MCP Communication Servers: Slack, Gmail, Teams (2026)

Communication servers are the fastest-growing category in the Model Context Protocol (MCP) server ecosystem. Independent evaluations of every significant server in this category, covering team chat, email, consumer messaging, and SMS/voice platforms, not directory listings.

MCP lets AI clients read messages, search threads, draft replies, and send notifications across Slack, Gmail, Discord, Microsoft Teams, and other platforms through a standardized JSON-RPC 2.0 interface. Anthropic introduced MCP as an open standard in November 2024. The Linux Foundation’s Agentic AI Foundation (AAIF) now governs the specification (Linux Foundation, “Agentic AI Foundation Launch,” December 9, 2025). 7 servers compete in this category as of mid-2026. 3 have official vendor-maintained servers. 4 rely on community implementations.

The full MCP server directory covers all 14 server categories. This page focuses on communication servers alone.

What Does a Communication MCP Server Do?

A communication MCP server exposes messaging, email, and voice capabilities as callable tools. The AI client reads channels, searches threads, drafts messages, and sends replies through a standardized JSON-RPC interface. The server processes authentication and rate limiting on behalf of the agent.

Communication servers differ from other MCP categories in one fundamental way: they operate on private, permission-scoped data. A database server queries tables. A search server queries the public web. A communication server reads private messages, internal discussions, and confidential email threads. Authentication and permission scoping are the defining constraints.

4 platform types define this category:

Team chat servers connect to Slack, Microsoft Teams, and similar enterprise messaging platforms. Tools expose channels, threads, direct messages, reactions, and file uploads.
Email servers connect to Gmail, Outlook, and SMTP/IMAP providers. Tools expose inbox search, thread reading, draft composition, and sending.
Consumer messaging servers connect to Discord, Telegram, WhatsApp, and similar platforms. Tools expose message history, channel management, and bot-style interactions.
SMS and voice servers connect to Twilio and similar telephony APIs. Tools expose text message sending, voice call initiation, and webhook-based notifications.

Each platform type carries different authentication requirements, governance models, and rate limits. A Slack integration that works for a 50-person startup requires different scoping than a Slack integration for a 10,000-person enterprise.

How Do You Evaluate Communication Servers?

Evaluate communication servers on 5 criteria: platform coverage, authentication model, enterprise governance, tool surface breadth, and official vs community maintenance. These dimensions determine whether a server fits a production workflow or creates a security liability.

Platform Coverage

Slack MCP covers one platform deeply. The Google Workspace MCP suite covers 5 platforms (Gmail, Drive, Calendar, People, Chat) through 5 separate servers. Twilio MCP covers SMS and voice. Match the server to the platform where the agent needs to operate.

Authentication Model

Slack MCP uses confidential OAuth 2.0 with user-level permissions. Gmail MCP uses OAuth 2.0 through a Google Cloud project. Discord MCP implementations use bot tokens from the Discord developer portal. Twilio MCP uses an API key. The authentication model determines what data the agent can access and what audit trails the organization can enforce.

Enterprise Governance

Slack provides workspace admin controls for approving, restricting, or revoking MCP client integrations. Microsoft Teams provides preview-stage governance through the Work IQ layer. Discord provides no enterprise governance for MCP integrations. Enterprise governance controls determine whether IT teams can manage AI agent access centrally.

Tool Surface Breadth

Slack MCP exposes messaging, search, canvas creation, reactions, file reading, and user profile access. Gmail MCP exposes search, read, draft, send, and label management. Discord community servers expose 46+ tools in advanced implementations. Broader tool surfaces increase context window consumption. Each tool definition occupies 500 to 2,500 tokens.

Official vs Community Maintenance

Vendor-maintained servers receive security patches, API updates, and enterprise features. Community servers depend on volunteer maintenance and lag behind API changes. The distinction matters for production deployments where security vulnerabilities require rapid patching.

The rubric above applies to every server profiled in the next section.

Which Servers Connect to Messaging and Email Platforms?

