Revise Blog - Building a post-AI word processor
AI Document Review tools compared - 2026
Eight popular AI tools compared for where they can help improve your documents
Artur Sapek, Founder of Revise12 min read
You have a document, and you want to find & fix all the problems with it before sending it over to your boss, your colleagues, your professor, or your client. What's the right tool to use? It really depends on what you're doing, and what result you want. There are countless AI products out there each with different strengths.
We compared eight popular ones with a real document review task, taking notes on how they did across the full review workflow: how easily you can bring in a real document, what the AI can find, whether it can propose useful fixes, how you review those fixes, what happens to the original formatting, and how easy it was to use.
Eight AI document review tools at a glance
These tools are built around different review workflows, but we've done our best to break it down by what they each excel at. Our overall verdict is below, followed by a summary of our test for each tool.
- Revise: gave a solid review yielding comments & tracked changes; intuitive to talk to in comment threads; citations not linked
- Microsoft Word + Copilot: successful review, though without using comments or tracked changes; easy to use
- Google Docs + Gemini: took more nudging but successfully placed comments and made suggested changes; chat UI a bit hard to read
- ChatGPT: gave great feedback with good citations, but struggled with document editing; relied on Python; confined to upload/download
- Claude: asked great questions before starting review, the best tool at context gathering; struggled with DOCX file format, also confined to upload/download
- Grammarly: mostly focused on grammar and sentence polish, missing the bigger picture; comments disappeared after a page refresh; Pro upgrade gated
- Adobe Acrobat AI Assistant: reviewing and questioning PDFs with citations
- Spellbook: legal contract review against standards and playbooks
What is AI document review?
A summary is not a review, nor is a simple rewrite. A useful document-review tool should take you through the entire workflow:
- Find: identify errors, inconsistencies, weak reasoning, missing information, risky clauses, or style problems.
- Explain: make the case for why an issue matters and point to the relevant passage or source.
- Suggest: propose edits to content and formatting via comments and tracked changes.
- Apply: let you selectively apply suggested fixes, accepting ones that make sense and rejecting ones that don't. Keeping you in control is important because the AI tool may not have all the context it needs.
Chatbots are often strong at finding and explaining, but they can't collaborate with you in a real document editor. AI writing assistants are fast at finding and fixing sentence-level problems, but many are limited to basic formatting and can't handle Word files properly. Specialist PDF and legal products add citations but are confined to the limits of a PDF.
An AI document editor is the most suited for agentic document review, and it has the hardest job: it must complete the loop while preserving a usable document.
How we compared the tools
We evaluated each product against eight practical questions:
- Document context: Can the AI reason about the whole document rather than one pasted paragraph?
- Review depth: Does it catch only grammar, or can it assess structure, consistency, reasoning, and intent?
- Actionable output: Does it return observations, comments, rewritten text, or edits to the actual document?
- Human control: Can you inspect and accept or reject individual changes?
- File fidelity: What happens to formatting, layout, comments, and revision history?
- File support: Can it handle DOCX, PDF, Markdown, plain text, or several sources at once?
- Collaboration and evidence: Can teammates review the result, and can the AI cite the source for its claims?
- Friction to first useful review: Does the tool have a free tier? How hard is it to try?
To ensure a fair test, we used the same document with each tool - a DOCX file of simple legal contract with subtle hidden mistakes and flaws. Here is what we found.
AI document review tools compared
Revise: easy to use with great comment threads
Revise is a browser-based AI document editor. Import a DOCX, PDF, Markdown, or text file and the document opens in an actual word processor. The agent can read the full document, identify problems, leave comments, and propose edits directly in the page.
Revise took about 35 seconds to review our document, and left several insightful comments in the margins.
Revise is able to have conversations in comment threads, and the agent was making document edits in response to our comment replies. Each suggestion it made could be accepted or rejected individually.
You can try Revise without creating an account, and it has a free tier with a daily AI limit. No need to install an add-in or enter payment details.
Microsoft Word with Copilot: reliable, the vanilla choice
Microsoft 365 Copilot is the natural choice when you're already using Word. When we tried having Copilot review our contract, it did find similar issues and discrepancies but the way it presented them was less intuitive. Rather than make inline comments, Copilot presented a stack of cards in its chat UI which we had to step through one at a time.
When asked to address an issue, Copilot surprisingly didn't use tracked changes but rather a blue highlight and "undo" button. Not what we expected, but still a decent performance.
If you're already in Word and have Microsoft 365 and Copilot access, Copilot can do the job and is probably your easiest choice.
Google Docs with Gemini: decent but a bit confusing
Gemini in Google Docs combines AI drafting and rewriting in the most popular collaborative word processor in the world. It's a natural choice for documents already in Drive. So how did it do?
When asked to review our document, Gemini defaulted to simply offering a long markdown chat reply which was hard to read through even when expanding it into a full sidebar.
Gemini eventually did leave contextual comments in the document, but not as itself - the comments were authored under my own name. This was confusing - if I'm working together with an AI agent, I want it to be clear what came from the agent versus from myself. Even better if we can go back and forth within a comment thread, like in Revise.
Gemini was also able to apply edits using tracked changes, or as Google Docs calls it, suggestions.
