Last updated: March 2026
What Is the AI Writing Improver?
The AI Writing Improver is a free tool that polishes your writing using Claude AI. Whether you need to fix a few grammar mistakes, tighten up confusing sentences, or completely rewrite a paragraph for professional impact, this tool gives you three distinct modes to match the level of editing you need.
Unlike generic grammar checkers that only flag errors, the AI Writing Improver shows you a word-level diff of every change — green highlights for additions, red strikethroughs for deletions — so you can see exactly what was modified and learn from each correction. You stay in control of your text while getting AI-powered editing that would cost hundreds of dollars from a human editor.
How to Use the Writing Improver
Choose the right mode for your needs. "Fix Grammar Only" is best when your writing is already solid but may have typos or punctuation issues. "Improve Clarity" works well for drafts that need restructuring. "Full Rewrite" is ideal for transforming rough notes into polished prose.
Set the tone to match your audience. Keep Original preserves your voice. Professional sharpens language for business contexts. Academic adds formal structure and precision. Casual relaxes the tone for blogs or social posts. Persuasive strengthens arguments and calls to action.
Review the diff carefully. The side-by-side view lets you compare your original text against the improved version. Toggle between "Show Diff" to see highlighted changes and "Show Clean" for the final text without markup. This review step is where real learning happens.
Iterate with different modes. After reviewing one improvement, try a different mode on the same text. A "Fix Grammar" pass followed by an "Improve Clarity" pass often produces better results than jumping straight to "Full Rewrite."
When to Use Each Mode
Fix Grammar Only: Use this when your ideas and structure are strong but you want to catch errors before hitting send. Perfect for emails, reports, and documents where your voice matters and you just need a safety net for typos and grammatical mistakes.
Improve Clarity: Use this when readers have told you your writing is hard to follow. The clarity mode breaks up run-on sentences, replaces vague words with specific ones, and reorganizes ideas for better logical flow. Ideal for technical writing, instructions, and educational content.
Full Rewrite: Use this when you have a rough draft or notes that need to become polished, professional content. The rewrite mode transforms stream-of-consciousness writing into structured, engaging prose. Great for cover letters, proposals, and published articles.
Frequently Asked Questions
How does the AI Writing Improver work?
Paste your text, choose a mode (Fix Grammar, Improve Clarity, or Full Rewrite), and optionally select a tone. The tool sends your text to Claude AI, which returns an improved version. A word-level diff highlights every change so you can review additions and deletions at a glance.
What is the difference between the three modes?
Fix Grammar Only corrects spelling, punctuation, and grammar without changing your style or word choice. Improve Clarity restructures sentences for better readability while fixing errors. Full Rewrite completely rewrites your text for maximum polish and professional impact while preserving your core message.
Is my text stored or shared?
Your text is sent directly from your browser to the Anthropic API using your own API key. It is processed per Anthropic's privacy policy and is not stored by this tool. Your API key is saved only in your browser's local storage and never sent to our servers.
Why is there a 10-improvement limit per session?
The session limit prevents accidental overuse of your API key. Each improvement uses a small amount of API credits. Refresh the page to reset the counter. This limit exists to protect your API balance, not to restrict the tool.