Aug 21, 2026

How to Connect Multiple Gmail Accounts to Claude Code

One Claude Code session can search, draft, and send across every Gmail account you own once Carly is holding them. Authorize each Google identity in Carly, register one MCP server, and the terminal addresses whichever inbox you name. The same Carly account holds your Outlook mailboxes and every calendar on both sides, so you set this up once for all of it.

Claude Code reaches mail the way it reaches everything outside your repository: through the Model Context Protocol. That makes the account question a server question, not a Claude Code setting. Whichever server you register decides how many inboxes exist.

What one session can do afterwards

Search two employers’ inboxes in the same question.
Pull the thread that explains a failing deploy from whichever account received it.
Build a morning briefing grouped by inbox.
Draft or send from the exact address you name.
Label, archive, or move mail in the correct account.
Read several calendars while writing to only one.

Nothing is merged and nothing is forwarded. Each Google identity keeps its own authorization, and Carly keeps every account separately addressable.

Why one server beats one per account

The usual route is a per-inbox Gmail MCP server, often with your own Google Cloud project and OAuth client behind it. That is survivable for one address. Three addresses means three server entries in your config, three OAuth apps to keep alive, and no shared vocabulary for telling Claude which inbox you meant.

Carly inverts it. Each Google identity is authorized once inside Carly, and Claude Code sees a single server that addresses any of them by email address. Adding a fourth account later changes nothing in your configuration.

Connector authorization is per identity, not per person. ChatGPT, Claude, and Gemini each hold one Google account at a time, so the second inbox is reachable only by replacing the first. Both OpenAI and Anthropic have open feature requests asking for several named accounts on one connector, which is a fair signal that it is not possible today.

1. Give each Gmail account a role

For example, all fictional:

Address	Role
`fictional.priya.raman@gmail.com`	Personal
`fictional.priya.raman@stripe.com`	Main Company
`fictional.priya.raman@shopify.com`	Client

Use the role in ordinary queries and the full address before anything that changes an inbox.

2. Connect every Gmail account to Carly

Sign in at carlyassistant.com.
Open carlyassistant.com/integrations.
Find Gmail and click Connect.
Choose the first Google account and approve access.
Confirm the connected address in Carly.

Repeat for each additional identity, choosing Use another account if Google preselects the first login. Verify the full address after every authorization before adding the next.

If a Google Workspace account requires administrator review, ask that Workspace administrator to approve the connection, then finish authorization. Each Workspace approves independently.

3. Register Carly as an MCP server

Carly is a remote HTTP server, so one command does it:

claude mcp add --transport http --scope user carly https://carlyassistant.com/mcp/

--scope user stores the server in ~/.claude.json and loads it in every project, which is what you want for mail. Drop the flag and it lands in local scope, available only in the directory where you added it. Use --scope project instead to write it into a committed .mcp.json and share it with a team.

Then authenticate:

claude mcp login carly

That opens a browser for the OAuth flow. Sign in to the Carly workspace holding the Gmail accounts. You can also complete the same flow from the /mcp panel inside a session.

Confirm the server is live before moving on:

claude mcp list

A healthy entry reads ✔ Connected. ! Needs authentication means the OAuth flow did not finish, and ✘ Failed to connect means the URL or network is the problem, not your Carly account.

4. Test every inbox read-only first

Take one account per prompt to start:

In fictional.priya.raman@stripe.com, list the sender and subject of the five newest unread messages. Do not change anything.

In fictional.priya.raman@shopify.com, find the newest thread containing “webhook failure.” State the source account and do not draft.

Then a cross-account query:

Search the Stripe and Shopify example accounts for “incident” from the last 30 days. Include the full source address in every row.

MCP tool definitions load on demand rather than all at once, so the first mail request may take a beat while Claude Code fetches Carly’s tools. Run /context if you want to see what is loaded.

5. Reuse this routing prompt

Treat fictional.priya.raman@gmail.com as Personal, fictional.priya.raman@stripe.com as Main Company, and fictional.priya.raman@shopify.com as Client. Always state the target address before changing data. Ask before sends, moves, deletes, or labels.

