How to fix spelling and tone in Slack messages on macOS before you hit send

You just fired off a Slack message to your manager. Three seconds later, you re-read it. There's a typo in the second sentence. The tone sounds blunt. You meant "Let's revisit the timeline" but it reads more like "You missed the deadline." Now you're editing in a thread, hoping nobody screenshot the original.

This happens dozens of times a week. Slack moves fast, and fast communication breeds sloppy writing. The stakes are low per message but high over time. The colleague who always sounds clear and composed? They're not a better thinker. They just catch their mistakes before sending.

The problem is that most writing tools don't work where you actually write. They live inside documents, not inside Slack.

macOS has built-in spell check. It catches obvious typos. But it won't tell you that your message sounds passive-aggressive, or that "per my last message" has become a meme for a reason.

Tone is harder than spelling. A sentence can be grammatically perfect and still land wrong. "Sounds good" and "That works for me, thanks!" carry the same information but leave very different impressions. In Slack, where messages are short and there's no body language to soften the edges, tone is most of the message.

What you really need is a tool that handles both: catches the typos and adjusts how your writing sounds, right there in the Slack compose box, before anyone sees it.

Some people paste their Slack messages into ChatGPT, ask for a rewrite, then paste the result back. This works, technically. But it breaks your flow. You leave Slack, open a browser tab, write a prompt, wait for output, copy it, switch back, and paste. For a two-sentence message, that's absurd.

Others rely on Grammarly's browser extension. It works in Slack's web client, but not in the desktop app. And even in the browser, Grammarly focuses on grammar rules. It doesn't rewrite for tone unless you pay for the premium tier, and even then it suggests changes one word at a time. You're still doing the heavy lifting.

The friction isn't in any single step. It's in the context switching. Every time you leave the app you're writing in, you lose momentum. You start second-guessing whether the rewrite is even worth the effort. Most of the time, you just hit send and hope for the best.

The ideal tool doesn't ask you to go anywhere. It works inside whatever app you're already using, including the Slack desktop app on macOS.

WordPolish does exactly this. It sits in your menu bar and waits until you need it. When you've typed a Slack message and want to clean it up, you highlight the text and press a keyboard shortcut. WordPolish reads your selection, considers the surrounding context, and suggests a rewrite that fixes spelling, grammar, and tone in one pass.

Here's what that looks like in practice:

1. Type your message in Slack as you normally would.

2. Highlight the text you want to improve. Could be the full message, could be one sentence.

3. Press ⌘⇧X (or click Polish in the menu bar).

4. Review the suggestion in a quick diff overlay that shows exactly what changed.

5. Apply or skip. One click and the polished text replaces your original, right inside Slack.

The entire process takes a few seconds. You never leave the app. You never open a browser tab. You never write a prompt.

Three things matter here, and they're easy to overlook.

It works in any app, not just the browser. Grammarly needs a browser extension or a supported integration. Wordtune is the same. WordPolish uses macOS accessibility APIs to work system-wide. Slack desktop, Apple Mail, Notion, even your code editor. If you can select text, you can polish it.

It rewrites for tone, not just correctness. Most grammar tools flag errors. WordPolish suggests a complete rewrite that matches the tone you want. You can set writing traits per app. Slack messages get rewritten to sound natural and friendly. An email to a client gets a more professional treatment. You configure this once and forget about it.

It stays out of your way. There are no inline underlines. No pop-ups while you type. No distracting squiggly lines pulling your attention away from what you're trying to say. WordPolish only appears when you invoke it. You stay in control of when your writing gets checked.

Tone in Slack is a moving target. A message to your team channel sounds different from a DM to your manager, which sounds different from a thread with a client in a shared channel.

WordPolish lets you set writing traits that describe the voice you want. For Slack, something like "natural, friendly, concise" works well. The AI uses those traits alongside the context of your message to produce a rewrite that sounds like you on a good day, not like a robot or a corporate press release.

This matters more than most people think. Studies on workplace communication consistently find that tone drives trust. People don't remember exactly what you wrote. They remember how it made them feel. A tool that helps you land the right tone, consistently, compounds over months and years.

You don't need to polish every Slack message. A quick "sounds good" or a thumbs-up emoji doesn't need AI assistance. But for anything longer than a sentence, especially messages going to people you want to impress or situations where miscommunication has real consequences, running a quick polish is worth the two seconds it takes.

Good candidates for a quick polish:

• Status updates to your team or manager
• Messages in shared channels with external partners or clients
• Anything you've rewritten twice and still aren't happy with
• Messages where you're giving feedback or pushing back on something

The goal isn't to make every message perfect. It's to catch the mistakes and tone issues that would otherwise slip through because Slack moves too fast.

WordPolish is a macOS menu bar app. Download it, grant the accessibility permission it needs to read your selected text, and you're set. The keyboard shortcut works in Slack and everywhere else on your Mac.

Your writing already says what you mean. WordPolish just makes sure it sounds that way too.