login-cdp

name	login-cdp
description	Use when user says "login", "登录", "fix expired sessions", "refresh login", or needs to re-authenticate CDP browser sessions for any platform. Auto-detects expired platforms and guides interactive re-login via MCP browser tools. Triggers: "login", "登录", "CDP login", "refresh login", "expired session", "re-authenticate"

CDP Platform Login

Auto-detect expired CDP browser sessions and re-authenticate interactively via MCP browser tools. Supports multiple CDP ports for multi-account setups.

When to Use

• Sessions on RedNote, Twitter, LinkedIn, Weibo, etc. have expired and need re-login
• Multi-account CDP setup needs re-authentication on a specific port (9222 vs 9223)
• Chrome MCP / Playwright MCP returns login pages instead of expected content
• User asks to "login", "登录", or "refresh sessions" before running a scraping/posting workflow

Prerequisites

• Chrome running with --remote-debugging-port=<port>
• MCP browser tools available (Playwright MCP or Chrome MCP)

CDP Port Configuration

Two CDP ports, two independent Chrome instances, each with its own login sessions:

Port	Account	Session Directory	Purpose
9222	Account 1 (default)	$HOME/chrome-debug-v2	General browsing, Twitter scraping, posting
9223	Account 2	$HOME/chrome-debug2	RedNote publishing (secondary account)

Startup commands:

# Account 1 — CDP 9222 — Session: ~/chrome-debug-v2
/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome \
  --remote-debugging-port=9222 \
  --user-data-dir="$HOME/chrome-debug-v2"

# Account 2 — CDP 9223 — Session: ~/.chrome-cdp/rednote-account2
/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome \
  --remote-debugging-port=9223 \
  --user-data-dir="$HOME/chrome-debug2"

Quick check:

curl -s --noproxy '*' http://127.0.0.1:9222/json/version  # Account 1
curl -s --noproxy '*' http://127.0.0.1:9223/json/version  # Account 2

# Check which Chrome instances are running and their session directories
ps aux | grep "[G]oogle Chrome" | grep -v "Helper\|GPU\|Renderer" | grep -o 'user-data-dir=[^ ]*'

Arguments

Arg	Default	Description
--port	9222	CDP port to check/fix
platform names	rednote, twitter	Comma-separated or space-separated platform names

Examples:

• /login-cdp — check rednote + twitter on port 9222
• /login-cdp twitter — check only twitter
• /login-cdp --port 9223 rednote — check rednote on port 9223

Flow

Step 0: Verify CDP is Running

curl -s --noproxy '*' http://127.0.0.1:<port>/json/version

If connection refused → print the exact Chrome startup command as a fenced bash block for the user to paste into their own terminal, then STOP. Do NOT try to run it yourself — Chrome must be launched from the user's shell so it stays attached to their session.

Format the output like this (fill in the port/profile that matches the request):

CDP <port> is not running. Paste this into your terminal:

​```bash
/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome \
  --remote-debugging-port=<port> \
  --user-data-dir="$HOME/<profile-dir>"
​```

Then re-run /login-cdp.

Port → profile mapping: 9222 → chrome-debug-v2, 9223 → chrome-debug2.

If CDP is reachable, also check which --user-data-dir is being used:

ps aux | grep "[G]oogle Chrome" | grep -v "Helper\|GPU\|Renderer\|Utility\|Plugin" | grep -o 'user-data-dir=[^ ]*'

Report: "CDP running, profile: "

Step 1: Detect Expired Sessions

Check login status by navigating to each platform's check URL.

For each platform:

1. Navigate to the platform's check_url via MCP browser tools
2. Take a screenshot or snapshot
3. If redirected to a login page (URL contains "login", "flow/login", or page shows sign-in form) → expired
4. If page shows logged-in content (dashboard, feed, profile, account name) → healthy
5. Close the tab immediately after checking

If all healthy → "All platforms healthy, nothing to do." → STOP.

