diff --git a/.github/workflows/pr-ci.yml b/.github/workflows/pr-ci.yml
index 7991a48a4..ef0ca25d1 100644
--- a/.github/workflows/pr-ci.yml
+++ b/.github/workflows/pr-ci.yml
@@ -436,7 +436,27 @@ jobs:
       image: ghcr.io/tinyhumansai/openhuman_ci:rust-1.93.0
     env:
       CARGO_INCREMENTAL: "0"
+      # The instrumented Tauri shell binary (whole tauri/zbus/CEF graph) is
+      # dominated by DWARF debug info, which exhausts the runner disk and
+      # SIGBUSes the linker (collect2: ld terminated with signal 7) during the
+      # final link. Drop debug info — llvm-cov reads coverage from the embedded
+      # __llvm_covmap/__llvm_covfun sections, NOT from DWARF, so coverage
+      # numbers are unaffected. Mirrors rust-core-coverage.
+      CARGO_PROFILE_DEV_DEBUG: "0"
     steps:
+      - name: Free disk space
+        run: |
+          # Coverage-instrumented builds produce huge binaries that exhaust the
+          # runner's ~14GB free disk during linking (SIGBUS). Inside a container,
+          # host paths are bind-mounted:
+          #   /opt/hostedtoolcache → /__t
+          #   /home/runner/work    → /__w
+          # Deleting /__t frees ~8GB on the same partition the build uses.
+          # Mirrors rust-core-coverage.
+          rm -rf /__t/* || true
+          echo "Disk after cleanup:"
+          df -h /__w || true
+
       - name: Checkout code
         uses: actions/checkout@v5
         with:
@@ -471,6 +491,11 @@ jobs:
 
       - name: Run cargo llvm-cov for Tauri shell
         run: bash scripts/ci-cancel-aware.sh cargo llvm-cov --manifest-path app/src-tauri/Cargo.toml --lcov --output-path lcov-tauri.info
+        env:
+          # Serialize codegen/link to cap peak memory + disk during the
+          # instrumented Tauri-shell link (SIGBUS otherwise). Mirrors
+          # rust-core-coverage.
+          CARGO_BUILD_JOBS: "1"
 
       - name: Save CEF binary distribution cache
         if: always() && steps.cef-cache.outputs.cache-hit != 'true'
diff --git a/app/src/components/accounts/WebviewHost.tsx b/app/src/components/accounts/WebviewHost.tsx
index 1cf8126bf..20e48f48b 100644
--- a/app/src/components/accounts/WebviewHost.tsx
+++ b/app/src/components/accounts/WebviewHost.tsx
@@ -226,7 +226,9 @@ const WebviewHost = ({ accountId, provider }: WebviewHostProps) => {
           />
           <span
             className={`text-xs font-medium tracking-wide ${isLoading ? '' : 'text-stone-500 dark:text-neutral-400'}`}>
-            {isLoading ? `${t('accounts.webviewHost.loading')} ${providerName}...` : providerName}
+            {isLoading
+              ? t('accounts.webviewHost.loading').replace('{providerName}', providerName)
+              : providerName}
           </span>
           {isLoading ? (
             <div
@@ -251,7 +253,9 @@ const WebviewHost = ({ accountId, provider }: WebviewHostProps) => {
           aria-live="polite"
           aria-label={t('accounts.webviewHost.loadTimeout')}>
           <div className="max-w-sm space-y-1">
-            <p className="text-sm font-semibold text-stone-800 dark:text-neutral-100">{`${providerName} ${t('accounts.webviewHost.takingLonger')}`}</p>
+            <p className="text-sm font-semibold text-stone-800 dark:text-neutral-100">
+              {t('accounts.webviewHost.takingLonger').replace('{providerName}', providerName)}
+            </p>
             <p className="text-xs text-stone-600 dark:text-neutral-300">
               {t('accounts.webviewHost.timeoutHint')}
             </p>
diff --git a/app/src/components/accounts/__tests__/WebviewHost.test.tsx b/app/src/components/accounts/__tests__/WebviewHost.test.tsx
index ba539890b..6ca0896dd 100644
--- a/app/src/components/accounts/__tests__/WebviewHost.test.tsx
+++ b/app/src/components/accounts/__tests__/WebviewHost.test.tsx
@@ -83,6 +83,25 @@ describe('WebviewHost — issue #1233 loading UX', () => {
     expect(screen.queryByTestId(`webview-loading-${ACCOUNT_ID}`)).not.toBeInTheDocument();
   });
 
+  // Issue #3759: the loading/timeout copy must SUBSTITUTE the provider name
+  // into the `{providerName}` slot, not concatenate it — otherwise the raw
+  // placeholder token leaks to screen ("Loading {providerName}... Slack...").
