Slack MCP Server with Canvas Support

Enhanced MCP Server for the Slack API, enabling AI assistants like Claude to interact with Slack workspaces including comprehensive Canvas functionality with dynamic channel support.

✨ Key Features

🔄 Dynamic Channel Support

No static configuration required: Automatically discovers all public and private channels via API
Real-time channel access: Always up-to-date with your workspace's channel structure
Pagination support: Handles workspaces with hundreds of channels efficiently

🎨 Complete Canvas API Support

Canvas Creation: Create standalone and channel-specific canvases
Advanced Editing: 6 different edit operations with full flexibility
Access Control: Granular permissions for users and channels
Content Management: Full lifecycle management from creation to deletion

🛠️ Original Slack Features

All original Slack MCP server functionality is preserved and enhanced.

📋 Available Tools

Messaging & Communication

slack_list_channels - ENHANCED: Now fetches all channels dynamically
slack_post_message - Post messages to any channel
slack_reply_to_thread - Reply to message threads
slack_add_reaction - Add emoji reactions
slack_get_channel_history - Retrieve message history
slack_get_thread_replies - Get thread conversations
slack_get_users - List workspace users
slack_get_user_profile - Get detailed user information

Canvas Management (NEW)

slack_canvas_create - Create standalone canvases
slack_canvas_edit - Edit existing canvases
slack_channel_canvas_create - Create channel-specific canvases
slack_canvas_get - Retrieve canvas content
slack_canvas_delete - Delete canvases
slack_canvas_access_set - Manage canvas permissions

File Management (NEW)

slack_files_upload - Upload files to Slack
slack_files_list - List files with filtering options
slack_files_info - Get detailed file information
slack_files_delete - Delete files from workspace

Search (NEW)

slack_search_messages - Search messages across workspace
slack_search_files - Search files in workspace

Reminders (NEW)

slack_reminders_add - Create reminders
slack_reminders_list - List active reminders
slack_reminders_delete - Delete reminders

Channel Management (NEW)

slack_conversation_create - Create new channels (public or private)
slack_conversation_archive - Archive channels
slack_conversation_unarchive - Unarchive channels
slack_conversation_invite - Invite users to channels
slack_conversation_kick - Remove users from channels
slack_conversation_rename - Rename channels
slack_conversation_set_purpose - Set channel purpose
slack_conversation_set_topic - Set channel topic
slack_conversation_join - Join a channel
slack_conversation_leave - Leave a channel

Pins (NEW)

slack_pins_add - Pin messages or files to channels
slack_pins_remove - Unpin items from channels
slack_pins_list - List all pinned items in a channel

Extended Reactions (NEW)

slack_reactions_remove - Remove reactions from messages
slack_reactions_get - Get all reactions for a specific message
slack_reactions_list - List items the user has reacted to

Views/Modals (NEW)

slack_views_open - Open modal dialogs
slack_views_update - Update existing modals
slack_views_push - Push new views onto the modal stack

🚀 Quick Start

1. Installation

cd slack_mcp_server
npm install
npm run build

2. Slack App Configuration

Create Slack App: Visit Slack Apps

Configure Bot Token Scopes:

channels:history      # View messages in public channels
channels:read         # View basic channel information
channels:manage      # Create, archive, rename channels
chat:write           # Send messages
reactions:read       # View reactions
reactions:write      # Add and remove reactions
users:read           # View users and their basic information
users.profile:read   # View detailed user profiles
canvases:read        # Access canvas contents
canvases:write       # Create, edit and remove canvases
files:read           # View files in workspace
files:write          # Upload and delete files
search:read          # Search messages and files
reminders:read       # View reminders
reminders:write      # Create and delete reminders
pins:read            # View pinned items
pins:write           # Pin and unpin items
groups:read          # View private channels
groups:write         # Manage private channels

Install to Workspace and copy the Bot Token (xoxb-...)
Get Team ID (starts with T)

3. Claude Desktop Configuration

{
  "mcpServers": {
    "slack": {
      "command": "node",
      "args": ["slack_mcp_server/dist/index.js"],
      "env": {
        "SLACK_BOT_TOKEN": "xoxb-your-actual-token-here",
        "SLACK_USER_TOKEN": "xoxp-your-user-token-here",
        "SLACK_TEAM_ID": "T1234567890",
        "SLACK_MCP_LOG_LEVEL": "info"
      }
    }
  }
}

Notes:

SLACK_CHANNEL_IDS is no longer needed! The server now dynamically discovers all channels.
SLACK_USER_TOKEN is required for file uploads, reminders, search operations, and some Canvas operations.

