Everything MCP Server

What it does

The everything server is a protocol test server, not a utility server. The README says it is not intended to be useful, but rather to exercise MCP features so client builders can test prompts, tools, resources, sampling and related behavior.

It can run over stdio by default, and it also supports SSE and streamable HTTP when run from source or by passing the transport name to the installed package. The SSE transport is marked deprecated as of 2025-03-26 in the README.

Because it demonstrates broad protocol surface, including a tool that prints environment variables, it belongs in development and testing setups rather than production agent stacks.

Configuration

Run with npx @modelcontextprotocol/server-everything for stdio, or pass sse or streamableHttp to run those transports.

{
  "mcpServers": {
    "everything": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-everything"]
    }
  }
}

Source: https://github.com/modelcontextprotocol/servers/tree/main/src/everything. Placeholders only. Replace them in your own environment, and never commit real keys to a repository.

No environment variables are required per the official documentation.

Verified tools and features

• echo Config checked

  Echoes back an input message for basic connectivity checks.

• add Config checked

  Adds two numbers and returns the result.

• longRunningOperation Config checked

  Runs a timed operation with progress notifications, using duration and steps inputs.

• getTinyImage Config checked

  Returns a small base64 encoded test image.

• sampleLLM Config checked

  Demonstrates MCP sampling by sending a prompt to the client LLM with a maxTokens limit.

Security notes