Short answer
AI connects to Slack through Slack’s own AI features on paid plans, through the Real-time Search API, which searches on behalf of a user without storing copies, or through the Slack MCP server, generally available since 17 February 2026. For New Zealand teams, a staff knowledge assistant should answer only from an approved list of channels and reply privately whenever an answer draws on a private source.
- AI search and recaps are on Business+ and Enterprise+; Pro gets thread summaries and huddle notes.
- Only Marketplace-published and internal apps may use the Slack MCP server.
- The Real-time Search API returns only what the asking user can access, without storing copies.
- Public-channel search scope covers public channels the user has not joined.
- Slack’s nearest data residency region is Sydney, on Business+ and Enterprise.
What Slack’s built-in AI does today
Slack repackaged its plans in 2025 and stopped selling the Slack AI add-on on its website. Pro now includes conversation and thread summaries and huddle notes. Business+ and Enterprise+ add AI search, recaps, translations, file summaries and workflow automation, and enterprise search is Enterprise+ only (Slack Help). From a New Zealand connection on 19 October 2026, Slack showed Pro at US$8.75 and Business+ at US$18 per user per month, paid monthly (Slack pricing). Slack says it “does not train generative AI models on Customer Data”, and admins can turn individual AI features on or off.
Integration routes and when to use each
| Route | What it gives you | Use it when |
|---|---|---|
| Slack AI (Business+) | Search answers and recaps across what each person can see | General “where was that decided?” questions |
| Real-time Search API | assistant.search.context, searching as the user without storing copies | A custom assistant that also uses documents outside Slack |
| Slack MCP server | Search, read, send, canvases, lists and files for MCP clients | Staff working in Claude, Cursor or your own agent |
| Events API and Web API | Mentions, DMs, thread replies, conversation history | The bot that receives questions and posts answers |
| n8n, Make or Zapier | Slack triggers plus AI steps | Alerts, digests and simple routing |
The MCP server at mcp.slack.com uses confidential OAuth with user tokens, and admins approve client apps through Slack’s normal app approval. Only Marketplace-published and internal apps may use it; “unlisted apps are prohibited from using MCP”. Our guide to MCP for business systems covers when an MCP route beats a direct API build.
Automation 1: a staff knowledge assistant with channel controls
- Inputs
- A question sent to the app by mention or direct message.
- Retrieval
- The Real-time Search API, called with the asking person’s token, plus policy documents from your wiki.
- Access control in code
- Keep only results from channel IDs on an approved list, such as #policies, #it-help and #ops-announcements. Exclude direct messages entirely.
- Model step
- Answer with permalinks and dates, prefer official channels over chat, and say when sources conflict or are more than a year old.
- Reply rule
- If any cited source is a private channel, reply privately to the asker, never in a public thread.
- Human review
- Channel owners review answers marked unhelpful each week.
- Write-back
- A threaded reply only.
| Slack field | Used for | Rule |
|---|---|---|
| Channel ID | Allow-list check | Compare IDs, not names; names change |
| Channel type | Reply rule | Private source means private reply |
| ts and thread_ts | Citations and threading | Every claim links to a message |
| Permalink | The citation the user clicks | Shown with the message date |
| User ID | Access and audit log | Log question, sources and answer |
The retrieval and citation design follows our guide to building private AI search, and our lesson on building a searchable business knowledge base covers getting the source content into shape.
Automation 2: a weekly decision digest
- Read. An internal app reads three named project channels for the week.
- Extract. The model lists decisions, owners and dates, each linked to the message it came from.
- Approve. The project lead edits and approves the draft in a DM.
- Publish. The app writes the approved digest to a canvas and posts the link in the channel.
Permissions, scopes and approval design
The Real-time Search API needs at least search:read.public, and Slack’s docs say that scope covers public channels in the workspace “the searching user need not be a member of” (RTS API). A public channel full of salary discussions is therefore searchable by everyone’s assistant. The private-channel, group and direct message scopes need a user token and each person’s consent. Request search:read.private only if approved channels are private, and never request the direct message scopes for a knowledge assistant. Build it as an internal app, so it can use MCP and keeps normal rate limits. Tell staff which channels it reads: reusing chat for a new purpose still has to fit the Privacy Act’s purpose limits. See agent permissions and approvals.
Costs and limits
Since 29 May 2025, commercially distributed apps not approved for the Slack Marketplace get 1 request a minute and 15 objects per call on conversations.history and conversations.replies for new installs; internal apps keep 50 or more requests a minute (changelog). MCP tools carry the same limits as the matching Web API methods. Illustrative example: 2,000 questions a month at 10,000 input and 400 output tokens costs about US$48 on Claude Sonnet 5.5 (US$2 and US$10 per million tokens, 19 October 2026). Business+ for 30 people at the monthly rate shown is US$540 a month.
Where it goes wrong
- Private content in public threads. The most common leak. The reply rule above prevents it.
- Chat treated as policy. “I think we allow that” in #general is not a policy. Rank official channels and documents first.
- Stale answers. A 2023 message about leave is confidently wrong in 2026. Show dates and flag old sources.
- Vendor rate limits. A vendor’s unlisted app may be stuck on Tier 1 history limits and barred from MCP. Ask before you buy.
- Data location. Slack’s nearest residency region is Sydney; model processing may be elsewhere.
- Manual recovery. Delete a bad answer, correct the source message or document, and log the fix. A switch that disables the app’s event subscription stops it instantly.
Using Microsoft instead? See AI and Microsoft Teams. If your knowledge lives in Notion, see AI and Notion. We build cited knowledge assistants through our RAG development service.
Sources
- Updates to feature availability and pricing for Slack plans, Slack Help, accessed 19 October 2026
- Slack pricing, Slack, accessed 19 October 2026
- The Slack MCP server and Real-time Search API are now generally available, Slack, 17 February 2026
- Slack MCP server overview, Slack Developer Docs, accessed 19 October 2026
- Real-time Search API, Slack Developer Docs, accessed 19 October 2026
- Rate limits, Slack Developer Docs, accessed 19 October 2026
- Rate limit changes for non-Marketplace apps, Slack Developer Docs, 29 May 2025
- Data residency for Slack, Slack Help, accessed 19 October 2026
- Claude API pricing, Anthropic, accessed 19 October 2026
Written by the Levy Street team in Wellington. Last updated 19 October 2026.