Gemini MCP: How to Add a Custom Server in 2026
Yes, Gemini supports custom MCP servers. The feature lives inside Gemini Spark, under Connected Apps, and it takes any HTTPS MCP server URL. What surprises most people is not the setup, which is three clicks, but the list of conditions Google attaches to it. Five separate gates decide whether the option even appears for you.
Here is the setup, every gate stated plainly, and the thing an MCP connection still will not do.
Adding a custom MCP server to Gemini
On a computer, in the Gemini web app:
- Open Settings & help → Connected Apps.
- Under Custom apps for Spark, click Add a custom app.
- Enter the app’s MCP server URL.
- Click Next and follow the prompts.
On mobile it is the same path: under Custom apps for Spark, tap Add a custom app and enter the URL. The URL must be HTTPS and commonly ends in /mcp.
The five conditions Google attaches
This is where people get stuck, and none of it is obvious from the settings screen:
- A personal Google Account. Google’s own wording is that the feature “isn’t available if you sign in with a work or school Google Account.” If your Gemini sign-in is a Workspace address, the option is not there.
- Access to Gemini Spark. Spark is not the free tier. It rolls out to Google AI Pro subscribers in English in the US, and to AI Ultra subscribers more broadly.
- 18 or over, and in the US.
- Keep Activity switched on. Google states plainly that Gemini cannot connect to custom apps when that setting is off, which sends a lot of people hunting through the wrong menu.
- English only, in the Gemini mobile app and the web app at gemini.google.com.
If you sign in to Gemini with a work account, that first condition is the one that stops you, and no amount of retrying the menu changes it.
Gemini CLI is a separate path
The Gemini CLI reads MCP servers from its own configuration file rather than from Connected Apps, so none of the Spark conditions above apply to it. It is the route developers usually want, and it is unrelated to the web app setup. The two share a protocol and nothing else.
Why Gemini alone still misses your other accounts
None of the major assistants let one connector carry two accounts at once. ChatGPT, Claude, and Gemini all authorize a single Google identity per connection, and the documented way to reach the other one is to disconnect and sign in again. A question that spans both inboxes cannot be answered in a single conversation. Carly answers it.
That is the limit people meet before they ever get to MCP. Gemini reads the Google account you signed in with. Personal mail and Workspace mail do not appear in the same conversation, which is odd given Gemini is Google’s own assistant, and it is the reason so many searches for Gemini MCP are really searches for a way to reach everything at once.
What no MCP server will do, in Gemini or anywhere
MCP servers wait to be asked. The protocol has no scheduler and no event mechanism, and its maintainers acknowledge that change detection today means polling. An MCP connection can answer a question. It cannot notice something on its own. Carly's workflows are what do that part.
Worth being concrete about, because it disappoints people who expected otherwise: a custom app answers when Spark calls it. It does not watch anything. Mail arriving at 11pm, a form submitted on Saturday, a record changing in your CRM, none of it reaches Gemini until you open a conversation and ask.
Give Gemini every account, and something that acts
Carly is an MCP server built to cover both gaps at once. It holds as many accounts as you connect to it, and it runs workflows on real events rather than waiting to be asked.
- Add your accounts to Carly. Sign in at carlyassistant.com, open Integrations, find the service, click Connect, and authorize. Click Connect again for the next one and keep going for as many as you want, Outlook included. Carly connects to thousands of apps, so calendars, files, and your CRM ride the same connector.
- Add Carly to Gemini. Open Settings & help → Connected Apps, and under Custom apps for Spark choose Add a custom app. Enter
https://carlyassistant.com/mcp/. - Ask across all of it. One conversation now reaches every account you connected, and Carly sends real mail from the address a thread arrived on instead of leaving you a draft.
If the Spark conditions above rule you out, the same URL drops straight into Claude or ChatGPT, neither of which gates it that way, and Carly keeps working in the background regardless of which assistant you talk to. Free Zapier-style workflows; AI agents from $35/month, and connecting Carly costs nothing.
Frequently Asked Questions
Does Gemini support MCP?
Yes. Gemini Spark accepts custom MCP servers through Settings & help → Connected Apps → Custom apps for Spark → Add a custom app, using the server’s HTTPS URL.
Why is there no option to add a custom app in my Gemini?
Almost always the account type. Custom apps require a personal Google Account, and Google does not offer the feature to work or school accounts. It also needs Gemini Spark access, Keep Activity on, English, and a US location.
Do I need to pay for Gemini to use MCP?
Effectively yes. Custom apps require Gemini Spark, which rolls out to Google AI Pro subscribers in the US and to AI Ultra subscribers more widely, rather than to the free tier.
Can Gemini use MCP to read two Gmail accounts at once?
Not on its own, because the Google connection covers the one account you signed in with. Connecting each mailbox to Carly and adding Carly as the custom app puts all of them in one conversation.
Can a Gemini MCP server run on a schedule or a trigger?
No. MCP has no scheduler and no event mechanism, so a custom app only responds inside a conversation you start.
More: Can Gemini access Gmail? · Connect multiple Gmail accounts to Gemini · What is Gemini Spark? · Claude MCP · ChatGPT MCP · MCP servers: the complete list
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