Add conarti/mattermost-mcp to Communication section

README.md

@@ -360,6 +360,7 @@ Integration with communication platforms for message management and channel oper
 - [carterlasalle/mac_messages_mcp](https://github.com/carterlasalle/mac_messages_mcp) 🏠 🍎 🚀 - An MCP server that securely interfaces with your iMessage database via the Model Context Protocol (MCP), allowing LLMs to query and analyze iMessage conversations. It includes robust phone number validation, attachment processing, contact management, group chat handling, and full support for sending and receiving messages.
 - [chaindead/telegram-mcp](https://github.com/chaindead/telegram-mcp) 🏎️ 🏠 - Telegram API integration for accessing user data, managing dialogs (chats, channels, groups), retrieving messages, and handling read status
 - [chigwell/telegram-mcp](https://github.com/chigwell/telegram-mcp) 🐍 🏠 - Telegram API integration for accessing user data, managing dialogs (chats, channels, groups), retrieving messages, sending messages and handling read status.
+- [conarti/mattermost-mcp](https://github.com/conarti/mattermost-mcp) 📇 ☁️ - MCP server for Mattermost API. List channels, read/post messages, manage threads and reactions, monitor topics. Supports flexible configuration via CLI args, environment variables, or config files.
 - [Danielpeter-99/calcom-mcp](https://github.com/Danielpeter-99/calcom-mcp) 🐍 🏠 - MCP server for Calcom. Manage event types, create bookings, and access Cal.com scheduling data through LLMs.
 - [discourse/discourse-mcp](https://github.com/discourse/discourse-mcp) 🎖️ 💎 ☁️ 🏠 💬 🍎 🪟 🐧 - Official Discourse MCP server for forum integration. Search topics, read posts, manage categories and tags, discover users, and interact with Discourse communities.
 - [elie222/inbox-zero](https://github.com/elie222/inbox-zero/tree/main/apps/mcp-server) 🐍 ☁️ - An MCP server for Inbox Zero. Adds functionality on top of Gmail like finding out which emails you need to reply to or need to follow up on.