revoke fails names the vendor revoke page', async () => {
+    FIXTURE_ENTRY.revoke.endpoint = 'https://mcp.linear.app/revoke';
+    const warn = jest.spyOn(console, 'warn').mockImplementation(() => {});
+    global.fetch
+      .mockResolvedValueOnce({
+        ok: true,
+        json: async () => ({ access_token: 'access-overbroad', refresh_token: 'refresh-overbroad', scope: 'read openid write' }),
+      })
+      .mockResolvedValueOnce({ ok: false, status: 503, json: async () => ({}) });
+
+    try {
+      const res = await callback();
+
+      expect(outcome(res)).toEqual({
+        status: 302,
+        hostedMcp: 'error',
+        code: 'unrequested_scope',
+        entryId: 'linear',
+        revokeAt: FIXTURE_ENTRY.revoke.page,
+      });
+      expect(global.fetch).toHaveBeenCalledTimes(2);
+      expect(connectorSecrets.put).not.toHaveBeenCalled();
+    } finally {
+      warn.mockRestore();
+    }
+  });
+
+  it('a refused overbroad grant on an entry with no revoke endpoint names the vendor revoke page', async () => {
+    const warn = jest.spyOn(console, 'warn').mockImplementation(() => {});
+    global.fetch.mockResolvedValueOnce({
+      ok: true,
+      json: async () => ({ access_token: 'access-overbroad', refresh_token: 'refresh-overbroad', scope: 'read openid write' }),
+    });
+
+    try {
+      const res = await callback();
+
+      expect(outcome(res)).toEqual({
+        status: 302,
+        hostedMcp: 'error',
+        code: 'unrequested_scope',
+        entryId: 'linear',
+        revokeAt: FIXTURE_ENTRY.revoke.page,
+      });
+      expect(global.fetch).toHaveBeenCalledTimes(1);
+      expect(connectorSecrets.put).not.toHaveBeenCalled();
+    } finally {
+      warn.mockRestore();
+    }
+  });
+
+  it('an unreadable scope whose grant cannot be revoked names the vendor revoke page', async () => {
+    global.fetch.mockResolvedValueOnce({
+      ok: true,
+      json: async () => ({ access_token: 'access-1', refresh_token: 'refresh-1', scope: ['read'] }),
+    });
+
+    const res = await callback();
+
+    expect(outcome(res)).toEqual({
+      status: 302,
+      hostedMcp: 'error',
+      code: 'exchange_invalid_scope',
+      entryId: 'linear',
+      revokeAt: FIXTURE_ENTRY.revoke.page,
+    });
+    expect(connectorSecrets.put).not.toHaveBeenCalled();
+  });
+
   it('accepts the exact requested scope set regardless of order or comma separators', async () => {
     global.fetch.mockResolvedValue({
       ok: true,
diff --git a/backend/__tests__/unit/services/installableCatalogService.test.js b/backend/__tests__/unit/services/installableCatalogService.test.js
index 58fcda7f0f..a850a004f2 100644
--- a/backend/__tests__/unit/services/installableCatalogService.test.js
+++ b/backend/__tests__/unit/services/installableCatalogService.test.js
@@ -288,6 +288,10 @@ it("a hosted entry's tool row carries its connect descriptor and only its own co
     expect(linear.connectNotice).toBeUndefined();
     expect(acmeRow.accessPage).toBe(acme.accessPage);
     expect(linear.accessPage).toBeUndefined();
+    // The page a refused connect's error return may name (TASK-344): the
+    // browser shows a link only when the callback's page equals this one.
+    expect(acmeRow.revokePage).toBe(acme.revoke.page);
+    expect(linear.revokePage).toBe(linearEntry.revoke.page);
     // Each row sees its own vendor's connection and not the other's.
     expect(linear.connections).toEqual([
       { connectionId: 'conn-linear', owner: '', repo: '' },
diff --git a/backend/routes/hostedMcpConnect.ts b/backend/routes/hostedMcpConnect.ts
index 21a1958048..ef20208efb 100644
--- a/backend/routes/hostedMcpConnect.ts
+++ b/backend/routes/hostedMcpConnect.ts
@@ -95,15 +95,22 @@ const parseScopeSet = (scope: string): Set<string> => new Set(
   scope.split(/[\s,]+/).map((value) => value.trim()).filter(Boolean),
 );
 
-/** A refused grant is never stored; revoke its refresh token when the entry can. */
+/**
+ * A refused grant is never stored; revoke its refresh token when the entry can.
