import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import {
CallToolRequestSchema,
ListToolsRequestSchema,
ListPromptsRequestSchema,
GetPromptRequestSchema,
ListResourcesRequestSchema,
ReadResourceRequestSchema,
} from "@modelcontextprotocol/sdk/types.js";
import { TOOLS, handleToolCall } from './tools/index.js';
import fs from 'fs';
import path from 'path';
import { fileURLToPath } from 'url';
import { dirname } from 'path';
const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);
/**
* Register all MCP handlers on a server instance
* This is shared across all transport types
*/
export function registerHandlers(server: Server) {
// Register tools handler
server.setRequestHandler(ListToolsRequestSchema, async () => ({
tools: TOOLS
}));
server.setRequestHandler(CallToolRequestSchema, async (request) => {
try {
const result = await handleToolCall(request.params.name, request.params.arguments);
return {
content: [
{
type: "text",
text: JSON.stringify(result, null, 2)
}
]
};
} catch (error: any) {
return {
content: [
{
type: "text",
text: `Error: ${error.message}`
}
],
isError: true
};
}
});
// Register prompts handler
server.setRequestHandler(ListPromptsRequestSchema, async () => ({
prompts: [
{
name: "query-employees",
title: "Query_Employees",
description: "Query employees table using natural language instructions",
arguments: [
{
name: "instructions",
description: "Natural language query instructions (e.g., 'count female employees', 'show 10 recent hires')",
required: true
}
]
},
{
name: "insert-employee",
title: "Insert_Employee",
description: "Insert a new employee with all related information (department, title, salary)",
arguments: [
{
name: "employee_info",
description: "Employee details including name, birth date, gender, department, title, and salary",
required: true
}
]
},
{
name: "delete-employee",
title: "Delete_Employee",
description: "Delete an employee and all related records from the database",
arguments: [
{
name: "employee_identifier",
description: "Employee number or name to delete (e.g., '10001' or 'John Smith')",
required: true
}
]
},
{
name: "manage-departments",
title: "Manage_Departments",
description: "Insert a new department or delete an existing department",
arguments: [
{
name: "instructions",
description: "Department operation (e.g., 'add Marketing department', 'delete department d005')",
required: true
}
]
}
]
}));
// Register GetPrompt handler
server.setRequestHandler(GetPromptRequestSchema, async (request) => {
if (request.params.name === "query-employees") {
const promptPath = path.join(__dirname, 'specs', 'query-employees.md');
const promptContent = fs.readFileSync(promptPath, 'utf-8');
const userInstructions = request.params.arguments?.instructions || "";
const messages = [
{
role: "user" as const,
content: {
type: "text" as const,
text: promptContent.replace('$ARGUMENTS', userInstructions)
}
}
];
return {
description: "Query employees table using natural language instructions",
messages
};
}
if (request.params.name === "insert-employee") {
const promptPath = path.join(__dirname, 'specs', 'insert-employee-info.md');
const promptContent = fs.readFileSync(promptPath, 'utf-8');
const employeeInfo = request.params.arguments?.employee_info || "";
const messages = [
{
role: "user" as const,
content: {
type: "text" as const,
text: promptContent.replace('$ARGUMENTS', employeeInfo)
}
}
];
return {
description: "Insert a new employee with all related information",
messages
};
}
if (request.params.name === "delete-employee") {
const promptPath = path.join(__dirname, 'specs', 'delete-employee.md');
const promptContent = fs.readFileSync(promptPath, 'utf-8');
const employeeIdentifier = request.params.arguments?.employee_identifier || "";
const messages = [
{
role: "user" as const,
content: {
type: "text" as const,
text: promptContent.replace('$ARGUMENTS', employeeIdentifier)
}
}
];
return {
description: "Delete an employee and all related records",
messages
};
}
if (request.params.name === "manage-departments") {
const promptPath = path.join(__dirname, 'specs', 'manage-departments.md');
const promptContent = fs.readFileSync(promptPath, 'utf-8');
const instructions = request.params.arguments?.instructions || "";
const messages = [
{
role: "user" as const,
content: {
type: "text" as const,
text: promptContent.replace('$ARGUMENTS', instructions)
}
}
];
return {
description: "Manage departments (insert or delete)",
messages
};
}
throw new Error(`Unknown prompt: ${request.params.name}`);
});
// Register resources handlers
server.setRequestHandler(ListResourcesRequestSchema, async () => ({
resources: [
{
uri: "bun-db-mcp://general-database",
name: "Database Schema",
description: "Complete documentation of the employee database schema including tables, relationships, and query patterns",
mimeType: "text/markdown"
}
]
}));
server.setRequestHandler(ReadResourceRequestSchema, async (request) => {
if (request.params.uri === "bun-db-mcp://general-database") {
const schemaPath = path.join(__dirname, 'specs', 'database-schema.md');
const schemaContent = fs.readFileSync(schemaPath, 'utf-8');
return {
contents: [
{
uri: request.params.uri,
mimeType: "text/markdown",
text: schemaContent
}
]
};
}
throw new Error(`Unknown resource: ${request.params.uri}`);
});
}
/**
* Create a new MCP server instance with all handlers registered
*/
export function createMCPServer() {
const server = new Server(
{
name: "database-mcp",
version: "2.0.0",
},
{
capabilities: {
tools: {},
prompts: {},
resources: {}
}
}
);
registerHandlers(server);
return server;
}
