Can ChatGPT Do Line Editing? I Put It to the Test
- Iris Marsh
- 11 mei
- 13 minuten om te lezen
Table of Contents
AI is here to stay, whether we like it or not. And while I personally don't think it should create "art" (real art is emotion, and genAI can't fake that), it does also offer opportunities.
This post isn't here to talk about the ethical side of things. There are loads of companies and services that are ethically questionable and bad for the environment. Whether you want to use genAI is up to you.
And I do get the temptation. After all, why hire an editor if something like ChatGPT can do the same?
When I finished my first novel, my budget was held together with duct tape and crossed fingers. I wanted a line editor, but $2,000 felt more like a fantasy than my book.
Like many indie authors, I knew my prose needed refining. But between editing, covers, and marketing, the costs pile up quickly. You need to make choices. Informed ones.
But can AI actually do editing well? That’s the question I wanted to answer when I trained a ChatGPT to mimic my own editing style.
I picked line editing specifically because it’s one of the most artistic (and subjective) forms of editing that goes deeply into the writer’s voice, subtext, metaphors, and all the subtleties of language.
It's all about refining emotion, in my view.
To test how well ChatGPT can handle this type of editing, I didn’t just use a generic prompt.
Instead, I built a customGPT—essentially a personalized version of ChatGPT—and trained it on my editing style, key terminology, and examples of past line edits.
That way, it could offer more thoughtful suggestions that align with how I’d approach line editing. Once it was trained, I gave it a sample excerpt from a fiction manuscript and asked it to do a line edit.
Then I compared it to my own edit.
As expected, the GPT was a bit heavy-handed with its edits and did do away with the writer's voice. It didn't quite grasp the nuances.
In this article, I’ll show you what I did and what the outcome was.
What Is Line Editing Again?
Before we start, let’s quickly revisit what line editing is: it’s a sentence-level edit, also called a stylistic edit, that serves to enhance your voice, elevate your writing, and clarify meaning.
It focuses on the flow of language, word choices, and how characters speak—ensuring consistency in voice and POV.
This is where we want to add in more emotional layers and resonance, making sure we make the most impact on readers.
Before you dive into this editing phase, make sure your manuscript is ready.
Want to know the exact steps you can use to revise your sentences & create beautiful prose? Get your checklist now!
What You Need to Know
Before we dive into the actual user case of ChatGPT and line editing, let’s talk a bit about these models and what will happen if you give it your writing.
First, it’s important to realize that ChatGPT was trained on thousands and thousands of stories, as well as other AI models like Claude. Judges don't yet seem to be on the same line on whether it's fair use to use these for training after purchase.
Second, know that if you use the regular version of ChatGPT (the free one) and give it your manuscript, it will be used to further train the language model, and you won’t know exactly what it’ll do with it.
Third, genAI is a very hot topic and can get heated pretty quickly. Like I said, I don't personally feel we should use it to write a book (for many reasons), but using AI for things like editing is also a no-go for many in the writing community.
Those caveats aside, I believe everyone should make up their own mind whether or not they use AI and how they use it. You can disagree with it, but all you can do is make your own decisions about how you want to use it (or not use it).
For the purposes of this experiment, I created a custom GPT, which has more privacy than using a regular chat. You can read more about them on the OpenAI website.
What Can ChatGPT Do and Not Do?
Before jumping into the examples, I asked ChatGPT what it thought it was good at when acting as a line editor, and where it felt humans still had the edge.
Here’s a quick summary:
Where ChatGPT excels
Consistency checks (spelling, formatting, repeated words)
Tightening prose and improving flow
Spotting overused words and cliches
Tone matching (with guidance)
Handling large volumes quickly
Where humans still win
Emotional nuance and intuition
Subjective judgment and voice preservation
Big-picture line-level choices
Collaborative feedback and pushback
I did find most AI tools are still inconsistent througout a longer manuscript (but that might change in the future), especially on consistency checks and grammar.