+ * Whatever happens the connect stays refused and no token is kept. When the
+ * vendor did not confirm the revoke, the grant is still live there and only the
+ * person can remove it, so the redirect names the entry's own revoke page
+ * (TASK-344). The page is the server's; the browser never supplies it.
+ */
 const revokeRefusedGrant = async (
   entry: HostedMcpEntry,
   client: { clientId: string; clientSecret?: string },
   tokens: TokenResponse,
-): Promise<void> => {
-  if (!hostedMcpRevokeTarget(entry)?.endpoint) return;
+): Promise<{ manualRevoke?: { entryId: string; revokeAt: string } }> => {
+  const target = hostedMcpRevokeTarget(entry);
+  const leftLive = target?.page ? { manualRevoke: { entryId: entry.id, revokeAt: target.page } } : {};
   const token = tokens.refresh_token || tokens.access_token;
-  if (!token) return;
+  if (!target?.endpoint || !token) return leftLive;
   try {
     await revokeTokenAtVendor({
       entry,
@@ -112,8 +119,9 @@ const revokeRefusedGrant = async (
       token,
       tokenTypeHint: tokens.refresh_token ? 'refresh_token' : 'access_token',
     });
+    return {};
   } catch {
-    // The connect remains refused and no token is retained if vendor revoke fails.
+    return leftLive;
   }
 };
 
@@ -501,8 +509,7 @@ const finishCallback = async (req: Request, res: Response, flow: CallbackFlow) =
 
   const scopeWasReturned = Object.prototype.hasOwnProperty.call(tokens, 'scope');
   if (scopeWasReturned && typeof tokens.scope !== 'string') {
-    await revokeRefusedGrant(entry, client, tokens);
-    return callbackRedirect(res, 'error', 'exchange_invalid_scope');
+    return callbackRedirect(res, 'error', 'exchange_invalid_scope', await revokeRefusedGrant(entry, client, tokens));
   }
   const grantedScope = scopeWasReturned ? tokens.scope as string : entry.scopes.join(' ');
   const grantedScopes: Set<string> = scopeWasReturned
@@ -517,8 +524,7 @@ const finishCallback = async (req: Request, res: Response, flow: CallbackFlow) =
       entryId: entry.id,
       extraScopeCount: extraScopes.length,
     }));
-    await revokeRefusedGrant(entry, client, tokens);
-    return callbackRedirect(res, 'error', 'unrequested_scope');
+    return callbackRedirect(res, 'error', 'unrequested_scope', await revokeRefusedGrant(entry, client, tokens));
   }
   // Store the parsed set in the canonical OAuth space-delimited form. This
   // keeps a vendor's comma-separated response useful to later scope checks.
diff --git a/backend/services/installable/installableCatalogService.ts b/backend/services/installable/installableCatalogService.ts
index 43a6541c94..f12460617a 100644
--- a/backend/services/installable/installableCatalogService.ts
+++ b/backend/services/installable/installableCatalogService.ts
@@ -173,6 +173,7 @@ const toolEntriesFor = async (userId: string): Promise<{ entries: unknown[]; hid
       description: row.description || '',
       ...(hostedEntry?.connectNotice ? { connectNotice: hostedEntry.connectNotice } : {}),
       ...(hostedEntry?.accessPage ? { accessPage: hostedEntry.accessPage } : {}),
+      ...(hostedEntry?.revoke?.page ? { revokePage: hostedEntry.revoke.page } : {}),
       connectionType: meta.connectionType,
       ...(meta.entryId ? { entryId: meta.entryId } : {}),
       available: readiness.available,
diff --git a/frontend/src/i18n/locales/en.json b/frontend/src/i18n/locales/en.json
index b12793f2ac..61ebf99c4d 100644
--- a/frontend/src/i18n/locales/en.json
+++ b/frontend/src/i18n/locales/en.json
@@ -2424,6 +2424,10 @@
     "hostedMcpManualRevoke_supabase": "Commonly may still be authorized in the Supabase organization you connected before. Removing Commonly under Authorized apps disconnects everyone who connected that organization.",
     "hostedMcpReviewAuthorization": "Open {{provider}}'s connected apps",
     "hostedMcpReviewAuthorization_supabase": "Open Supabase Authorized apps",
