Sep 4, 2026

Claude Code With Multiple Accounts (2026)

Claude Code has no bundled mail or calendar integration, so how many accounts it reaches is decided entirely by which MCP server you register. Authorize every account in Carly, register one server, and the terminal addresses all of them by email address, across Microsoft tenants included.

That is a better position than it sounds. Where other assistants make you fight a connector that holds one identity, here the account question is a server question, and one server can hold as many as you authorize.

1. Connect every account to Carly

Sign in at carlyassistant.com.
Open carlyassistant.com/integrations.
Find Gmail or Outlook, click Connect, and authorize the account.
Click Connect again for the next one, choosing Use another account if the provider preselects the first login, and keep going for as many as you want.
Repeat for Calendar on each account that has one.

Verify the full address after every authorization before adding the next. If a Workspace or tenant requires administrator review, ask that administrator to approve the connection, then finish authorization. Each organization approves independently.

Carly connects to thousands of apps, so while you are on that page you can add your CRM, files, and anything else you want Claude Code to reach through the same server.

2. 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 and calendars. 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 and confirm:

claude mcp login carly
claude mcp list

Sign in to the Carly workspace holding the connections. 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.

3. Address the account you want

Name the address and the work happens there.

Search every connected inbox for the Varonex deploy thread. Include the source address on every row.

Draft the reply from michael.reyes@northwind.com. Do not send it yet.

Check every connected calendar for conflicts Thursday 1:00 to 4:00 PM Eastern, then book the review at 2:00 on the Northwind calendar only.

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

Routines run somewhere else, and it matters

A local server added with claude mcp add lives on your machine. Routines run in the cloud against the connectors on your claude.ai account, so a server you registered locally is not there.

To use Carly inside 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. 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 client emailing you, which is the usual reason people want a second inbox watched. A Carly workflow covers that half and needs no repository.

Per-account servers versus Carly in Claude Code

Need	Per-account MCP servers	Carly MCP server
Reach one account	Yes	Yes
Reach several accounts	One server per account	One server, all of them
Gmail and Outlook as one workload	Another server again	Same server
Mailboxes in different Microsoft tenants	One server per tenant	Yes
Address a specific account in a prompt	No shared convention	Yes, by email address
Manage your own 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 toolset instead of a stack of per-account servers. Carly offers free Zapier-style workflows; AI agents start at $35/month.

Quick fixes

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
Carly is missing inside a routine	Add it at claude.ai/customize/connectors, or commit it to `.mcp.json`
The same account connected twice	Remove the duplicate in Carly and reconnect with Use another account
Claude queries the wrong account	Use the full address and require source attribution

Frequently asked questions

How many accounts can Claude Code 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.

Does this cover Outlook as well as Gmail?

Yes, on the same server, including mailboxes in different Microsoft tenants. See multiple Outlook accounts in Claude Code.

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.

Is this the same setup as claude.ai?

The account side is identical, because both point at the same Carly workspace. The registration step differs: the terminal uses claude mcp add, and claude.ai uses Customize → Connectors. See Claude with multiple accounts.

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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