And I'm not sure it's actually that great at tightening prose and improving flow, as it's currently likely to revert to "AI-isms" like "It's not this. It's this" or use three short punchy sentences "I froze. Turned around. Screamed."
(Note: those things alone do not prove AI use. Please don't go off on a witch hunt.)
Example of Line Editing with ChatGPT
Below, you’ll find the actual case study with the example of the paragraphs, how ChatGPT edited it, how I edited it, and a comparison of the two.
Original sample
For the sample, I used an earlier draft of Intertwined, the 2nd book in my YA UF duology. I picked some paragraphs to show here that had a mixture of dialogue, narration, and some short action beats.
These are some paragraphs of the original sample:
Carmen looked me up and down for a moment, assessing me. "So, this new side-project of yours… It doesn't have anything to do with that whole American crown business? You talked with them yesterday, right?"
I sighed and shook my head. "I just thought it would be nice to feel like I'm actually doing something, you know?" I shrugged. "I'm not much help with finding the crown, anyway."
I'd had a few quiet days at Mom's, mostly watching some shows, reading, and hanging out with Alex. It had been nice, almost normal. But it was difficult as always to ignore that call within me—the want for power. The need to be whole again. So when Dad had asked me if I could come to their meeting on Monday, I hadn't been able to say no. My curiosity had gotten the better of me.
"But you could." Carmen raised an eyebrow. "You still have your powers."
I grimaced. "Yes. That's what they said as well." I hadn't expected it, but even Jason and Caleb had been adamant that I should use my bracelet to add my power to theirs for this ritual they'd found that could potentially locate the crown. I shook my head. "But I can't do that, Carmen. You know I can't."
ChatGPT’s version
Let’s see some AI editing for fiction!
For the GPT’s version, I first had it read the entire manuscript, then do a voice analysis, and tell me the voice characteristics of all the main and secondary characters.
That way, it could keep that in mind during its line edit.
I asked it to edit the entire chapter, and this is how it revised the paragraphs above:
Carmen tilted her head. "This little side project of yours... it doesn’t have anything to do with that crown stuff in the States, does it? You met with them yesterday, right?"
I sighed. "I just wanted to feel useful, you know? Like I’m doing something." I shrugged. "I’m not exactly a crown-finding expert."
I’d spent a few quiet days at Mom’s—shows, books, time with Alex. It had almost felt normal. But underneath it all, the hunger lingered. The craving for power. So when Dad asked me to join Monday’s meeting, I said yes. Curiosity had won.
"But you could help," Carmen said, raising an eyebrow. "You still have your powers."
I grimaced. "Yeah. That’s what they said too. Even Jason and Caleb were pushing me to use the bracelet. They think I should add my power to theirs for this ritual to find the crown." I shook my head. "But I can’t, Carmen. You know I can’t."
GPT’s explanations for the edit
It condensed Carmen’s dialogue to preserve natural cadence while highlighting her emotional intelligence.
For Nikki’s response, it broke the line into shorter beats to reflect her defensiveness and her habit of deflecting vulnerability with humor.(I actually liked the first line—wish I’d thought of that! But I wasn’t a fan of the “crown-finding expert” part, since it shifts the meaning.)
The internal monologue was compressed for momentum. It streamlined the list to suggest a surface-level calm that contrasts with the darker second half. It also swapped “the call within me—the want for power. The need to be whole again.” with “the hunger lingered. The craving for power.” to echo Nikki’s obsessive loop.(Here it scrubbed too much of my voice. That original construction was intentional.)
It changed “My curiosity had gotten the better of me.” to “Curiosity had won,” which I actually liked.
Carmen’s reply became “But you could help,” which clarifies her point. (This is why I didn’t love the earlier “crown-finding” tweak—her line originally responded to Nikki saying she couldn’t find it, and that nuance was lost.)
