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Slack MCP Server
for AI Agents

Connect your AI agent to StackOne's Slack MCP server and give it 38 MCP tools out of the box. Auth, tool execution, and security all managed.

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Slack MCP Server
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Coverage

38 Agent Actions

Create, read, update, and delete across Slack — and extend your agent's capabilities with custom actions.

MCP Actions → Build Actions →

Authentication

Agent Tool Authentication

Per-user OAuth in one call. Your Slack MCP server gets session-scoped tokens with zero credentials stored on your infra.

Agent Auth →

Security

Agent Protection

Every Slack tool response scanned for prompt injection in milliseconds — 88.7% accuracy, all running on CPU.

Prompt Injection Defense →

Performance

Max Agent Context. Min Cost.

Free up to 96% of your agent's context window to enhance reasoning and reduce cost, on every Slack call.

Tools Discovery →

What is the Slack MCP Server?

A Slack MCP server lets AI agents read and write Slack data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Slack MCP server ships with 38 pre-built actions, fully extensible via the Connector Builder — plus managed authentication, prompt injection defense, observability, and agent execution runtime. Connect it from MCP clients like Claude Desktop, Claude Code, Cursor, Goose, and VS Code, or from agent frameworks like OpenAI Agents SDK, LangChain, and Vercel AI SDK.

All Slack MCP Tools

Every action from Slack's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.

Conversations

  • Create Conversation

    Create a new conversation (channel)

  • List Conversations

    List all conversations (channels, groups, DMs) from Slack and find channel IDs by name

  • Get Conversation

    Get details of a specific conversation

Files

  • List Files

    List files for a team, channel, or user

  • Get File

    Get detailed information about a file

  • Delete File

    Delete a file from Slack

Messages

  • Send Message

    Send a message to a channel or conversation

  • List Messages

    List messages from a conversation

  • Update Message

    Update an existing message

  • Delete Message

    Delete a message

Scheduled Messages

  • List Scheduled Messages

    List all scheduled messages

  • Delete Scheduled Message

    Delete a scheduled message

Users

  • List Users

    List all users in the Slack workspace and find user IDs by name or email

  • Get User

    Get details of a specific user

User Profiles

  • Get User Profile

    Retrieve a user's profile information including status text and emoji, title, phone, and custom profile fields

  • Set User Profile

    Update a user's profile information

User Presences

  • Get User Presence

    Get the presence of a user

  • Set User Presence

    Manually set the user's presence

Other (20)

  • Send Ephemeral Message

    Send a private temporary message visible only to a specific user in a channel (use for private welcome notes, warnings, or notifications)

  • List Conversation Members

    List all members of a conversation

  • List Thread Replies

    Retrieve a thread of messages posted to a conversation

  • List Slack Connect Invites

    List shared channel invites that have been generated or received

  • Get File Upload URL

    Get an external URL to upload a file to Slack

  • Get Message Permalink

    Get a permanent link to a message

  • List User Conversations

    List conversations a user is a member of

  • Get User By Email

    Get user details by email address (use to find user ID from email)

  • Remove User From Conversation

    Remove a user from a conversation

  • Join Conversation

    Join an existing conversation (use before sending messages to new channels)

  • Leave Conversation

    Leave a conversation

  • Rename Conversation

    Rename a conversation

  • Invite Users To Conversation

    Invite users to a conversation

  • Invite Shared Conversation

    Send an invitation to a Slack Connect channel

  • Open Conversation

    Open or resume a direct message or multi-person direct message

  • Complete File Upload

    Complete an external file upload and optionally share to channels

  • Share File Public URL

    Create a public URL for a file

  • Revoke File Public URL

    Revoke public sharing for a file

  • Schedule Message

    Schedule a message to be sent at a specific time

  • Lookup Discoverable Contact

    Check if an email is discoverable on Slack

Set Up Your Slack MCP Server in Minutes

One endpoint. Any framework. Your agent is talking to Slack in under 10 lines of code.

MCP Clients

Claude Desktop setup guide
Claude Code setup guide
Cursor setup guide
Goose setup guide

Agent Frameworks

Claude Desktop
{
  "mcpServers": {
    "stackone": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote@latest",
        "https://api.stackone.com/mcp?x-account-id=<account_id>",
        "--header",
        "Authorization: Basic <YOUR_BASE64_TOKEN>"
      ]
    }
  }
}

Check More Communication MCP Servers

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128+ actions

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112+ actions

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100+ actions

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98+ actions

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All Communication MCP Servers →

Slack Resources

Slack MCP Server: Capabilities, Limitations, and Alternatives

A review of the official Slack MCP server: capabilities, limits, and an alternative, to help you choose which to use for your AI agent.