+  it('substitutes the provider name into the loading copy (issue #3759)', () => {
+    seedAccount('loading');
+    renderHost();
+    const placeholder = screen.getByTestId(`webview-placeholder-${ACCOUNT_ID}`);
+    expect(placeholder).toHaveTextContent('Loading Slack...');
+    expect(placeholder.textContent).not.toContain('{providerName}');
+  });
+
+  it('substitutes the provider name into the timeout copy (issue #3759)', () => {
+    seedAccount('timeout');
+    renderHost();
+    const timeout = screen.getByTestId(`webview-timeout-${ACCOUNT_ID}`);
+    expect(timeout).toHaveTextContent('Slack is taking longer than expected.');
+    expect(timeout.textContent).not.toContain('{providerName}');
+  });
+
   it('renders the phase hint after 5s of loading and escalates after 10s', () => {
     seedAccount('loading');
     renderHost();
diff --git a/app/src/components/composio/ComposioConnectModal.test.tsx b/app/src/components/composio/ComposioConnectModal.test.tsx
index 8b14568e7..27b6eb80b 100644
--- a/app/src/components/composio/ComposioConnectModal.test.tsx
+++ b/app/src/components/composio/ComposioConnectModal.test.tsx
@@ -716,3 +716,30 @@ describe('<ComposioConnectModal> — WhatsApp WABA id parity (#2127)', () => {
     });
   });
 });
+
+describe('ComposioConnectModal — connection-failed copy (issue #3759)', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('substitutes the status into the failure message when polling sees a FAILED connection', async () => {
+    // A PENDING connection resumes polling on mount; the first poll observes a
+    // FAILED connection and must SUBSTITUTE {status} into the error copy
+    // (issue #3759) — not concatenate/leak the literal placeholder.
+    vi.mocked(composioApi.listConnections).mockResolvedValue({
+      connections: [{ id: 'ca_err', toolkit: 'gmail', status: 'FAILED' }],
+    });
+
+    render(
+      <ComposioConnectModal
+        toolkit={mockToolkit}
+        connections={[{ id: 'ca_pending', toolkit: 'gmail', status: 'PENDING' }]}
+        onClose={() => {}}
+      />
+    );
+
+    expect(await screen.findByText('Connection failed (status: FAILED).')).toBeInTheDocument();
+    // Regression guard: the raw placeholder must never reach the screen.
