The short answer
An MCP server is a program that gives an AI app, such as ChatGPT or Claude, tools for reaching one service, like your analytics or your store. It follows the Model Context Protocol (MCP), an open standard that Anthropic introduced in November 2024. ChatGPT and Claude on the web connect to remote servers: you add one by its address as a custom connector and, if the server needs an account, sign in with OAuth. SAR Intelligence is one hosted example, with tools that only read your data.
To see what a read-only MCP server reads in practice, start with the Google Analytics connection for ChatGPT and Claude.
Key points
- MCP is an open standard for connecting AI apps to outside systems, and both ChatGPT and Claude support it.
- A server gives the AI app tools. Some tools only read data, and others can change it.
- ChatGPT and claude.ai connect to remote servers only. A server running on your own computer does not work there.
- Before you approve a server, check who runs it, which tools it has and which permissions it asks for.
- SAR Intelligence is a hosted, read-only MCP server that reaches one organization per connection.
Local and remote MCP servers
| Question | Local server | Remote server |
|---|---|---|
| Where it runs | On your own computer, started by the AI app | On the provider's servers, over the internet |
| How it talks to the AI app | Standard input and output (STDIO) on the same machine | Streamable HTTP |
| How you sign in | Credentials come from the computer it runs on | OAuth, when the server needs an account |
| Works in ChatGPT and on claude.ai | No | Yes, as a custom connector added by its address |
| Who keeps it running | You | The provider |
What the Model Context Protocol is
The Model Context Protocol (MCP) is an open standard for connecting AI apps to outside systems, such as files, databases and business tools. Anthropic introduced it on 25 November 2024 as an open standard and an open-source project.
The official MCP site compares it to a USB-C port for AI apps: one shared way to connect instead of a separate integration for each app. Among the apps that support it, the site lists Claude, ChatGPT, Visual Studio Code and Cursor.
What an MCP server offers
The AI app asks the server for a list of what it offers. When you ask a question, the app picks a tool, calls it and writes its answer from the result. The MCP specification defines three kinds of offering:
- Tools: functions the AI app calls, such as a traffic report or an order search
- Resources: data that gives context, such as the contents of a file
- Prompts: ready-made templates that help the AI app use the tools
Why ChatGPT and Claude on the web need a remote server
A local server runs on your computer and talks to the AI app on the same machine. A remote server runs on its provider's servers, and the AI app reaches it over the internet.
OpenAI says ChatGPT does not connect to a local server directly, only to remote ones. Anthropic says Claude reaches a custom connector from Anthropic's cloud, even in Claude Desktop, and that local servers set up in Claude Desktop are not available on claude.ai. So for ChatGPT or Claude to read your data, you add a remote server's address as a custom connector. In ChatGPT that needs developer mode turned on, and OpenAI calls the result an app.
What read-only tools mean
Whoever builds a server decides what each tool does. A tool can read data, or it can create, change or delete it. A read-only server gives the AI app only tools that read.
A tool can declare that it only reads. ChatGPT asks for confirmation before write actions by default, and treats any tool without that declaration as a write action. The MCP specification adds that apps must treat such declarations as untrusted unless the server is trusted. Before you approve a server, check:
- Who builds it and who runs it
- Its tool list, and whether any tool changes data
- The permissions it asks for when you sign in
- How you take access back when you no longer need it
How sign-in to a remote server works
The MCP specification bases sign-in for servers reached over HTTP on OAuth 2.1. The AI app sends you to the service's sign-in page, you approve access, and the app receives a token instead of your password.
Anthropic says this way Claude never sees your password, and that you revoke access by disconnecting the connector in Claude or in the service's security settings. ChatGPT accepts servers that use OAuth, no sign-in, or a mix of both.
One example: SAR Intelligence
SAR Intelligence is a hosted MCP server at https://mcp.sar-soft.com/mcp. In the SAR Intelligence app you connect Google Analytics, Search Console, WordPress, WooCommerce or Magento, choosing one property, site or store for each connection. Then you add the address to ChatGPT or Claude, sign in with OAuth and authorize one organization.
Other options exist, such as servers that software vendors run themselves or open-source servers you run on your own. Put them through the same checks. For SAR Intelligence the answers are:
- The AI app gets only tools that read. It cannot change your site, your store or your analytics settings.
- One connector reaches one organization, and each organization is isolated from every other.
- You revoke an AI app in the SAR Intelligence app, and it takes effect within about a minute.
- SAR has no AI model of its own. ChatGPT or Claude writes the answer, which can be wrong or incomplete.
Questions to try
- How much traffic did we get in the last 30 days, compared with the 30 before?Sources: Google Analytics
- Which search queries brought us the most clicks in the last 28 days?Sources: Search Console
- What were our best-selling products this month?Sources: WooCommerce
- Which pages get plenty of search impressions but little actual traffic?Sources: Search Console · Google Analytics
Questions people ask
Is MCP only for Claude?
No. Anthropic introduced it as an open standard, and the MCP site lists ChatGPT, Visual Studio Code and Cursor among the apps that also support it. The ChatGPT and Claude plans that can add a custom connector are listed below.
- ChatGPTOn a Plus, Pro, Business, Enterprise or Edu plan, on the web, with developer mode turned on.OpenAI's guide
- ClaudeOn any plan. Free allows one custom connector, and on Team and Enterprise an owner adds it first.Anthropic's guide
Is an MCP server the same as a custom connector?
Nearly. The MCP server is the program that offers the tools. A custom connector is how Claude adds a remote server by its address. ChatGPT does the same with an app in developer mode.
Do I need to install anything to use a remote MCP server?
Not on your computer. The server runs on its provider's servers, and you add its address to ChatGPT or Claude. Some servers need something on the source itself, such as the SAR Commerce Connector plugin on WordPress.
Can an MCP server change my data?
That depends on its tools. Some servers have tools that create, change or delete data. SAR Intelligence gives the AI app only tools that read.
References
- Model Context ProtocolWhat is the Model Context Protocol (MCP)?
- Model Context ProtocolArchitecture overview
- Model Context ProtocolAuthorization
- Model Context ProtocolTools
- AnthropicIntroducing the Model Context Protocol
- AnthropicGet started with custom connectors using remote MCP
- OpenAIChatGPT developer mode
- OpenAIDeveloper mode and MCP apps in ChatGPT