Slack

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Warning

On May 29, 2025, Slack implemented significant API changes that affect third-party applications, including Dust's Slack integration:

• Marketplace Requirement: All commercial apps must be listed on the official Slack Marketplace to maintain full API access
• Rate Limiting: Non-Marketplace apps face drastically reduced rate limits on critical endpoints (conversations.history and conversations.replies)
• Restricted Use Cases: Slack's updated Marketplace terms prohibit bulk data indexing and enterprise search functionalities

As a response, we have released a Slack MCP tool as a limited pre-release in order to allow agents to leverage new Slack messages. This will unfortunately include a slightly degraded search experience compared to the Slack Connector.

The team plans to leverage the Slack Realtime Search API as soon as it is made available.

Please see our Status Report Page for all updates.

Overview

Slack tools let you add to your agent the capability to interact with Slack content using your personal credentials. This provides the ability to search Slack messages, post messages, and access workspace information.

This document provides general information about our Slack tools (available tools, setup, and authentication).

Since this uses personal credentials, all actions performed by agents will appear as if you performed them directly.

Connection Setup

The setup process requires personal Slack authentication and uses OAuth to connect your individual Slack account to Dust. This ensures that agents only have access to the channels and content that you can personally access.

1. Under Administration -> Tools, select Add Tools
2. Select Slack from the available MCP servers
3. Complete OAuth authorization with your personal Slack credentials.

Adding Tools to Agents

Admins can provide workspace users access to these tools by adding it to a Dust space. Users can then add the tools to an agent by selecting Slack in the agent builder.

Available Tools

Search Messages

Search messages across all channels and direct messages accessible to your user account.

Parameters: Keywords, time frame, channel filters, user filters
Limitations: Keyword-based search (not semantic)

Post Message

Post a message to a channel or send a direct message.

Parameters: Recipient (channel/user), message content, optional thread timestamp
Formatting: Supports Slack-flavored markdown

List Users

Retrieve all users in the workspace with optional name filtering.

List Public Channels

List all public channels in the workspace with optional filtering.

Advanced Features

Thread Support

• Reply to existing message threads using thread timestamps
• Maintain conversation context within Slack threads
• Find thread IDs through message search functionality

User and Channel References

• Mention users using <@USER_ID> format
• Reference channels using <#CHANNEL_ID> format
• Never use plain names as they won't be parsed correctly

Limitations & Considerations

• Standard Slack API limits apply
• Slack API supports keyword-based search only (not semantic search)