Authentication in the MCP protocol in 2026: past, present, and future

The Model Context Protocol (MCP), which Anthropic presented in November 2024, was conceived as a local interface for simple commands—but the transition to remote servers made authentication a mandatory part of the protocol, not an optional layer.

What MCP Was Initially

MCP is designed to give a model an interface to communicate with some system, program, or server—this technology came with the development of agents and large language models and became something completely new for the industry literally a couple of years ago. The first versions of MCP could only work locally: a user could ask the model to "run a calculator," "check the calendar," or "delete unnecessary photos from the gallery," and the agent would execute the command on the same device without needing to connect anywhere.

• The Model Context Protocol was developed by Anthropic in November 2024
• The first use cases for MCP were local: running a calculator, checking a calendar, deleting files from a gallery
• Authentication in the first versions of the protocol was not required—the model and MCP server worked on one device

What Changed with Remote Servers

MCP evolved quite quickly from a local tool into a protocol for remote servers: a user enters the address of their MCP server in Claude, and the model itself figures out what that server can do, where to connect, and how to communicate with it.

As soon as the server stops being part of a single device, the question arises of who exactly is accessing it and whether it should respond to this request at all. A model that has received the address of a third-party server can no longer rely on it being physically located with the user—it needs to trust only those servers that have proven who they are. This is the task of authentication.

"As soon as MCP became remote, authentication stopped being optional," states the article on

Habr dedicated to the history and future of authentication in MCP.

Why This Is Important for Developers

While MCP remained a local tool, the developer didn't need to think about who was connecting to the server—the server and model shared one device and one circle of trust. With the transition to remote servers, this separation disappeared, and authentication became a fundamental element of architecture that must be laid in from the start of server development rather than added after the fact.

This is precisely why the author of the material on Habr structures the narrative around three stages—"how it was," "how it is," and "how it will be": MCP went through a path from a local tool without a single connection verification mechanism to a protocol where the question of remote access and server trust arises for each new integrator.

What This Means

For teams connecting MCP servers to Claude and other agents, this means the question "who and how verifies the connection" can no longer be postponed—it becomes part of the basic architecture of any remote server from day one.

Frequently Asked Questions

When Did the MCP Protocol Appear?

The Model Context Protocol was developed by Anthropic in November 2024—as an interface through which a model can communicate with external systems, programs, and servers.

How Did MCP Work Before Transitioning to Remote Servers?

Initially, MCP was local and solved modest tasks: typical requests—"run a calculator," "check the calendar," "delete unnecessary photos from the gallery"—were executed on one device without requiring authentication.

Why Is the MCP Protocol Needed at All?

To give a model a single interface for communication with external systems, programs, and servers—instead of writing a separate integration for each tool every time.