+    "hostedMcpRefusedStillListed": "{{provider}} may still list Commonly as connected. Remove it there.",
+    "hostedMcpRefusedStillListed_linear": "Linear may still list this as an MCP grant under its connected apps. Revoke it there.",
+    "hostedMcpRefusedStillListed_sentry": "Sentry may still list its MCP server app as connected. Revoking it there ends every client that server holds for the account, not only Commonly.",
+    "hostedMcpRefusedStillListed_supabase": "Commonly may still be authorized in the Supabase organization you chose. Removing it under Authorized apps disconnects everyone who connected that organization.",
     "hostedMcpAuthenticationRequired": "Sign in to Commonly, then try connecting again.",
     "hostedMcpClientSetup": "This connector’s sign-in setup needs attention. Ask an administrator to check it.",
     "hostedMcpConsentDenied": "You didn’t approve this connection. Nothing was saved.",
diff --git a/frontend/src/i18n/locales/zh-CN.json b/frontend/src/i18n/locales/zh-CN.json
index 58be3e9018..0edb2a52a2 100644
--- a/frontend/src/i18n/locales/zh-CN.json
+++ b/frontend/src/i18n/locales/zh-CN.json
@@ -2414,6 +2414,10 @@
     "hostedMcpManualRevoke_supabase": "Commonly 可能仍在你之前连接的 Supabase 组织中获得授权。在“已授权应用”中移除 Commonly，会断开所有连接该组织的成员。",
     "hostedMcpReviewAuthorization": "打开 {{provider}} 的已连接应用",
     "hostedMcpReviewAuthorization_supabase": "打开 Supabase 已授权应用",
+    "hostedMcpRefusedStillListed": "{{provider}} 可能仍显示 Commonly 已连接，请到那里移除。",
+    "hostedMcpRefusedStillListed_linear": "Linear 的已连接应用中可能仍有这项 MCP 授权，请到那里撤销。",
+    "hostedMcpRefusedStillListed_sentry": "Sentry 中可能仍显示它的 MCP 服务器应用已连接。在那里撤销，会断开此账号下该服务器的所有客户端，不只是 Commonly。",
+    "hostedMcpRefusedStillListed_supabase": "Commonly 可能仍在你刚才选择的 Supabase 组织中获得授权。在“已授权应用”中移除，会断开所有连接该组织的成员。",
     "hostedMcpAuthenticationRequired": "请先登录 Commonly，再重新连接。",
     "hostedMcpClientSetup": "此连接器的登录配置有问题，请联系管理员检查。",
     "hostedMcpConsentDenied": "你没有同意此次授权。连接未保存。",
diff --git a/frontend/src/v2/__tests__/ConnectorsPage.channels.test.tsx b/frontend/src/v2/__tests__/ConnectorsPage.channels.test.tsx
index 2f71ccd3a3..71ea3224e5 100644
--- a/frontend/src/v2/__tests__/ConnectorsPage.channels.test.tsx
+++ b/frontend/src/v2/__tests__/ConnectorsPage.channels.test.tsx
@@ -595,6 +595,64 @@ describe('Connectors page: channels', () => {
     expect(screen.queryByText('unrequested_scope')).toBeNull();
   });
 
+  // TASK-344: a refused grant is never stored, so when the vendor revoke can't be
+  // confirmed the grant is still live there. The link comes from the catalogue's
+  // own page for that entry; the callback's value only has to equal it.
+  const refusedReturn = (revokeAt) => (
+    `/v2/connectors?hostedMcp=error&code=unrequested_scope&entryId=linear&revokeAt=${encodeURIComponent(revokeAt)}`
+  );
+
+  it('a refused connect whose grant may still be live links the provider revoke page', async () => {
+    const revokePage = 'https://linear.app/settings/security';
+    window.history.replaceState({}, '', refusedReturn(revokePage));
+    mockGets([], [{ ...hostedLinearCatalogEntry(), connections: [], revokePage }]);
+    renderPage();
+
+    const alert = await screen.findByRole('alert');
+    expect(alert).toHaveTextContent("The provider granted access Commonly didn’t ask for, so the connection wasn’t saved.");
+    const link = await within(alert).findByRole('link', { name: "Open Linear's connected apps" });
+    expect(link).toHaveAttribute('href', revokePage);
+    expect(link).toHaveAttribute('target', '_blank');
+    expect(link).toHaveAttribute('rel', 'noopener noreferrer');
+    expect(alert).toHaveTextContent('Linear may still list this as an MCP grant under its connected apps. Revoke it there.');
+    expect(window.location.search).toBe('');
+  });
+
+  // Removing Commonly in Supabase ends it for the whole organization, so a
+  // refused connect there must say so rather than just say "remove it".