🎯 Canvas API Examples

Create a Project Status Canvas

{
  "title": "Q1 Project Status",
  "document_content": {
    "type": "markdown",
    "markdown": "# Q1 Project Status\n\n## 🎯 Goals\n- [ ] Launch Feature A\n- [ ] Improve Performance\n\n## 📊 Progress\n75% complete\n\n## 👥 Team\n- @U123456 (Lead)\n- @U789012 (Dev)"
  },
  "channel_id": "C123456789"
}

Edit Canvas with Multiple Operations

{
  "canvas_id": "F1234567890",
  "changes": [
    {
      "operation": "insert_at_end",
      "document_content": {
        "type": "markdown",
        "markdown": "\n\n## 🚀 Next Steps\n1. Code review\n2. QA testing\n3. Production deployment"
      }
    },
    {
      "operation": "insert_at_end",
      "document_content": {
        "type": "markdown",
        "markdown": "\n\n## 📅 Timeline\n- **Week 1**: Development\n- **Week 2**: Testing\n- **Week 3**: Launch"
      }
    }
  ]
}

Canvas Markdown Features

Canvas supports rich markdown with Slack-specific elements:

# Project Dashboard

## 👥 Team Members
- @U123456 (displays as user card)
- @U789012 (project lead)

## 📢 Channels
- ![](#C123456) - Project Channel (displays as channel link)
- ![](#C789012) - General Discussion

## 📊 Status
:large_green_circle: On Track
:warning: Needs Attention
:red_circle: Blocked

## 📋 Tasks
- [x] Setup repository
- [ ] Implement auth
- [ ] Deploy to staging

## 💻 Code
\`\`\`javascript
const config = {
  apiUrl: 'https://api.example.com'
};
\`\`\`

## 📎 Resources
[Design Doc](https://example.com/design)

📁 File Management Examples

Upload a File

{
  "content": "# Project Report\n\n## Summary\nQ1 performance exceeded expectations...",
  "filename": "q1-report.md",
  "title": "Q1 2024 Report",
  "initial_comment": "Here's the Q1 report for review",
  "channels": ["C123456789"]
}

Search Files

{
  "query": "type:pdf from:U123456",
  "sort": "timestamp",
  "sort_dir": "desc"
}

🔍 Search Examples

Search Messages with Operators

{
  "query": "from:@alice in:#general has:link during:today",
  "sort": "timestamp",
  "highlight": true
}

Search Query Syntax

from:@username - Messages from specific user
in:#channel - Messages in specific channel
has:link - Messages containing links
has:star - Starred messages
during:today - Time-based filters
"exact phrase" - Exact phrase matching

⏰ Reminder Examples

Create a Reminder

{
  "text": "Review pull requests",
  "time": "tomorrow at 9am"
}

Create Reminder for Another User

{
  "text": "Submit timesheet",
  "time": "Friday at 5pm",
  "user": "U789012"
}

Time Formats Supported

Unix timestamp: 1234567890 (seconds since epoch, must be in the future)
Natural language: "in 2 hours", "next Monday", "tomorrow at 3pm"
Specific times: "3:00pm", "15:30", "9am tomorrow"
Relative times: "in 30 minutes", "2 hours from now"

Common Issues with Reminders

Time zone: Natural language times use the user's Slack timezone
Past times: Cannot create reminders for times in the past
User token required: Must have SLACK_USER_TOKEN with reminders:write scope
Format errors: Avoid ambiguous times like "soon" or "later"

