ChatGPT Custom Instructions for Writers: How I Stopped My AI From Forgetting My Novel’s Plot

Have you ever spent hours building your story world, only to have ChatGPT forget your main character’s name by chapter three? Trust me, I get it.

Picture this: You’re writing your sci-fi thriller. Life gets busy. You come back to ChatGPT a few days later, and boom—it’s like you’re starting from scratch. All those character details you carefully explained? Gone. That complex plot you spent weeks planning? Disappeared.

Sound familiar? It drove me crazy until I cracked the code.

Everything changed when I learned how to use ChatGPT custom instructions for writers together with AI memory features. Now my AI writing buddy remembers everything. Character names? Check. Story timelines? Check. That sneaky subplot from chapter two? Yep, it remembers that too.

Want to know my secret? I’m going to show you exactly how I set up character consistency AI that actually works. Whether this is your first book or your tenth, you’ll walk away knowing how to make ChatGPT remember your story like a real writing partner should.

What Are Custom Instructions? (And Why You Really Need Them)

Okay, let’s break this down super simple.

Think of custom instructions like this: They’re your AI’s rule book. Unlike normal prompts that ChatGPT forgets the second you close the chat, custom instructions stick around forever.

Here’s why that’s awesome: You write the rules one time. Then ChatGPT follows those rules in every single conversation. No more repeating yourself. No more starting from zero.

For writers working on big projects (like novels), this is a game-changer. Instead of explaining your story genre and character voices every single time, those details become part of ChatGPT’s brain.

When I first set up custom AI prompts for my thriller, I couldn’t believe the difference. I told ChatGPT once about my main character’s military past. I explained the dark, tense mood I wanted. I asked it to double-check earlier chapters before suggesting new plot ideas.

And you know what? This AI context retention made everything smoother. Way smoother.

The real magic? Consistency. Instead of getting cookie-cutter answers that could work for anyone, you’re training ChatGPT specifically for your writing project. Better story continuity AI. Fewer mistakes. Less time fixing contradictions.

ChatGPT Custom Instructions for Writers: Step-by-Step Guide

Step 1: Figure Out Your Writing Style First

Here’s a mistake I made (so you don’t have to).

I jumped straight into setting up custom instructions without really understanding my own writing voice. Big mistake. I told ChatGPT to “write like a thriller author.” That’s it. Super vague, right?

The result? Boring, flat writing that didn’t sound like me at all.

So I tried something different. And it worked like magic.

Here’s what you need to do:

Grab three pages from your manuscript. Pick scenes that show different moods or character viewpoints. Then paste them into ChatGPT and ask:

“Look at how I write in this sample. What patterns do you notice? How do I build sentences? What makes my dialogue different from my descriptions? What’s special about my writing style?”

When I did this with my thriller chapters, ChatGPT spotted stuff I’d never even noticed about my own writing. Turns out, during tense scenes, my characters talk in short, choppy sentences. I use lots of sensory details instead of long explanations. My sentences are usually about 14 words long, which creates a fast pace.

This wasn’t just interesting trivia. This became the backbone of my entire AI writing memory system.

Pro tip: Save what ChatGPT tells you about your writing. You’ll need it for the next step.

Step 2: Write Instructions That Actually Work

Okay, this is where the magic happens.

ChatGPT’s custom instructions have two boxes you need to fill out. Both are super important for novel consistency AI, so don’t skip either one.

Box #1: “What would you like ChatGPT to know about you?”

This is your story bible. Think of it as the stuff ChatGPT absolutely must remember about your book. Here’s what I put in mine:

• My book’s genre (techno-thriller with cyberpunk vibes)
• Main characters and their key traits (Marcus is an ex-military hacker with a scarred left hand who doesn’t trust anyone)
• When the story happens (72 hours in March 2029)
• Important world details (quantum encryption failed in 2027, changing everything)
• Big themes in my story (freedom vs. surveillance, loyalty vs. survival)

Keep it simple. Bullet points work great because ChatGPT can scan them fast. Just make sure each point is specific enough that ChatGPT can’t misunderstand.

Box #2: “How would you like ChatGPT to respond?”

This controls how ChatGPT talks to you and helps with AI context management. Here’s what mine looks like:

“Write like my thriller samples show: sharp, tight sentences that are usually 12-16 words. Focus on action, not long explanations. Keep dialogue short and packed with hidden meaning. Before you suggest any plot ideas, check if they match what my characters would actually do and if they fit my timeline. If you spot any story mistakes from earlier chapters, tell me right away. When suggesting scenes, format them like this: [Where it happens] → [The problem] → [What the character chooses] → [What happens because of it].”

See the difference? I’m not just saying “write in my style.” I’m giving ChatGPT clear rules it can actually follow. Plus, I built in a continuity checker.

