Everything MCP Server

This MCP server attempts to exercise all the features of the MCP protocol. It is not intended to be a useful server, but rather a test server for builders of MCP clients. It implements prompts, tools, resources, sampling, and more to showcase MCP capabilities.

Components

Tools

1. echo

   • Simple tool to echo back input messages
   • Input:
     • message (string): Message to echo back
   • Returns: Text content with echoed message

2. add

   • Adds two numbers together
   • Inputs:
     • a (number): First number
     • b (number): Second number
   • Returns: Text result of the addition

3. longRunningOperation

   • Demonstrates progress notifications for long operations
   • Inputs:
     • duration (number, default: 10): Duration in seconds
     • steps (number, default: 5): Number of progress steps
   • Returns: Completion message with duration and steps
   • Sends progress notifications during execution

4. sampleLLM

   • Demonstrates LLM sampling capability using MCP sampling feature
   • Inputs:
     • prompt (string): The prompt to send to the LLM
     • maxTokens (number, default: 100): Maximum tokens to generate
   • Returns: Generated LLM response

5. getTinyImage

   • Returns a small test image
   • No inputs required
   • Returns: Base64 encoded PNG image data

6. printEnv

   • Prints all environment variables
   • Useful for debugging MCP server configuration
   • No inputs required
   • Returns: JSON string of all environment variables

7. annotatedMessage

   • Demonstrates how annotations can be used to provide metadata about content
   • Inputs:
     • messageType (enum: “error” | “success” | “debug”): Type of message to demonstrate different annotation patterns
     • includeImage (boolean, default: false): Whether to include an example image
   • Returns: Content with varying annotations:
     • Error messages: High priority (1.0), visible to both user and assistant
     • Success messages: Medium priority (0.7), user-focused
     • Debug messages: Low priority (0.3), assistant-focused
     • Optional image: Medium priority (0.5), user-focused
   • Example annotations:

     {
       "priority": 1.0,
       "audience": ["user", "assistant"]
     }
     

Resources

The server provides 100 test resources in two formats:

• Even numbered resources:

  • Plaintext format
  • URI pattern: test://static/resource/{even_number}
  • Content: Simple text description

• Odd numbered resources:

  • Binary blob format
  • URI pattern: test://static/resource/{odd_number}
  • Content: Base64 encoded binary data

Resource features:

• Supports pagination (10 items per page)
• Allows subscribing to resource updates
• Demonstrates resource templates
• Auto-updates subscribed resources every 5 seconds

Prompts

1. simple_prompt

   • Basic prompt without arguments
   • Returns: Single message exchange

2. complex_prompt

   • Advanced prompt demonstrating argument handling
   • Required arguments:
     • temperature (number): Temperature setting
   • Optional arguments:
     • style (string): Output style preference
   • Returns: Multi-turn conversation with images

Usage with Claude Desktop

Add to your claude_desktop_config.json:

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