7 communication servers expose MCP-compatible tools as of mid-2026. Slack MCP and Gmail MCP lead the category with official, vendor-maintained servers. Discord, Telegram, and Outlook rely on community implementations or third-party platforms.

Slack MCP

Slack (Salesforce) maintains the official Slack MCP server. The server reached general availability (GA) in February 2026, first announced at Dreamforce in October 2025. Transport: streamable HTTP at mcp.slack.com/mcp. Auth: confidential OAuth 2.0 with user-level permissions. Apps require directory publication or internal status. Unlisted apps are blocked.

The server exposes tools for sending and drafting messages, reading channels and threads, creating channels, and adding reactions. Canvas creation, Real-Time Search API access, member listing, emoji listing, file reading, and user profile fetching round out the tool surface. 5 new tools shipped on May 13, 2026: reactions, channel creation, member listing, emoji listing, and file reading.

MCP responses use markdown with hydrated entity names instead of raw API JSON. Tool discovery is scoped to the authenticated user’s permissions. Agents see only the tools they are authorized to use. Workspace admins approve and revoke all MCP client integrations centrally.

Anthropic published an early Slack reference server as one of its original implementations. A link unfurling vulnerability was reported on May 27, 2025. Anthropic archived the repository 2 days later on May 29, 2025. The official Slack server replaced it with enterprise-grade security and governance.

Slack MCP server profile covers OAuth configuration, tool surface, and enterprise deployment.

Gmail MCP

Google maintains the official Gmail MCP server as part of the Google Workspace MCP suite. The server is remote hosted at gmailmcp.googleapis.com. Auth: OAuth 2.0 through a Google Cloud project. The server exposes tools for searching threads, reading email content and attachments, composing and revising drafts, sending emails, and managing labels and threads.

The Google Workspace suite separates Gmail, Google Drive, Google Calendar, Google People, and Google Chat into 5 independent MCP servers. Each server authenticates independently through the same Google Cloud project. This modular architecture lets agents install only the communication tools they need without loading the full suite’s tool definitions into the context window.

Gmail MCP requires a Claude Enterprise, Pro, Max, or Team plan for use with Claude Desktop. Google recommends reviewing all actions taken by the AI client to ensure alignment with user intent.

Discord MCP

Discord has no official MCP server. Community implementations wrap the Discord.js library or Discord REST API. Advanced implementations expose 46+ tools: messaging, moderation, role management, event scheduling, and community administration. Auth: bot token from the Discord developer portal. Cost: free (Discord bot standard limits apply).

The absence of an official server means no vendor-maintained security patches, no enterprise governance controls, and no guaranteed API compatibility after Discord updates. Community servers are functional for development and small-team use. Production deployments require careful evaluation of the specific implementation’s maintenance status.

Microsoft Teams MCP

Microsoft maintains the official Teams MCP server under the “Work IQ” intelligence layer. The server lives in the microsoft/work-iq repository (805 GitHub stars). The server exposes 24 tools for CRUD operations on chats, channels, teams, and messages. Status: preview.

The Teams server lacks search and file operations compared to Slack’s GA server. The Teams SDK added optional MCP support as of April 2026, allowing developers to expose MCP tools directly from Teams apps. Microsoft Teams has 320 million monthly active users. The preview status means behavior and available features are subject to change.

Outlook MCP

Outlook MCP implementations connect to Microsoft’s email platform through the Microsoft Graph API. Community-built servers and third-party platforms (Zapier, Composio) expose inbox reading, email sending, calendar access, and contact management. No first-party Microsoft MCP server exists exclusively for Outlook. The Teams “Work IQ” server covers some messaging functionality but not full Outlook email management.

Telegram MCP

Community-maintained Telegram MCP servers connect agents to the Telegram Bot API. Tools expose message sending, chat management, and bot interactions. The platform targets international and mobile-first audiences. Auth: Telegram bot token from BotFather. Multiple community implementations exist with varying tool coverage and maintenance activity.

Twilio MCP

Twilio provides an MCP server for SMS and voice communication. The server exposes text message sending, voice call handling, and webhook-based notifications. Pricing: pay-as-you-go at $0.0075 per SMS (rates vary by country). Twilio MCP covers the SMS and voice layer that team chat and email servers do not reach.