Finally, GPT moved a section of Nikki’s internal monologue into her spoken dialogue, which felt odd. That said, it did a nice job streamlining the internal lines for rhythm—lengthening them slightly to reflect rising pressure, before snapping back with the short “I shook my head.”
My version
Below you can see what I came up with, both with tracked changes and the fully accepted one.
Carmen studied me. "This new side-project of yours… Is it about that whole American crown business?"
I had a few quiet days at Mom’s, watching shows, reading books, and snuggling Alex. It was nice, almost normal. "I thought it would be nice to feel like I'm actually doing something, you know?"
But, as always, I couldn’t ignore the call within—the want for power. The need to be whole again. When Dad asked if I could come to their Monday meeting, I couldn’t say no. My curiosity had gotten the better of me.
I sighed and shook my head. "I'm not much help with finding the crown, anyway."
"But you could." Carmen raised an eyebrow. "You still have your powers."
I grimaced. "Yes. That's what they said as well." Even Jason and Caleb wanted me to use my bracelet to add my power to theirs; they'd found some ritual to locate the crown. "But I can't do that, Carmen. You know I can't."
My explanations for the edits:
I shortened “looked me up and down” to “Carmen studied me.” It’s more concise and still gives readers a strong visual.
I would query the author here—should we add a simile? Is she studying Nikki like a therapist? Or like a parent assessing whether their kid broke the vase? Those create very different vibes.
In the dialogue, I cut the filler word “so” and simplified the question. I also removed the last line, which leaned into “as you know, Bob” territory.
(Side note: “So” can be great for voice, but use it too often and it loses impact.)
The streamlined question feels more like Carmen and keeps the informal tone with “that whole American crown business,” while trimming the wordy “It doesn’t have anything to do with...”
Next comes a heavier edit: I shifted some narration into the dialogue to better integrate thoughts, action, and pacing. This also helps break up the paragraph visually, making it more dynamic.
I reworked the list-style sentence (“watching shows, reading books”) to echo its structure with “snuggling Alex.” Though I’d query whether this fits Nikki’s voice—or whether “hanging out with Alex” feels more natural.
I removed “it was difficult” since that’s implied, and trimmed the sentence about her dad’s ask. “I couldn’t say no” also feels truer to Nikki’s voice than “I hadn’t been able to say no.”
I moved “I sighed and shook my head” to just before her next line—it fits better there, after her internal thoughts. I also cut the shrug, which was an empty action.
For the final paragraph, I tweaked the tone to match Nikki more closely. “I hadn’t expected it” is implied by “Even,” and “been adamant that” didn’t quite suit her voice.
I split one longer sentence into two with a semicolon to control pacing without a hard stop.
Lastly, I removed a redundant head shake (empty dialogue tag action). We already understand her emotional state from the context and her next line.
Comparison: AI vs. Human
So—how did we do?
I pasted both edits into a neutral ChatGPT (just the regular one) and asked it to compare them side by side. Here’s the summary it gave:
Category | Better Version | Reason |
Clarity & Flow | Iris Marsh | Smoother sentence structures, natural pacing |
Voice Preservation | Iris Marsh | Stronger internal voice, more consistent tone |
Dialogue | Iris Marsh | More believable, emotionally grounded |
Technical Accuracy | Iris Marsh | Fewer issues (GPT has a typo) |
Emotional Impact | Iris Marsh | More subtext-driven, subtle |
Depth / Reflection | GPT | Adds internal layers, if that fits the story style |
Its final verdict?
Iris Marsh’s line edit is more polished overall. It maintains narrative voice, enhances emotional depth through subtlety, and improves clarity without overstepping. GPT’s version shows potential, especially if a slightly more introspective or dramatic tone is desired, but it needs refinement to match Iris’s balance of voice, tone, and clean storytelling.
Naturally, I’m pretty pleased with the result.
Still, the GPT wasn't as horrible as I thought it would be. It's a bit heavy-handed at times, but as long as you stay in control of what to keep and what to tweak—just like you would with a human editor—it can be a powerful tool to streamline your edits.
