What is an MCP server? Explained simply
An MCP server lets AI apps like ChatGPT and Claude use your tools and data. What MCP means, how it works, MCP vs API, real examples and how to build one.
On this page
- 01What does MCP stand for in AI?
- 02What is an MCP server in simple terms?
- 03How does an MCP server work?
- 04What is the difference between a local and a remote MCP server?
- 05What is an MCP server used for?
- 06MCP server vs API: what's the difference?
- 07MCP vs A2A, RAG, skills and CLI
- 08Is an MCP server safe?
- 09How do I try an MCP server?
- 10Does my business need an MCP server?
- 11How Transica helps
- 12Common questions
- 13Sources
An MCP server is a program that gives AI apps such as ChatGPT and Claude tools they can use: search this catalog, read this calendar, create this ticket. The AI app decides when a tool would help, the server does the work, and the result goes back into the chat. MCP stands for Model Context Protocol, the open standard they use to talk to each other.
What does MCP stand for in AI?
Model Context Protocol. The official site calls it an open-source standard for connecting AI applications to external systems, and compares it to a USB-C port: one standard plug, so each AI app doesn't need a custom connection to each tool.
Anthropic created it, and in December 2025 gave it to the Agentic AI Foundation, a Linux Foundation directed fund. It's supported by Claude, ChatGPT, Visual Studio Code, Cursor and many others.
What is an MCP server in simple terms?
Think of it as a menu with a kitchen behind it. The menu lists what's available and what each item needs. The AI app reads the menu and places an order. The kitchen makes it and sends it back.
Say a customer asks ChatGPT, "Where's my order?" with a store's app connected:
- ChatGPT sees the server offers a
get_order_statustool. - It decides that tool fits, and calls it with the order number.
- The server looks up the order in the store's system.
- It returns the status, and ChatGPT answers in plain English.
The AI model never touches the store's database. It only gets what the tool returns.
How does an MCP server work?
| Part | What it is | Example |
|---|---|---|
| Host | The AI app the person is using | Claude Desktop, ChatGPT, VS Code |
| Client | The connection inside the host, one per server | Built into the host |
| Server | The program offering tools and data | A GitHub, Notion or Sentry server |
They exchange JSON-RPC messages. The client asks for the list of tools with tools/list, then runs one with tools/call.
A server can offer three kinds of things:
- Tools: actions the AI can run, such as a database query or an API call. Most servers are mainly this.
- Resources: data for context, such as a file or a database schema.
- Prompts: reusable templates for common tasks.
What is the difference between a local and a remote MCP server?
| Local | Remote | |
|---|---|---|
| Runs on | Your computer | A server on the internet |
| Connection | stdio | Streamable HTTP |
| Usually serves | One person | Many people |
| Sign-in | Keys on your machine | OAuth, usually |
| Example | Filesystem | Sentry |
| Reach | Your own coding and desktop tools | Claude on the web and mobile, ChatGPT, directories |
To reach customers, you need a remote server: Claude connects from Anthropic's cloud, so the server must be on the public internet.
What is an MCP server used for?
From the official examples and common servers:
- Personal assistants: reading your Google Calendar and Notion.
- Coding: Claude Code building from a Figma design, or working with GitHub issues.
- Company data: a chatbot querying several databases.
- Other software: driving Blender to make a 3D model.
- Customer-facing apps: a business's product inside ChatGPT or Claude, where customers check orders or search a catalog.
MCP server vs API: what's the difference?
An API is how software talks to your product. An MCP server is how an AI app finds out what it can do and asks for it. Most MCP servers call an API behind the scenes.
| API | MCP server | |
|---|---|---|
| Built for | Developers writing code | AI apps choosing tools at run time |
| Discovery | Read the docs, write the integration | The app asks the server what it offers |
| Each new app | Needs its own integration | Works with any app that supports MCP |
| Descriptions | For people | For the model, so it picks the right tool |
| Sign-in | Varies | OAuth is what MCP recommends for remote servers |
MCP doesn't replace your API. It sits in front of it. Turning an API into an MCP server is mostly choosing which operations to offer and describing them well.
