How to Connect Multiple Gmail Accounts to Gemini Spark
Gemini Spark reads the Gmail belonging to the Google account you signed in with. Connect every inbox to Carly, wire Carly into Spark as a custom MCP connector, and one Spark session can search or act across all of them.
What one Spark session can do afterwards
- Search personal and work Gmail in the same request.
- Compare threads sitting in different company accounts.
- Produce a morning brief grouped by inbox.
- Draft or send from the exact address you choose.
- Label, move, or archive in the correct account.
- Check several calendars while writing to only one.
Nothing is merged. Each inbox keeps its own credentials and stays individually addressable.
Spark’s native reach is one Google identity
Google describes Spark as connecting “natively with your favorite Google apps like Gmail, Calendar, Drive, Docs, Sheets, Slides, YouTube, and Google Maps.” That native reach follows the signed-in account, which is the same shape as the Gemini app: switching inboxes means switching accounts, and a request spanning both cannot run in one session.
Spark is also gated. Google says it is “currently available for Google AI Ultra subscribers over 18 in select countries as well as select business users,” so check Google’s availability page before planning around it.
The custom MCP path is the part that helps
Spark’s June 2026 update added connected apps (Google Tasks, Google Keep, Canva, Dropbox, Instacart, OpenTable, Zillow Rentals) and, more usefully here, support for “custom Model Context Protocol (MCP), giving you the ability to connect your favorite apps directly into Spark.”
That is the opening. Spark does not need to hold three Gmail accounts itself if a connector it trusts already holds them.
There is no such thing as an MCP trigger. The protocol's own working group states plainly that clients find out about server-side changes by polling for them, and a real event mechanism remains unshipped.
Worth knowing before you design around it: an MCP connection answers when asked. Spark’s own proactive behavior is what runs on its schedule, and Carly is what keeps account-specific work running when neither is watching.
1. Give each Gmail account a role
For example, all fictional:
| Address | Role |
|---|---|
fictional.rosa.medina@gmail.com | Personal |
fictional.rosa.medina@heineken.com | Main Company |
fictional.rosa.medina@fedex.com | Client |
Use the role when searching and the full address before any send or modification.
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.
Then repeat for each additional Google identity. Choose Use another account if Google preselects the first login, and 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 and then finish authorization. Each Workspace approves independently.
3. Add Carly to Spark over MCP
- Open Spark’s settings and find connected apps.
- Choose the option to add a custom MCP connector.
- Paste
https://carlyassistant.com/mcp/. - Complete authorization.
- Sign in to the Carly workspace holding the Gmail accounts.
Custom app support has rolled out unevenly across Spark’s surfaces and tiers, so if the option is missing, confirm your plan and platform against Google’s availability documentation rather than assuming the connector is at fault.
4. Test every inbox read-only first
One account per prompt:
In
fictional.rosa.medina@heineken.com, list the sender and subject of the five newest unread messages. Do not change anything.
In
fictional.rosa.medina@fedex.com, find the newest thread containing “shipment delay.” State the source account and do not draft.
Then a cross-account search:
Search the Heineken and FedEx example accounts for “invoice” from the last 30 days. Include the full source address in every row.
Once Spark attributes every result correctly, move on to drafts, labels, sends, and calendar work.
5. Reuse this routing prompt
Treat
fictional.rosa.medina@gmail.comas Personal,fictional.rosa.medina@heineken.comas Main Company, andfictional.rosa.medina@fedex.comas Client. Always state the target address before changing data. Ask before sends, moves, deletes, labels, or calendar changes.
Then name the target in each action:
Draft the reply from
fictional.rosa.medina@heineken.com. Do not send yet.
Add the Finance label in
fictional.rosa.medina@fedex.comonly.
Send the approved reply from the account that received the original thread.
Native Gmail in Spark versus Carly
| Need | Native Spark connection | Carly over MCP |
|---|---|---|
| Search the signed-in Google account | Yes | Yes |
| Hold several Google identities at once | No | Yes |
| Compare two inboxes in one session | No | Yes |
| Draft and send from a chosen address | Limited to the signed-in identity | Yes |
| Reach a non-Google mailbox | No | Yes |
| Run the same routing outside Spark | No | Yes |
| Available without an AI Ultra tier | No | Yes |
Carly gives Spark one account-aware toolset over several Gmail connections, and the same routing keeps working outside Spark’s availability gates. Carly offers free Zapier-style workflows; AI agents start at $35/month.
Quick fixes when an inbox does not appear
| Problem | Fix |
|---|---|
| Custom MCP option is missing in Spark | Confirm your tier and platform against Google’s availability docs |
| 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 |
| Spark searches only the signed-in inbox | Name the full address and require source attribution |
| Spark cannot act while you are away | Put the recurring work in a Carly workflow |
Frequently asked questions
Can Gemini Spark hold two Gmail accounts natively?
Spark’s native Google reach follows the account you sign in with. Carly is the way to make several separately authorized Gmail accounts available in one session.
Do I need Google AI Ultra for this?
Spark itself is gated to AI Ultra subscribers and select business users in select countries. Carly’s multi-account routing does not depend on that tier, so the same setup works in other assistants too.
Does this merge the inboxes?
No. They stay separate. Spark can search across them while Carly routes each draft, label, send, or move to the address you name.
Related: What is Gemini Spark · Multiple Gmail accounts in Gemini · Gemini Spark alternatives · Manage multiple email accounts with AI · Carly’s Gmail integration
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