/**
* Example Custom Module for MCP Server
*
* This is an example of how to create a custom module for the MCP server.
* This module adds a simple calculator tool that can perform basic arithmetic operations.
*/
import { logger } from '../../src/utils/logger.js';
/**
* Calculator tool implementation
* @param {Object} params - Calculator parameters
* @returns {Object} Calculation result
*/
function calculator(params) {
const { operation, a, b } = params;
if (typeof a !== 'number' || typeof b !== 'number') {
throw new Error('Parameters a and b must be numbers');
}
let result;
switch (operation) {
case 'add':
result = a + b;
break;
case 'subtract':
result = a - b;
break;
case 'multiply':
result = a * b;
break;
case 'divide':
if (b === 0) {
throw new Error('Division by zero');
}
result = a / b;
break;
default:
throw new Error(`Unknown operation: ${operation}`);
}
return { result };
}
/**
* Register this module with the Hono app
* @param {import('hono').Hono} app - The Hono app instance
*/
export async function register(app) {
logger.info('Registering calculator module');
// Register the calculator tool
app.get('/tools/calculator/info', c => {
return c.json({
name: 'calculator',
description: 'Performs basic arithmetic operations',
parameters: {
operation: {
type: 'string',
description: 'The operation to perform (add, subtract, multiply, divide)',
required: true,
},
a: {
type: 'number',
description: 'The first operand',
required: true,
},
b: {
type: 'number',
description: 'The second operand',
required: true,
},
},
});
});
// Register the calculator endpoint
app.post('/tools/calculator', async c => {
try {
const params = await c.req.json();
// Validate required parameters
if (!params.operation) {
return c.json({ error: 'Missing required parameter: operation' }, 400);
}
if (params.a === undefined) {
return c.json({ error: 'Missing required parameter: a' }, 400);
}
if (params.b === undefined) {
return c.json({ error: 'Missing required parameter: b' }, 400);
}
// Perform the calculation
const result = calculator(params);
return c.json({
tool: 'calculator',
operation: params.operation,
a: params.a,
b: params.b,
result: result.result,
timestamp: new Date().toISOString(),
});
} catch (error) {
return c.json({ error: error.message }, 400);
}
});
// Register the module info endpoint
app.get('/modules/calculator', c => {
return c.json(metadata);
});
logger.info('Calculator module registered successfully');
}
/**
* Unregister this module (cleanup)
*/
export async function unregister() {
logger.info('Unregistering calculator module');
// Perform any cleanup here
}
/**
* Module metadata
*/
export const metadata = {
name: 'Calculator Module',
version: '1.0.0',
description: 'A simple calculator module that provides basic arithmetic operations',
author: 'MCP Server Team',
tools: ['calculator'],
};
