mcp-server-bash

What is mcp-server-bash?

mcp-server-bash is a minimalistic MCP (Model Context Protocol) server written entirely in shell script. It implements the MCP lifecycle—initialization and operation—and provides a single tool to add two numbers, serving as a reference for learning MCP basics.

How to use mcp-server-bash?

Download the mcp_add.sh script, make it executable (chmod +x mcp_add.sh), then test it from the CLI by piping JSON-RPC messages to the script (e.g., echo '{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}' | bash mcp_add.sh). For use with LLM hosts, add the script’s path to a JSON configuration file under mcpServers.

Key features of mcp-server-bash

• Written entirely in shell script (bash)
• Implements full MCP lifecycle (handshake + operation)
• Provides a single “addition” tool
• Can be tested directly from the command line
• Configurable for Claude Desktop and mcphost
• Minimal codebase for learning MCP internals

Use cases of mcp-server-bash

• Learning how an MCP server works through a minimal example
• Adding two numbers via an LLM host (e.g., Claude Desktop, mcphost)
• Testing MCP protocol messages (tools/list, tools/call) in a shell environment
• Building a foundation for custom MCP servers in shell scripts

FAQ from mcp-server-bash

What does this MCP server do?

It is a minimal shell script that implements the MCP protocol and exposes a single tool named “addition” which takes two numbers and returns their sum.

How do I test the server without an LLM host?

Pipe JSON-RPC requests directly to the script. For example, to list tools use echo '{"method":"tools/list","id":2,"jsonrpc":"2.0"}' | bash mcp_add.sh. To call the addition tool use echo '{"jsonrpc":"2.0","id":20,"method":"tools/call","params":{"name":"addition","arguments":{"num1":"1","num2":"2"}}}'.

How do I configure this server for Claude Desktop or mcphost?

Add an entry to the MCP configuration JSON with the command set to the full path of mcp_add.sh and an empty args array, as shown in the README.

What are the runtime requirements?

The server requires a Unix-like environment with bash and optionally jq for formatted output during CLI testing. The script is self-contained.

Does this server support multiple tools or resources?

No—the server provides only one tool (“addition”). It is designed as a minimal example, not a full-featured implementation.