MCP vs A2A, RAG, skills and CLI
| Compared with | What that is | How it relates to MCP |
|---|---|---|
| A2A | A protocol for agents talking to other agents | MCP connects an agent to tools. They can work together |
| RAG | Retrieving documents to give a model context | A retrieval system can be offered through an MCP tool |
| Skills | Packaged instructions for how to do a task | A skill tells the model how; MCP gives it access. A ChatGPT plugin can hold both |
| CLI | A command-line program | A coding agent can run one directly. MCP also works in apps with no terminal |
Is an MCP server safe?
It's as safe as the server and what you approve. A server can read or change whatever its tools allow, so:
- Use servers from developers you trust. Anthropic's listing pages say it can't verify what third-party tools do.
- Give a local server access only to what it needs, because it runs with your user's permissions.
- Check what a tool wants to do before approving it.
If you run one, follow the security best practices. In particular, only accept tokens issued for your server, and don't pass a client's token on to another API. Sign-in details.
How do I try an MCP server?
Add one to Claude in a minute. This is Transica's own public server, with no sign-in. It has two read-only tools: one checks a web page for AI readiness, and one checks an MCP server against the directory rules.
`` https://transica-mcp.transica.dev/mcp ``
Paste it as a custom connector, then ask Claude to check a website. Steps for Claude, Claude Desktop and Claude Code.
Does my business need an MCP server?
Only if customers should be able to do something with your product from inside an AI app, such as check an order or search your catalog. To be mentioned in AI answers, you need AEO, not a server.
You have five main ways to get one: build it with the official SDKs, generate it from OpenAPI, host it on a platform such as Cloudflare or Vercel, use an integration platform, or use a tool such as Transica.
How Transica helps
- Build. Transica builds an MCP server from your API or from AI agents exploring your site, and you approve each tool. Building is free.
- Secure. Customers sign in with the login they already have, and you choose which tools need it.
- List. Transica checks tools against ChatGPT's and Claude's rules and prepares both submissions.
- Maintain. It hosts the server and checks it every 15 minutes, from $19 a month.
- Free directory check. Paste a server's address into the MCP directory check, no account.
Common questions
What does MCP mean?
Model Context Protocol, an open standard for connecting AI apps to outside tools and data.
What is an MCP server in AI?
A program that offers tools and data to AI apps over MCP, so a model can act on real systems instead of only answering from what it was trained on.
What is an MCP server in Claude?
A connection that gives Claude extra tools. Claude's apps call the remote ones connectors. You can add one from its directory or by URL.
Is an MCP server an actual server?
It's a program. It can run on your own computer as a local process or on the internet as a hosted service, and both count as MCP servers.
What is an MCP server URL?
The web address of a remote server, usually ending in /mcp. You paste it into an AI app to connect. Local servers have a command instead of a URL.
What is an MCP integration?
A connection between an AI app and a product through an MCP server. Once a server exists, any app that supports MCP can connect to it.
Do I need to code to use an MCP server?
Not to use a remote one: paste its URL or add it from a directory. Local servers need a config file, and building one needs code or a no-code tool.
Do AI models need MCP to use tools?
No. Models can call tools without it. MCP is the shared standard, so a tool built once works across many AI apps.
Who created MCP?
Anthropic. It now sits in the Agentic AI Foundation, a Linux Foundation directed fund co-founded by Anthropic, Block and OpenAI.
Does ChatGPT support MCP?
Yes. ChatGPT plugins connect to a remote MCP server. How to list one.
Where can I find a list of MCP servers?
The official MCP Registry, Claude's Connectors Directory, ChatGPT's plugin directory and community directories.
Sources
All read on 5 November 2026.
- Model Context Protocol: What is MCP?, Architecture overview, Security best practices, MCP joins the Agentic AI Foundation
- Anthropic: Custom connectors using remote MCP