Want a ready-to-use template? Here’s one for sci-fi writers:

Box #1 (What ChatGPT should know):

I’m writing hard sci-fi set in 2089. Earth’s magnetic field collapsed. Main character: Dr. Sarah Chen (she’s an astrophysicist who feels guilty about not predicting it, very logical and careful). Other characters: Marcus (pilot, acts first and thinks later, Sarah’s ex-boyfriend), Yuki (AI expert, super practical). Story starts 18 months after the collapse. Key technology: mag-shield generators, underground colonies, solar flare prediction systems.

Box #2 (How ChatGPT should respond):

Keep the science accurate but don’t over-explain. Use real scientific terms. When writing Sarah’s chapters: thoughtful, detailed observations. When writing Marcus’s chapters: fast-paced, lots of sensory stuff. Before suggesting any plot points, make sure they don’t mess up the magnetic collapse timeline or what characters already know. Point out plot holes before I waste time writing them.

Step 3: Use AI Memory Like a Pro

Custom instructions are awesome. But ChatGPT’s memory feature? That’s when things get really cool.

The memory system learns stuff automatically as you chat. But here’s the secret: You can also tell it exactly what to remember. This creates real AI persistent memory that grows with your book.

Here’s my trick:

After I finish each chapter, I run this simple prompt:

“Remember this: In Chapter 7, Marcus found Sarah’s research notes from before the collapse. He knows something she doesn’t know he knows. This creates secret tension when they meet again. Also, Sarah’s guilt makes her obsessively check data now. New timeline fact: Shanghai colony failed three weeks ago, so there are only four safe zones left.”

ChatGPT saves this info forever. So later, when I’m writing chapter 12 and Marcus confronts Sarah, the AI already knows about those secret notes. It suggests dialogue that feels real because it remembers what the characters know.

That’s not all. I’ve got another weapon in my AI memory for writing arsenal.

Upload your character bible.

I keep a Google Doc with everything about my characters. What they look like. Their backstories. How they feel about each other. What they want from life. Before I start writing, I upload it to ChatGPT.

Now watch what happens when you combine everything:

• Custom instructions set the rules
• Memory tracks what happens in your story
• Uploaded docs give all the background details

Together? They solve the story continuity AI problem completely. No more forgetting. No more contradictions.

One more trick for when you start a new chapter:

Before writing Chapter 9, try this prompt:

“Let’s review Chapter 8 before we start Chapter 9. What important stuff happened? What problems are still hanging? What do the characters know now that they didn’t know before?”

This makes ChatGPT actively remember instead of just waiting for you to remind it. I’ve caught so many mistakes this way.

Step 4: The Prompts That Keep Your Characters On Track

Even with perfect custom instructions and memory, you’ll still need some specific prompts while you’re actually writing.

These are my go-to templates that changed everything:

Character Consistency Check:

“Look at this scene where Sarah makes a quick decision. Does this match her careful, think-it-through personality from the character bible? If not, how can we change her choice so it feels more like Sarah while still getting the same result?”

This catches when your characters act weird. In chapter 15, Sarah needed to take a big risk. ChatGPT pointed out that she wouldn’t just wing it. She’d only take the risk if she had tons of data proving it was the right move. That saved me from a character mistake.

Plot Continuity Cross-Check:

“I want Marcus to find the solar flare prediction system in Chapter 18. Check the earlier chapters—what does Marcus already know that would change how he reacts? What other plot points does this connect to?”

ChatGPT scans everything it remembers and finds connections you might’ve forgotten. This AI context retention stops plot holes before they happen.

Timeline Checker:

“Let’s map out the timeline from Chapter 1 to Chapter 11. How many hours passed? What time is it right now in the story? Does this fit with my 72-hour time limit?”

Time mistakes kill thrillers. I almost had my characters see the sun rise twice in six hours. This prompt caught it.

Dialogue Tester:

“Write three different versions of this conversation between Sarah and Yuki. Version 1: Like when they first met in Chapter 3. Version 2: With the tension they have now after the Shanghai news. Version 3: If they totally trusted each other (just to see the contrast). Keep how each person talks the same from the character bible.”

Seeing three options helps you pick the best one. Plus, it makes sure your dialogue sounds natural as relationships change.

Bonus: Five templates you can copy and paste:

• Character arc tracker (checks if growth makes sense)
• Tension escalation analyzer (makes sure excitement builds)
• Subplot checker (connects side stories to main plot)
• Foreshadowing placer (plants hints for later)
• Pacing checker (finds slow or rushed parts)

What to Do When ChatGPT Messes Up

Let’s be real. Even with a perfect setup, stuff goes wrong sometimes. Here’s how I fix it.

Problem: ChatGPT gives boring, generic ideas that don’t fit your genre.

Your custom instructions probably aren’t specific enough. Don’t just write “thriller.” Get detailed. Mine now says stuff like: “Don’t dump a bunch of background info. Show information through what characters do and the problems they face. Keep the mood tense and paranoid where nobody fully trusts anyone.”

Problem: ChatGPT contradicts something you wrote chapters ago.

