Comparison · Slack AI
Slack AI vs Tessa: AI inside Slack, or an assistant working across Slack, email and meetings
Slack AI adds AI summaries and search inside Slack. Tessa lives in Slack too, but connects what happens in channels with email, meetings and tasks, and handles the follow-through.
You know what happened in the channel. Now who owns it?
Summarising a channel with a hundred unread messages is a relief. But at a company of 20 or 120 people, work doesn't stay in Slack: a request starts in a thread, continues by email with the customer, gets decided in a meeting and ends up as a task someone has to remember. If the AI only sees part of it, the summary tells you what happened, not who owns it or whether it got done.
If you're weighing Slack AI against other options, the useful question isn't which AI summarises better. It's where work slips through the cracks: inside Slack, or between Slack and everything else.
How it works with Tessa
- 1
Install Tessa in your Slack
An admin connects her from Tessera in one click and she shows up as "Tessa". Each person links their Slack and Google accounts.
- 2
Requests land in your inbox
Slack messages and emails that ask you for something become tasks with a priority and a suggested reply. Reply in the thread and they close themselves.
- 3
Talk to @Tessa in the channel
"@Tessa summarise this thread", "create a task for Ana" or "what did we agree with this customer?". She answers with sources from Slack, email, notes and documents.
- 4
Compare for a few weeks
If you already have Slack AI, run both side by side and see which one turns requests into finished work.
What you get
- Slack, email and meetings togetherWhat gets asked in a channel and confirmed by email is one task, not two things to remember.
- Owned tasks, not just summariesEvery request becomes a task with a date, and Tessa tells whoever asked if it stalls.
- Meeting notes posted to SlackTessa takes notes in Meet (Zoom and Teams in beta) and posts the recap with tasks to Slack and email.
- Company memory with sourcesDecisions from channels and meetings go into a wiki that respects who can see what. DMs between people aren't used.
- Approval for anything going outReplies to customers and external emails wait for your go-ahead unless you say otherwise.
What Slack AI is
Slack AI is the set of AI features Slack builds into its own app. According to its website, it can summarise channels and threads, send regular recaps of channels you pick, answer questions in search based on your conversations and take notes in huddles, among other features Slack keeps adding.
Its big advantage is that there's nothing else to install or learn: it's inside Slack, it follows Slack's permissions and it's managed in the same place. For a team that does nearly everything in Slack, it's the most direct way to catch up.
Information about Slack AI is based on its public website as of October 2026; it may change.
How Tessa is different
Slack AI helps you understand what's happening in Slack. Tessa works across Slack, email, calendar, meetings and tasks, and her goal isn't only to summarise but to make sure what's asked and agreed gets done: she creates owned tasks, drafts replies, tracks commitments and flags when something stalls.
She's also built for European companies: data is stored encrypted in the EU, what Tessa reads for each person is visible only to them, and managers get no individual metrics.
- An inbox of tasks from Slack and Gmail (Outlook in beta), with a suggested reply in your tone.
- Meeting notes with tasks per owner and the recap sent (Meet; Zoom and Teams in beta).
- Commitment tracking and a weekly pulse per department, with a minimum of 5 people.
- Search across email, Slack, notes, documents, tasks and contacts, with sources cited.
- Plain-language routines: "every Friday, post this week's decisions in #product".
When to choose Slack AI
If nearly all your work happens in Slack and what you need is to catch up fast (channel summaries, answers in search, huddle notes), Slack AI is the natural choice: it's built in, adds no new tool and is managed by the same people who run Slack.
It also fits if keeping AI inside the Slack environment is your priority, or if email and customer meetings play a small part in your day.
When to choose Tessa
Tessa is the better fit for tech and digital companies running on Google Workspace and Slack together, where the problem isn't reading channels but that decisions from meetings, emails and threads don't get done, or nobody knows who owns them.
And you don't have to choose: Tessa lives inside Slack like a teammate, so she can sit alongside Slack AI. Some teams use Slack AI to catch up and Tessa for tasks, follow-ups and meetings.
| Slack AI | Tessa | |
|---|---|---|
| Main focus | AI inside Slack | An assistant working across Slack, email and meetings |
| Channel and thread summaries | ✓ Its strength | ✓ "@Tessa summarise this thread" |
| Email as a source of work | Not its focus | ✓ Gmail (Outlook in beta) |
| Owned tasks and follow-ups | Check its website | ✓ |
| Video call notes | Huddle notes, per its website | ✓ Meet; Zoom and Teams in beta |
| No extra tool to install | ✓ Already in Slack | Installs in Slack in one click |
| Data stored in the EU (Tessa) | Check its data policy | ✓ Encrypted on EU servers |
What Tessa reads for each person stays private, your data is stored in the EU and nothing goes out without your approval.
Frequently asked questions
What's the difference between Slack AI and Tessa?
Slack AI summarises and searches inside Slack. Tessa connects Slack with email, meetings and tasks and handles the follow-through: she turns requests into tasks, drafts replies and tracks commitments.
Can I use Slack AI and Tessa together?
Yes. Tessa installs in Slack as a bot and doesn't interfere with Slack's AI features. Running both for a while is a good way to compare.
Does Tessa read direct messages?
Only the ones you send her. DMs between colleagues aren't used for the wiki or company memory, and content from a private channel is visible to its members only.
Does Tessa work in English and Spanish?
Yes. Write to her in either language and she replies in the one you use.
Which Tessa plan includes Slack?
Slack is on Tessa's Team and Business plans, with a 14-day free trial. For Slack AI plans, check Slack's website.
Keep reading
- IntegrationsA Slack AI assistant that reads the channels for youMention @Tessa to create tasks, summarise threads or ask what was agreed. Requests aimed at you land in your inbox and close themselves once you reply.
- GuidesHow to get more out of Slack with AIHow to use AI in Slack: summarise threads, turn messages into tasks, find past decisions and ask in-channel. Plus habits that help with or without AI.
- FeaturesEvery email that asks for something becomes a taskTessa reads your email and Slack, turns every request into a prioritized task with a due date and clears what's already done. Try it free.
- FeaturesOne search box for everything at your companySearch your email, Slack, meeting minutes, docs, tasks and contacts at once, and get answers from Tessa with every source cited. Try it free.
- FeaturesTessa takes the notes, assigns the work and sends the recapTessa takes notes in your meetings, writes the minutes, assigns each action item to its owner and sends the recap to attendees. Try 14 days free.
- CompareGlean vs Tessa: search for the whole company, or an assistant that also does the workGlean searches across a large company's apps. Tessa searches email, Slack and notes, then turns open items into owned tasks. Compare and try it free.
What does your team look like?
Same AI for both. Where you start is what changes.
Startups
5 to 30 people
Grow without losing the thread
Tasks from email and Slack, follow-ups, sales and investors, without everything landing on the founders.
Companies
30 to 250 people
What gets decided gets done
Minutes and tasks from every meeting, commitments that get followed up and a pulse per team, without watching anyone.
Install Tessa in your Slack, connect your email and see what happens to the requests you get this week.
Start freeFree plan for teams of up to 3 people. Anything that leaves the company waits for your approval.