8 min read

MCP Code Mode: Keeping Tool Responses Out of Agent Context

Anthropic's code_execution processes data already in context. Custom MCP code mode keeps raw tool responses in a sandbox. 14K tokens vs 500.

11 min

Comparing BM25, TF-IDF, and Hybrid Search for MCP Tool Discovery

Benchmarking BM25, TF-IDF, and hybrid search for MCP tool discovery across 916 tools. The 80/20 TF-IDF/BM25 hybrid hits 21% Top-1 accuracy in under 1ms.

10 min

Indirect Prompt Injection Defense for MCP Tools: A Technical Guide

MCP tools that read emails, CRM records, and tickets are indirect prompt injection vectors. Here's how we built a two-tier defense that scans tool results in ~11ms.

12 min

MCP vs A2A: Architecture, Security, and When to Use Each

MCP vs A2A: what each protocol standardizes, how they differ, their shared security risks including indirect prompt injection, and when to use one, both, or a hybrid architecture.

12 min

MCP vs API: What 200+ Connector Builds Taught Us

MCP wraps APIs, it doesn't replace them. After building 200+ connectors that serve both, here's when each approach wins.

14 min read

Slack MCP Server FAQ

Does StackOne have a Slack MCP server?
Yes. StackOne offers a hosted Slack MCP server with 38 pre-built actions, and every action is tested and QA'd by StackOne. Connect it to Claude, Cursor, and any other MCP client, or to any agent framework through the AI Action SDK. It ships with managed agent authentication, prompt injection defense, and tool discovery with server-side execution that preserve your agent's context window and keep reasoning performance.
Slack MCP server vs direct API integration — what's the difference?
A Slack MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Slack. A Slack MCP server is for AI agents — MCP clients like Claude and Cursor, plus framework agents built with OpenAI, LangChain, or Vercel AI — discovering and calling Slack at runtime. StackOne provides both.
How does Slack authentication work for AI agents?
Slack authentication for AI agents works through a StackOne Connect Session. Create one via the dashboard or the SDK — you get an auth link and ready-to-paste config for Claude Desktop, Cursor, and other MCP clients. Your user authenticates their own Slack account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via origin_owner_id.
Are Slack MCP tools vulnerable to prompt injection?
Yes — Slack MCP tools can be vulnerable to indirect prompt injection. Any tool that reads user-written content — documents, messages, tickets, records, or free-text fields — is a potential vector. StackOne Defender scans every tool response before it enters the agent's context — regex patterns in ~1ms, then a MiniLM classifier in ~4ms. 88.7% accuracy, CPU-only.
What is the context bloat of a Slack agent and how do I avoid it?
Context bloat happens when Slack tool schemas and API responses eat your Slack agent's memory, preventing it from reasoning effectively. A single Slack query can return a massive JSON response, and connecting multiple tools compounds the problem. Tools Discovery and Code Mode reduce context bloat — loading only relevant tools per query and keeping raw responses out of the agent's context.
Can I limit which actions my Slack agent can access?
Yes — you can limit which actions your Slack agent can access directly from the StackOne dashboard. Toggle actions on or off, or restrict them to specific accounts, with no code changes to your agent. Session tokens can be scoped to exact actions so if one leaks, exposure stays contained.
Can I create custom agent actions for my Slack MCP server?
Yes — you can create custom agent actions for your Slack MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Slack's API, generate production-ready connector YAML, test against the live API, and validate before you ship.
When should I NOT use a Slack MCP server?
Skip a Slack MCP server if your integration is purely software-to-software — direct Slack API integration is simpler when no AI agent is involved. For deterministic, compliance-critical operations (financial transactions, regulatory reporting), direct API gives you predictable behavior without agent-driven decision-making. MCP shines when AI agents need to dynamically discover and call Slack actions at runtime.
What AI frameworks and AI clients does the StackOne Slack MCP server support?
The StackOne Slack MCP server supports both. MCP clients (paste-and-go apps): Claude Desktop, Claude Code, Cursor, VS Code, Goose. Agent frameworks (code SDKs you build with): OpenAI Agents SDK, Anthropic, Vercel AI, Google ADK, CrewAI, Pydantic AI, LangChain, LangGraph, Azure AI Foundry.

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