But that only works if you really know the underlying reasoning for changes.
When a Human Line Editor Is Better
So… do you still need to fork over all that money for a human line editor?
Short answer: it does add value over AI, especially in a time with a lot of AI-written slop.
Why a Human Editor Still Adds Value
As we’ve seen, a human editor brings nuance that ChatGPT still struggles with. Things like:
deep sensitivity to voice and subtext
the ability to read emotionally charged scenes with empathy.
In addition, human editors have more objective distance from your work than you do. They don’t care you worked so long on that one sentence if it doesn’t have the right tone.
A human editor sees not just the line but the impact of that line on the larger story and edits accordingly.
When AI Might Fall Short
Genre and style matter here too. If you write:
literary fiction (you can see an example of this here)
voice-driven work
stories rich in imagery, emotional layering, or figurative language…
GPT might smooth out too much of what makes your voice distinct. It can unintentionally “sanitize” your prose, especially if you haven’t trained it well.
If a Line Editor Isn’t in the Budget
If hiring a professional isn’t financially doable, you can still produce a high-quality book by using craft books and courses specifically for line editing. You can do a lot of self-editing yourself.
That will give you the understanding you need to hone your craft and perhaps use an AI to help edit your work if that's what you want.
You can also try other editing tools for authors:
ProWritingAid: Offers sentence variety checks, pacing insights, echo word detection, and more. It's mostly great for copyediting, but some features (like rephrasing) can inspire line-level edits too.
AutoCrit: I haven’t tested this yet, but it’s geared toward fiction. Worth exploring if you want a more genre-specific tool.
Hemingway App: Highlights adverbs, passive voice, and complex sentences. Not a line editor, but a quick aid for tightening.
Learn to Line Edit
The best investment you can make—whether you use GPT or not—is in your own skills. I recommend:
Editing Fiction at Sentence Level by Louise Harnby
Understanding Show, Don’t Tell by Janice Hardy
Spellbinding Sentences by Barbara Baig
And of course, YouTube is full of line editing tutorials and examples.
Want to know the exact steps you can use to revise your sentences & create beautiful prose? Get your checklist now!
Low-Budget Human Editing Options
Even on a budget, you can still work with a pro. For example:
Book a line writing assessment (like mine!).
Both options give you a clear view of how a professional edits your work—so you can apply the same techniques to the rest of your manuscript.
And know that there are line editors out there who will work with a smaller budget. I know, because that's what I ended up going with for my next novel (rather than doing all the edits myself and missing way too much).
On top of that, if you're still building your editing skills, working with a human editor (even in a limited capacity) can help you develop a critical eye. They’ll show you how to preserve voice, elevate emotional moments, manage pacing, and enhance subtext—all areas where AI still struggles.
Can You Get A Quality Book Using ChatGPT For Editing Prose?
Maybe. If you train a custom GPT well or create a skill (for Claude) that works well, it could help you create a quality book.
But there was a moment, halfway through reading ChatGPT’s edits, when I paused and thought: This doesn’t sound like me anymore.
The prose was clean but lacked the emotion and artistry I was going for. An AI can clean up your writing, but it can’t feel your story.
So, can AI replace a skilled editor? Not yet.
You need to apply your own judgment. That means understanding line editing techniques (and how they differ from other types of editing, such as copyediting) so you know when to accept GPT’s suggestions and when to ignore them.
As you saw in the example, GPT often overedits. It tends to favor clarity and brevity, sometimes at the expense of voice or emotional nuance.
If you blindly accept all its edits, your prose might end up flatter or more generic.
Prose Revision Mastery
Ready to self-edit your sentences without the overwhelm?
My Prose Revision Mastery course helps you line edit & copyedit your own novel with a step-by-step framework so you walk away with a publishable novel and better writing skills!
The best part? You get personal feedback from me to guide you through.
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