MCP Server Development

Server Requirements

To be listed in Testra's directory, MCP servers must meet these requirements:

Core Requirements

MCP v1.0+ Support

  • Implement all required MCP endpoints

  • Follow protocol specifications

  • Provide proper error handling

Documented API

  • Complete API documentation

  • Function descriptions and examples

  • Parameter and return type definitions

Security Audit Preferred

  • Optional but recommended security review

  • Vulnerability assessments

  • Best practices compliance

Open Source or Verifiable Builds

  • Public source code repository, OR

  • Verifiable build artifacts

  • Reproducible deployments

MCP Endpoint Reference

GET /health – Health Check

Basic status check used to confirm that a server is operational.

Method: GET URL: https://your-server.com/health

Response Example:

{
  "status": "ok",
  "uptime": 102934,
  "timestamp": "2025-06-30T12:34:56Z"
}

  • status: Should return ok if the server is operational

  • uptime: Time (in seconds) the server has been up

  • timestamp: ISO 8601 timestamp of the check

GET /capabilities – Function Discovery

Returns a list of callable functions exposed by the MCP server.

Method: GET URL: https://your-server.com/capabilities

Response Example:

{
  "functions": [
    {
      "name": "extract_entities",
      "description": "Extracts named entities from a string",
      "inputs": ["text"],
      "outputs": ["entities"]
    },
    {
      "name": "get_exchange_rate",
      "description": "Returns current exchange rate between two currencies",
      "inputs": ["from", "to"],
      "outputs": ["rate"]
    }
  ]
}

  • name: Function identifier to be used with /execute

  • description: Human-readable explanation of function

  • inputs: List of expected input keys

  • outputs: List of output keys

POST /execute – Function Execution

Main execution endpoint for calling any available function listed in /capabilities.

Method: POST URL: https://your-server.com/execute Headers:

Content-Type: application/json

Request Example:

{
  "function": "get_exchange_rate",
  "input": {
    "from": "USD",
    "to": "EUR"
  }
}

Response Example:

{
  "output": {
    "rate": 0.9254
  }
}

  • function: Must match a name returned by /capabilities

  • input: Object with named parameters expected by the function

  • output: Object with named result keys as defined by the server

Development Templates

Node.js Template

const express = require('express');
const app = express();

// Middleware
app.use(express.json());
app.use(require('cors')());

// Server configuration
const SERVER_CONFIG = {
  name: 'My MCP Server',
  version: '1.0.0',
  mcpVersion: '1.0.0',
  description: 'Description of your server'
};

// Function registry
const functions = new Map();

// Register a function
function registerFunction(name, handler, schema) {
  functions.set(name, { handler, schema });
}

// Health endpoint
app.get('/health', (req, res) => {
  res.json({
    status: 'healthy',
    timestamp: new Date().toISOString(),
    version: SERVER_CONFIG.version,
    mcpVersion: SERVER_CONFIG.mcpVersion
  });
});

// Capabilities endpoint
app.get('/capabilities', (req, res) => {
  const functionList = Array.from(functions.entries()).map(([name, func]) => ({
    name,
    description: func.schema.description,
    parameters: func.schema.parameters,
    returns: func.schema.returns
  }));

  res.json({
    mcpVersion: SERVER_CONFIG.mcpVersion,
    server: {
      name: SERVER_CONFIG.name,
      version: SERVER_CONFIG.version,
      description: SERVER_CONFIG.description
    },
    functions: functionList
  });
});

// Execute endpoint
app.post('/execute', async (req, res) => {
  const { function: functionName, parameters, requestId } = req.body;
  
  try {
    const func = functions.get(functionName);
    if (!func) {
      return res.status(400).json({
        error: {
          code: 'FUNCTION_NOT_FOUND',
          message: `Function '${functionName}' not found`
        },
        requestId
      });
    }

    const startTime = Date.now();
    const result = await func.handler(parameters);
    const executionTime = Date.now() - startTime;

    res.json({
      requestId,
      result,
      executionTime
    });
  } catch (error) {
    res.status(500).json({
      error: {
        code: 'EXECUTION_ERROR',
        message: error.message
      },
      requestId
    });
  }
});

