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Browser automation and testing using chrome-devtools MCP server. Use when automating web browsers, taking screenshots, inspecting console logs, monitoring network requests, testing responsive layouts, collecting performance metrics, or debugging web applications. Critical for visual testing workflows and browser-based automation tasks.
npx skill4agent add gsmlg-dev/code-agent chrome-devtools-mcpnpx chrome-devtools-mcp@latest --helplist_pagesselect_pagetake_snapshotuiduidnavigate_pagenew_pagewait_fortake_snapshotuidclickfillfilePathpageIdxpageSizetypesincludeSnapshot: falsetake_snapshottake_screenshotevaluate_scriptchrome-devtools-mcpchrome-devtools-mcp// ✓ CORRECT: Viewport-only (default)
take_screenshot({ fullPage: false })
// ✓ CORRECT: Save to filesystem for large pages
take_screenshot({ fullPage: false, path: './screenshots/page.png' })
// ✗ AVOID: Full-page without size check
take_screenshot({ fullPage: true })const height = execute_script('return document.documentElement.scrollHeight')
if (height > 8000) {
take_screenshot({ fullPage: false, path: './screenshot.png' })
} else {
take_screenshot({ fullPage: true })
}take_screenshot({ fullPage: false, path: './top.png' })
execute_script('window.scrollBy(0, window.innerHeight)')
take_screenshot({ fullPage: false, path: './middle.png' })navigate('https://example.com')
wait(1000) // Minimum recommended wait
// For dynamic apps, wait for specific elements
navigate('https://example.com')
execute_script(`
return new Promise(resolve => {
const check = () => {
if (document.querySelector('#app')) resolve();
else setTimeout(check, 100);
};
check();
});
`)const errors = execute_script(`
return performance.getEntriesByType('navigation')[0].type === 'reload'
? []
: (window.__consoleErrors || []);
`)const failed = execute_script(`
return performance.getEntriesByType('resource')
.filter(r => r.transferSize === 0 && r.duration > 0)
.map(r => ({ url: r.name, duration: r.duration }));
`)const issues = execute_script(`
const issues = [];
// Horizontal overflow
if (document.documentElement.scrollWidth > window.innerWidth) {
issues.push({ type: 'horizontal-overflow', width: document.documentElement.scrollWidth });
}
// Elements outside viewport
document.querySelectorAll('*').forEach(el => {
const rect = el.getBoundingClientRect();
if (rect.right > window.innerWidth) {
issues.push({ type: 'overflow-right', element: el.tagName });
}
});
return issues;
`)const viewports = [
{ width: 375, height: 667, name: 'mobile' },
{ width: 768, height: 1024, name: 'tablet' },
{ width: 1440, height: 900, name: 'desktop' }
];
for (const vp of viewports) {
set_viewport(vp.width, vp.height);
wait(500); // Allow reflow
take_screenshot({
fullPage: false,
path: `./screenshots/${vp.name}.png`
});
}// Hover state
execute_script(`
const el = document.querySelector('#button');
el.dispatchEvent(new MouseEvent('mouseenter', { bubbles: true }));
`);
take_screenshot({ fullPage: false, path: './hover.png' });
// Focus state
execute_script(`
document.querySelector('#input').focus();
`);
take_screenshot({ fullPage: false, path: './focus.png' });
// Active/pressed state
execute_script(`
const el = document.querySelector('#button');
el.dispatchEvent(new MouseEvent('mousedown', { bubbles: true }));
`);
take_screenshot({ fullPage: false, path: './active.png' });const metrics = execute_script(`
return {
fcp: performance.getEntriesByName('first-contentful-paint')[0]?.startTime,
lcp: performance.getEntriesByType('largest-contentful-paint')[0]?.startTime,
cls: performance.getEntriesByType('layout-shift')
.reduce((sum, entry) => sum + (entry.hadRecentInput ? 0 : entry.value), 0),
resources: performance.getEntriesByType('resource').length,
totalSize: performance.getEntriesByType('resource')
.reduce((sum, r) => sum + r.transferSize, 0)
};
`);const a11y = execute_script(`
const issues = [];
// Missing alt text
document.querySelectorAll('img:not([alt])').forEach(img => {
issues.push({ type: 'missing-alt', src: img.src });
});
// Missing form labels
document.querySelectorAll('input:not([aria-label]):not([id])').forEach(input => {
if (!input.closest('label')) {
issues.push({ type: 'missing-label', name: input.name });
}
});
// Empty links
document.querySelectorAll('a').forEach(link => {
if (!link.textContent.trim() && !link.getAttribute('aria-label')) {
issues.push({ type: 'empty-link', href: link.href });
}
});
return issues;
`);function audit_page(url, name) {
// Navigate
navigate(url);
wait(1000);
// Screenshot (viewport only to avoid size errors)
const screenshot_path = `./screenshots/${name}.png`;
take_screenshot({ fullPage: false, path: screenshot_path });
// Page metrics
const height = execute_script('return document.documentElement.scrollHeight');
const viewport = execute_script('return window.innerHeight');
// Error detection
const console_errors = execute_script('return window.__errors || []');
const network_failures = execute_script(`
return performance.getEntriesByType('resource')
.filter(r => r.transferSize === 0 && r.duration > 0)
.map(r => r.name);
`);
const layout_issues = execute_script(`
return document.documentElement.scrollWidth > window.innerWidth
? ['horizontal-overflow']
: [];
`);
return {
name,
url,
screenshot_path,
page_height: height,
viewport_height: viewport,
needs_scroll: height > viewport,
console_errors,
network_failures,
layout_issues,
has_issues: console_errors.length > 0 ||
network_failures.length > 0 ||
layout_issues.length > 0
};
}fullPage: falsetry {
take_screenshot({ fullPage: false });
} catch (error) {
if (error.includes('8000 pixels')) {
take_screenshot({ fullPage: false, path: './fallback.png' });
}
}try {
navigate(url);
wait(5000);
} catch (error) {
// Log failure and continue
console.log(`Failed to load: ${url}`);
}const exists = execute_script(`return !!document.querySelector('#target')`);
if (!exists) {
take_screenshot({ fullPage: false, path: './missing-element.png' });
// Handle accordingly
}fullPage: false