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Install

Install Crosscheck from inside Claude Code

One command registers the MCP server, opens your browser to sign in and subscribe, and walks you through your provider keys — which never leave your machine.

New to GitHub, VS Code, or the terminal?

Start with the complete beginner guide — accounts, API keys, editor setup, and your first project, step by step. Open the Startup Guide →

✓ Recommended setup · Claude Code in VS Code

Install in one command

Paste this into the Claude Code chat — it’ll run it for you — or run it yourself in any terminal:

$npx -y crosscheck-cli@latest install

Tip: you can also just tell Claude Code run npx -y crosscheck-cli@latest install.

  • →Registers the crosscheck MCP server in Claude Code (user scope — every workspace).
  • →Opens your browser to sign in, accept the agreement, and subscribe.
  • →Sets up your provider keys (Anthropic, OpenAI, Google, xAI) — stored locally on your machine, never sent to us.
  • →Verifies with a first confer call.

Requires Node 20+. One more step after it finishes — see below.

Last step · turn it on

Activate crosscheck in Claude Code

The installer registers the server, but Claude Code only loads it after a restart:

  1. 1Quit Claude Code completely (press ⌘Q) and reopen it — or reload the window.
  2. 2In the chat, type /mcp.
  3. 3Find crosscheck in the list and click Enable (or Reconnect).

Then try it — ask Claude Code to use crosscheck to confer on <your question>. Something off? Run npx -y crosscheck-cli@latest doctor.

Requirements

  • Node.js 20 or newer — the installer runs on Node — check with node -v, or get it at nodejs.org
  • VS Code + the Claude Code extension — the recommended host; crosscheck also works in any MCP client or a plain terminal
  • A Google account — to sign in and tie the install to your seat
  • At least one provider API key — Anthropic, OpenAI, Google, or xAI — your keys, stored locally, never sent to us (note: xAI keys need credits/billing on your xAI account before they work)
  • A payment method — $20 / seat / month — first month free with code WELCOME100
  • macOS, Linux, or Windows — keys are saved in an encrypted file on your machine (no password); your OS keychain is an optional alternative

Prefer the browser?

One subscription also covers the Chrome extension — same panel, no second seat.

Browser extension

Crosscheck in your browser

Your same subscription works in a Chrome extension — ask the whole panel from any tab, with a compact popup that expands to a full workspace. Best for research, financial, and business work; not for heavy coding.

Add to Chrome →
  1. 1Add Crosscheck to Chrome from the Web Store.
  2. 2Open the extension → Account → Activate this browser. It uses the seat you already have — no second subscription.
  3. 3Add your provider keys in the extension — encrypted on your device, never sent to us.

Other ways to install

Any MCP client / terminal

The same installer works outside Claude Code — it prints the MCP config to add to your client if it can't self-register.

$npx -y crosscheck-cli@latest install

Prefer to set up billing in the browser first?

Sign in, accept the agreement, and subscribe on the web, then run the installer to activate your machine.

Sign in & subscribe →

Already subscribed? Open your dashboard to manage seats and machines.

install — crosscheck