Then name the target in each action:

Draft the reply from fictional.priya.raman@stripe.com. Do not send yet.

Add the Incidents label in fictional.priya.raman@shopify.com only.

Send the approved reply from the account that received the original thread.

Keep approvals on while you are testing. A coding agent with send scopes and three inboxes is worth a confirmation step.

The part that outlives the session

A terminal session ends when you close it. Most inbox work does not: triage every morning, chase the quote that went quiet, file the receipts, answer the third client in the same voice as the first two.

That work belongs in a Carly workflow or a Carly agent, which runs with nothing open and no session attached. Carly watches each connected mailbox individually, so a rule can fire on mail arriving in the client account and stay silent on the personal one. Claude Code then becomes the place you go to ask questions about work that already happened, rather than the thing that has to be running for the work to happen at all.

There is a wrinkle worth knowing if you want Carly available inside a Claude Code routine. Routines run in the cloud and use the connectors on your claude.ai account, and a server you added locally with claude mcp add lives on your machine rather than your account. To use Carly in a routine, add it at claude.ai/customize/connectors as well, or declare it in a committed .mcp.json so it arrives with the cloned repository. Claude Code routines also start from a schedule, a GitHub pull request or release, or an HTTP call you build yourself, and every one of them requires a repository. None of that notices a lead emailing you.

Per-account MCP servers versus Carly in Claude Code

Need	Per-account Gmail MCP server	Carly MCP server
Reach one inbox	Yes	Yes
Reach several inboxes	One server per account	One server, all accounts
Address a specific account in a prompt	No shared convention	Yes, by email address
Manage your own Google OAuth client	Usually required	No
Add a fourth account later	New server entry	No config change
Keep the work running with the terminal closed	No	Yes

Carly gives Claude Code one account-aware mail toolset instead of a stack of per-inbox servers. Carly offers free Zapier-style workflows; AI agents start at $35/month.

Quick fixes when an inbox does not appear

Problem	Fix
Server shows `! Needs authentication`	Run `claude mcp login carly` and finish the browser flow
Server missing in another project	Re-add with `--scope user`, or move the entry out of local scope
`claude -p` reports the tools are unavailable	Sign in interactively once with `/mcp`, then rerun the script
Google connected the same Gmail twice	Remove the duplicate and reconnect with Use another account
A Workspace blocks authorization	Ask that Workspace administrator to approve Carly
Claude queries the wrong inbox	Use the full address and require source attribution

Frequently asked questions

Does Claude Code have a built-in Gmail connector?

Claude Code reaches outside services through MCP servers rather than a bundled mail integration, so what it can do with Gmail is decided by the server you register. Point it at Carly at https://carlyassistant.com/mcp/ and every inbox Carly holds becomes reachable from one session.

How many Gmail accounts can this reach?

As many as you authorize in Carly. Claude Code connects to one server, so the account count is a Carly setting rather than a Claude Code one.

Will this work in a non-interactive run?

Yes, once you have signed in. Claude Code cannot run the OAuth flow during a claude -p run, so complete claude mcp login carly from an interactive session first and the script inherits the stored token.

Should I use Claude Code for inbox work?

For scripted, one-off mailbox work from a terminal, it is a genuine fit. Recurring triage, drafting, and follow-up belong in a Carly workflow that runs without a session open.

Ready to automate your busywork?

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See what people say

"Before Carly, I relied on a Calendly link, but the whole process felt impersonal and not very professional. Carly changed that by handling all the back-and-forth, so I'm no longer stuck in endless email threads trying to line up schedules.

Now Carly reaches out to candidates, shares my real-time availability, lets them pick a slot, then sends a Zoom link and drops it straight into my calendar. She sends reminders to both of us before each call, which has significantly reduced no-shows and last-minute confusion.

On top of scheduling, Carly acts like a full executive assistant, sending me my schedule the night before so I can prepare for each call. It reminds me of the old x.ai assistant, but Carly is noticeably smarter, faster, and better suited to my healthcare recruitment business."

Gus Ibrahim, Founder & Director, IHR