lua-resty-mcp

Model Context Protocol (MCP) SDK implemented in Lua for OpenResty.

Status

Production ready.

Table of Contents

• Features
• Quickstart
• Server APIs
  • mcp.server
  • mcp.transport.streamable_http.endpoint
  • server:run
  • server:register
  • server:unregister_*
  • server:resource_updated
  • server:replace_*
  • server:list_roots
  • server:create_message
  • server:elicit
  • server:log
  • server:ping
  • server:wait_background_tasks
  • server:shutdown
• Writing MCP Clients
• Client APIs
  • mcp.client
  • client:initialize
  • client:wait_background_tasks
  • client:shutdown
  • client:expose_roots
  • client:list_prompts
  • client:get_prompt
  • client:list_resources
  • client:list_resource_templates
  • client:read_resource
  • client:subscribe_resource
  • client:unsubscribe_resource
  • client:list_tools
  • client:call_tool
  • client:prompt_complete
  • client:resource_complete
  • client:set_log_level
  • client:ping
• Known Issues
  • Cancel request on server that uses stdio transport
• License

Features

• [x] Transports
  • [x] stdio
  • [x] Streamable HTTP
  • [x] WebSocket (non-specification)
• [x] Protocols
  • [x] Lifecycle
  • [x] Prompts
  • [x] Resources
  • [x] Tools
  • [x] Roots
  • [x] Sampling
  • [x] Elicitation
  • [x] Utilities
    • [x] Pagination
    • [x] Progress
    • [x] Cancellation
    • [x] Completion
    • [x] Logging
    • [x] Ping

Quickstart

A simple server demonstrating prompts, resources, tools:

-- Import lua-resty-mcp module
local mcp = require("resty.mcp")

-- Create an MCP server session with stdio transport
local server = assert(mcp.server(mcp.transport.stdio, {}))

-- Register a prompt
assert(server:register(mcp.prompt("echo", function(args)
  return "Please process this message: "..args.message
end, {
  description = "Create an echo prompt",
  arguments = {
    message = {required = true}
  }
})))

-- Register a resource template