feat(file): add existsPath API and UI feedback for file existence

src/main/main.ts

@@ -5956,6 +5956,20 @@ ipcMain.handle('file:openFile', async (_event, filePath: string) => {
   }
 });
 
+ipcMain.handle('file:existsPath', async (_event, filePath: string) => {
+  try {
+    const resolvedPath = expandLocalPathShorthand(
+      filePath,
+      normalizeLocalPathPlatform(process.platform),
+      app.getPath('home')
+    );
+    return { exists: existsSync(resolvedPath) };
+  } catch (error) {
+    console.error('Failed to check file existence:', error);
+    return { exists: false };
+  }
+});
+
 // File operations - write/save file content
 ipcMain.handle(
   'file:writeContent',

src/preload/preload.ts

@@ -1319,6 +1319,9 @@ const electronAPI = {
     openFile: (filePath: string): Promise<{ success: boolean; error?: string }> => {
       return ipcRenderer.invoke('file:openFile', filePath);
     },
+    existsPath: (filePath: string): Promise<{ exists: boolean }> => {
+      return ipcRenderer.invoke('file:existsPath', filePath);
+    },
     writeContent: (
       filePath: string,
       content: string

src/renderer/components/MessageItem.tsx

@@ -1,4 +1,4 @@
-import React, { memo, useMemo } from 'react';
+import React, { memo, useEffect, useMemo, useState } from 'react';
 import ReactMarkdown from 'react-markdown';
 import remarkGfm from 'remark-gfm';
 import { ClockIcon, FileIcon, VolumeMuteIcon, CodeBlockWithCopy } from './';
@@ -420,6 +420,8 @@ interface FilePathLinkProps {
   variant?: 'default' | 'code';
 }
 
+const pathExistenceCache = new Map<string, boolean>();
+
 function FilePathLink({
   path,
   platform,
@@ -428,6 +430,50 @@ function FilePathLink({
   variant = 'default',
 }: FilePathLinkProps): React.ReactElement {
   const className = getLinkClassName(tone, variant);
+  const cacheKey = `${platform}:${homePath ?? ''}:${path}`;
+  const [pathExists, setPathExists] = useState<boolean | null>(
+    pathExistenceCache.has(cacheKey) ? pathExistenceCache.get(cacheKey)! : null
+  );
+
+  useEffect(() => {
+    const cachedValue = pathExistenceCache.get(cacheKey);
+    if (cachedValue !== undefined) {
+      setPathExists(cachedValue);
+      return;
+    }
+
+    let isActive = true;
+
+    window.electronAPI.file
+      .existsPath(path)
+      .then(({ exists }) => {
+        pathExistenceCache.set(cacheKey, exists);
+        if (isActive) {
+          setPathExists(exists);
+        }
+      })
+      .catch((error) => {
+        console.error('Failed to verify file path from message:', error);
+        pathExistenceCache.set(cacheKey, false);
+        if (isActive) {
+          setPathExists(false);
+        }
+      });
+
+    return () => {
+      isActive = false;
+    };
+  }, [cacheKey, path]);
+
+  if (pathExists !== true) {
+    return variant === 'code' ? (
+      <code className="bg-copilot-bg px-1 py-0.5 rounded text-copilot-warning text-xs break-all">
+        {path}
+      </code>
+    ) : (
+      <>{path}</>
+    );
+  }
 
   return (
     <a

tests/components/MessageItem.test.tsx

@@ -1,19 +1,21 @@
 import { describe, expect, it, vi, beforeEach } from 'vitest';
-import { render, screen } from '@testing-library/react';
+import { render, screen, waitFor } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
 import React from 'react';
 import { MessageItem } from '../../src/renderer/components/MessageItem';
 import type { Message } from '../../src/renderer/types';
 
 describe('MessageItem', () => {
   const openFile = vi.fn().mockResolvedValue({ success: true });
+  const existsPath = vi.fn().mockResolvedValue({ exists: true });
 
   beforeEach(() => {
     vi.clearAllMocks();
     Object.assign(window.electronAPI, {
       platform: 'darwin',
       homePath: '/Users/idofrizler',
       file: {
+        existsPath,
         openFile,
       },
     });
@@ -46,7 +48,7 @@ describe('MessageItem', () => {
     const user = userEvent.setup();
     renderMessage('Created /Users/idofrizler/project/src/MessageItem.tsx.');
 
-    const link = screen.getByRole('link', {
+    const link = await screen.findByRole('link', {
       name: '/Users/idofrizler/project/src/MessageItem.tsx',
     });
 
@@ -59,19 +61,20 @@ describe('MessageItem', () => {
 
   it('renders inline-code full paths as clickable links', () => {
     renderMessage('Open `/Users/idofrizler/project/src/MessageItem.tsx`.');
+    return waitFor(() => {
+      const link = screen.getByRole('link', {
+        name: '/Users/idofrizler/project/src/MessageItem.tsx',
+      });
 
-    const link = screen.getByRole('link', {
-      name: '/Users/idofrizler/project/src/MessageItem.tsx',
+      expect(link).toHaveClass('bg-copilot-bg');
     });
-
-    expect(link).toHaveClass('bg-copilot-bg');
   });
 
   it('renders ~/ home-relative paths as clickable links', async () => {
     const user = userEvent.setup();
     renderMessage('Saved ~/temp/folder-contents.docx');
 
-    const link = screen.getByRole('link', { name: '~/temp/folder-contents.docx' });
+    const link = await screen.findByRole('link', { name: '~/temp/folder-contents.docx' });
 
     expect(link).toHaveAttribute('href', 'file:///Users/idofrizler/temp/folder-contents.docx');
 
@@ -82,11 +85,26 @@ describe('MessageItem', () => {
 
   it('uses a different link color in user messages', () => {
     renderMessageWithRole('Check ~/temp/folder-contents.docx', 'user');
+    return waitFor(() => {
+      const link = screen.getByRole('link', { name: '~/temp/folder-contents.docx' });
+
+      expect(link).toHaveClass('text-amber-100');
+      expect(link).not.toHaveClass('text-copilot-accent');
+    });
+  });
+
+  it('keeps non-existent path-like text as plain text instead of a link', async () => {
+    existsPath.mockResolvedValueOnce({ exists: false });
+    renderMessage('Status is /not-loaded, which renders as a red dot.');
 
-    const link = screen.getByRole('link', { name: '~/temp/folder-contents.docx' });
+    await waitFor(() => {
+      expect(existsPath).toHaveBeenCalledWith('/not-loaded');
+      expect(screen.queryByRole('link', { name: '/not-loaded' })).not.toBeInTheDocument();
+    });
 
-    expect(link).toHaveClass('text-amber-100');
-    expect(link).not.toHaveClass('text-copilot-accent');
+    expect(
+      screen.getByText('Status is /not-loaded, which renders as a red dot.')
+    ).toBeInTheDocument();
   });
 
   it('keeps normal markdown links intact', () => {

tests/components/setup.ts

@@ -29,6 +29,9 @@ if (typeof window !== 'undefined') {
         getTargetBranch: vi.fn().mockResolvedValue({ success: true, targetBranch: 'main' }),
         setTargetBranch: vi.fn().mockResolvedValue({ success: true }),
       },
+      file: {
+        existsPath: vi.fn().mockResolvedValue({ exists: false }),
+      },
     },
   });