diff --git a/desktop/src/components/chat/MessageList.test.tsx b/desktop/src/components/chat/MessageList.test.tsx
index 603ee9a2..ca1e83d2 100644
--- a/desktop/src/components/chat/MessageList.test.tsx
+++ b/desktop/src/components/chat/MessageList.test.tsx
@@ -281,4 +281,32 @@ describe('MessageList nested tool calls', () => {
       '先看 CLI 和服务端入口。\n再看 desktop 前后端边界。'
     )
   })
+
+  it('shows raw startup details under translated CLI startup errors', () => {
+    useChatStore.setState({
+      sessions: {
+        [ACTIVE_TAB]: makeSessionState({
+          messages: [
+            {
+              id: 'error-1',
+              type: 'error',
+              code: 'CLI_START_FAILED',
+              message:
+                'CLI exited during startup (code 1): Claude Code on Windows requires git-bash (https://git-scm.com/downloads/win).',
+              timestamp: 1,
+            },
+          ],
+        }),
+      },
+    })
+
+    render(<MessageList />)
+
+    expect(screen.getByText('Failed to start CLI process.')).toBeTruthy()
+    expect(
+      screen.getByText(
+        'CLI exited during startup (code 1): Claude Code on Windows requires git-bash (https://git-scm.com/downloads/win).',
+      ),
+    ).toBeTruthy()
+  })
 })
diff --git a/desktop/src/components/chat/MessageList.tsx b/desktop/src/components/chat/MessageList.tsx
index 4ee13c6b..a50286ea 100644
--- a/desktop/src/components/chat/MessageList.tsx
+++ b/desktop/src/components/chat/MessageList.tsx
@@ -222,9 +222,18 @@ export const MessageBlock = memo(function MessageBlock({
       const errorKey = message.code ? `error.${message.code}` as TranslationKey : null
       const errorText = errorKey ? t(errorKey) : null
       const displayMessage = (errorText && errorText !== errorKey) ? errorText : message.message
+      const showRawDetail =
+        Boolean(message.message) &&
+        message.message.trim() !== '' &&
+        message.message !== displayMessage
       return (
         <div className="mb-3 px-4 py-2.5 rounded-lg bg-red-50 border border-red-200 text-sm text-[var(--color-error)]">
           <strong>Error:</strong> {displayMessage}
+          {showRawDetail && (
+            <div className="mt-1 whitespace-pre-wrap text-xs text-red-700/85">
+              {message.message}
+            </div>
+          )}
         </div>
       )
     }