+    expect(screen.queryByText(/\{status\}/)).not.toBeInTheDocument();
+  });
+});
diff --git a/app/src/components/composio/ComposioConnectModal.tsx b/app/src/components/composio/ComposioConnectModal.tsx
index 10cc312ad..b11a47f72 100644
--- a/app/src/components/composio/ComposioConnectModal.tsx
+++ b/app/src/components/composio/ComposioConnectModal.tsx
@@ -298,7 +298,9 @@ export default function ComposioConnectModal({
           if (state === 'error') {
             stopPolling();
             setPhase('error');
-            setError(`${t('composio.connect.connectionFailed')} (status: ${hit.status}).`);
+            setError(
+              t('composio.connect.connectionFailed').replace('{status}', String(hit.status))
+            );
             return;
           }
           if (state === 'expired') {
@@ -539,7 +541,7 @@ export default function ComposioConnectModal({
       } catch (err) {
         const msg = err instanceof Error ? err.message : String(err);
         setPhase('error');
-        setError(`${t('composio.connect.disconnectFailed')}: ${msg}`);
+        setError(t('composio.connect.disconnectFailed').replace('{msg}', msg));
         setClearMemoryOnDisconnect(false);
       }
     },
diff --git a/app/src/components/intelligence/IntelligenceTasksTab.tsx b/app/src/components/intelligence/IntelligenceTasksTab.tsx
index 6d780d33b..a4d7fb466 100644
--- a/app/src/components/intelligence/IntelligenceTasksTab.tsx
+++ b/app/src/components/intelligence/IntelligenceTasksTab.tsx
@@ -527,7 +527,7 @@ export default function IntelligenceTasksTab() {
     const title =
       thread?.title && thread.title.trim().length > 0
         ? thread.title
-        : `${t('intelligence.tasks.threadPrefix')} ${shortId(threadId)}`;
+        : t('intelligence.tasks.threadPrefix').replace('{thread}', shortId(threadId));
 
     boardEntries.push({ threadId, title, board, live: Boolean(liveBoard) });
   }
diff --git a/app/src/lib/i18n/en.ts b/app/src/lib/i18n/en.ts
index 21bd884dc..2199e7c21 100644
--- a/app/src/lib/i18n/en.ts
+++ b/app/src/lib/i18n/en.ts
@@ -3375,7 +3375,7 @@ const en: TranslationMap = {
   'composio.connect.dynamicsOrgNameHint':
     'For example, "myorg" for myorg.crm.dynamics.com. Enter the short org name only, not the full URL.',
   'composio.connect.dynamicsOrgNameLabel': 'Dynamics 365 Organization Name',
-  'composio.connect.connectionFailed': 'Connection failed (status: ${hit.status}).',
+  'composio.connect.connectionFailed': 'Connection failed (status: {status}).',
   'composio.connect.disconnectFailed': 'Disconnect failed: {msg}',
   'composio.connect.disconnecting': 'Disconnecting…',
   'composio.connect.idleDescription': 'Connect your',
@@ -3594,7 +3594,7 @@ const en: TranslationMap = {
   'intelligence.tasks.failedToLoad': 'Failed to load',
   'intelligence.tasks.live': 'live',
   'intelligence.tasks.loadingBoards': 'Loading task boards…',
-  'intelligence.tasks.threadPrefix': 'Thread {id}',
+  'intelligence.tasks.threadPrefix': 'Thread {thread}',
   'intelligence.tasks.subtitle': 'Your tasks and agent task boards across the workspace.',
   'intelligence.tasks.newTask': 'New task',
   'intelligence.tasks.personalBoardTitle': 'Agent Tasks',
diff --git a/app/src/lib/i18n/zh-CN.ts b/app/src/lib/i18n/zh-CN.ts
index 4fee4a1aa..d2d0dca7b 100644
--- a/app/src/lib/i18n/zh-CN.ts
+++ b/app/src/lib/i18n/zh-CN.ts
@@ -2709,7 +2709,7 @@ const messages: TranslationMap = {
   'composio.connect.dynamicsOrgNameHint':
     '例如，myorg.crm.dynamics.com 的组织名称为 "myorg"。仅输入简短的组织名称，而不是完整 URL。',
   'composio.connect.dynamicsOrgNameLabel': 'Dynamics 365 组织名称',
-  'composio.connect.connectionFailed': '连接失败。',
+  'composio.connect.connectionFailed': '连接失败（状态：{status}）。',
   'composio.connect.disconnectFailed': '断开连接失败：{msg}',
   'composio.connect.disconnecting': '断开中…',
   'composio.connect.idleDescription': '连接你的',
@@ -2899,7 +2899,7 @@ const messages: TranslationMap = {
   'intelligence.tasks.failedToLoad': '加载失败',
   'intelligence.tasks.live': '实时',
   'intelligence.tasks.loadingBoards': '正在加载任务看板…',
-  'intelligence.tasks.threadPrefix': '对话',
+  'intelligence.tasks.threadPrefix': '对话 {thread}',
   'intelligence.tasks.subtitle': '整个工作区中的你的任务和智能体任务看板。',
   'intelligence.tasks.newTask': '新建任务',
   'intelligence.tasks.personalBoardTitle': '智能体任务',