Claude MCP: add a remote MCP server as a custom connector
To add a remote MCP server to Claude, open Customize → Connectors, click + Add, then Add custom connector, and paste the server’s URL. Claude calls these custom connectors. A connector you add once works in Claude on the web, Claude Desktop and the mobile apps, because it is stored on your Claude account rather than on one device. Free plans can add one custom connector; Pro, Max, Team and Enterprise can add more.
This guide covers the steps, the sign-in options, how to use the connector in a chat, and what to check when it fails. The example server is datatomcp, which lets Claude query a CSV or Google Sheet.
Remote connectors vs claude_desktop_config.json
Claude has two ways to use MCP:
| Custom connector (remote) | claude_desktop_config.json (local) |
|
|---|---|---|
| Server runs | On the internet, at a URL | On your computer, started by Claude Desktop |
| Works in | Claude web, Desktop, mobile, Cowork | Claude Desktop only |
| Added from | Customize → Connectors | A JSON file you edit by hand |
| Sign-in | OAuth or request headers | Environment variables in the file |
If the server gives you a URL, use a custom connector. Don’t put a remote URL in claude_desktop_config.json; that file is for local commands. For Claude Code, see the Claude Code MCP guide.
1. Add the connector (Pro and Max)
- In Claude, open Customize → Connectors.
- Click + Add, then Add custom connector.
- Enter a name (this is what you’ll see in the connector list) and the server URL, for example
https://app.datatomcp.com/mcp. Click Continue. - Claude detects how the server signs in. Review it and click Continue.
- Under Authentication, choose Sign in now for an OAuth server. Under OAuth client, keep Use Claude’s published identity (Recommended) unless the server’s docs say otherwise.
- Click Add, then complete the sign-in window that opens. For datatomcp you sign in with your datatomcp account and approve read access to your datasets.
If a server uses an API key instead of OAuth, choose No sign in and put the key under Request headers, for example Authorization: Bearer <key>.
1b. Team and Enterprise
An owner adds the connector once for the organization: Organization settings → Connectors → Add, hover Custom, choose Web, then the same fields as above. Members then open Customize → Connectors, find the connector and click Connect. Each member signs in with their own account, so each sees only their own data.
Connectors from the directory
Some servers are listed in Claude’s connector directory, and connecting one from there skips the URL step. datatomcp is listed at claude.ai/directory/datatomcp; connecting from that page leads to the same sign-in as the custom connector.
2. Use it in a chat
Click + at the lower left of the chat box, open Connectors and make sure the connector is switched on for this conversation. Then ask a question the server can answer. The first time, name it:
Use datatomcp: how many orders came from France in September, and what was the revenue?
Claude asks before it runs a tool. Read the request and click Allow. Allow always is fine for read-only servers you trust. You can switch individual tools off from the Search and tools menu.
With our 50,000-row test orders sheet, Claude called describe_dataset to learn the columns, then one aggregate call, and answered 277 orders and €50,279.50. The numbers come from a database query over every row, not from Claude reading the file.
How to check it worked
- The connector shows as connected under Customize → Connectors, with its tools listed.
- In a chat, the tool call appears in Claude’s answer with its input and result. Expand it to see what was sent.
- If Claude answers without calling a tool, the connector is probably off for that chat.
Troubleshooting
- “Couldn’t connect” when adding. Claude connects from Anthropic’s servers, not from your computer. A server on
localhost, behind a VPN or a firewall can’t be reached. The URL must be public HTTPS. - Sign-in window closes and nothing happens. Pop-up blockers can stop it. Allow pop-ups for claude.ai and click Connect again.
- Connector added but the tools are missing. Remove the connector and add it again. To change a connector’s URL you also remove and re-add it.
- Free plan: “limit reached”. Free accounts get one custom connector. Remove the old one or upgrade.
- Tools run in Research without asking. Research can call connector tools without approval. That’s harmless for read-only servers like datatomcp; for servers that can write, switch the write tools off first.
What a useful remote server looks like
A good MCP server for Claude returns small, exact answers. datatomcp gives Claude five read-only tools over your spreadsheets:
| Tool | What Claude uses it for |
|---|---|
list_datasets |
See which datasets exist, their row counts and freshness |
describe_dataset |
Learn the columns, types, example values and today’s date |
distinct_values |
Get exact spellings (“United States”, not “USA”) before filtering |
aggregate |
Counts, sums, averages, min and max, grouped by any column |
query_rows |
Filtered, sorted rows, up to 1,000 per call |
To try it, create a free account, add a CSV or Google Sheet under Add data, and add the connector as above. For a sheet-specific walkthrough with screenshots, see Connect Google Sheets to Claude.
FAQ
Can I add an MCP server to Claude on the free plan? Yes, one custom connector.
Do connectors work on Claude mobile? Yes. Add them on the web or desktop; they follow your account to the mobile apps.
Can a connector reach a server on my own computer? No. Use a local server in Claude Desktop’s config file, or Claude Code, for that.
How do I remove a connector? Customize → Connectors, then Remove or the three-dot menu next to it. You can also revoke access on the server’s side; for datatomcp that’s in the app.
More clients: How to add a remote MCP server to any AI client · ChatGPT · Cursor