Connect Multiple Email Accounts to Codex
Yes, you can connect multiple email accounts to Codex with Carly. Add every personal Gmail, Google Workspace, and Microsoft 365 mailbox to Carly once, register one MCP server in the Codex CLI, and a single session can search or act in whichever inbox you name without disconnecting anything.
Codex’s own plugins are one account each. The Gmail plugin authorizes a single Google identity, and the outlook-email plugin beside it works against one configured Microsoft connector, so a second address of either kind replaces the first rather than joining it.
1. Add your Gmail and Outlook mailboxes to Carly
- Sign in at carlyassistant.com.
- Open carlyassistant.com/integrations.
- Find Gmail and Outlook, click Connect, and authorize the mailbox.
- Click Connect again for the next one, and keep going for as many mailboxes as you want.
Mix providers freely. A second Gmail sits beside the first, and an Outlook mailbox sits beside both. If a Google Workspace or Microsoft 365 account needs administrator review, ask that administrator to approve. Each tenant approves independently, so one company declining does not block the rest.
Carly connects to thousands of apps, so while you are on that page you can add your calendars, files, CRM, and anything else you want Codex to reach through the same connector.
2. Register Carly as an MCP server in Codex
The CLI route is the shortest:
codex mcp add carly --url https://carlyassistant.com/mcp/Servers added this way land in ~/.codex/config.toml at user scope. The hand-written equivalent:
[mcp_servers.carly]
url = "https://carlyassistant.com/mcp/"A trusted project can carry its own .codex/config.toml if you would rather scope the server to one repository than to your whole machine.
Then authenticate:
codex mcp login carlyThat opens the browser OAuth flow. Sign in to the Carly workspace holding your mailboxes. Codex supports OAuth against remote HTTP MCP servers, including Client ID Metadata Documents and Dynamic Client Registration, so no secret has to sit in a config file. Confirm the server is live:
codex mcp listWhat one Codex session can do afterwards
- Search a personal Gmail and a work Outlook in the same prompt.
- Compare a thread in one employer’s mailbox against another client’s.
- Pull every message about a failed deploy across all connected accounts at once.
- Draft or send from the exact address you choose.
- Label, move, flag or archive in the correct account.
- Read a client mailbox while writing only to your own.
Nothing is merged into a single pooled inbox. Each account stays individually addressable by its full address, and every result names the account it came from.
Where Codex’s local design helps, and where it stops
Codex is a local process you configure yourself, which is a real advantage over a hosted assistant: its MCP servers live in a TOML file on your machine rather than a vendor’s settings screen, so you decide what it reaches. That freedom does not extend to the account count inside a first-party connector.
What the first-party plugins still cover
Several Google accounts since August 2026, worked from a terminal, is a genuine capability. Microsoft has no first-party plugin at all. Install either from the plugin browser at /plugins in the Codex CLI. The IDE extension does not support plugins at all.
They stop at the second identity on the same provider, at Outlook formatting beyond plain text, at any shared mailbox whose principal name you cannot supply exactly, and at anything that has to happen while the terminal is closed. Those are the walls people hit: a client account arrives, a second employer shows up on the same provider, or the triage needs to run overnight. They have the same fix.
Codex plugins and per-account MCP servers versus Carly
| Codex plugins | One MCP server per account | Carly | |
|---|---|---|---|
| Gmail accounts at once | One | One each | Every one you connect |
| Outlook accounts at once | One | One each | Every one you connect |
| Gmail and Outlook together | One account of each | Two setups | Yes, any number of each |
| OAuth apps you maintain | None | One per account | None |
| Adding a fourth account | Not possible | New config entry | No config change |
| Says which account it used | Not consistently | No shared convention | On every action |
| Runs with no session open | No | No | Yes |
Carly’s agents carry their own name, email address and memory, so a client can write to one directly and the work starts on arrival rather than the next time you open a terminal. Around the mail sit thousands of other apps. Carly offers free Zapier-style workflows; AI agents start at $35/month.
Connect every inbox at carlyassistant.com.
Quick fixes when a mailbox does not appear
| Problem | Fix |
|---|---|
| No tools in the session | Start a new Codex session after adding the server |
codex mcp login never completes | Finish the browser OAuth flow, then rerun codex mcp list |
| The provider reused your signed-in account | Choose Use another account rather than the suggested profile |
| A work account stalls at consent | Ask that Google Workspace or Microsoft 365 administrator to approve |
| Codex answered from the wrong inbox | Name the address in the prompt |
Frequently asked questions
Can Codex connect to multiple email accounts?
Yes, through Carly. Codex’s own plugins carry one account per provider, so a second Gmail or a second Microsoft 365 mailbox replaces the first. Connecting every mailbox to Carly and registering one MCP server lets a single Codex session reach all of them.
Can Codex reach Gmail and Outlook in the same session?
Yes, through Carly. Both providers arrive as one account-aware mail toolset, so a prompt can cross from a personal Gmail to a work Microsoft 365 mailbox.
How many mailboxes can this reach?
As many as you authorize in Carly. Codex talks to one server, so the account count is a Carly setting rather than a Codex one.
Will it tell me which account it used?
Yes. Every action reports the source address, which is what makes cross-account work safe to trust.
Should I run inbox work inside Codex?
Codex is a coding agent, and terminal mail suits scripted or one-off tasks. Recurring triage and follow-up belong in a Carly workflow that runs with nothing open.
More: Multiple Gmail accounts in Codex · Multiple Outlook accounts in Codex · Connect multiple email accounts to ChatGPT · Connect multiple email accounts to Claude · Carly’s Gmail integration · Carly’s Outlook integration
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