build-depends:
    base
  , servant
  , servant-server
  , servant-auth-server
  , aeson
  , mcp

build-depends:
    base
  , aeson
  , mcp-types

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TypeFamilies #-}

import Control.Concurrent.MVar (newMVar)
import MCP.Server

-- Define your handler state and user types
type instance MCPHandlerState = ()
type instance MCPHandlerUser  = MyUser

-- Create server state with capabilities
mkServerState :: IO (MVar MCPServerState)
mkServerState = do
  let impl = Implementation "my-server" "1.0.0" Nothing
      caps = ServerCapabilities
        { logging      = Nothing
        , prompts      = Nothing
        , resources    = Nothing
        , tools        = Just (ToolsCapability { listChanged = Just True })
        , completions  = Nothing
        , experimental = Nothing
        }
      handlers = withToolHandlers myTools defaultProcessHandlers
  newMVar $ initMCPServerState () Nothing Nothing caps impl Nothing handlers

-- Define tools using the ToolHandler framework
myTools :: [ToolHandler]
myTools =
  [ toolHandler "greet" (Just "Say hello") greetSchema $ \_args ->
      return $ ProcessSuccess $ toolTextResult ["Hello!"]
  ]

cabal run mcp-example

# Initialize the session (replace $TOKEN with the printed token)
curl -s -X POST http://localhost:8080/mcp \
  -H 'Content-Type: application/json' \
  -H "Authorization: Bearer $TOKEN" \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"curl","version":"1.0"}}}'

# Send initialized notification
curl -s -X POST http://localhost:8080/mcp \
  -H 'Content-Type: application/json' \
  -H "Authorization: Bearer $TOKEN" \
  -d '{"jsonrpc":"2.0","method":"notifications/initialized","params":null}'

# List available tools
curl -s -X POST http://localhost:8080/mcp \
  -H 'Content-Type: application/json' \
  -H "Authorization: Bearer $TOKEN" \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}'

# Call the add tool
curl -s -X POST http://localhost:8080/mcp \
  -H 'Content-Type: application/json' \
  -H "Authorization: Bearer $TOKEN" \
  -d '{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"add","arguments":{"a":17,"b":25}}}'

mcp-types/               # Core protocol types package
├── src/MCP/
│   ├── Aeson.hs             # Custom Aeson parsing options
│   ├── Protocol.hs          # JSON-RPC protocol messages
│   └── Types.hs             # Core MCP data types
└── mcp-types.cabal

mcp-server/               # Server implementation package
├── src/MCP/
│   ├── Server.hs            # Re-exports Common, HTTP, and Stdio
│   └── Server/
│       ├── Common.hs        # Types, state, request routing, tool helpers
│       ├── HTTP.hs          # Servant-based HTTP transport with JWT auth
│       └── Stdio.hs         # Stdio transport
├── test/
│   ├── Main.hs              # Test entry point
│   └── MCP/
│       ├── Integration.hs       # HTTP integration tests (hspec-wai)
│       ├── StdioIntegration.hs  # Stdio integration tests
│       ├── TestServer.hs        # Test server configuration
│       └── TestUtils.hs         # Test utilities and request builders
├── example/
│   ├── Main.hs              # Example server (tools, resources, prompts, etc.)
│   ├── mcp-example.cabal    # Standalone cabal project
│   ├── mcp-config.json      # Claude Desktop MCP configuration template
│   └── SKILL.md             # Build, run, and test instructions
└── mcp.cabal

cabal build all
cabal test all