+  it('a refused Supabase connect warns that removing it there disconnects the organization', async () => {
+    const revokePage = 'https://supabase.com/dashboard/org/_/apps';
+    window.history.replaceState({}, '', `/v2/connectors?hostedMcp=error&code=unrequested_scope&entryId=supabase&revokeAt=${encodeURIComponent(revokePage)}`);
+    mockGets([], [{
+      ...hostedLinearCatalogEntry(), installableId: 'supabase', label: 'Supabase', entryId: 'supabase', connections: [], revokePage,
+    }]);
+    renderPage();
+
+    const alert = await screen.findByRole('alert');
+    const link = await within(alert).findByRole('link', { name: 'Open Supabase Authorized apps' });
+    expect(link).toHaveAttribute('href', revokePage);
+    expect(alert).toHaveTextContent('Removing it under Authorized apps disconnects everyone who connected that organization.');
+  });
+
+  // Equality with the catalogue's page, not a same-origin check: the right
+  // host on another path is as forged as another host.
+  it.each([
+    ['another host', 'https://evil.example/'],
+    ['the provider host on another path', 'https://linear.app/evil-path'],
+    ['a script URL', 'javascript:alert(1)'],
+  ])('a refused connect never links a revoke page the catalogue does not name (%s)', async (_label, forged) => {
+    window.history.replaceState({}, '', refusedReturn(forged));
+    mockGets([], [{ ...hostedLinearCatalogEntry(), connections: [], revokePage: 'https://linear.app/settings/security' }]);
+    renderPage();
+
+    const alert = await screen.findByRole('alert');
+    expect(alert).toHaveTextContent("The provider granted access Commonly didn’t ask for, so the connection wasn’t saved.");
+    await waitFor(() => expect(window.location.search).toBe(''));
+    await act(async () => { await new Promise((resolve) => { setTimeout(resolve, 0); }); });
+    expect(within(alert).queryByRole('link')).toBeNull();
+    expect(document.body.innerHTML).not.toContain(forged);
+  });
+
   it.each([
     ['unknown_entry', 'hostedMcpUnknownEntry'],
     ['invalid_state', 'hostedMcpInvalidState'],
diff --git a/frontend/src/v2/connectors/ConnectorsPage.tsx b/frontend/src/v2/connectors/ConnectorsPage.tsx
index 445775012e..b00075a32e 100644
--- a/frontend/src/v2/connectors/ConnectorsPage.tsx
+++ b/frontend/src/v2/connectors/ConnectorsPage.tsx
@@ -9,7 +9,7 @@ import { useNavigate } from 'react-router-dom';
 import { catalogDescription } from '../utils/connectorCatalogDescription';
 import { ADD_PLATFORMS, TYPE_LABELS } from './channelModel';
 import type { ListItem } from './channelModel';
-import { entryCovers, entryIsGranted, isDead } from './toolModel';
+import { PER_ENTRY_REVOKE_COPY, entryCovers, entryIsGranted, isDead } from './toolModel';
 import type { ToolCatalogEntry, ToolGrant } from './toolModel';
 import { useChannelConnectors } from './useChannelConnectors';
 import { useToolConnectors } from './useToolConnectors';
@@ -505,9 +505,36 @@ const ConnectorsPage: React.FC = () => {
   const errorText = c.hostedMcpCallbackError || c.error || c.slackCallbackError || (
     !m.draft && !m.selected && !m.githubAppSetup ? m.error : null
   );
+  // A refused connect that may have left a grant live at the provider. The
+  // callback error leads errorText, so this always sits beside its own notice.
+  const callbackRevoke = c.hostedMcpCallbackError ? c.hostedMcpCallbackRevoke : null;
+  // Per-entry copy names what that vendor's page lists, and what removing it there ends.
+  const callbackRevokeContext = callbackRevoke && PER_ENTRY_REVOKE_COPY.has(callbackRevoke.entryId)
+    ? callbackRevoke.entryId : undefined;
   const noticeBlock = (
     <>
-      {errorText && <p className="v2-cx-error" role="alert">{errorText}</p>}
+      {errorText && (
+        <p className="v2-cx-error" role="alert">
+          {errorText}
+          {callbackRevoke && (
+            <>
+              {' '}
+              {t('connectors.hostedMcpRefusedStillListed', {
+                defaultValue: '{{provider}} may still list Commonly as connected. Remove it there.',
+                context: callbackRevokeContext,
+                provider: callbackRevoke.provider,
+              })}{' '}
+              <a href={callbackRevoke.revokePage} target="_blank" rel="noopener noreferrer">
+                {t('connectors.hostedMcpReviewAuthorization', {
+                  defaultValue: "Open {{provider}}'s connected apps",
+                  context: callbackRevokeContext,
+                  provider: callbackRevoke.provider,
+                })}
+              </a>
+            </>
+          )}
+        </p>
+      )}
       {m.removedHiddenNotice && (
         <p className="v2-cx-note" role="status">
           {m.removedHiddenNotice.revokePage
diff --git a/frontend/src/v2/connectors/channelModel.ts b/frontend/src/v2/connectors/channelModel.ts
index 66638aa54e..8410922bc8 100644
--- a/frontend/src/v2/connectors/channelModel.ts
+++ b/frontend/src/v2/connectors/channelModel.ts
@@ -89,6 +89,10 @@ export interface CatalogEntry {
   unavailableReason?: string;
   // Tool entries provide the provider name for the hosted connection row.
