Slack MCP Server

Give your AI agents full Slack access — messages, threads, DMs, channels, canvases, reactions, and search. 27 tools over the Slack Web API with enterprise governance and audit-ready risk classification.

Architecture

MCP Slack Architecture

Tools (27)

| Tool | Purpose | Risk Class | |------|---------|------------| | list_channels | List public and private channels | Read-only | | list_channels_paginated | List channels with cursor pagination | Read-only | | get_channel_history | Get recent messages from a channel | Read-only | | get_history_paginated | Get history with cursor pagination | Read-only | | get_thread | Get thread replies for a message | Read-only | | search_messages | Search messages across all channels | Read-only | | list_users | List workspace users | Read-only | | get_user | Get user profile info by ID | Read-only | | list_members | List members of a channel | Read-only | | list_dms | List direct message conversations | Read-only | | list_emoji | List custom emoji in the workspace | Read-only | | list_files | List files shared in a channel | Read-only | | get_file | Get file metadata and download URL | Read-only | | read_canvas | Read/export a canvas as markdown | Read-only | | list_bookmarks | List bookmarks in a channel | Read-only | | list_scheduled_messages | List scheduled (draft) messages | Read-only | | send_message | Send a message to a channel or thread | External write | | open_dm | Open a DM conversation with users | External write | | add_reaction | Add an emoji reaction to a message | External write | | set_channel_topic | Set a channel's topic | External write | | upload_file | Upload a text file to a channel | External write | | create_channel | Create a new public or private channel | External write | | create_canvas | Create a rich document in a channel | External write | | update_canvas | Update canvas content (markdown) | External write | | add_bookmark | Add a bookmark link to a channel | External write | | schedule_message | Schedule a message for future delivery | External write | | delete_scheduled_message | Cancel a scheduled message | External write |

Comparison with Other Slack MCP Servers

| Feature | Slack Official | korotovsky/slack-mcp | Ours | |---------|---------------|---------------------|----------| | Thread replies (read) | ✅ | ✅ | ✅ | | DMs / Group DMs | ✅ | ✅ | ✅ | | Canvases (create/read/update) | ✅ | ❌ | ✅ | | Create channel | ✅ | ✅ | ✅ | | List channel members | ✅ | ✅ | ✅ | | Custom emoji list | ✅ | ❌ | ✅ | | Send messages + threads | ✅ | ✅ | ✅ | | Reactions | ✅ | ✅ | ✅ | | Search | ✅ | ✅ | ✅ | | File upload + reading | ✅ | ❌ | ✅ | | Draft/scheduled messages | ✅ | ❌ | ✅ | | Bookmarks | ❌ | ✅ | ✅ | | Pagination (cursor) | ✅ | ✅ | ✅ | | OAuth/user tokens | ✅ | ✅ (cookie) | Bot token | | Registry governance | ❌ | ❌ | ✅ | | Risk classification | ❌ | ❌ | ✅ | | HealthCheck trait | ❌ | ❌ | ✅ | | Rust / single binary | ❌ (Node) | ❌ (Node) | ✅ |

Installation

Build from source

git clone https://github.com/zavora-ai/mcp-slack
cd mcp-slack
cargo build --release

From crates.io

cargo install mcp-slack

Configuration

Environment Variables

| Variable | Required | Description | |----------|----------|-------------| | SLACK_BOT_TOKEN | ✅ | Bot User OAuth Token (xoxb-...) | | SLACK_TOKEN | Alternative | Alias for SLACK_BOT_TOKEN | | RUST_LOG | ❌ | Log level (default: info) |

Required Bot Token Scopes

channels:read        — list channels
channels:history     — read messages
channels:manage      — set topic
groups:read          — private channels
groups:history       — private channel messages
chat:write           — send messages
reactions:write      — add reactions
search:read          — search messages
users:read           — list/get users
files:write          — upload files
channels:join        — self-join channels (optional)

Slack App Manifest

display_information:
  name: MCP Slack Bot
  description: AI agent access to Slack via MCP protocol
features:
  bot_user:
    display_name: MCP Bot
    always_online: true
oauth_config:
  scopes:
    bot:
      - channels:read
      - channels:history
      - channels:manage
      - groups:read
      - groups:history
      - chat:write
      - reactions:write
      - search:read
      - users:read
      - files:write
settings:
  org_deploy_enabled: false
  socket_mode_enabled: false
  token_rotation_enabled: false

Client Configuration

Claude Desktop

{
  "mcpServers": {
    "slack": {
      "command": "mcp-slack",
      "args": [],
      "env": {
        "SLACK_BOT_TOKEN": "xoxb-your-token"
      }
    }
  }
}

Kiro

Add to .kiro/settings/mcp.json:

{
  "mcpServers": {
    "slack": {
      "command": "mcp-slack",
      "args": [],
      "env": {
        "SLACK_BOT_TOKEN": "xoxb-your-token"
      }
    }
  }
}

Cursor

Add to .cursor/mcp.json:

{
  "mcpServers": {
    "slack": {
      "command": "mcp-slack",
      "args": [],
      "env": {
        "SLACK_BOT_TOKEN": "xoxb-your-token"
      }
    }
  }
}

Codex (OpenAI)

{
  "mcpServers": {
    "slack": {
      "command": "mcp-slack"
    }
  }
}

Windsurf

Add to ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "slack": {
      "command": "mcp-slack",
      "args": [],
      "env": {
        "SLACK_BOT_TOKEN": "xoxb-your-token"
      }
    }
  }
}

Quick Start

# Set token
export SLACK_BOT_TOKEN="xoxb-your-token"

# Verify token works
curl -s -H "Authorization: Bearer $SLACK_BOT_TOKEN" https://slack.com/api/auth.test

# Run server
mcp-slack

Test with MCP Inspector

npx @modelcontextprotocol/inspector mcp-slack

Usage Examples

List channels

"List my Slack channels"
→ calls list_channels

Read a thread

"What did the team say in the thread about the deployment?"
→ calls search_messages → get_thread

Send a message

"Post in #engineering: the release is ready for QA"
→ calls send_message with channel + text

Reply in a thread

"Reply to that message saying I'll review it"
→ calls send_message with thread_ts

Open a DM

"Send a DM to James asking about the PR"
→ calls open_dm → send_message

Create a channel

"Create a private channel called project-alpha"
→ calls create_channel with is_private=true

MCP Server Manifest

server_id = "mcp_slack"
display_name = "Slack"
version = "1.1.0"
domain = "collaboration"
risk_level = "medium"
writes_allowed = "gated"
transports = ["stdio"]
credentials = ["vault://slack-bot-token"]

Testing

# Build
cargo build

# Run tests
cargo test

# Integration test (requires SLACK_BOT_TOKEN)
echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}
{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"list_channels","arguments":{"limit":5}}}' | cargo run

Roadmap

[ ] OAuth user token support (for user-level access beyond bot)
[ ] Workflow triggers (workflows.triggers.create)
[ ] Pin messages (pins.add, pins.list)
[ ] User presence/status (users.setPresence, users.profile.set)

Registry Compliance

This server implements the ADK MCP SDK contract:

HealthCheck — async health probe for registry monitoring
mcp-server.toml — manifest declaring tools, risk classes, and credentials
Structured tracing — RUST_LOG env-filter for observability

Contributors

|
_{James Karanja Maina} | |:---:|

License

Apache-2.0 — see LICENSE for details.

Part of the ADK-Rust Enterprise MCP server ecosystem.

Built with ❤️ by Zavora AI

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