Dec 2025 · 5 min read · Slack (Mac)
Fix Weird Slack Formatting When Pasting AI Text on Mac
If you paste text from ChatGPT, Claude, Gemini, or Copilot into Slack on Mac and it comes out wrong — weird spacing, broken bullets, messy blocks — you’re not imagining it.
The words are usually fine. The formatting breaks because Slack is trying to convert whatever you copied (often rich HTML with hidden styles) into Slack’s own markdown-like editor.
Works in: Slack for Mac, channels, DMs, threads.
This guide is for macOS.
Quick answer (Mac)
Short message: Paste and Match Style (strips weird styling).
Need bullets / bold / links to survive: Clean the paste before it hits Slack.
This happens daily: Use a native clean-paste tool so it’s one step, not a ritual.
Key idea
If a paste looks wrong, editing the message won’t fix it. Fix the paste.
Your goal is to give Slack predictable structure (real paragraphs, flat lists, simple emphasis) instead of imported styling.
Common symptoms when pasting AI text into Slack on Mac:
- Paragraph spacing looks inconsistent
- Bullets lose indentation or turn into odd dashes
- Numbered lists renumber or collapse into a block
- Text looks “foreign” compared to the channel’s normal tone
This happens most often when copying from browser-based AI tools, where the clipboard includes rich HTML and inline styles.
The Slack-safe format (use this before you paste)
Slack rewards “message formatting,” not “document formatting.” The safest pattern is:
- Bold lead-in instead of headings
- Short paragraph (1–3 sentences)
- Flat list (one level)
- Code in triple backticks
Example that Slack renders reliably
Update: Fix is ready and shipping behind a flag.
- Enable flag in staging
- QA with 3 real accounts
- Roll out gradually if metrics hold
If you paste this and it still looks wrong, the content isn’t the issue. The clipboard is.
Avoid “soft returns”
AI drafts sometimes include manual line wrapping (soft returns). Slack can render that as dense blocks or weirdly wrapped lists. Prefer real paragraphs and real lists instead of handcrafted line breaks.
Mac paste workflows that actually work
Method comparison
| Method | Keeps rich lists | Keeps rich formatting | Speed | Best for |
|---|---|---|---|---|
| Paste and Match Style | Sometimes | No | Very fast | Short messages |
| Neutral-field plain text (TextEdit/Notes) | No | No | Medium | Occasional cleanup |
| Clean-paste tool | Yes (simple lists) | Mostly | Fast | Daily Slack use |
Option 1
Paste and Match Style (fastest)
This strips imported styling so Slack receives plain-ish text.
Common shortcut in many Mac apps: Option–Shift–Command–V.
Use this for short messages where structure doesn’t matter much.
Option 2
Neutral-field plain text (works, but annoying)
Paste into TextEdit, then Format → Make Plain Text, copy again, then paste into Slack.
This is fine occasionally. If you do it daily, it’s a bad workflow.
Option 3
Clean-paste (best if you care about bullets and speed)
A clean-paste step removes hidden styles while keeping Slack-friendly structure (paragraphs, simple lists, bold, links).
If this is a daily Mac workflow, Purifai is the most practical option: it cleans AI and web text before it hits Slack, without the “paste into another app first” detour.
If you only hit this problem occasionally, you don’t need a tool. If it happens multiple times per day, you’re wasting time without one.
Troubleshooting: common Slack paste failures
- Dense blocks after pasting → Remove manual line breaks (soft returns). Use real paragraphs.
- Bullets lose indentation → Keep lists flat (one level). Clean the paste if Slack still breaks it.
- Code gets mangled → Wrap it in triple backticks before pasting so Slack doesn’t reinterpret it.
- Spacing looks random → Paste and Match Style, or use a clean-paste step for consistent structure.
The message isn’t the issue.
The clipboard format is.
The takeaway
If you don’t care about structure, paste and match style and move on.
If you do care — bullets, clean spacing, links — stop pasting rich HTML into Slack and hoping it behaves.
If this is a daily Mac problem, Purifai is the cleanest workflow: clean once, paste normally, done.
One-line summary
Short message: Paste and Match Style. Structured message: clean the paste.