Server selection depends on the platform. Slack MCP is the default for enterprise team communication. Gmail MCP covers email workflows. Discord community servers work for developer and gaming communities.

The sections above define communication MCP servers, provide an evaluation rubric, and profile every significant server in the category. The sections below compare official and community server maintenance, break down authentication models, and answer the questions that surface during platform selection.

Which Platforms Have Official MCP Servers?

3 platforms provide official, vendor-maintained MCP servers: Slack (Salesforce, GA February 2026), Gmail (Google, remote hosted), and Microsoft Teams (Microsoft “Work IQ,” preview). Discord has no official MCP server. All community implementations for Discord lack enterprise governance controls.

The official vs community distinction affects 3 production-critical areas:

Security patching happens at vendor speed for official servers. Community servers depend on volunteer response times. The Slack reference server vulnerability illustrates the risk: Anthropic’s archived implementation received no patch after the vulnerability report.
API compatibility is guaranteed for official servers. Vendors update their MCP servers when their platform APIs change. Community servers break when unannounced API changes ship.
Enterprise governance is built into official servers. Slack provides workspace admin controls. Google respects existing Google Cloud IAM permissions. Community servers provide no centralized access management.

For production deployments, official servers are the default. Community servers work for development, prototyping, and platforms where no official server exists.

What Authentication Models Do These Servers Use?

Slack MCP uses confidential OAuth 2.0 with user-level permissions. Gmail MCP uses OAuth 2.0 through a Google Cloud project. Discord MCP implementations use bot tokens. Twilio MCP uses an API key. The authentication model determines what the agent can access and what audit trails exist.

OAuth 2.0 servers (Slack, Gmail, Teams) scope access to the authenticated user’s permissions. The agent sees only what the user can see. Audit trails track which user authorized which agent actions. Token refresh and revocation follow standard OAuth flows.

Bot token servers (Discord) scope access to the bot’s invited channels and assigned roles. The agent acts as the bot identity, not as a specific user. Attribution in message history shows the bot name, not the authorizing user.

API key servers (Twilio) scope access to the account level. Rate limits and billing apply to the account, not to individual users. No per-user permission scoping exists.

The authentication model also affects security posture. OAuth-based servers enforce the principle of least privilege. Bot token servers grant broad channel access once invited. API key servers grant full account access to anyone holding the key.

Frequently Asked Questions

What Happened to Anthropic’s Slack Reference Server?

Anthropic published a Slack MCP server as one of its original reference implementations in November 2024. A security researcher reported a link unfurling data exfiltration vulnerability on May 27, 2025. Anthropic archived the repository on May 29, 2025. The official Slack MCP server, maintained by Slack (Salesforce), reached GA in February 2026 with enterprise-grade security and workspace admin governance.

Can One Server Cover Slack, Email, and Discord?

No single MCP server covers all communication platforms. Each platform requires its own dedicated server with platform-specific authentication. Aggregation platforms (Zapier MCP, Composio) connect to multiple communication services through a single server. The tradeoff: they add a third-party dependency and consume additional context window tokens for their abstraction layer.

Does Gmail MCP Require a Paid Claude Plan?

Gmail MCP requires a Claude Enterprise, Pro, Max, or Team plan for use with Claude Desktop. The Google Workspace MCP suite (Gmail, Drive, Calendar, People, Chat) follows the same requirement. The server works with any MCP-compatible client that supports streamable HTTP transport, including Cursor, Claude Code, and VS Code.

How Many Tools Does Each Server Expose?

Slack MCP exposes 15+ tools (expanded from 10 at GA with 5 new tools in May 2026). Gmail MCP exposes tools for search, read, draft, send, and label management. Discord community servers expose up to 46+ tools in advanced implementations. Microsoft Teams MCP exposes 24 tools. Twilio MCP exposes SMS and voice tools. Each server’s tool definitions consume context window tokens at session start.

Which MCP Servers Connect to Communication Platforms?