What Are MCP Servers?
August 23, 2026 · 4 min read
An MCP server is a program that exposes tools to AI agents via the Model Context Protocol. It sits between your application's data and the AI agent that wants to use it — translating natural-language tool calls into real operations on your system.
How an MCP Server Works
An MCP server does three things:
1. Advertises tools — When an agent connects and calls tools/list, the server returns a list of available tools with names, descriptions, and input schemas.
2. Executes tool calls — When an agent calls tools/call with a tool name and arguments, the server runs the operation and returns results.
3. Authenticates callers — The server verifies who's asking (typically via Bearer token) and scopes access to their data only.
What MCP Servers Provide
Different MCP servers expose different capabilities depending on the application they front:
Knowledge servers
Notes, docs, wikis — search and retrieve information
Action servers
Send emails, create tickets, trigger deployments
Data servers
Query databases, fetch analytics, pull metrics
Memory servers
Persistent context across sessions (like xNotePadAI)
Local vs Remote MCP Servers
MCP servers come in two flavours:
| Type | How it runs | Example |
|---|---|---|
| Local (stdio) | Spawned as a subprocess on your machine | File system server, git server |
| Remote (HTTP) | Hosted on the internet, accessed via URL | xNotePadAI, cloud APIs |
Remote servers (like xNotePadAI) use "type": "http" in the client config and authenticate with Bearer tokens. Local servers use "type": "stdio" and run as child processes — no network needed.
xNotePadAI as an MCP Server
xNotePadAI runs a 13-tool remote MCP server on Cloudflare Workers. When you connect an AI agent:
- • The agent calls
initialize— gets back server name and version - • Then
tools/list— discovers all 13 tools with schemas - • Then
tools/call— creates notes, searches, asks questions, organises - • All scoped to your tenant via the Bearer token — no cross-tenant access
The endpoint is POST https://www.xnotepadai.com/api/mcp/ — one URL, all 13 tools, zero infrastructure to manage.
How to Connect to an MCP Server
For remote HTTP servers like xNotePadAI, add this to your client's MCP config:
{
"mcpServers": {
"xnotepad": {
"type": "http",
"url": "https://www.xnotepadai.com/api/mcp/",
"headers": {
"Authorization": "Bearer YOUR_TOKEN"
}
}
}
}Get your token from Settings — it's pre-generated and ready to copy.