📢 Channel Management Examples

Create a Channel

{
  "name": "project-alpha",
  "is_private": false
}

Invite Users to Channel

{
  "channel": "C123456789",
  "users": "U123456,U789012,U345678"
}

Set Channel Topic and Purpose

// Set topic
{
  "channel": "C123456789",
  "topic": "Q1 2024 Product Launch 🚀"
}

// Set purpose
{
  "channel": "C123456789",
  "purpose": "Coordinate all activities for the Q1 product launch"
}

📌 Pins Examples

Pin a Message

{
  "channel": "C123456789",
  "timestamp": "1234567890.123456"
}

List Pinned Items

{
  "channel": "C123456789"
}
// Returns both pinned messages and files

😀 Reactions Examples

Get All Reactions for a Message

{
  "channel": "C123456789",
  "timestamp": "1234567890.123456",
  "full": true  // Get all reactions, not just first 25
}

Remove a Reaction

{
  "channel": "C123456789",
  "timestamp": "1234567890.123456",
  "name": "thumbsup"
}

🪟 Views/Modals Examples

Open a Modal Dialog

{
  "trigger_id": "12345.98765.abcd",
  "view": {
    "type": "modal",
    "title": {
      "type": "plain_text",
      "text": "Feedback Form"
    },
    "blocks": [
      {
        "type": "input",
        "block_id": "feedback_input",
        "element": {
          "type": "plain_text_input",
          "multiline": true,
          "action_id": "feedback"
        },
        "label": {
          "type": "plain_text",
          "text": "Share your feedback"
        }
      }
    ],
    "submit": {
      "type": "plain_text",
      "text": "Submit"
    }
  }
}

Update Modal Content

{
  "view_id": "V123456",
  "view": {
    "type": "modal",
    "title": {
      "type": "plain_text",
      "text": "Success!"
    },
    "blocks": [
      {
        "type": "section",
        "text": {
          "type": "mrkdwn",
          "text": "✅ Your feedback has been submitted successfully!"
        }
      }
    ]
  }
}

🧪 Testing

Run Tests

# Run all tests
npm test

# Run tests in watch mode
npm run test:watch

# Generate coverage report
npm run test:coverage

Test Structure

test/slackClient.test.ts: SlackClient class unit tests
test/mcpServer.test.ts: MCP server integration tests
test/canvasFeatures.test.ts: Canvas API functionality tests
test/filesApi.test.ts: Files API functionality tests
test/searchApi.test.ts: Search API functionality tests
test/reminderApi.test.ts: Reminder API functionality tests
test/conversationApi.test.ts: Channel management API tests
test/pinsApi.test.ts: Pins API functionality tests
test/reactionsApi.test.ts: Extended reactions API tests
test/viewsApi.test.ts: Views/Modals API tests
test/e2e.test.ts: End-to-end workflow tests

Coverage Goals

80%+ coverage across all metrics
Comprehensive error scenarios tested
Performance tests for large operations
End-to-end workflows validated

🔧 Development

Project Structure

/slack_mcp_server/
├── src/
│   └── index.ts          # Main server implementation
├── test/
│   ├── setup.ts          # Test configuration and mocks
│   ├── slackClient.test.ts
│   ├── mcpServer.test.ts
│   ├── canvasFeatures.test.ts
│   └── e2e.test.ts
├── package.json
├── tsconfig.json
├── jest.config.js
└── README.md

Build Commands

npm run build      # Compile TypeScript
npm run watch      # Watch mode compilation
npm run test       # Run test suite
npm run prepare    # Build for distribution

🚨 Important Changes from Original

✅ What's New

Dynamic channel discovery: No more static channel configuration
Complete Canvas API: Full create, read, update, delete operations
File Management API: Upload, list, view, and delete files
Search API: Search messages and files with advanced query syntax
Reminder API: Create and manage reminders with natural language
Channel Management: Create, archive, rename, and manage channels
Pins API: Pin and unpin messages or files to channels
Extended Reactions: Remove reactions and get detailed reaction data
Views/Modals API: Create interactive modal dialogs
Enhanced permissions: Comprehensive access control
Comprehensive logging: Debug mode with detailed API tracking
Comprehensive testing: 80%+ test coverage with 87 tests
Better error handling: Graceful failure recovery with detailed error logs

