How do I install the Chrome skill?

Run npx skillmds@latest add modbender/chrome in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Chrome safe to use?

This skill has not completed SkillMD's automated safety review yet. Independent scanners report: SkillSpector: PASS, Skill Scanner: PASS. Capability flags: makes network calls. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Chrome?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Chrome free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Chrome?

modbender (@modbender) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Chrome by modbender — Agent Skill

Name: Chrome
Rating: 4.2 (5 reviews)
Author: modbender

File contents

Chrome DevTools Protocol (CDP)

Get tab WebSocket URL first: Never connect to ws://localhost:9222/devtools/browser directly. Fetch http://localhost:9222/json/list and use webSocketDebuggerUrl from the active tab.

Enable domains before use: Runtime.enable and Page.enable must be called before any Runtime.evaluate or Page.navigate commands.

CDP is async: Wait for response before sending next command. Use Promise-based wrapper with response ID tracking.

Screenshot on high-DPI: Include fromSurface: true and scale: 2 in Page.captureScreenshot params for Retina displays.

Get response body separately: Network.responseReceived doesn't include body. Call Network.getResponseBody with requestId after response completes.

Chrome Extension Manifest V3

Permissions split: Use permissions for APIs, host_permissions for URLs. Never use http://*/* in permissions.

Service workers terminate: No persistent state. Use chrome.storage.local instead of global variables. Use chrome.alarms instead of setInterval.

Content script isolation: Can't access page globals. Use chrome.scripting.executeScript with func for page context. Use window.postMessage for content↔page communication.

Storage is async: chrome.storage.local.get() returns Promise, not data. Always await. Handle QUOTA_EXCEEDED errors.

Context Detection

Detect actual Chrome (not Edge/Brave): Check window.chrome && navigator.vendor === "Google Inc." and exclude Opera/Edge.

Extension context types:

chrome.runtime.id exists → content script
chrome.runtime.getManifest exists → popup/background/options
chrome.loadTimes exists but no runtime → regular Chrome web page

Manifest version check: Wrap chrome.runtime.getManifest() in try-catch. Use chrome.action for V3, chrome.browserAction for V2.

Performance Debugging

Memory API conditional: Check 'memory' in performance before accessing performance.memory.usedJSHeapSize.

Use performance marks: performance.mark() and performance.measure() for sub-frame timing. Clear marks to prevent memory leaks.

Layout thrash detection: PerformanceObserver with entryTypes: ['measure', 'paint', 'largest-contentful-paint']. Flag entries >16.67ms.

Network Debugging

Block before navigate: Call Network.setBlockedURLs before Page.navigate, not after.

Request interception: Use Network.setRequestInterception with requestStage: 'Request' for granular control. Return errorReason: 'BlockedByClient' to block.

Security Contexts

Mixed content: HTTPS pages can't load HTTP resources. Check location.protocol vs resource URL.

CORS errors: TypeError on cross-origin fetch usually means CORS. Check DevTools Network tab for specific error.

Secure context required: File System Access API, Clipboard API require window.isSecureContext === true and user gesture.

---name: chromedescription: Chrome DevTools Protocol, extension Manifest V3, and debugging patterns that prevent common automation failures.--- ## Chrome DevTools Protocol (CDP) **Get tab WebSocket URL first**: Never connect to `ws://localhost:9222/devtools/browser` directly. Fetch `http://localhost:9222/json/list` and use `webSocketDebuggerUrl` from the active tab. **Enable domains before use**: `Runtime.enable` and `Page.enable` must be called before any `Runtime.evaluate` or `Page.navigate` commands. **CDP is async**: Wait for response before sending next command. Use Promise-based wrapper with response ID tracking. **Screenshot on high-DPI**: Include `fromSurface: true` and `scale: 2` in `Page.captureScreenshot` params for Retina displays. **Get response body separately**: `Network.responseReceived` doesn't include body. Call `Network.getResponseBody` with requestId after response completes. ## Chrome Extension Manifest V3 **Permissions split**: Use `permissions` for APIs, `host_permissions` for URLs. Never use `http://*/*` in permissions. **Service workers terminate**: No persistent state. Use `chrome.storage.local` instead of global variables. Use `chrome.alarms` instead of `setInterval`. **Content script isolation**: Can't access page globals. Use `chrome.scripting.executeScript` with `func` for page context. Use `window.postMessage` for content↔page communication. **Storage is async**: `chrome.storage.local.get()` returns Promise, not data. Always await. Handle `QUOTA_EXCEEDED` errors. ## Context Detection **Detect actual Chrome** (not Edge/Brave): Check `window.chrome && navigator.vendor === "Google Inc."` and exclude Opera/Edge. **Extension context types**: - `chrome.runtime.id` exists → content script - `chrome.runtime.getManifest` exists → popup/background/options - `chrome.loadTimes` exists but no runtime → regular Chrome web page **Manifest version check**: Wrap `chrome.runtime.getManifest()` in try-catch. Use `chrome.action` for V3, `chrome.browserAction` for V2. ## Performance Debugging **Memory API conditional**: Check `'memory' in performance` before accessing `performance.memory.usedJSHeapSize`. **Use performance marks**: `performance.mark()` and `performance.measure()` for sub-frame timing. Clear marks to prevent memory leaks. **Layout thrash detection**: PerformanceObserver with `entryTypes: ['measure', 'paint', 'largest-contentful-paint']`. Flag entries >16.67ms. ## Network Debugging **Block before navigate**: Call `Network.setBlockedURLs` before `Page.navigate`, not after. **Request interception**: Use `Network.setRequestInterception` with `requestStage: 'Request'` for granular control. Return `errorReason: 'BlockedByClient'` to block. ## Security Contexts **Mixed content**: HTTPS pages can't load HTTP resources. Check `location.protocol` vs resource URL. **CORS errors**: `TypeError` on cross-origin fetch usually means CORS. Check DevTools Network tab for specific error. **Secure context required**: File System Access API, Clipboard API require `window.isSecureContext === true` and user gesture.

Frequently asked questions

Chrome