Step 2: Present Expired Platforms

CDP <port> (<user-data-dir>)

Expired sessions:
  1. RedNote Creator — expired
  2. Twitter/X — expired

Healthy:
  ✓ (none)

Which to fix? (e.g., "1,2" or "all")

Step 3: Sequential Login Loop

For each selected platform:

a) Open login page via MCP browser tools.

b) Notify user:

• "Opened [platform] login page in Chrome (CDP ). Please log in, then say 'done'."
• For QR-code platforms: add "Requires QR code scanning — check your Chrome window."

c) Wait for user to say "done", "ok", or "next".

d) Verify — navigate to check_url again, confirm logged-in state.

e) Handle failure — "Still not logged in. Try again or skip?"

f) Close tab — ALWAYS close after each platform.

Step 4: Summary

Login refresh complete (CDP <port>):
  ✓ RedNote Creator — logged in
  ✗ Twitter/X — still expired

Platform Reference

Platform	Display Name	Check URL	Login URL	QR?
rednote	RedNote Creator	https://creator.xiaohongshu.com/publish/publish	https://creator.xiaohongshu.com/login	No
rednote_www	RedNote Web	https://www.xiaohongshu.com/explore	https://www.xiaohongshu.com/explore	No
twitter	Twitter/X	https://x.com/home	https://x.com/i/flow/login	No
weibo	Weibo	https://weibo.com	https://weibo.com/login.php	No
linkedin	LinkedIn	https://www.linkedin.com/feed	https://www.linkedin.com/login	No
wechat_mp	WeChat MP	https://mp.weixin.qq.com/cgi-bin/home	https://mp.weixin.qq.com	Yes
bilibili	Bilibili	https://www.bilibili.com/	https://passport.bilibili.com/login	Yes
youtube	YouTube	https://www.youtube.com/	https://accounts.google.com	No
youtube_studio	YouTube Studio	https://studio.youtube.com/	https://accounts.google.com	No
bilibili_creator	Bilibili Creator	https://member.bilibili.com/platform/home	https://passport.bilibili.com/login	Yes

MCP Tool Selection

This skill works with either MCP browser tool:

• Chrome MCP (chrome-devtools-mcp) — connects to existing CDP Chrome via --browserUrl
• Playwright MCP (@playwright/mcp) — needs --cdp-endpoint to connect to existing Chrome

Prefer whichever is configured to connect to the target CDP port. If both available, use Chrome MCP (it connects to CDP by default).

Key Rules

• Always verify CDP is running first (Step 0) — don't assume
• Never launch Chrome yourself — if CDP is down, print the startup command as a copy-paste bash block and stop. The user runs it in their own terminal.
• Report the user-data-dir — so user knows which Chrome profile is being checked
• No hardcoded selectors — read snapshots/screenshots to identify login state
• Always close tabs — CDP tabs accumulate
• Sequential only — one platform at a time
• Use --noproxy '*' for all curl commands to localhost — machine may have proxy configured

Anti-Patterns

Anti-Pattern	What goes wrong	Fix
Launching Chrome via the assistant's own Bash	Chrome detaches from user's terminal session, may not pick up keychain/GUI	Print the startup command and stop; user pastes into their own terminal
Skipping Step 0 (CDP reachability check)	Later MCP calls fail with cryptic errors	Always curl http://127.0.0.1:<port>/json/version first
Hardcoding DOM selectors to detect login state	Selectors break on every platform UI update	Use snapshot/screenshot heuristics (URL + visible text)
Leaving check tabs open	Tabs accumulate, slowing CDP and leaking state	Close after every check (Step 1 step 5, Step 3 step f)
Parallel login across platforms	User can only authenticate in one tab at a time, QR codes overlap	Sequential loop only
Curl to localhost without --noproxy '*'	System proxy intercepts loopback, false negatives	Add --noproxy '*' to every loopback curl
Silently falling back to WebFetch when CDP is down	Hides the real failure; scrapes wrong (logged-out) view	Stop and surface the failure; print startup command

See Also

• tmux — Companion shell setup; tmux pane is where the user pastes the Chrome startup command
• claude-code-config — Global Chrome CDP configuration (ports, profiles)
• github-cli — Authenticate gh in a similar interactive way for GitHub flows
• fail-fast-ml-engineering — Same "no silent fallbacks" discipline applied here (fail loudly when CDP is down)