It wasn't the smoothest experience, but Gemini did do the job and left intelligent comments. The biggest drawback was simply model choice - you can only use Gemini in Google Docs. If you like Gemini, and you're already in the Google ecosystem, then it's a fine choice.
ChatGPT: great feedback, not so good document handling
ChatGPT is an interesting one; it's arguably the most powerful software product in the world. When asked to review our document, it took a lot longer than other platforms we looked at but it did leave excellent comments. One thing we noticed is ChatGPT seems to use Python scripts to work with .docx files in some kind of sandbox.
The feedback we got from ChatGPT was solid, and presented as a simple chat response (no surprise). It included excellent citations to local laws, but took a little more cognitive work to correlate each line in the bullet list to what part of our document it referred to. Notably, the section feedback was not in numerical order.
When we asked it to make changes to address its feedback, ChatGPT spent over 2 minutes generating a new .docx file using more scripts. The edits were made, but not with tracked changes so we could not see the before & after easily.
ChatGPT is a general purpose chat app, not an AI document editor - so this experience wasn't surprising and all things considered it was pretty good. It's also worth noting that ChatGPT has plugins for both Google Docs and Revise, so it can work with external word processors.
Claude: by far the most thoughtful
Claude started its review doing something no other tool did: asking questions. We were given two multiple choice questions specific to our request before Claude did any work. This was very impressive.
What followed was also the longest we had to wait for results. Claude Opus worked for over 11 minutes doing research and reading how to work with our DOCX file. Like ChatGPT, Claude also seemed to work with Python to manipulate the document.
At the end of it, Claude produced a valid .docx file with lots of thoughtful comments in it.
However, the feeling I felt at the end of all this was, "man I wish Claude and I could go back and forth here." I wanted to discuss these comments with Claude, but in order to do so I would have to go back and have it generate another document. Copilot, Gemini, and Revise are the only tools I've tried so far where I could do this.
Grammarly: not really built for documents
Grammarly is primarily a simple grammar checker, but it does have a document editor tool called Coda which they acquired in 2024. We gave this tool a shot with our document review request.
At first Grammarly's AI chat just spat out a long chat response, but when asked to leave comments in the document it did do so. The comments it made were relatively trivial, and it never tried to do any research or cite sources. This feature also seems to be gated on Grammarly's Pro subscription, which we were given a "free sample" of.
Grammarly's document editor is not really a Word-capable editor. It does import and export .docx, but only preserves basic text and it doesn't render pages like a typical word processor would. The .docx it exported at the end had 0 page margins, so clearly formatting is not surviving the round trip very well. I wouldn't have any confidence running complex documents through this tool.
Adobe Acrobat AI Assistant: strongest for reviewing PDFs
Acrobat AI Assistant is the specialist pick for PDFs. It supplies summaries with links to supporting passages, answers questions about files, recognizes contracts, and can combine many files and links in PDF Spaces.
Citations are its clearest advantage: reviewers can inspect the source instead of trusting an unsupported summary. Acrobat also offers PDF editing and rewriting, but its center of gravity is understanding fixed documents rather than collaborating on a rich-text draft with granular AI suggestions.
Spellbook: strongest for AI contract review
Spellbook is a product built specifically for reviewing contracts against legal standards, so I had high expectations. It did a very good job of reviewing my document. Its AI agent first offered a table of suggested changes, but when asked it did open an in-app document editor and create tracked changes for me.
At $500/month this tool isn't accessible to everyone, and probably overkill for most AI document review. Spellbook is clearly targeting attorneys looking for a specialized product.
Which AI document reviewer should you choose?
| If your main job is… | Strongest fit | Why |
|---|---|---|
| Review a document and apply controlled AI edits | Revise | Whole-document agent plus accept/reject suggestions |
| Keep a corporate document inside Microsoft Word | Microsoft 365 Copilot | Native Word and Microsoft governance workflow |
| Review collaboratively in Google Workspace | Google Docs + Gemini | Gemini assistance plus comments and suggestions |
| Use a custom rubric and ask follow-up questions | ChatGPT | Flexible prompting and conversational iteration |
| Get substantive feedback on a long, complex draft | Claude | Long-form analysis and nuanced critique |
| Catch grammar, clarity, and tone problems everywhere | Grammarly | Fast, continuous sentence-level suggestions |
| Ask cited questions about PDFs | Adobe Acrobat AI Assistant | Source citations and PDF-native analysis |
| Review contracts against legal standards | Spellbook | Playbooks, risk flags, and redlines |
If the deliverable is a list of observations, ChatGPT, Claude, or Acrobat may be enough. If the deliverable is the improved document itself, prioritize a tool that preserves the file and gives you a real way to review its edits.
The bottom line
Grammarly catches small writing problems with minimal interruption. Claude and ChatGPT are excellent thinking partners. Acrobat is built around PDF evidence. Spellbook earns its price when a missed contract issue carries legal risk. Word and Google Docs are sensible when changing an existing team workflow would cost more than the AI saves.
Revise is designed for reviews where the AI works on the actual document, proposes fixes in context, and leaves you in control of every change. You can test that workflow on your own file for free, without creating an account.