---
title: "MCP Articles | Len P. van der Hof"
description: How a Model Context Protocol connection is authenticated, and why a valid connection is not permission to call each tool.
image: "https://lenvanderhof.com/photos/len-portrait-1.jpg"
---

Tag

# MCP

How a Model Context Protocol connection is authenticated, and why a valid connection is not permission to call each tool.

AI Systems

## [MCP vs function calling: two layers of the same tool call](https://lenvanderhof.com/en/blog/mcp-vs-function-calling/)

In most MCP setups the model still makes a function call. MCP changes where the tool lives, not how the model asks for it.

Len P. van der Hof25 September 2026