Writing & MediaFree
Client Voice Match Check for Ghostwriters
Paste your draft and the client's samples. Get comments wherever it stops sounding like them, with evidence from their words and a rewrite in their voice.
River's client voice match analyzer checks a ghostwritten draft against how the client really talks and writes. Paste the chapter, article or speech, plus the client's interview transcripts, emails, posts or voice guide. River comments on every passage that drifts: words they would not use, a rhythm that is too polished, an opinion that is out of character, a story told in someone else's way. Each comment quotes the client's real pattern as evidence and offers a rewrite of the passage in their voice.
General tone checkers measure readability or score text as formal or friendly. They cannot tell you whether a sentence sounds like one particular person, because they have never heard that person. This compares the draft with the client's own words. With no samples, it uses the passages of the draft that sound most like the client as the reference and marks where later chapters drift. That is how a book's voice usually slips: gradually, as the writer tires and their own habits return.
It is for ghostwriters before a draft goes to the client, agencies reviewing a junior writer's work, and editors taking over a project midway. Run it on each chapter before you send it, and again on the full manuscript before the final read. If you have not documented the client's voice yet, the ghostwriting style guide creator builds the reference first. For notes on structure rather than voice, use the AI book editor.
Why ghostwritten drafts drift, and how to catch it
Drift rarely happens in the first chapter. The writer has just finished the interviews and the client's voice is loud in their head. It happens around the middle, when the deadline tightens and the writer's own habits creep back: a favourite transition, tidier sentences, a joke the client would never make. Readers will not name it, but the client will, usually by saying a chapter feels off without knowing why. Checking every chapter catches it while the fix is a sentence, not a rewrite.
The fixes are usually small. Swap a word the client would not use for one they do. Break a polished sentence into the two short ones they would actually say. Replace an abstract claim with the concrete example they told in the third interview. Remove a hedge from a topic they feel strongly about. Even tiny words carry a voice: statisticians showed that Madison wrote the disputed Federalist Papers partly from how often he used everyday words like "also" and "by". Each fix is easy once someone shows the client's real pattern beside the passage.
Treat the client's edits as evidence too. When they change "commence" to "start", or cut a paragraph of reflection, they are telling you how they sound. Paste their marked-up chapters back in as samples, and later checks will reflect what they actually accept, not just what they said in interviews. Over a long project this tightens the voice with each round, and it gives a second writer joining the project a concrete record to work from rather than a vague description.
How it works
Paste your draft
A chapter, article, speech or whole manuscript, pasted or attached as a file.
Add the client's words
Interview transcripts, emails, posts or a voice guide; the more natural, the better.
Read the comments
Each drifting passage is marked with evidence from the client's words and a rewrite.
Fix and recheck
Ask River in chat to apply the rewrites you accept, then check the next chapter.
What you get
- Comments on each passage that does not sound like the client, quoting the draft exactly
- Evidence from the client's own transcripts, emails or posts showing how they really say it
- A suggested rewrite of every flagged passage in the client's voice, keeping your content
- Checks across vocabulary, rhythm, formality, humour, opinions and the way stories are told
- Drift across chapters caught even without samples, using the draft's strongest passages as reference
- A short summary of where the voice holds and where it slips, chapter by chapter
Common questions
Do I need samples of the client's voice?
They make the check far sharper, so add them if you have any: transcripts, emails, posts or a voice guide. The client onboarding questionnaire is a simple way to ask for them. Without samples, River uses the passages of your draft that sound most like the client as the reference, marks where the rest drifts away, and tells you that is what it did.
Will River rewrite my whole draft?
No. It comments on the passages that drift and suggests a rewrite for each, leaving the rest of your text alone. You decide which suggestions to accept. If you want them applied, ask in chat and River makes only those changes in the document, so you stay in control of the draft.
How is this different from a style or grammar checker?
Style checkers compare your writing with general rules, such as shorter sentences or fewer adverbs. This compares it with one person. A sentence can pass every grammar rule and still sound nothing like your client, and a fragment a checker would flag might be exactly how they talk. The reference is the client, not a rulebook.
Can I check a whole manuscript at once?
Yes. Attach the full manuscript and River reviews it chapter by chapter, then summarises where the voice holds and where it slips. For a long book, checking each chapter as you finish it is often more useful, because the fixes are smaller and what you learn carries into the next chapter.
What if I disagree with a comment?
Ignore it, or tell River why in chat. Sometimes a client deliberately sounds different in one section, such as a formal letter quoted in a memoir. Explaining that helps River check the rest of the manuscript with the exception in mind. The comments are evidence and suggestions, not rules you must follow.
Built by
Chandler Supple
Co-founder & CEO, River
Chandler has spent the last six years working in AI, building tools for millions of users and Fortune 100 companies. In 2025, he co-founded River to build a new kind of operating system for AI agents.
Client Voice Match Check for Ghostwriters
Describe what you need, add any files you have, and your workspace opens with the work already underway.