   entryId?: string;
+  // The entry's own revoke page. A refused connect can leave a grant live at
+  // the provider, and the callback's `revokeAt` is linked only when it equals
+  // this server-owned value.
+  revokePage?: string;
   installation: CatalogInstallation | null;
   integration: Connector | null;
 }
diff --git a/frontend/src/v2/connectors/useChannelConnectors.ts b/frontend/src/v2/connectors/useChannelConnectors.ts
index 4139b93f4e..133a2dd2a8 100644
--- a/frontend/src/v2/connectors/useChannelConnectors.ts
+++ b/frontend/src/v2/connectors/useChannelConnectors.ts
@@ -67,6 +67,13 @@ export const useChannelConnectors = () => {
   const [slackCallbackError, setSlackCallbackError] = useState<string | null>(null);
   const [slackLeadChoices, setSlackLeadChoices] = useState<Record<string, string>>({});
   const [hostedMcpCallbackError, setHostedMcpCallbackError] = useState<string | null>(null);
+  // A refused connect whose grant the server could not withdraw. `pending` is
+  // what the callback URL claimed; `hostedMcpCallbackRevoke` is set only once
+  // the catalogue confirms it.
+  const [pendingCallbackRevoke, setPendingCallbackRevoke] = useState<{ entryId: string; revokeAt: string } | null>(null);
+  const [hostedMcpCallbackRevoke, setHostedMcpCallbackRevoke] = useState<{
+    entryId: string; provider: string; revokePage: string;
+  } | null>(null);
   const pollRef = useRef<ReturnType<typeof setInterval> | null>(null);
   const podPickerRef = useRef<HTMLSelectElement | null>(null);
   // Ages must advance while the page sits open, and the source must be re-read
@@ -135,8 +142,13 @@ export const useChannelConnectors = () => {
     const query = new URLSearchParams(window.location.search);
     if (query.get('hostedMcp') !== 'error') return;
     setHostedMcpCallbackError(hostedMcpErrorNotice(t, query.get('code')));
+    const entryId = query.get('entryId');
+    const revokeAt = query.get('revokeAt');
+    if (entryId && revokeAt) setPendingCallbackRevoke({ entryId, revokeAt });
     query.delete('hostedMcp');
     query.delete('code');
+    query.delete('entryId');
+    query.delete('revokeAt');
     query.delete('extraScope');
     query.delete('error');
     query.delete('error_description');
@@ -171,6 +183,18 @@ export const useChannelConnectors = () => {
     );
   }, [load, t]);
 
+  // A refused connect has no row to read, so the catalogue entry is the
+  // authority: the page is linked only when it is the one the entry names.
+  useEffect(() => {
+    if (!pendingCallbackRevoke || loading || hostedCatalog === null) return;
+    const entry = hostedCatalog.find((candidate) => candidate.entryId === pendingCallbackRevoke.entryId);
+    const { revokeAt } = pendingCallbackRevoke;
+    if (entry?.label && entry.revokePage === revokeAt && safeProviderRevokePage(revokeAt)) {
+      setHostedMcpCallbackRevoke({ entryId: pendingCallbackRevoke.entryId, provider: entry.label, revokePage: revokeAt });
+    }
+    setPendingCallbackRevoke(null);
+  }, [hostedCatalog, loading, pendingCallbackRevoke]);
+
   // The hosted-MCP callback says when a previous provider authorization may
   // need manual attention. Resolve its page from the authenticated connection
   // row and match the callback copy to that server-owned value; never turn an
@@ -977,6 +1001,7 @@ export const useChannelConnectors = () => {
     setSlackLeadChoices,
     hostedMcpCallbackError,
     setHostedMcpCallbackError,
+    hostedMcpCallbackRevoke,
     pollRef,
     podPickerRef,
     now,