Setting up your MCID

MCID is your Marx Compute Club identity. It signs you in to MCC services (chat, source forge) with a passkey — no password to choose, remember, or leak. This guide walks the one-time setup.

Time: about three minutes. Do it on a device you keep (phone or laptop), not a public machine.

Before you start

• You need the setup link from your invitation email. It works once and expires in 30 days. Opening it signs you in; there is no password fallback.
• Have a passkey store ready. Any one of these works:
  • your phone (Face ID / fingerprint / screen lock),
  • your laptop (Touch ID / Windows Hello / device PIN),
  • a password manager that supports passkeys (1Password, Bitwarden, iCloud Keychain, Google Password Manager),
  • a hardware key (YubiKey).

Steps

1. Open the setup link from the email. It lands you on your MCID account page, already signed in for this one session.

2. Set your username (optional but do it now). This is your handle across MCC services. Changing it later is possible on the account page, but do it before your first sign-in to the forge — that service copies the name once and won't follow a later change.

3. Add a passkey. Click Add passkey (or Register passkey). Your browser or operating system takes over and shows its own dialog:

   • on a phone: Face ID, fingerprint, or your screen lock,
   • on a laptop: Touch ID, Windows Hello, or your device PIN,
   • with a password manager: it offers to save the passkey,
   • with a hardware key: insert and tap it. Approve, and the passkey is registered to your MCID.

4. Add a second passkey. Strongly recommended. Repeat step 3 with a different device or your password manager. Because there is no password, your passkeys are the only way in — one passkey works, two is safe. With two, losing a phone or laptop is a non-event.

That's it. Your MCID exists and you can sign in to MCC services.

Signing in afterward

• Chat (Zulip): open the invitation you were sent, or go to the MCC Zulip and choose MCID on the login screen — never the email/password form. Complete the passkey prompt.
• Source forge: go to the forge, choose Sign in with MCC, complete the passkey prompt. Your forge account is created on that first sign-in.

If something goes wrong

• You closed the tab before adding a passkey. The link is single-use, so it won't reopen — you're locked out of a still-empty account. This is harmless; just ask the operator for a fresh link and try again.
• The link says expired or already used. Same fix: ask for a new one-time link.
• You lost the device with your only passkey. If you added a second passkey, sign in with it and add a replacement. If you had only one, account recovery is an operator action — ask for a recovery link.
• The passkey dialog never appears. Your browser or OS may not support passkeys; try a current Chrome/Safari/Firefox, or use a password manager that provides them.

Notes

• MCID is separate from the MCC announcement email list. Setting it up does not change your email subscription either way.
• The setup link is a credential. Do not forward it; anyone who opens it first becomes you.