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Glean now uses Slack Real-Time Search (RTS) to search your Slack messages and channels. This guide explains how the new search experience works and provides tips for getting the best results. Slack Real-Time Search is a new way Glean searches your Slack workspace. Instead of maintaining a separate copy of your Slack data, Glean now queries Slack directly in real time when you search. This means:
  • Always up to date: Search results reflect the latest Slack content
  • Permission-aware: You only see messages you have access to in Slack
  • Per-user authorization: You need to connect your Slack account to Glean to see Slack results

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What’s changed from the previous experience

If you previously searched Slack through Glean, you may notice some differences with the new Real-Time Search experience.

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Search behavior

Previous ExperienceReal Time Search
Glean indexed Slack content and applied its own rankingGlean queries Slack directly and returns results based on Slack’s search
Search results were based on Glean’s indexSearch results are live from Slack
Cross-app relevance ranking included SlackSlack results appear in a dedicated section
Real-Time Search uses keyword-based search by default. This means:
  • Search queries match exact words and phrases in your Slack messages
  • Natural language questions may not return results unless the exact keywords appear in messages
  • Searching for “Q4 revenue forecast” will find messages containing those specific words
Semantic search availability: If your organization has Slack AI Search enabled, Glean can leverage semantic search capabilities. Semantic search is triggered when your query is phrased as a natural language question (e.g., starts with “what”, “where”, or “how”, or ends with a question mark). Check with your administrator to see if Slack AI Search is enabled for your workspace.

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Authorization requirement

Each user must individually authorize Glean to access their Slack data. If you haven’t connected Slack yet:
  1. Look for the Slack authorization banner on the Glean Search or Home page
  2. Click Connect Slack and follow the prompts
  3. After authorization, Slack results will appear in your searches
You can manage your Slack connection in your Glean Settings page at any time.

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Content coverage and limitations

Real-Time Search supports searching across:
  • Public channel messages and threads
  • Private channel messages and threads (channels you have access to)
  • Direct messages (DMs) and group DMs

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What is not supported

Real Time Search currently has limited support for certain Slack content types:
  • Files and attachments: Files shared in Slack (PDFs, images, documents) are not searchable through Real-Time Search. To find files, search directly in Slack or look for references to files in message content.
  • Canvases: Slack Canvases are not indexed by Real-Time Search.
  • Slack Connect channels: Depending on your organization’s configuration, external Slack Connect channels may have limited coverage.
If you need to find a file that was shared in Slack, try searching for keywords from the conversation where the file was shared, or search directly in Slack’s native search.

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Tips for effective searching

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Use specific keywords

Since Real-Time Search is keyword-based by default, use specific terms that are likely to appear in the messages you’re looking for:
  • Instead of: “What was decided about the product launch?”
  • Try: “product launch decision” or “launch date confirmed”

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Include relevant context

Add context words that might appear in the conversation:
  • Channel names or project names
  • Names of people involved
  • Dates or timeframes mentioned in messages

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Check your Slack connection

If you’re not seeing Slack results:
  1. Verify that you’ve authorized Slack in Glean
  2. Check that you have access to the channels or messages you’re searching for
  3. Try the same search in Slack directly to confirm the content exists

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Analytical and deep‑research queries over Slack

Slack Real Time Search (RTS) is optimized for finding specific messages and threads, not for large “analyze everything about X over the last year”–type questions. For broad or analytical Slack queries, you may see:
  • Higher latency compared with other data sources.
  • Incomplete coverage if Slack RTS hits rate limits mid‑query.
  • Timeouts or partial answers for long‑running agent or deep‑research tasks over Slack.
These behaviors come from Slack’s RTS service and rate limits, not from a misconfiguration in your Glean deployment. To improve results over Slack:
  • Narrow the scope with time ranges and specific channels.
  • Break up big questions into smaller, focused prompts and synthesize the answers yourself.
  • Use Slack mainly for context, and rely on documents, tickets, or wikis for heavy analysis where possible.
  • Retry after a short delay if you see a rate‑limit message, as Slack enforces back‑off under load.
  • Send use your feedback for both search and chat.
If you repeatedly see severe timeouts, very incomplete results, or unusable latency for important Slack‑heavy workflows, contact your Glean admin so they can collect examples and, where appropriate, coordinate with Slack on RTS quality or rate‑limit issues.

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Using Slack results in Glean Assistant

When using Glean Assistant or Glean in Slack, Slack messages found through Real-Time Search can be included as context for AI-generated responses. The Assistant will show relevant messages and threads that help answer your questions. Keep in mind that the same keyword-based search behavior applies, so framing your questions with specific terms will help the Assistant find relevant Slack content.