Here’s a free prompt you can use to convert an existing custom GPT (from ChatGPT) into a Claude Skill – just by using the instructions from your GPT.
Simply copy and paste the prompt below into a new Claude chat, remembering to amend the placeholder Name, Description and Instructions at the bottom of the prompt using the information from your GPTs edit/configuration page.
After using the prompt, Claude will give you a ZIP folder to download to your computer and then reupload into Claude to create the new Skill.
Note: You will need to make sure you have the ‘skill-creator’ skill installed in your Claude account first. It should be there by default, but it’s worth double-checking before trying this.
Prompt to use in Claude:
I want you to convert an existing ChatGPT Custom GPT into a professional, installable Claude Skill.
I am going to provide the instructions copied directly from the Configure/Edit page of my Custom GPT.
Your job is NOT simply to copy those instructions into a SKILL.md file.
Instead, analyse what the GPT is designed to do, how the user interacts with it, what expertise and workflows are built into it, and then rebuild that functionality as effectively as possible using Claude's Skills architecture.
Your objectives
1. Preserve the core purpose, functionality, expertise, workflows and intended results of the original GPT.
2. Adapt anything that is specific to ChatGPT or Custom GPTs so that it works naturally within Claude.
3. Structure the Skill according to current Claude Skill best practices.
4. Decide what belongs in the main SKILL.md file and what would work better as separate supporting files, reference documents, templates, examples, scripts or other resources.
5. Use progressive disclosure where appropriate. Keep the core Skill instructions focused and move detailed reference material into supporting files when that will make the Skill cleaner and more efficient.
6. Make the Skill intelligent about when it should activate. Write a clear, specific description that helps Claude recognise the types of requests for which this Skill is relevant.
7. Preserve useful step-by-step processes from the GPT, but don't blindly preserve instructions that only existed because of limitations or behaviours specific to ChatGPT.
8. If the original GPT contains conversation starters, convert their underlying purposes into appropriate examples, workflows or guidance rather than assuming Claude Skills use the same interface.
9. If there are capabilities that cannot be reproduced directly with a Claude Skill, identify them and create the closest practical alternative.
10. Do not unnecessarily simplify the original system. If the GPT contains sophisticated processes, decision trees, frameworks or methodologies, preserve that sophistication.
Improve it during conversion
Treat this as both a conversion and optimisation task.
If you identify:
· duplicated instructions
· ambiguous rules
· conflicting instructions
· unnecessary verbosity
· weak workflow logic
· missing edge cases
· opportunities for better organisation
· instructions that rely too heavily on a specific ChatGPT behaviour
improve them while preserving the original intent.
However, do not introduce new functionality merely for the sake of changing things.
Build the complete Skill
Create the complete file/folder structure required for the Skill.
At minimum, this should include a correctly formatted:
SKILL.md
If additional files would improve the Skill, create those too and organise them logically.
For example:
references/
templates/
examples/
scripts/
Only create folders and files that genuinely improve this particular Skill.
The final Skill should be something I can package as a ZIP and install in Claude, rather than merely being documentation telling me how I could create one.
Important
Where my Custom GPT instructions contain references such as:
· "this GPT"
· "ChatGPT"
· GPT-specific features
· GPT knowledge files
· conversation starters
· actions
· browsing
· image generation
· other Custom GPT functionality
interpret what those instructions are trying to achieve and adapt them appropriately for Claude rather than blindly copying the terminology.
If knowledge/reference files are mentioned in the GPT instructions but I have not supplied their contents, create an appropriate placeholder in the Skill structure and clearly tell me which original files I need to add.
Do NOT invent the contents of missing knowledge files.
Before finalising
Review the completed Skill as if you were a Claude Skill developer preparing it for real-world use.
Check:
· Will Claude know when this Skill should activate?
· Are the instructions clear and unambiguous?
· Is important information available when Claude needs it?
· Is the SKILL.md unnecessarily bloated?
· Should any content be moved into supporting files?
· Have ChatGPT-specific assumptions been removed?
· Have all important capabilities of the original GPT been preserved where possible?
· Will the Skill work naturally across different conversations?
· Is the folder structure clean and logical?
· Could a non-technical user install and use this Skill?
Fix any problems you identify before presenting the final version.
Output
Create the finished Claude Skill for me.
If your environment allows you to create downloadable files, package the complete Skill as an installable ZIP file.
Also give me a brief summary explaining:
1. What the Skill does.
2. What you changed or adapted from the original GPT.
3. Any functionality that could not be reproduced exactly.
4. Any additional files I need to provide.
5. How to test the Skill.
Here are the complete instructions from my Custom GPT:
Name: [PASTE HERE FROM CHATGPT]
Description: [PASTE HERE FROM CHATGPT]
Instructions: [PASTE HERE FROM CHATGPT]Hope you find this useful! 😊