⚠️ Breaking Changes

Environment variable removed: SLACK_CHANNEL_IDS is no longer used
New permissions required: Multiple new scopes needed:
- canvases:read and canvases:write for Canvas features
- files:read and files:write for File management
- search:read for Search functionality
- reminders:read and reminders:write for Reminders
- channels:manage for Channel creation and management
- groups:read and groups:write for Private channel management
- pins:read and pins:write for Pins functionality
- reactions:read for Extended reactions features
User token required: Some features (files, reminders) need SLACK_USER_TOKEN
Paid workspace requirement: Canvas features require paid Slack workspace

🔒 Backward Compatibility

All original MCP tools continue to work exactly as before
Existing Claude Desktop configurations work (just remove SLACK_CHANNEL_IDS)
No changes to existing tool interfaces

🐛 Troubleshooting

Common Issues

Canvas operations fail
- Ensure workspace is on a paid Slack plan
- Verify canvases:read and canvases:write scopes are added
- Check that app is installed to workspace
Channel list is empty
- Verify SLACK_TEAM_ID is correct
- Ensure bot has access to channels (invite bot to private channels)
- Check channels:read scope is enabled
Permission errors
- Confirm all required scopes are added to Slack app
- Reinstall app to workspace after adding scopes
- Verify SLACK_BOT_TOKEN starts with xoxb-
Search operations fail with "not_allowed_token_type"
- Ensure SLACK_USER_TOKEN is set (starts with xoxp-)
- Search APIs require user tokens, not bot tokens
- User token must have search:read scope

🔍 Logging and Debugging

The server includes comprehensive logging to help debug issues with API calls.

Environment Variables

SLACK_MCP_LOG_LEVEL: Control logging verbosity
- debug - All logs including debug information
- info (default) - Information, warnings, and errors
- warn - Only warnings and errors
- error - Only errors

Example Debug Configuration

{
  "mcpServers": {
    "slack": {
      "command": "node",
      "args": ["slack_mcp_server/dist/index.js"],
      "env": {
        "SLACK_BOT_TOKEN": "xoxb-...",
        "SLACK_USER_TOKEN": "xoxp-...",
        "SLACK_TEAM_ID": "T...",
        "SLACK_MCP_LOG_LEVEL": "debug"
      }
    }
  }
}

Log Output Features

Color-coded output for easy reading
Timestamps for all log entries
API request/response details in debug mode
Error stack traces for troubleshooting
Slack API error details including missing scopes

Common Debug Scenarios

API Permission Errors

[ERROR] Slack API error: missing_scope
needed: channels:manage
provided: channels:read,chat:write

Network Issues

[ERROR] Network error for POST https://slack.com/api/chat.postMessage

Tool Execution

[INFO] Tool called: slack_post_message
[DEBUG] API Request: POST https://slack.com/api/chat.postMessage
[SUCCESS] Tool slack_post_message completed successfully

📄 License

This project extends the original Model Context Protocol Servers Slack implementation. See NOTICES file for attribution.

🤝 Contributing

Follow existing code patterns
Add tests for new features
Ensure 80%+ test coverage
Update documentation
Test with real Slack workspace

Ready to transform your Slack workspace management with MCP! 🎨✨

Name		Name	Last commit message	Last commit date
Latest commit History 13 Commits
src		src
test		test
.gitignore		.gitignore
API_EXTENSION_PLAN.md		API_EXTENSION_PLAN.md
CLAUDE.md		CLAUDE.md
LICENSE		LICENSE
NOTICES		NOTICES
README.md		README.md
SETUP.md		SETUP.md
jest.config.js		jest.config.js
package-lock.json		package-lock.json
package.json		package.json
test.js		test.js
tsconfig.json		tsconfig.json
validate-tests.js		validate-tests.js

License

bitengineers/slack_mcp_server

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