Jan 2026 • 5 min read • Slack • AI tells
Why Your Slack Message Looks AI-Generated (And How to Fix It on Mac)
Most “AI detection” at work isn’t software.
It’s vibe.
Slack is where that vibe gets judged the fastest — because Slack is high-frequency, low-formality writing. People know what “normal typing” looks like there.
This guide explains the most common Slack-specific AI tells — and how to remove them on macOS without rewriting everything.
It’s not about being anti-AI.
It’s about not looking lazy.
Short answer
Slack messages look “AI-generated” when they contain AI punctuation (smart quotes, em dashes), over-structured formatting, and overly polished phrasing.
The fastest fix is punctuation normalization plus slightly rougher, more human Slack structure.
You don’t need to rewrite. You need to remove the obvious tells.
Key idea
Slack is where “professional polish” becomes “suspicious polish.”
In newsletters, em dashes and perfectly balanced paragraphs are fine. In Slack, they read like a generated template.
Here are the most common Slack AI tells, in order of impact:
- Em dashes everywhere — especially spaced em dashes ( — )
- Smart quotes (“ ”) and curly apostrophes (’)
- Perfectly even paragraph rhythm (3–4 lines each)
- Too much structure: headings + subheadings + “Key takeaways”
- Overly diplomatic tone (“I hope this message finds you well” energy)
This post focuses on what you can fix quickly — without changing what you’re actually trying to say.
Slack-specific tell #1: AI punctuation
AI tools love:
- Em dashes (—) as the default connector
- Spaced em dashes ( — ) in casual messages
- Curly quotes (“ ” / ‘ ’) and curly apostrophes (’)
None of this is “wrong.” It just doesn’t match what people type in Slack.
The quick replacements
- “ / ” → "
- ‘ / ’ → '
- — / — / -- → - (or parentheses)
Brutal truth: a spaced hyphen is normal in Slack. An em dash isn’t.
Slack-specific tell #2: over-structured formatting
Slack isn’t a memo. When a message looks like a mini blog post, people assume it’s generated.
Common “AI structure” patterns in Slack:
- Headline + subheadline + “Short answer”
- Too many bullet layers
- Perfectly balanced sections
Slack style is usually: short intro, bullets, quick ask, done.
A more human Slack structure
Instead of:
Update: Here are the key takeaways…
Context: …
Next steps: …
Do this:
Quick update:
• what changed
• what it affects
• what you need from people (if anything)
Slack-specific tell #3: “too polite” phrasing
AI writes like it’s trying not to offend a committee. Slack doesn’t.
Watch for these patterns:
- “Hope you’re doing well” in internal threads
- Long disclaimers and hedging (“it may be possible that…”)
- Over-explaining obvious context
Slack writing is direct. It’s allowed to be slightly imperfect.
Fast humanization rule
Cut the first sentence if it’s “polite filler.” Keep the content.
How to fix this on Mac (without wasting time)
Option 1: Manual replace (fine if it’s rare)
If you only paste AI output occasionally, do quick find/replace in your editor before sending.
- Find: — Replace: -
- Find: “ Replace: "
- Find: ” Replace: "
- Find: ‘ Replace: '
- Find: ’ Replace: '
Option 2: Normalize before you paste (best if it’s daily)
If Slack updates are part of your job, you want an automatic cleanup step.
A macOS tool like Purifai normalizes punctuation and strips paste artifacts before the text reaches Slack:
- “ / ” → "
- ‘ / ’ → '
- — / — / -- → consistent output
- Hidden formatting removed, structure kept readable
This is the lowest-effort way to stop broadcasting “AI wrote this.”
The Slack rule
If it looks like you wouldn’t type it, people assume you didn’t.
Normalize punctuation, keep it short, send it.
Slack isn’t where you prove you can write.
It’s where you prove you can be clear.
The takeaway
Using AI at work is normal now.
Shipping obvious AI tells is optional.
Fix punctuation first. Then keep the structure Slack-native. That’s it.