diff --git a/desktop/src/components/chat/MermaidRenderer.integration.test.tsx b/desktop/src/components/chat/MermaidRenderer.integration.test.tsx
index eafb81c8..137491e6 100644
--- a/desktop/src/components/chat/MermaidRenderer.integration.test.tsx
+++ b/desktop/src/components/chat/MermaidRenderer.integration.test.tsx
@@ -58,6 +58,24 @@ describe('MermaidRenderer Mermaid integration', () => {
     expect(surface.innerHTML).not.toContain('onerror')
   })
 
+  it('auto-quotes flowchart labels containing forward slashes to avoid lexical errors', async () => {
+    render(
+      <MermaidRenderer
+        code={[
+          'flowchart TD',
+          '  D1[/api/dcl] --> D2[直接调用 dclService]',
+          '  D2 --> R[返回结果]',
+        ].join('\n')}
+      />,
+    )
+
+    const surface = await screen.findByTestId('mermaid-diagram-surface')
+
+    expect(surface).toHaveTextContent('/api/dcl')
+    expect(surface).toHaveTextContent('直接调用 dclService')
+    expect(screen.queryByText('Mermaid Error')).not.toBeInTheDocument()
+  })
+
   it('renders generated flowchart labels with HTML breaks and structural characters', async () => {
     render(
       <MermaidRenderer
diff --git a/desktop/src/components/chat/MermaidRenderer.tsx b/desktop/src/components/chat/MermaidRenderer.tsx
index 8c5151dd..4489b05c 100644
--- a/desktop/src/components/chat/MermaidRenderer.tsx
+++ b/desktop/src/components/chat/MermaidRenderer.tsx
@@ -40,7 +40,7 @@ type MermaidThemeColors = {
 
 const FLOWCHART_START = /^\s*(?:graph|flowchart)\b/i
 const FLOWCHART_NODE_START = /^([A-Za-z][\w-]*)\[/
-const UNQUOTED_FLOWCHART_LABEL_UNSAFE = /<br\s*\/?>|[{}[\]*]/i
+const UNQUOTED_FLOWCHART_LABEL_UNSAFE = /<br\s*\/?>|[{}[\]*\/]/i
 
 function isFlowchartDiagram(code: string) {
   const firstMeaningfulLine = code