Add Kalendis to README

[DavidCabal]

Description

Adding Kalendis MCP server to the official MCP servers list. Kalendis is a scheduling backend API that provides an MCP server for generating TypeScript clients and framework-specific
API route handlers (Next.js, Express, Fastify, NestJS).

Server Details

• Server: N/A (New server addition to README)
• Changes to: README.md - Adding Kalendis to the alphabetically sorted server list

Motivation and Context

Kalendis provides a production-ready MCP server that solves a common developer pain point: integrating scheduling APIs into applications. The MCP server generates:

• Backend clients that call the Kalendis API directly with proper authentication
• Frontend clients for browser-based applications
• Framework-specific API route handlers for Next.js, Express, Fastify, and NestJS

This enables developers to quickly scaffold scheduling functionality without manually writing API integration code, reducing development time from hours to minutes.

How Has This Been Tested?

• Tested extensively with Claude Code and Cursor
• Scenarios tested:
  • Generating backend TypeScript clients for all environments (production, staging, development)
  • Generating frontend clients with custom types import paths
  • Generating API routes for all four supported frameworks (Next.js, Express, Fastify, NestJS)
  • Listing all available Kalendis API endpoints with full descriptions
• Published to npm as @kalendis/mcp version 1.0.6
• Open source repository: https://github.com/kalendis-dev/kalendis-mcp

Breaking Changes

No breaking changes - this is a new server addition to the README list only.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Protocol Documentation
• My changes follows MCP security best practices
• I have updated the server's README accordingly
• I have tested this with an LLM client
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have documented all environment variables and configuration options

Additional context

The Kalendis MCP server follows MCP best practices:

• Implements all four standard MCP tools (generate-backend-client, generate-frontend-client, generate-api-routes, list-endpoints)
• Uses proper JSON schema validation for tool inputs
• Returns generated code as text content in MCP-compliant format
• No environment variables required for the MCP server itself (API keys are only needed for the generated clients)
• MIT licensed and open source
• Fully TypeScript-based with comprehensive type definitions
• Published and maintained on npm registry

The server is actively maintained and used in production by Kalendis customers for scheduling integrations.