// Example function registration
registerFunction('getPrice', async (params) => {
  // Your function logic here
  return {
    price: 2345.67,
    timestamp: new Date().toISOString(),
    symbol: params.symbol
  };
}, {
  description: 'Get current price for a trading pair',
  parameters: {
    type: 'object',
    properties: {
      symbol: { type: 'string', description: 'Trading pair symbol' }
    },
    required: ['symbol']
  },
  returns: {
    type: 'object',
    properties: {
      price: { type: 'number' },
      timestamp: { type: 'string' },
      symbol: { type: 'string' }
    }
  }
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
  console.log(`MCP Server running on port ${PORT}`);
});

Python Template

from flask import Flask, request, jsonify
from datetime import datetime
import time

app = Flask(__name__)

# Server configuration
SERVER_CONFIG = {
    'name': 'My MCP Server',
    'version': '1.0.0',
    'mcpVersion': '1.0.0',
    'description': 'Description of your server'
}

# Function registry
functions = {}

def register_function(name, handler, schema):
    functions[name] = {'handler': handler, 'schema': schema}

@app.route('/health', methods=['GET'])
def health():
    return jsonify({
        'status': 'healthy',
        'timestamp': datetime.utcnow().isoformat() + 'Z',
        'version': SERVER_CONFIG['version'],
        'mcpVersion': SERVER_CONFIG['mcpVersion']
    })

@app.route('/capabilities', methods=['GET'])
def capabilities():
    function_list = []
    for name, func in functions.items():
        function_list.append({
            'name': name,
            'description': func['schema']['description'],
            'parameters': func['schema']['parameters'],
            'returns': func['schema']['returns']
        })
    
    return jsonify({
        'mcpVersion': SERVER_CONFIG['mcpVersion'],
        'server': {
            'name': SERVER_CONFIG['name'],
            'version': SERVER_CONFIG['version'],
            'description': SERVER_CONFIG['description']
        },
        'functions': function_list
    })

@app.route('/execute', methods=['POST'])
def execute():
    data = request.get_json()
    function_name = data.get('function')
    parameters = data.get('parameters', {})
    request_id = data.get('requestId')
    
    try:
        if function_name not in functions:
            return jsonify({
                'error': {
                    'code': 'FUNCTION_NOT_FOUND',
                    'message': f"Function '{function_name}' not found"
                },
                'requestId': request_id
            }), 400
        
        start_time = time.time()
        result = functions[function_name]['handler'](parameters)
        execution_time = int((time.time() - start_time) * 1000)
        
        return jsonify({
            'requestId': request_id,
            'result': result,
            'executionTime': execution_time
        })
    
    except Exception as e:
        return jsonify({
            'error': {
                'code': 'EXECUTION_ERROR',
                'message': str(e)
            },
            'requestId': request_id
        }), 500

# Example function
def get_price(params):
    return {
        'price': 2345.67,
        'timestamp': datetime.utcnow().isoformat() + 'Z',
        'symbol': params.get('symbol')
    }

# Register the function
register_function('getPrice', get_price, {
    'description': 'Get current price for a trading pair',
    'parameters': {
        'type': 'object',
        'properties': {
            'symbol': {'type': 'string', 'description': 'Trading pair symbol'}
        },
        'required': ['symbol']
    },
    'returns': {
        'type': 'object',
        'properties': {
            'price': {'type': 'number'},
            'timestamp': {'type': 'string'},
            'symbol': {'type': 'string'}
        }
    }
})

if __name__ == '__main__':
    app.run(debug=True, port=3000)

Testing Your Server

Before submitting to Testra, test your server locally:

# Install testing tools
npm install -g @testra/test-suite

# Test your server
testra-test http://localhost:3000 --comprehensive

# Example output:
# Health check endpoint
# Capabilities discovery
# Function execution
# Error handling
# Schema validation
# Rate limiting not implemented
# Security scan passed
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