HrvatskiFile 1
Who we are
One page: what you do, for whom, your one-sentence description and your main products.
Brand OS Portal
How to keep ChatGPT Projects and Claude Projects on brand.
Put the same brand instructions and the same brand files in both tools. Then check what each one says about you.
Give both tools the same two things: one set of project instructions with your voice rules and limits, and the same brand files, such as your approved facts and voice guide.
Keep one master copy of each, update both projects the same day, and test both with the same task every month. If the drafts sound different, fix the shared files, not one tool.
By Vedran Obradović · Updated 4 November 2026
What ChatGPT Projects and Claude Projects give you.
Both tools let you save instructions and files in one workspace. Checked on 4 November 2026 in each company's help pages.
| ChatGPT Projects | Claude Projects | |
|---|---|---|
| Instructions for the project | Yes, project instructions | Yes, project instructions |
| Files the tool reads | Yes, uploaded files | Yes, project knowledge |
| Instructions apply | Only inside that project | Only inside that project |
| Share with a team | Depends on your plan | Team and Enterprise plans |
Checked on 4 November 2026 on OpenAI's and Anthropic's own help pages. Plans and limits change, so check your own plan.
The idea is the same in both: a project is a small room with its own rules. Your job is to put the same brand in both rooms. Deeper setup for each tool: ChatGPT brand guidelines and brand guidelines for Claude.
Free tool
First, see what AI says about you today.
Type your company name and website. You see how AI tools describe you right now, before any project setup. It is free and runs right here.
The four brand files to add to both projects.
Short files work better than one giant PDF.
File 2
Approved facts
Numbers, customer names and claims you may use, each with a source and a date.
File 3
Voice guide
Three to five voice rules with right and wrong lines, and words you never use.
File 4
Examples
Three to five of your best real posts, emails or pages. Tools copy examples well.
Need the voice guide first? Start with brand voice guidelines and B2B brand voice examples.
Project instructions you can paste in both tools.
Paste the same text into ChatGPT and Claude. Change the brackets.
Brand project instructions (ChatGPT and Claude)
You write for [company]. [Company] [does what] for [who]. Always: - Follow the voice guide in the project files. If it and my request disagree, ask me. - Use only facts from "Approved facts". If you need a fact that is not there, write [FACT NEEDED] and keep going. - Write short sentences. Plain words. [British / US] spelling. - Match the length and shape of the examples file. Never: - Never invent numbers, customers, quotes or awards. - Never use these words: [list]. - Never promise prices, dates or results that are not in the files. Before you answer, check your draft against the voice guide and fix anything that breaks it. At the end, list any [FACT NEEDED] gaps.
Brand OS Portal
Get 3 templates in your brand. Free.
Leave your email. I design them by hand and send them to you within 48 hours. It costs you nothing.
Got it. I start on yours today. Your 3 free templates reach you within 48 hours.
I write to you from [email protected]. If you do not see it, check spam.
How to set it up in six steps.
Step 1
Write the four files
Who we are, approved facts, voice guide, examples. Plain text or Markdown.
Step 2
Keep one master copy
Store them in one place, like your brand portal. Never edit the copy inside a tool.
Step 3
Make the ChatGPT project
Add the instructions and upload the four files.
Step 4
Make the Claude project
Add the same instructions and the same four files.
Step 5
Run the same test
Ask both for the same LinkedIn post. Compare tone, facts and length.
Step 6
Update both the same day
New fact or new rule? Change the master, then replace the file in both projects.
Why projects drift off brand, and the fix.
| What happens | Why | Fix |
|---|---|---|
| Drafts invent numbers | No facts file, or it is too long | Short approved facts file and the [FACT NEEDED] rule |
| ChatGPT and Claude sound different | Different files in each project | One master copy, same files in both |
| Old claims come back | An old file was never removed | Replace files, do not add new ones next to old ones |
| Each person sounds different | People use private chats | Ask the team to use the shared project |
| Tone gets stiff | Rules with adjectives only | Add right and wrong lines and real examples |
Your monthly check for both projects.
Ten minutes, once a month. Your ticks stay on this device.
0 of 8 done
Want the bigger picture? Read how to make ChatGPT use your brand voice and Claude for branding.
Social Studio
Try one Brand OS Portal tool
From an on-brand draft to an on-brand post.
This is a real tool from a real Brand OS Portal, on the MTG brand. Paste the words your AI project wrote. The design stays right.
Straight answers.
Can I use the same instructions in ChatGPT and Claude?
Yes. Both have project instructions. Paste the same text in both and keep one master copy.
What should I upload to a ChatGPT Project for my brand?
Four short files: who you are, approved facts, a voice guide with examples of right and wrong lines, and a few of your best real pieces.
Why does Claude sound different from ChatGPT with the same brand?
Usually the files or instructions are not the same, or they are too vague. Add right and wrong lines and real examples, then test both with the same task.
Do project instructions override my custom instructions?
In ChatGPT, OpenAI says project instructions apply inside the project and take priority over your general custom instructions there. Check your tool's help page, since this can change.
How often should I update my brand projects?
The same day a fact or rule changes, plus a short test once a month.
Is a custom GPT better than a project for brand voice?
Both can hold instructions and files. Read custom GPT and your brand voice before you build one.
Does AI get your brand right? Check it free.
See what ChatGPT says about your company, and how to fix it.
Rather write to me?
Got it.
You hear from me within 2 to 8 hours.