Memory isn’t perfect, especially in really long conversations. Here’s my fix: Every few writing sessions, I run this “Story Bible Refresh” prompt:

“Quick check before we keep going. Tell me what you remember about: 1) Sarah, Marcus, and Yuki’s main personality traits. 2) The big events that happened in the story so far. 3) The rules about how the magnetic collapse works in this world. If anything’s fuzzy, look at my character bible document again.”

Think of it like clearing your computer’s cache. It forces ChatGPT to reload all the important stuff.

Problem: The writing sounds too fancy or like a textbook.

Go back to your voice analysis from Step 1. I added this to my instructions: “Don’t use flowery, over-the-top descriptions. Keep it sharp and urgent like my sample chapters. When you’re not sure how to word something, pick the simpler, punchier option.”

Here’s an example. “Marcus gazed contemplatively at the horizon” versus “Marcus watched the skyline.” Seems small, right? But when you’re writing 80,000 words, those little choices add up fast.

Problem: ChatGPT keeps forgetting stuff mid-conversation.

ChatGPT has limits on how much it can remember in one chat. My solution? I break big tasks into smaller conversations. Instead of one huge chat for a whole chapter, I do separate chats for planning, writing, and editing. Each one keeps your custom instructions and memory, but starts fresh on the conversation part.

Level Up: Build Your Own Custom GPT

Once you get the hang of custom instructions, there’s an even cooler option.

You can build your own Custom GPT just for your novel. Think of it like custom instructions times a hundred. You upload all your story documents once, and the GPT keeps them forever. No re-uploading every single time.

I made one called “Quantum Collapse Assistant” for my book. Here’s what’s inside:

• My complete character bible (12 pages)
• Timeline spreadsheet
• Research notes about magnetic fields and solar physics
• Three sample chapters showing my writing style
• All my detailed instructions from Step 2

Now every time I open that GPT, it knows everything about my novel automatically. The continuity checking happens in the background because all my reference stuff lives right there in the system.

Setting one up takes about 30 minutes. Go to “Explore GPTs” in ChatGPT, click “Create,” and upload your files. It’s basically the same as custom instructions, but everything stays permanent.

Here’s the really cool part: If you’re writing multiple books at the same time, make a separate Custom GPT for each one. Your thriller gets its own setup. Your romance gets another. Your memoir gets a third. Each one maintains perfect character consistency AI without mixing stuff up.

Your Turn: Make ChatGPT Remember Your Story

Learning ChatGPT custom instructions for writers completely changed how I write my novel.

I used to waste hours explaining my plot and characters every time I opened ChatGPT. Now? I jump straight into writing. ChatGPT tracks everything automatically, catches mistakes before I make them, and suggests ideas that actually fit my characters.

It’s like having a writing partner who never forgets anything.

Here’s your game plan:

• Analyze your writing voice using a few sample chapters
• Set up custom instructions with clear, specific rules
• Feed ChatGPT’s memory system after each chapter
• Use the targeted prompts to check for mistakes
• Maybe build a Custom GPT if you’re feeling ambitious

Yeah, the setup takes time. Maybe two hours to get everything dialed in. But those two hours save you hundreds of hours later. Less time fixing continuity errors. Less frustration. More time actually writing.

Feeling overwhelmed? Start small. Even basic instructions about your genre and main characters will make a huge difference. You can always add more detail as you figure out what works for you.

The point is to make ChatGPT work for you, not the other way around.

FAQs

1. How often should I update my custom instructions?

I tweak mine after finishing big story sections or when ChatGPT starts drifting from what I need. Most writers do well checking them every three months. But if you’re still learning what works? Update them weekly for the first month.

2. Can I use the same instructions for different novels?

Only if they’re the same genre and writing style. My thriller instructions would bomb for a cozy mystery—totally different vibe. But your general writing habits (“use active voice,” “keep sentences around 12-16 words”) can transfer fine. For book-specific stuff, Custom GPTs work better.

3. What happens when ChatGPT’s memory fills up?

The memory system keeps the newest stuff and what you specifically tell it to remember. But here’s my backup plan: I keep my character bible and timeline in a Google Doc. I upload those files regularly so ChatGPT can check them even if some memories fade.

4. How detailed should my character bible be?

Focus on personality, motivations, and relationships. Skip the physical stuff mostly. ChatGPT needs to understand why Sarah thinks things through carefully and why she doesn’t trust Marcus. That drives the story. Eye color and height? Not as important for keeping your plot consistent. I keep each character to one page max, focusing on psychology and backstory.

5. Does this work for other genres besides sci-fi and thrillers?

Absolutely. Romance writers can track relationship beats and emotional turning points. Fantasy authors can maintain magic system rules and world details. Historical fiction needs timeline accuracy and period-appropriate language. The system adapts—you’re just teaching ChatGPT what matters most for your specific genre.

6. What’s the biggest mistake I see writers make?

Being too vague. “Write in my style” doesn’t help ChatGPT at all. Give concrete rules it can follow: “Use active voice 90% of the time. Mix sentence lengths between 8-20 words. Focus on dialogue more than description. When characters argue, they cut each other off mid-sentence.” Real guidelines ChatGPT can actually use.